Document 3e71y181g1MMG8pJqz17bQY5a

THE KANIXFACXSKS OF KAUO PRODUCTS by V. C. Taylor Jxm* 10, 1959 W/J31146 DX5THIBTOI0N H25TBICT2D TO: Hr* E. S. Adams - Toledo Dr* L. F* Blefeld - Toledo B. . Boyd - Toledo J. M* Briley - Toledo P* B* Brown Newark F. B. Coumbe - Kansas City 2* S Grant - Toledo C. 7. Handel - Toledo 1* S* Kessler * Toledo 2* J. Paoletti - Barrington A* J Pearson - Newark 0* V. Pfeifer - Berlin W* X, Sidvall Toledo (6) A. C. Siefert - Newark A* L. Simlaon - Toledo H. 7. Smith - Toledo C. A* Sattcker Newark G. C. Stefaago - Toledo W. C. Taylor - Toledo E. J. Walker - Toledo P 1* Welsh - Newark 01 062 0?$5 Preface The purpose of this manual is to serre as an aid to good practise is the manufacture of Kayl products, and to provide lnforasti.es to those who nay sot be familiar vlth the nature of the operation* The material contained herein is the result of both laboratory research and plant experience over the years* Admittedly, some of what is written may still be classed aa theory, and some statements may even be considered as controversial* There remains orach to be learned* The manufacture of Kaylo prodarta is still a relatively new and "green* industry* This is probably all to the good, because when scoething is no longer green it stops growing and rot begins* Many, many persons have contributed to our present state of imovladge on the subject* This mamml represents an effort on the part of the author to correlate and integrate the information available at time* It is not the Intention here to describe in every detail, aTM* step by step, the various aspects of a prescribed operation* This has been dons In several manuals written by members of the staff at the Berlin plant* Bather, this maninO is designed to attempt to explain why certain things are done as they are or way certain changes in operation are indicated* 01 062 THE HXmxCT&Z OF K.ATLU PRODUCTS CONTENTS Chapter Page I. IKS TUTORS OFKA1LOPRODUCTS................................................ X II. TYPES OF KAYLOPRODUCTS............................................................ U HI. FORMULATIONS............................................................................ b Fcmnuation for Kayl-10 Insulation ......... ? Formulation for Xaylo-iO Cere Material......................... 3 Fonnulation for Kayic-20 Thermal Initiation . . . . . 9 . Formulation for Kaylo-20 Core Material..................... . II 17. ROLE OF IKE VARIOUS RAW MATERIALS . . . . ................... Asbestos.................. Chrysotlle. .................... Amosite ...... .................. .......... Wollastonite. .................................... lime. ....... Quicklime ....................................... Hydrated Lima ... Silica.................................... Tripoli............................................................................. Celstom (Biatomaceous Earth). ................................. Clay....................................................................................... Inert Ingredients .................. Ground Limestone. ................. Chrmti. ......................................................................... Surface Active Agents ................ Tsmol #731......................................................................... Coloring. ............... ................. Red Iron Oxide. ............ ................... 12 12 13 14 1? 17 18 19 18 19 20 20 21 22 22 22 22 22 7. RAW MATERIAL SPECIFICATIONS............................................... Chrysotile Asbestos ................. Amosite Asbestos. .................. Pulverized Quicklime........................ Rynrated Lime .................... Tripoli . ...................... Diataoeceous Earth. ................. Clay....................................................... Limestone Flour Iron Chranite Woilastonite .................... Rea Iron Oxide ................... Dispersing Agents .................. 23 23 2i 25 25 26 26 27 27 27 28 28 71. 3ATCKING AMD MIXING OPERATIONS......................................... 29 01 082 03?f] Chapter I IKE KATCHE CF KAILO FF.OBXTS Kayie is a regiatered trade mark employed to specify the hydrous calcium siOicate redacts manufactured by Owens-Coming Fiherglaa Corporation. Sayie is an adjective and should never be used as a noun. Furthermore, it should always be capitalized. As just mentioned, Kaylo products fall within the class of materials known as hydrous calcium silicates. Research over the years has revealed the existence of a large number of hydrous calcium silicates, but the majority of these are scarcely more than laboratory curiosities. That is to say, little or no use is known at this time for many of those compounds* The term hydrous calcium silicate denotes a chemical compound composed of CaO (lime), SiO^ (silica) and H^O (water). A specific hydrous calcium silicate has, of course, definite physical and chemical roperties. The feroation of hydrous calcium silicates can be effected in one of two ways? 1) By the reaction of water with previously formed anhydrous calcium silicates, such as occurs in the hardening of portland cements whan mixed with water; 2) The direct union of CaO, SiOg, and KgO. It is this method that is employed in the manufacture of Kaylo products. The two hydrous calcitaa silicates that are of interest In eo&neetion with Kaylo products are: tobenaorite, having the formula fcCaO.SSiOg.SHgOj and xcnotlite, having the formula 5CaO.5SiO2.K2O. Other hydrous calcium silicates can be, and sanetines are, present is Kaylo products. But the majority of these are of an accidental nature, and most are detrimental for one reason or another. Tobemorite, like so many minerals, can accomodate varying amounts of other constituents within Its crystal structure. This, when controlled, can be used to an advantage. More will be said of this later. Xonotiita apparently shows no tendency to incorporate any "foreign arides within its structure. In the formation of hydrous calcium silicates by hydrothermal methods, the Hme apparently first reacts readily and completely with silica to form lime-rich calcium silicate gels having variable compositions but characterized by Ca0/Si02 ratios in excess of unity. These products Is turn react with residual silica of the mix to form products poorer in lime. The order of formation and transformation is believed to be thus: lime-rich gel --'SCaO.i^aO.nHgO--P'CaO.SiOj.nHgO--?i^aO.53102 hCaO.5SiO2.5E2O (tobez&czits). To achieve the desired end product is the above progression, it is necessary to have the proper batch ratio of Use and silica in such form as to be reactive under conditions of the process, and to permit suffi cient time at a given temperature (pressure). If appreciable amounts of the intermediate products are present, the ware will show such undesirable properties as: high shrinkages upon drying, puhky structure and ~ strength, and/cr high shrinkages at elevated temperatures. vOZ V'' If tbs batcb ratio of line to silica is near unity, and if efficient time is permitted at temperatures and pressures in excess of about 3COK and 52 psig, respectively, the reaction given aiwve will continue as; hCsO.5SiO2.SH2O-- 5CaO.5SiO2.H2O (xonotlite). The coaposition of the intermediate product la the transformation of tobenaerite to xonotlite has not been fully resolved as yet. X-ray diffraction patterns generally show sens Haas characteristic of the two end members, but certain other key lines may be missing. Balative intensities nay also vary. It is generally the practice to refer to this intermediate product as "hybrid* material. The advantage that structures of xonotlite have ever those of toberaoritc Is higher temperature resistance. A structure of the hybrid material is intermediate in this respect. Tbs possibility still exists, however, that tobarmerlte is transformed directly into xc&otlite, and the hybrid material is in reality a mechanical mixture of the two. In any esse, ths effect is the same* As mentioned earlier, tobermerite can take certain other oxides into its structure. Alumina, AI2O3, in particular eAera ths structure readily. When this occurs to say appreciable extent, the transformation of tobermerite to xonotlite is retarded greatly; so much so that for practical purposes it may be considered as preventing the transformation. Because of this, batches intended for ths production of xonotlite must be free of any sub stantial amount of reactive 11203. Oa the other hand, tobermorite containing AI2O3 apparently forme more readily than ths pure compound, and also yields ware of higher strengths. However, high tmaperature resistance of the ware is decreased roughly in proportion to the amount of 11203. But it is possible to take advantage of the favorable characteristics imparted by a limited amount without the temperature resistance being lowered to a point that is critical for meat installations of the product. 5fcs positive identification of ths various chemical combinations or phases, either desirable or undesirable, that can exist in hydrous calcium silicate products is act easy or simple. Generally, in other systems, products are forms* which are readily discernible by means of the light microscope. Accordingly, optical properties aai other characteristics can readily be determined. Because the crystalline promote that are famed within reasonable times by hydrothermal means in the liae-eilicawater system are so extremely fine, identification is not posaible with the light microscope. Other means, such as X-ray diffraction and differ ential thermal analysis in particular, must be employed, less certainty of positive identification results. Furthermore, the extreme fineness of ths orystallins compounds results in behavior often more typical of a gel rather than a crystalline structure. In these cases, the water context and the distribution of this water throughout the structure has a distinct effeot on ths properties of ths product. Because of ths above circumstances, it is ths more canon practice to attempt corrective measures based on certain assumptions as ths cause of ware being off quality, rather than oa the results of extensive labora tory tests. That is to say, diagnoses are often mads without supporting laboratory data. In plant operation, time is all important and cures 01 062 oatiq 3 nrast be effected in the shortest possible tine* It Is sot iataaded to imply that these assumptions are mere guesses and without foundation* They are made by trained personnel and are baaed on the findings of past research and plant experience* It is being emphasized that considerable art is involved in the manufacture of Kaylo products, and successful operations are largely dependent upon the presence and decisions of persons thoroughly trained In the art* \ 01 062 05?o Chapter II T7FE3 C? JUTLO PHODBCIS In the previous chapter. It was pointed out that Xaylo products consist essentially of hydrous calcium silicate* The true density of these silicates is about 150 pounds per cubic foot* In fact, the over-all density of the constituent solids of Kaylc materials is about this value. The apparent density, which is considerably less, is determined and controlled by the ratio of water to solids employed in raw batch* By means of the proper selection of amounts and types of asbestos, together with farther fiber!sation, dilate suspensions or slurries are obtained which do not settle or lose water by bleeding* Prescribed treatment is also followed in the hydration of the line to assist in obtaining these stable suspensions. With slurries of this nature, the volute of the hardened body is sensibly the same as that of the cast slurry* When the water is removed by drying from the interstices of the solid framework of hydrous calcium silicate that has been formed in the process, a product of low apparent density results. It Is obvious that the higher the ratio of water to solids in the slurry, or the greater the percentage of total volume con tributed by the water, the lower the apparent density of the product after the free water has been removed by drying* Inasmuch as the synthesis, of hydrous calcium silicates is involved, sc&e water of the batch becomes fixed in that it becomes an integral part of the compound in question. But this amount represents a very small percentage of the original volmae* The chief products of the Berlin plant are generally considered as being of four types? characterized by two different apparent densities for each of two different hydrous calcium silicate compounds that con stitute the structure of the product. As mentioned in Chapter I, the two hydrous calcium silicates of Interest in.connection with Jtaylo prodicta are toberoorlte, UCaC.5SiO2.5E2O and xonotlite, 5OaO.5SiO2.H2O. The tobenaorite-type produsts are referred to within the organisation as Kaylc-10, 1-10, or regular Kayle* In tbs literature Saylo alone is ewployidj the products being called Kaylc Pipe Insulation, Eaylo Bloek Insulation, or Sayio Core Material* The Pipe and Block Insulation have a nnmtnal apparent density of ll.k pounds per cubic foot, and the Core material 20*0 pcf. Thus, the two classes of Kayio-10 products are distinguished fran each other by their difference In apparent density and their end use* The Saylo-10 products of the lighter density are designed primarily to afford thermal insulation at elevated temperatures up to 120QF> whereas the purpose of Kaylo-10 product of the heavier density is to .provide a structural material whose strength and fireproof nature together with its insulating value, make it highly desirable as the core of panels and doors of sandwich-type construction* The facing material that is applied by the customer may be wood, metal, transits, etc. Of 062 0a<3l Saylo~20 ware is characterized by having a xonotlite, 5CaO.5SiC2.H3C, structure. Included are Kaylo-20 Pipe Insulation and Haylo-20 Block Insulation having a seminal apparent density of 12#5 pounds per cubic foot, and 2-20 Core Material at 20.0 pcf. Similar to the aylo-10 ware, the end use of the Saylo-20 predicts dictates the production of two different densities. The advantage of Saylo-20 ware in each case is Its higher temperature resistance, the Unit being 1800?. instead of 1200F. the apparent density of the product in any case is chosen to yield a material having a hardness and strength demanded in its end service, or, as is the case with Saylo-20 thermal insulation, is the natural result of the water/aolids ratio required to give stable, non-settling slurries. In no case is a higher density employed than is considered to be a safe munder the circumstances. The strength of both Eaylo-10 end Kaylo-20 products expressed as modulus of rupture tends to vary roughly as the square of the density. For example, the modulus of rapture for I^ylo-10 thermal Insulation at 11.U pcf density may be expected to be about 75 psi, and that for Kaylo core material at 20 pcf density Is Likely to be about 230 psi; 75 x (20)2 . 230. (H3H2 A modulus of rupture of about 112 psi is not uncommon for SayLo-20 insulation of 13 pcf density, and about 265 psi can be expected for Kaylo*-20 core of 20 pcf density] Theoretically, for a given density the Keylo-20 material probably should not be quite as strong as the ayio-10 prodset. The reason for this is that the structure of the former is mare coarsely crystalline and presents less area of contact for the cohesive forces. Actually, however, in ccmmtreial production the reverse tends to be true is respect to modulus of rapture. The likely explanation is that Kaylo-20 material, being enposed of crystals of greater size, behaves less like a gel and is more stable In tbs drying process. During the drying at Saylo-10 ware, stresses are likely to be created and result In incipient cracks which adversely affect the tensile strength. Ccopresaive strengths on the other hand, are not as seriously affected by tbsee flaws in structures, and for a given density are generally higher for Kayi-10 than Xaylo-20 insulation and core material; It should be emphasized that these strength data represent general values and trends. A number of factors greatly affect the strength. These are discussed at greater length in a subsequent chapter. 01 062 0^a 6 Chapter III ( FCRKOUTIOHS A number of things have to be taken into consideration in designing a formulation for a given type of ayl product. Perhaps of utmost impor tance is the combination of properties in the end product. Among these for thermal insulation ares modulus of rupture, compressire strength, hardness, handleability (resistance to abuse), apparent density, appearance, shrinkage at eleeated temperatures, and thermal conductivity or *kn factor. It so happens that the optimum or ideal cannot be obtained for each and every property, at least at this time* A sacrifice in one is frequently made to benefit another. For example, the means that have been employed to bring about a reduction in nka factor have resulted In some loss of strength. Efforts, then, are directed toward the attainment of the best combination of properties that are possible, as indicated by custmer reactions* The design of a fonimlation is further complicated by the fact that a slurry must result which can be bandied most satisfactorily' by existing plant methods and equipment. Furthermore, the formulation must lend itself to the greatest possible speed of processing throughout the various steps from mix to trim. Here again a compromise must be mads between one or more of the desired properties and the ease or speed of processing. A case is point: it is known that shrinkage of the product at elevated temperatures can be reduced by employing less diatqaaceous earth and more crystalline silica, but it is alsoknown that the rate of prehardening would be lowered and longer periods of autoclaving would likely be needed* ' Farther complications are introduced by efforts to keep batch costs as low as possible. The effects of a substitute material, an additional constituent, or a change is density, have to be carefully observed and analysed to oetarmine if the change has been favorable in respect to speed of processing, quality of the product, and the amount of off-ware. An addition to batch cost may in affect represent a saving in the long run. 01 062 0&93 ! 7 Formulation or Sgylc-10 Insulation The following formulation is currently (March, 195?) employed for both Xaylo-10 pip covering and block, am has been in use since December, 1958: Raw Material Weighed Amount (Pounds) Dry Weight (Pounds) Percent AW aaosita asbestos 100 100 3.28 V-3 a&oslte asbestos 50 50 1.61 6D chrysotile asbestos 150 150 1.92 US chrysotile asbestos 200 200 6.56 Quicklime 8h0 81i0 27.55 Tripoli Celatca 350 350 LUIS 950 616 26.76 Clay Ground limestone Air-float chromite Voliastonite C-101 100 2hO lOO 100 100 3.28 2^0 7.8? 100 3.28 100 3.28 Taaol #731 Totals 12.5 3 3,Oh9 0.10 100.00 Water - 16,630 lbs. Vater/solids 5*53 Molar CaO/SiOg *77 Factors: CaO/quicklim# - .91 SlOg/Celatca - -83 SiOg/tripoli - .99 SiOg/elay - -U5 01 062 5 At the time of writing, there are no basic changes indicated in this f formulation. There is, however, continuing search for ingredients that v would lower the factor of the product without necessarily taking part is the chemical reactions involved in the formation of the desired product. If such an ingredient is found, the ancunt employed in the formulation will in all probability be minor in respect to the lime and siliceous materials. Arrangements are underway to conserve the slurry carried by the water in the periodic wash-out of the mixers and lines, and to return this diluted slurry to the batch. It is also proposed to return at least a significant portion of the waste Kaylo material resulting from trim and off-ware to the batch at the earliest possible date. Certain adjustments will be mde so that the proportions of the solids to each other and the ratio of total solids to water do not differ from those in the formulation given above. Formulation for Kaylo-10 Core Material Given below is the formulation employed in the msatsfacture of Kaylo-lO Core Material. It is sometime3 referred to as Hydrate Cars to distinguish it from another type of Eayio-iO core produced earlier. Raw Material Weighed Amount (Founds) Dry Veigit (Pounds) Percent 6D chiyaotile asbestos 150 150 h.U liZ chrysotlle asbestos 300 300 8.23 gydrated lise Tripoli Celatom Clay Totals 1,600 X'fcOO 375 so 1,366 l,ii00 360 _s 3,61*6 38.02 38.bG 9.87 1.37 100.00 Water - 10,200 lbs. Vater/solids 2.FX Molar Ca0/Si02 - .82 Factorst CaO/fedrated lime .73 5i0*elat<at - .83' SiOjj/tripeli SiOg/clay - >99 - .15 01 062 0fi*f5 5 *m formulation yields a product that is satisfactory as to strength, but the ware is often subject to drying cracks in the process. The formalation for Eaylo-10 core material should be the object of further study. The writer feels that more reinforcing, either asbestos fibers or the fibrous vollastoaite C-101, should be employed. It is also felt that an improved product would result under conditions csf practical autoclaving cycles if ths molar CaO/SiOj ratio were to be lowered to about 0.73* It will be observed that hydrated liae instead of quicklime is used. This is done to keep the consistency of slurry low enough for it to be handled satisfactorily in the casting operation. It would be advantageous if quicklime could be employed. Hydrate Is mere expensive for a gives CaO contest, deteriorates much sore rapidly, and represents an additional ray material to handle in the plant. Perhaps seas combination of asbestos and wollaatoaite C-101 can be found that will provide adequate reinforcing and will contribute leas to the consistency of the slurry, so that quicklime can be used for. the Kaylo-10 core formulation. ' * Formerly, a Kaylo-10 cere material that was satisfactory in most respects was made fresa a formulation in which pertland cement scrolled most of the line arid silica. It had been designed to fit into the Sayreville operation, which required a very rapid rate of prehardening. Early in July, 15571 complaints were received free a customer stating that Kaylo-10 core exhibited greater absorption of the adhesive in the laminating operation than did a competitive calcium silicate care material. The change to the above hydrate formulation in July 155?, resulted in a material shoving considerably less absorption of glue, and equal to competitive material is this respect. Forgal&tion for Kaylo20 Thermal Insulation it the time this is being written, there are two schools of thought in regard to the optimum formulation for ayl-20 thermal Insulation. Both groups can present data supporting their contentions. Some feel that tbs 1.017 molar Ca0/Si02 ratio of the formulation currently employed is too high for the amount of autoclaving permlassbls at present rates of production. Others are of the opinion that the great quantity of excellent ware produced from formulations having this CaQ/SiO* ratio indicates that it Is satisfactory. The writer is Inclined to feel that the 1.01? value represents Just about the maxisBB, and if for sees reason the ware does not receive the customary amount of autoclaving (the prescribed time, pressure, end temperature), higher than normal amount of shrinkage at l80CF will likely result. For this reason, he feels that a molar ratio of about 0.55 would prove more satisfactory day in and day out. oi o$2 10 Following ia a foroulation typical for the production of Xaylo-20 thermal insolation. The actual quantities vary depending upon the amount of slurry required for the particular train of molds to be filled, but the relative amounts of the ingredients are held constant* Saw Material W-3 a&oslte asbestos 60 chrysotile asbestos i chrysotile asbestos Quicklime. Tripoli Rad iron oad.de Wollastonite P-1 Totals Weight (Pounds) 375 150 50 1,025 1,02? 11 250 2,686 Percent 13*00 5.20 1.73 35.52 35.52 0*36 . 9.65 100.00 Water - 13,515 lbs. Water/solids - i*.71 Holer CaO/Si02- 1.01? Factors* CaO/qolc&iae - .9h SiOa/tripoU - .99 It is possible that an inert ingredient may be added in the future to function as an opaclfier to infra-red rays. Xaylo-20 thermal insulation is designed to serve at temperature ranges where radiation is an important factor in the conductance of beat. Extremely finely ground sircoa Is an example of a material that exhibits sca&e opacity to infra-red. 1 trial run of Kaylo-20 thermal: insulation containing 5% of zircon is awaiting test. 01 062 0,377 11 formulation for Kaylo-20 Core Material As Is the case with Kaylo-20 thermal Insulation, there is also a differede of opinion as to the best solar CaO/SiOg for Kaylo-20 core* The ratio was redoced to .977 from 1*00 In December 1958 with results that are not too clear cut. It In the writer's opinion that this ratio in still somewhat on the high side to be safe for plant production. In the current formulation given below, the computations are based on a CaO content of 73% for the hydrate. If by chance the CaO contest for the lot actually used was 7h% instead of 73% as found In the test sample, a molar CaO/SiQ^ ratio of .99 would obtain. The hydrate content is varied in accord with the amount of available CaO found to be present in the test samples. The following batch Is based on a 732 CaO hydrate. Raw Material Weighed Amount (Pounds) Dry Weight (Pounds) Percent IS chrysotile asbestos 550 . 550 10.83 Hydrated lias .1,880 1,10*8 35.06 Tripoli 1,520 1,520 kO.99 Sed iron Vollantonlte P-1 15 is o.uo ITS 175 U.72 Totals 3,70S 100.00 Water - 10,005 lbs. Water/solids *2.81 Molar CaO/SiOg - .977 Factorst CaOAydrated lime .73 SlOg/tripoli - .99 01 062 0a<8 12 Chapter 1Y ROLE OF THE VARIOUS RAW HATS2IAIS Asbestos 2fce tens asbestos is not definitive of an? specific chemical compound. It is a general term applied to any natural mineral that tends to occur in a fibrous form. Throughout the years, various minerals in this form have been tried in Kayl formulations, but only two, chrysotile asbestos and aaosite asbestos, have proved to be satisfactory quality-wise, or to be economically feasible* Asbestos is employed for two purposes. First, it Is an effective suspending agent. With proper fiberizatlon, it is possible to obtain stable, non-settling suspensions of as little as 3 or of asbestos in water. This jackstraw arrangement of fibers is capable of supporting and keeping other solids from settling out of suspension in dilute slurries. It makes possible the creation of the stable suspensions of high water content necessary for the production of lightweight products by our present process. Second, asbestos fibers provide reinforcing. They not only tand to prevent cracks from originating, but they also tend to held the piece together after a crack has occurred. The latter function is camonly referred to as hinging. * As recently as 1539, the role of asbestos as a reinforcing material was act appreciated, and it was even later that asbestos was employed to make light density products possible. The first hydrous calcium silicate products manufactured were of relatively heavy density. Easy were found to be subject to severe cracking, and even to disintegration with time when exposed to even moderate temperature changes, and to changes in humidity. The cementitious phase of Kaylo-10 products is essentially tebermorite. While this caapound is crystalline, the crystals are so ertrmely fins that the structure tends to behave as though it were a gel. That is to say, there is significant swelling or shrinking with changes in moisture content brought about by change in surroundings. Reinforcing in the form of asbestos is necessary to stabilise this gel-like structure. On the other hand, Kaylo-20 products are composed of xcnotlite. This material is more coarsely crystalline and the crystals themselves are needle-like. Heavy density Kayl-20 products are not subject to the cracidng tendency exhibited by Saylo-10 ware. Attempts have been made to substitute other fibers for asbestos in varying amounts. Glass fibers of alkali resistant compositions have bees tried and these failed on two counts. In the first place, contrary to the behavior of asbestos, they, tend to elrssp and ball-up. Instead of booming evenly dispersed throughout the slurry with mixing. In the second place, even the most resistant glasses exhibited an envelope of altered glass about the fiber. As a consequence, a satisfactory bond did not ctotata between the hydrous calcium silicate and the unaltered portion of the glass fiber. oi 062 Fiberized bagasse has also bees tried without success. This organic material undergoes some shrinkage in the processing and withdraws from intimate contact with the cementitious phase, rending it of little us# as a reinforcing fiber. . . Limited amounts of the fibrous mineral vollastonite are now being used for reinforcing in certain formulations. More will be said of this later. Chrysotile Chrysotile asbestos is essentially hydrous magnesium silicate of the seme chemical composition as its mother rock, serpentine. The pure mineral has the formula 3g0.2Si02.2H20, but caaaercial fibers invariably contain varying amounts of other o^das as impurities. Chrysotile is rather widely distributed, but about 60S of the world*s market is supplied by Canada and about 202 by Russia. Host of the chrysotile coming frees Canada is graded and labeled according to a unifora system which is universally recognized. The grading system is arranged to divide seven sain groups of asbestos into more than twenty- five grades. Standardization of the various grades is produced and main tained by regular testing on the Quebec Standard Testing Machine. This equipment consists of a nest of 3 screens and a pan measuring lfc-3/U"x k* deep, resting on a table which is movable and is driven by an eccentric rotating in a vertical plane at 328 rpa. The screen sizes are 2, h, and 10 mesh, respectively, A timing device allows exactly 600 revolutions per test. Testing Is done on a 16-ounce sample representative of the lot. The sample is divided into four fractions by the action of the testing machine. The weights in ounces of the fractions retained on each of the three screens and that caught in the pan are recorded. These weights define the quantity of the various fiber lengths In the sasple, and in this manner establish a certain grade. The greater the proportions of longer fiber, or the greater the amounts on the coarser screens, the lower the number designation of the grade. Within the numerical grads there is also further gradation defined by a letter of the alphabet; the lower the letter in the order of the alphabet, the greater.the proportions of the longer fibers. Chrysotile fibers tend to be relatively short. The price increases rapidly with increase in fiber length. Certain grades of long fiber may sell for considerably more than a thousand dollars per ton. In Saylo formulations, grade i and grade 6D are currently used. The delivered prices are about $226 and $102 per ton, respectively. The distri bution of the fibers in these two grades ares On #2 mesh On #b mesh On #10 mesh In Fan lit . 6D 0.0 .h 0 .9 ?. 3 ^9 01 062 0300  Ik Chrysotilc of good quality is a soft, yet strong fiber. The individual ( fibers of a given grade are in reality bandies of such finer fibers, is V sueh they have fine "hairs'* protruding frcn the sides, and tend to exhibit broomed ends. It is this make-up that is responsible for their remarkable ability to' stay in suspension, and to support other solids in dilute slurries. This structure also tends to hold vater within it, and iaparts non-bleeding characteristics to a slurry. The difference in structure between ehrysotile and glass fibers accounts for their different behavior when incorporated in slurries. Although the grading and labeling of Canadian ehrysotile is rigidly controlled, there are differences in quality of supposedly the sane grade from different sources, as far as being an ingredient in Kaylo products is concerned. The various chrysotilee may differ in suspending power, and differences in inherent strength nay be reflected in differences in strength of the ware. The only means known at this time to detect these differences is in the testing of the resulting Kaylo slurries and products. To date no Canadian ehrysotile has proved as satisfactory as that of J-H. However, the search is continuing, and it is likely that other sources of supply will bs found. a The Canadian system of labeling does not necessarily apply to ehrysotile from other countries. As a rule, samples of the various grades must be obtained and attempts made to classify them on the Canadian basis before choices are made for trial Kaylo batches. Limited amounts of Venezuelan ehrysotile have been used with success when blended with J-H material. It is questionable that it could be used to the exclusion of the latter. As mentioned above, ehrysotile is a hydrous compound. 7hs% is to say, water is an integral pert of its crystal structure. For this reason it begins to disintegrate and lose strength at relatively low temperatures In terms of thermal insulation. As recently as 19SS, ehrysotile was the only type of asbestos employed in Kaylo thermal insulations. The demands of the trade for greater stability at higher temperature, and for reduced thermal conductivity, led to the use of a blend of amosite asbestos with ehrysotile in Kaylo thermal insulation. Amosite Amosite is essentially an anhydrous ferrous silicate. When pure it has the formula, FeO.SiOg. Usually there is some MgO in the structure, along with a little CaO. The fibers tend to be very much longer than those of ehrysotile. For the grades used in Kaylo batches, & large percentage of the fibers are longer than one inch, with seme ranging up to about three Inches or more. Almost all of the fibers are longer than 3/8". The delivered prices at Berlin for these fibers are about $196 to $210 per ton. In com paring these prices with that for UK ehrysotile, it Is eTineot that a fiber of much greater length is obtained at a semevhat lower cost. Africa Is the only important comercial source of amosite asbestos. Each producer, who may buy crude from many sources, uses his own system of nomenclature for the various grades. Aside from filter length, the quality of amosite in respect to strength, brittleness, gangue content, etc., may vary 01 062 030/ greatly from reader to reader. Prices Ser material cf the same quality aay also vary considerably* However, it has bean found that the quality has remained quite constant of given grades supplied by forth American Asbestos* Prices also have compared favorably. From what has been learned, v presently appear to be in a position of a preferred customer of North American* As mentioned above, amosite is an anhydrous compound, vhich means, of course, that it contains no water as part of its structure* Partially for this reason, it can withstand higher temperatures than can chryaotile before breakdown begins. The substitution of amosite for chrysotile results in products having lover shrinkages at elevated temperatures* Another factor in favor of amosite is that lover *k factors, particularly at higher mean temperatures, result in the products when it replaces chryaotile* This is believed to be due to the fact that it is an iron ccapouad and as such is more effective in blocking infra-red radiation* Base of the ferrous iron of the amosite apparently undergoes a base exchange vith the line of the batch, and beccmas disseminated throughout the entire hydrous calcium silicate structure* That the entire body of the product becomes uniformly pink after being subjected to high temperatures is evidence of this* Eaylo products containing only chryaotile remain white. Just how such iron and lime are involved is not known* A study of this phenomenon would be most worthwhile* If the amount of lime that takes part in this reaction is significant, and if this lime is thus prevented fro cmbisa$ with the silica to fora hydrous calcium silicate, the true CaO/SiOg ratio may be different frea that designed and intended for the formation of the desired hydrous calcium silicate* Still another argument for the use of a certain percentage of the asbestos as amosite, is the pouring characteristics imparted to the slurries* Being a stiffer fiber, its presence makes for a slurry less prone to result in eddies as it is being cast into the molds by present methods. This differ ential aovaaent within the slurry, vith one portion eliding over another, results in slip planes or discontinuities within the ware* On the other hand, too high a proportion of amosite results la a *fcarshD slurry which tends to fold or tear as it is being east in the mold* These patterns are carried over into the finished ware as defects* While high amosite contents may yield a slurry that holds the solids veil enough, this stiff and relatively open framework of fibers may permit the loss of vater by bleeding. Consequently, a blend of amosite and chryaotile is employed in the production of Kaylo thermal insulation to take advantage of the favorable characteristics of each* However, in a process that does not involve the holding of the slurry for any length of time under quiescent coalitions, bleeding is sot a problem and solely amosite will most likely be used* This was true for the batch employed in the tubular molding operation, which was recently discontinued* It is of interest in this connection, that J-M uses only amosite in Its process. Since a very dilute slurry, 20 to 2? water/solids ratio is employed, harshness is not a problem* Nor does this slurry regain quiescent* Further more, the molding is a press and filter operation, which requires that the slurry possess a high degree of freeness* Thus J-K is able to take full advantage of the characteristics of amosite in both the slurry and the product. 01 062 oscs / The latest survey of cmpetitive hydrous calcium silicates revealed / that all but 1-M Theraobestes contained a blend of tvo types of asbestos, v Only chrysotile is used for Xaylo-10 and Kaylo-20 core materials. This Is dose to obtain the optimum pouring characteristics with these slurries of lower water content. Earlier it was stated that only ehrysotUe and amoslte types of asbestos have been found to be satisfactory, or to be econoiucslly feasible. Crociddit* asbestos gives highly satisfactory performance, but prices have been too high to permit its use. Idle aaoaita, it comes from Africa. In fact, deposits are frequently closely associated* It is cccmonly called "blue asbestos, and has the complex formula, SagO.SBeO.FegO^.fiSiC^.HgO. Wollastonite Camenta on wollastonite are inserted here because it is a fibrous material end is used for reinforcing of the hydrous calcium silicate In Zaylo products* Wollaston!to is anhydrous mono-calcium silicate, CaO.SlO?. It say be made synthetically, but ve are concerned here with the natural mineral. It is supplied In several degrees of fineness from a source in Hew lork State by Godfrey 1. Cabot, Inc. It will be recalled from discussions of formulations in Chapter IS that grade C-101 was used in K&ylo-lC theme! Insulation, and grade P-1 in Xaylo-20 thermal insulation and in Saylo-20 cere* The C-101 grade is a relatively coarse material having needle-like crystals up to l/h in length. It is used to replace a pert of the asbestos In an amount of ICO lbs. for 100 lbs. per batch. It functions solely as reinforcing and does not contribute to suspension. Therefore, the amount that can be substituted for asbestos is limited. It has all of the prop erties of a good reinforcing material, being strong, having good adhesion to the binder, and being unaffected by heat up to temperatures far beyond the limit that either type of asbestos can withstand. Sut perhaps the. greatest advantage is to be found in its lew cost, about $26 per ton delivered, compared with about eight times this amount for the asbestos it replaces. At a replacement of 100 lbs. for 100 lbs., a savings of about $10 per batch is realised. On a typical day, a total of 20 to 30 batches of Kayla-10 light density alurry may be poured. Wollaatonite C-101 first vent into the batch the latter park of August, 1953* Both Ksylo-10 end Kaylo-20 core formulations at present esploy hydrated lime instead of quicklime in order to keep the consistency of the slurry low enough to permit it to be cast satisfactorily. The writer feels there is a strong possibility that if quicklime were substituted for hydrate, and voUaatonlte C-101 for a part of the. asbestos, a satisfactory slurry and as good, if not better, product would result. Studies are indicated on this subject. ( 01 062 03C3 < s 17 Wide use of vollastonite can be expected If and when the manufacture of specialty items becomes of consequence. This especially applies to relatively high density xonotlite, or Kaylo-20, bodies. Ixperiaantal pieces of a body ccsrooaed of 50% xonotlite-^O? woliastomte C-101 at a density of 50 pcf have shown a modulus of rupture of 390 psi. After heating at 1800F for 2u hours, the modulus of rupture was 220 psi and the material had undergone a shrinkage of only 0.65. Vollastonite P-1 is an extremely fine, or pigment, grade. It is used in both Xaylo-20 theraal insulation and core batches. Being of pigment grade, it is, naturally, higher priced than C-101, but still is much cheaper then asbestos. 'Whether or not it is preferable to C-101 in Kaylo-20 batches is still s moot question, and should be resolved sometime. Plant personnel ere reluctant to change because of satisfactory experience with the finer material. It should be mentioned here that no thickening of Kaylo-20 slurries occurs at any stage prior to autoclaving, so that these slurries remain in a fluid state for longer periods than do those of Ksylo-10 formulations. Bleeding, or loss of water, from the east ware can be of major concern. This could be a determining factor in a choice between the finer and the coarser grades of vollastonite. Lime Lime, of course, supplies the C&O to combine with the SiO of the batch to form the hydrous calcium silicate binder. It must be a high calcium lime. Highly impure limes, or dolcoitlc Uses, containing appreciable amounts of magnesia are unsatisfactory. Ihe magneaim silicates which result from the reaction of KgO with S102 do not function as a cementitious material. But even worse, the delayed hydration of KgO to Kg(0H)2 involves expansion and results in a disruptive force after the Kaylo mass has set up. Fortunately, the composition of the product is closely controlled by reputable producers, and reasonably constant quality can be ejected frcs any one source. Quicklime Quicklime is employed in both Xaylo-lC and Kaylo-20 thermal insulation femulations. By means of controlled conditions of hydration during the batch mixing operation, a "fat1* lime putty results which contributes largely to the desired non-bleeding characteristics of the slurry. For this and other reasons, a very reactive lime is needed. To meet these needs, a "soft" burned lime, yet free Crm excessive amounts of uncalcined limestone, is required. Kasy producers cater to the steel manufacturers who prefer a "hard" burned lime. Such limes are not generally suitable. It has been the experience at Berlin that no readily available lime was quite as satis factory as that produced by Varner Ccaspany fresn its Beliefonte, Pennsylvania plant. 01 062 0304 18 Hydrated Lime Currently, hydrated lime is used is the heavier density Kaylo-10 and Xaylo-20 core formulations. If quieklise were to be employed in the present formulations, the consistencies of the slurries would prove too high for satisfactory handling in the casting operation. Commercial hydrate has certain disadvantages. The delivered price is higher for a given CaO content, and it is more susceptible to deterioration during storage. Small inventories and frequent analyses must be the practice. It is hoped that further studies of ore fradiations will result in modi fications which will permit the use of quicklime. Silica Two forms of silica are used in the Kaylo-10 thermal insulation and core formulations. They are the crystalline tripoli and the amorphous diatonaceoua earth. Kaylo-20 formulation contain only tripoli at the present tine, but limited amounts of diatcoaceous earth, up to about 20% of the siliceous fraction, have been used in the past. The amount of diatomaceous earth that can be employed in Kaylo-20 formulations is limited by its re active alumina content. Actually, it was found in laboratory tests with a diatcaaceous earth particularly low in AI2O3 that high quality Kayle-20 products were formed sore readily when the silica fraction consisted of 60S crystalline silica-bO diatercapeous earth than when cdeposed of entirely crystalline silica. But larger shipments of this particular brand of diatoaaceous earth proved to have higher alumina contents and to be quite variable is this respect* Consequently, advantage could not be taken of the characteristics shown by the laboratory sample. Amorphous silica in the form of silica gel is suitable for both Kaylo-10 and Kaylo-20 formulations, but the cost is much too high for use as a raw material in production. Tripoli The term tripoli has different connotations In various countries and In the literature. Is American usage, tripoli 1s a microcrystalline quarts. There are two extensive deposits located in southern Illinois and in Arkansas. Both are being exploited. The material being used at Berlin comes from the former, and is supplied by ni.inois Minerals Company. While it la in reality a quartz, the microcrystalliae structure renders it much more reactive than ordinary quarts of the same screes fineness. The delivered price at Berlin is $28.06 per ton for 95% minus 325 mesh, ccsapared to $15.60 for quartz ground to the seme fineness. This represents a difference of $2.13 per batch of Kaylo-10 thernal insulation, but experience has shown that the reductions in cylinder time made possible by its use more than compensate for the added cost of the tripoli. For the autoclaving periods accepted as standard in plant operations, greatly inferior ware results when quartz replaces tripoli. Or stated differently, longer autoclaving Is required to obtain ware of the seme quality when quartz is employed. 01 062 03D5 19 Attempts have bees mame to increase the reactivity of ordinary quartz by grinding to extras* fineness but the reactivity did not approach that of tripoli of a 95% minus 12$ aesn fineness* This experience indicates that the processing of plate glass grinding wastes to provide a source of silica does not hold great premise* In the formulation for Xsylo-10 thermal insulation* the tripoli con stitutes 30$ of the total silica* In the Saylo-10 core batch* the tripoli accounts for about 79$ of the siliceous fraction. Celatest (Diatmaceoas Earth) Delates is the trade naae of the diatomaeeous earth produced frem Nevada deposits by Eagie-Picher Company* This vendor selects material free only certain strata and blends it for our use* Prior to shipment* each lot is tested by their quality control laboratory for organic matter content* using the method and standards prescribed by us, to assure that the organic content is safely below injurious levels (about 200 ppm). Ibis tested and approved product is labeled Delate* N-370. The results of these determinations of organic content reach the plant by air mail before the Delates arrives* Diatomarsons earth* or dlatcaite* is the fossilised remains of diatms* Diatems are microscopic single-celled aquatic plants which have the ability to extract silica from the water in which they live* and with this silica build for themselves external skeletons* When the diatom dies* this skeleton settles to the bottom and remains after the organic part of the plant has disappeared. Over tea thousand different types of diatces have been iden tified* Naturally, there are great variations in size* shape* surface area* bulk density* etc** among the diatom!tea* Furthermore* although all are composed for the most part of amorphous silica* they differ greatly in the amounts of impurities or other oxides that they contain* All of these different attributes have a bearing on the suitability of a particular diatomite deposit for use aa a raw material in Saylo formulations* * Dlatcsaceeus earths other than Delates H-370 have been given thorough trials* They have generally proved less satisfactory because of lesser reactivity* or oecause of variable ccnpositlon frees shipment to shipment* In one instance* a vendor's supply of satisfactory diatcmlte became exhausted* While knowledge of the presence of gross amounts of impurities may eliminate a diatomite from further consideration* in many cases it is necessary to employ it in trial runs In order to evaluate it* Apparently many factors contribute to its measure of value ae a Saylo raw material. Certain diatesites* although pure enough and having high surface areas* do not react with lime as readily aa others. Celite from J-H falls in *m category* 01 062 03tP Dlatomaceous earth is used in the batch for two reasons. First* as an amorphous form of silica* It reacts very readily with line. This property permits the cast ware to set up or preharden in a relatively short time at temperatures in the neighborhood of 200F. The preliminary setting or pre hardening of the cast ware greatly facilitates the handling of the filled molds in subsequent operation* and also makes for easier stripping of certain sizes of ware after autoclaving. Also of importance is that scheduling of the cylinders is far less critical* because prhardened or set ware can stand for several hours on the floor if necessary before being autoclaved. 20 The second reason for using diatcmite in the batch is its contribution to the thickening of the slurry, giving it greater water-retaining and non-settling characteristics* It is true that no diatestaceous earth is employed in Kayl-20 foraulatioas, but Kaylo-20 products cannot be mad* at as lew apparent densities* The minimus density of Kaylo-20 ware that Is new practicable in production is about 12,5 pcf* That is to say, the absence of diatmaceous earth in the formulation makes necessary the use of slurries of lower water/solid ratios* Since the water/solids ratio of the Kaylo-XO core slurry is less than that for Kayl-10 theraal insulation slurry, less diatoaaceoua earth is required to give the same rate of prehardening and the same water-retaining properties* Clay It was mentioned earlier that it was advantageous to have a limited amount of reactive alumina present to enter the structure of the hydrous calcium silicate which constitutes the body of Xaylo-IQ ware. A fine grained china clay (kB.linlte type) it a most satisfactory and constant source of reactive alaciaa, and the silica of the clay Is also reactive* This type of clay is used in an amount of 3.28$ of the solids in the Kaylo-10 insu lation batch, and 1*37$ in the Kaylo-10 core formulation* These amounts appear to be about the optimum in each ease from the laboratesy studies and the plant trials that have been made* Strengths are greatly improved, and low shrinkages at elevated tesperatures result in the product* the presence of scssevbat higher quantities at alumina results is ware shoving excessive shrinkage at high temperatures* Thus, it is essential that the alumina contest of the femulation be closely controlled. Large variations in alumina content of the diatcmaceous earth fraction render this control moat difficult. Clays other than a kaolin or china clay might be used, but the use of a high grade china olgy insures that objectionable impurities such as organic matter, sulfates, chlorides, etc*, are not a problem* There is evidence that bentonite clays increase processing shrinkage* Alumina is the form of bauxite is set reactive in the Ksylo process* Inert Ingredients Studies have shown that the Inclusion of extremely fine inert ingra dients in the batch reduces the thermal conductivity of the product remarkably* Through the addition of 11S of fine inert materials to the batch, combined with a change to a blend of smosite and chrysotile instead of chrysotile alone, the "k factor at $5QT mean of the plant product has been reduced about O.lk from what it was in 1955* It is believed that this effect is mainly due to the increase in number of interfaces between dis similar .materials encountered as heat flows through the insulation* The studies have shown that combination of additives is better than a single inert substance. ( 01 062 O30n 21 k great number and variety of materials have been found to be effective, and the choice for use in precaution is dependent upon a number of factors. Hequisites for a satisfactory additive of this nature are: it should be inert and not interfere with the formation of the desired hydrous calcium silicate 5 the finer the grain size the better? infra-red blocking properties give an added advantage; it should not Impart undesirable color or shade to the product; it should be readily available and cheap* Carson black is by far the most effective additive found to date for lowering nk* factor, but its high cost and the darkening it gives to the product role it out, for the present at least* On the other hand, limestone ground to pass 200 mesh is not as effective, requiring 102 addition to produce the same amount of lowering of nk* factor as 2% of carbon black, but it is by far the cheapest of all of the batch ingredients and does not cause a color change in the product* The considerably cheaper ground magnetite, Fe^/ has been found to be almost as effective as ground chromite, FetCrOg^, but the latter doss not darken the product as much. As to be eapected, there is seme reduction in strength of the product as the amount of fine inert material in the batch increases* Thus in lowering the thermal conductivity by this means, some strength is sacrificed* Conse quently, a ccaprcmise must be reached is this matter* Tbs present formu lation calls for ?.8?2 of limestone and 3.28% of chromite for a total of 11.152 of additive. It is likely that 112 of limestone and h$ of ehromite could be carried without reducing the strength to a danger point or where it would be objectionable to the customer. A reaction of .03 in "k" factor at 5503? mean could be expected. However, the plant experienced a period of lew strengths in 1957 while employing 152 of additive, and may accordingly object to the return to this much. But the formulation has been changed in several other Important respects since then which have all contributed to higher strengths, and reoccurrence of the lew strengths of 1957 is not to be espected. A return to 152 of additives will not be proposed, however, until it has been first established that a product of sore than eaple strength can be made consistently with the return of waste slurry and of scrap Ssylo material to the batch. These two modifications to the batch are proposed for the Immediate future. Perhaps research will in the future reveal an additive more effective than any now known, and it will not be necessary to employ quantities to the extent the strength is seriously affected in order to obtain aka factors that compare favorably with those of competitive materials. Ground Limestone As mentioned above, ground limestone is one of the inert additives now in the Ksylo-10 thermal insulation formulation. It is supposedly a by-product in the lime industry, being too fine for most purposes. HminaXly it Is 902 minus 200 mesh, but most of the grains are as fine as face powder. 01 0G2 030$ f( v ( 22 Although it is added to the batch to decrease the thermal conductivity of the product, a cheaper batch results as a bonus. The aelivsred price of the bagged material at Berlin is only 311 per ton. The average of the prices for the other ten solids of the formulation is $4.7?8 per cvt., while that for limestone is only 30.550. the present material is a high calcium limestone, but a dolcaaitic limestone would serve as wall. The fineness is the important factor in this case. Chroalf Iron chromite is the second additive being used to lower the "k" factor of the Berlin product. It has the added advantage of being effective in blocking infra-red radiation. This particular material is known as airfloat chromite, and is available ecesaerclally, being a batch Ingredient in certain glass container plants. The delivered price of bagged material is 32.653 per cwt., which is still cheaper than the average for the other ingredients. Surface Active Agents Taaol #731 Certain surface active, or dispersing, agents are effective in increasing the fluidity or flcwability of a slurry. Taaol #731, which is supplied by Boha and Eaas, is of this class. The addition to the Saylo-10 insulation batch was begun on Boveober 10, 1958. It is employed in as amount of 0.105 of the weight of the solids. This addition has proved most valuable in imparting excellent pouring characteristics to a alurry that was otherwise too thick and stiff to cast properly. The incidence of air holes and folds has been greatly reduced in molded pipe covering. While it does add 32.34 to the batch cost, the saving resulting from a lever mount of off-ware more than compensates for this increase. Taaol #731 Is a new development, and Berlin was one of the first cus tomers. Promise has been made of likely print reductions in the future. A satisfactory dispersing agent fcr Kaylo slurries has been the subject fit research for several years. Many have been tried in the past, but their use was soon abandoned for one of two reasons; either they ware foam formers with a resulting unfavorable effect on the "k factor of the ware, or they caused unsightly staining of the product. Tamol #731 has neither of these disadvantages. Coloring Red Iron Oxide A amount {about 0.35) of fine red iron oxide is added to both types of Raylo-20 batches to give a pink color to tbs product. This is done to distinguish the ware on sight frees corresponding Kaylo-10 material. 01 062 030} 23 Chapter V HAW MATERIAL SFECXFICATICGS The specifications as given here are not to he considered as being: in final or standard fora. They are actually compilations of the properties and requisites of the various raw materials, made to serve as the bases for the drafting of formal specifications. It should be emphasised that passing a specification based on con formance to a limited number of chemical and physical properties is no assurance that one material will function as veil as another in Kaylo formulations. Certain variables can exist that are not easily detected except by observations of behavior of the materials in trial runs of batches containing the material in question. The specification for each ingredient should contain a clause stating that it shall prove to b* satisfactory for use in the production of Kaylo products. Final grounds for acceptance or rejection of a particular material should be whether or not it ecmparee favorably with standard performance in respect to speed of processing and to the quality of the product. No nev source of any of the batch ingredients should be given final approval before runs of laboratory and plant trial batches have been made and favorable results are obtained. Cnee a material has been approved, it Is one of the functions of the Process Control Engineering Section to conduct the necessary tests in its laboratory at the plant to insure that no significant variation fra# speci fications occurs. It is also the responsibility of this group to advise as to corrective measures to be taken when the character of material on band haa changed due to coalitions of storage or other reasons. Chryaotila Asbestos Chrysotile shall conform to the following requirements and in addition prove suitable in plant trials for the production of Kaylo products. Two grades of chrysotile are required for tha production of Kaylo products, a shingle fiber and the shorter, stucco or plaster fiber. The former shall prove to be the equivalent of Grade hX or better in the Quebec Standard Test; the latter the equivalent of Grade 6B or better. The vendor shall guarantee that each material Is of the chrysotile variety of asbestos. Optical properties rather than chesical analysis are to be the basis for judgment in case of dispute, on this point. Haxdarua impuritiess Cl .20$ S03 .75* The chrysotile shall be supplied in bags of uniform weight, with the grade of the material marked thereon. Conpressed material in paper bags is preferred. Approved vendors? Johns-Manvllls Oi 0S2 63 2k Aaosite Asbestos Amosite conform to the following roqairesenta, and In addition prove suitable in plant trials for the production of Xaylo prodwts. There is no uniform system employed in the grading of amosite asbestos. Generally speaking the grades of interest consist predominantly of fibers longer than 3/8 or 1/2% and about 20 or 25% longer than ln* The amosite shall contain no sore than 2*C% of non-fibreus material present as rook or dust* The chemical composition shall conform roughly to the foilwing; 50$ SiOz, 6? Al^O^j 37? FeO, k% KgO, 2? BgO. Before, a new and untried material is purchased, representative samples most be furnished for comparison vlth "standard1* fibers as to brittleness, tensile strength, fiber length distribution, etc. * The aaosite shall be supplied in burlap bags of uniform weight, with the grade and manufacturers name marked thereon* Approved vendors: North American Asbestos Corporation Pulverised QrigVUnm This line shall conform to the following requlreaenta, and la addition prove suitable in plant trials for the production of E^rlc products. Substantially all of the pulverized lime shall pass the No* 20 sieve and after slaking, not more than 1*0? by weight shall be retained on this size screes* Bequlrements as to chemical composition on an air dry basis are as fallen: When tested at Plant Place of Kfg* C&0 Total 30- Kin. ? Kin. ? Kaz* % K&x. $ Kax* i *iuS *2.5 2.0 3.0 0.3 *6.0 93.5 2.0 3.0 0.3 A.S*?*M* Designation C25-47 (sugar method) The lime shall be shipped in paper b&ga strong enough to withstand normal without bursting* Weight of lime in each bag shall not deviate more than one pound, plus or minus, from the average weight. . The bags shall be marked, "Pulverized Line", and shall also comply with the A.3.T.K* requirements for marldmg* { Approved vendorst Warner Lime Company 01 062 03IJ 25 /* Hydrated Lise This lime shall* confers to the following requirements, and in addition prove suitable in plant trials for the production of Kaylo products* Hot acre than i.Oi by weight shall be retained on the Ho* 30 sieve, nor acre than 15*0% on the Ho. 200 sieve. Requirements as to chemical exposition os an air dry basis are as When tested at Plant Flace of Ml's. CaO Total Min. * CaO Available* Kin. % as* Max. % Max. % S03 Max. % 72.0 69.5 1.5 2.0 0.25 ?30 70.0 1.5 2.0 0.25 *A.3.T.H. Designation 025*47 (sugar method) This lime shall be shipped in paper bags strong enough to withstand normal handling without bursting. Weight of lime in each bag shall not deviate more than one pound, pins or minus, frees the average weight. The bags shall be marked, "Hydrated Lime", and shall also comply with the A.S.T.M. requirements for marking. Approved vendors: Warner lime Company Tripoli This material shall conform to the following requirements, and in addition prove suitable in plant trials for the production of Ssyl products. Evidence must be presented that this.silica flour is produced from a form of ajcrocryits.ilirre quarts ecssabnly known in the 0.S.A. as "tripoll*. Not more than IS shall .be retained on the No. 100 sieve, nor sore than 55 on the No. 325 sieve. At least 5# by weight shall be finer than 25 microns. Requirements as to chemical composition on "as received* basis are: SiO* Kin. % 98.0 RjOj Max. % 1*5 Loss on Ignition Max. % 1.0 This silica flour shall be shipped In paper bags strong enough to with stand normal handling without bursting. Weight of contents in each bag shall dot deviate more than one pound, plus or minus, from the average weight. Approved vendors: Illinois Minerals Company ( 01 062 03KL 26 Diatonacecus Earth This material shall conform to the following requireaents, and in addition prove suitable in plant trials for the production of Eaylo products. Sot acre than- Q.1S shall be retained on the No. 20 sieve, nor more than 8*0$ on the No. 325 sieve. Requirements a* to chemical cdeposition on "as received" basis axe: SiC2 Min. % AloO-i Max. % T^oi Max. % Total &23 Max. % Loss on ignition Max. % Organics Max* 80.0 7.0 1.0 10.0 9.0 200 ppm* *Aa tested by OCF method, Jane 5, 1956 Revision, and employing color standards to be provided by OCF. This diatamite shall be shipped is paper bags strong enough to withstand normal handling without bursting, fright of contests in each bag shall sot deviate more than one pound, plus or wines, from the average weight. Approved grades and vendors: Celatoa N-370, Eagle-Picher Company 22SZ This material shall conform to the fellowing requirements and in addition prove suitable in plant trials for the production of Eaylo prodaste. The clay shall be the china or kaolinite type, and uncalcined. It shall be pulverised clajr shewing no more than 1.0% on a No. }2$ sieve. Requirements as to chemical composition on "as received" basis are: SiCU Range % bO to 50 AI2&3 Range % 35 to 3i02+Al203 Min. % 81.0 Loss on Ignition Max. % 15.0 The clay shall be shipped in paper bags strong enough to withstand normal handling without bursting. Weight of contents in each bag shall not deviate more than one pound, plus or minus, frem the average weight. Approved vendors: Georgia Kaolin Ccapany Kraft Chemical Company 01 062 0313 27 Limestone FIcar This material shall confers to the following requirements, and shall in addition prove to be suitable in plant trials far the production of Kaylo products* Extras* fineness Is a major requisite* At a given price, preference shall be gives to linestone floor having the smallest particle size. In any case, there shall be no. acre than-53 retained on Ho* 325. sieve; 90.03 or more of the limestone shall be finer than 10 microns* Both high calcium limestone and dolcenitlc limestone are acceptable* Requirements as to chemical composition on "as received" basis ares a0? or CaCOi+KfeCO* Moisture SiO? BgOj Min* % 97*0 Max* % 1*0 Max* % 1.0 Max. % 1*0 This material shall be shipped is paper bags strong enough to withstand normal handling without bursting. Weight of contents In each bag shall not deviate more than one pound, plus or minus, from the average weight* Approved vendors! Varner Lima Company Iron Chromite This material shall conform to the following requirements, and shall in addition prove to be suitable in plant trials for the production of Eaylo products* Extreme fineness is a major requisite* Ho more than 55 shall be retained on the Ho* 325 sieve* A suitable material is that known as "Air Float Chrcmite1, and is of a purity comparable to that of the chrcmita maployed as a colorant in the glass container industry. This material shall, be shipped in paper bags strong enough to withstand normal handling without bursting* Weight of contents in each bag shall not deviate more than one pound, plus or minus, fro# the average weight. Approved vendors! Frank Samuels and Company Wollastonite This material shall conform to the following requirements, and shall in addition prove to be suitable in plant trials for the production of Kaylo products* Tbs wollastonite shall be the natural mineral graded to give a definite particle size range* Two grades are of interest* They correspond to Grade C-101 and Grade P-1 as produced and labeled by Godfrey 1* Cabot, Inc* 01 062 03tq 28 This mineral shall be shipped is paper bags strong enough to withstand noraal handling without bursting. Weight of contents in each bag shall not deflate sore than one pound, plus or minus, frcas the average weight. Approved vendors s Godfrey L. Cabot, Inc. Bed Iron Oxide Ttda material shall be the pigment grade of red iron oxide. Approved vendors: C. X. Williams Corpany Dispersing Agents A dispersing agent to be acceptable Bust be capable of greatly increasing the fluidity of Xaylo slurries when asousts no greater than 0.10$ are added, suet noc cause the fcreation of foam during the mixing of the slurries, and oust not result in the staining of the product. The standard of performance is that of Tsaol l?31. Approved vendors: Roba and Haas Conpany \ ( 01 062 0315 Chapter FI BATCHING AND MIXDC OPERATIONS The detailed procedures to be followed in this step of the process, and in subsequent operations, are given in a manual prepared by C. F* Stlkvood, and approved by 0- W. Pfeifer, titled *Kayl Manufacturing; Process and Operational Control11. This manual was issued June 11, 195S It is the intention here to refer only to the high lights of the abovementioned manual, and to offer some further explanation where such is con sidered helpful* Formulation changes may be made only upon authorisation of the Plant Manager* It la the responsibility of the Chief Process Engineer to calculate the actual quantities of each of the raw materials and the amount of water required, to specify the temperature of the water, and to give detailed instructions to be followed in the treatment and mixing of the ingredients of the batch* All of this is recorded and published on a standard form. Bagged, rather than bulk, raw materials are employed in the batching operation. Formerly, the Sayreville plant operated with a weighing and accumulating system for its raw material handling and batching, bat experi ences there Indicated that the handling of bagged ingredients was to be preferred, both frea the standpoint of oner-all cost and eoctroi* The specified weights of the principal raw materials for the batch are determined by using an equivalent number of bags* Where possible, the weight of a particular ingredient is chosen so as to represent some whole number of bags* In eases where this is not feasible, some easily defined fraction of a bag is chosen* It la necessary, of course, with this scheme to make a regular check on the average bag weight of the raw materials as they are received* If a significant variation is evident, the material is Isolated, and means are devised for using it* In such oases the vendor is advised end asked to correct the condition* The batching and mixing operations begin with the measuring out of the predetermined amount of water at a prescribed temperature into one of the two tanks that are used to disperse the asbestos is water* These are cylin drical tanks with impellers located near the bottae* In the pumping froa one tank to the other, the suspension passes through a Bauer mill, the plates of which may be set at a desired clearance* The batching and *<** to be described is that for Kaylo-10 thermal insulation batch because the operation is the most complex* More ingredients are employed and the recovery of waste slurry Is involved* 01 062 03K* 30 The amount of water used for the batch is determined by the mount of dry solids plus the amount of solids contained in the tobase of waste slurry added* The volume of waste slurry to be used per batch is determined by the quantity that has been collected in the two salvage tanks (similar but somewhat smaller than the asbestos tanks)* and the cumber of batches of Kaylo-10 light density scheduled to be run for the day. The waste slurry is, of course, much acre dilute than the batch slurry, since it consists of the batch remaining in the lines and mixers plus the water used to wash out the equipment. After the prescribed amount of clear water for the batch has been metered into the Ho* 1 asbestos tank, and the Tamol #?3l added, a measured amount is pimped to the Ho* 2 asbestos tank, and thence to the hydrapulper for the hydration of the quicklime* This quantity is about four times the weight of the quicklime* To the water remaining in the Ho* 1 tank, a metered amount of the dilute waste slurry is added* To this tank is then added, all of the asbestos, the clay, and a half a bag or so of the quicklime going into the batch* (Asbestos disperses better.in lime water than in straight water*) These solids are put into suspension by the action of the impeller at the bottom of the tank and pumped into Ho* 2 asbestos tank through the Bauer mill running at a clearance of 0*020" The treatment given the asbestos is the Bauer mill, which Is a fibarising operation, is varied according to the blend of asbestos being used at the time and to the characteristics of the final slurry* If a higher consistency is desired, or If clogging of the pouring nozzles is being experienced, the plates of the Bauer mill may be eet closer together, or several passes may be made through the mill, or both. Also, if the slurry la shoving abnormal tendency to bleed, more work may be done on the asbestos by the Bauer mill* Vhila the asbestos suspendos is going through the Bauer mill, the operator dumps the remainder of the quicklime and the wollastcnite into the hydrapulper containing the water for the hydration of the lime* The hydrapulper is then set to run for about three minutes to thoroughly mix the lima and water, and to get the hydration of the lime well under way* After the asbestos suspension has gone through the Bauer mill into asbestos tank 2, it is pumped from there to the hydrapulper os top of the lime putty* When this is complete, the hydrapulper is put in motion and the diatcmaceous earth, tripoll, and additives added* The complete batch is allowed to nix for about eight minutes* The hydrapulper is a piece of equipment primarily designed for the production of pulp slurries In the paper industry* The violent action imparted to a fluid results, in very thorough mixing within a short time* Its action also, is effective in further opening of the asbestos fibers* Because of this, the hydrapulping period must be controlled* The consistency of Eaylo slurries increases with increases in time of mixing in this equipment* 01 062 03in. 31 For all of its affectivea#as as a mixer, there may oe a disadvantage in the use of a hydrapulper. There is a possibility that an undesirable aaount of air is entrapped in the slurry by the violent action. If this Is true, and if these air bubbles are for the most part carried through the process to the finished product, the n\c* factor of the ware is likely to be affected adversely. This should be a subject for study. Following in the hydrapulper, the slurry is pumped to a holding mixer, which is a Robinson ribbon mixer. At this point, samples of the slurry are taken for determinations of consistency, density, ana temperature. The consistency figure is the value obtained with equipment- specially designed to measure the resistance that a revolving brass cone meets as it penetrates the mass of slurry. Consistency must be held within certain defined limits because of its effect during the filling of the molds. A high consistency causes the slurry to flow sluggishly in the molds, resulting in air holes, slip planes, aad pouring folds or tears, tow consistency will result in bleeding after casting, water veins with subsequent cracks or separations, and shifting within the molds during handling. The density of the slurry is reported as weight per cubic foot. It is determined simply by weighing a known volume. Control of slurry density is essential in the control of the density of the product. Determination of slurry density also afforda a check on batching as to the solid raw material weights and quantity of water employed. All of the pertinent data are obtained, and recorded at this point. Departures frcm normal are promptly reported to the Production Superintendent and the Chief Process Engineer. The latter attempts to determine the reason for the departure, and must decide If the proper correction can be made, or if the slurry must be dumped. After it has been determined that the slurry is normal, it is held in the holding mixer on the batch floor, with just sufficient mixing action to uniformity, until demands on the pouring lines call for it to be pumped to any one of the pouring mixers. There Is one such mixer in the No. 2 pouring line (molded pipe covering easting), and there are two in the Ho. 1 pouring line (flat ware). These mixers are similar In type to the holding mixer on the batch floor. The sentence of only one holding mixer is a serious handicap to efficient operation, since it say be called upon to handle any one of four types of slurries. Scheduling, therefore, is extremely critical inasmuch as it most be free of any remnants of previous batch of different type at the time the new batch is ready to be pumped from the hydrapulper. The matter is further complicated in that its availability must be tied In with cylinder opening schedules. ,. Plant personnel have asked for assistance from General Engineering In planning for additional batch storage facilities, k holding mixer for Kaylo-20 v slurries is especially needed, and would be of unestlaable value in making' for more efficient operation. Kaylo-20 slurries can be held practically Indefinitely before casting. If storage facilities are available, mixing can be done when most convenient on the batch floor and independently of the cylinder schedules. n The astir* batch ail.3d.ng facilities should b the object of study and ecdprehensiv planning in view of the greatly Increased dssands fcr pro duction. Precast batch mxi.rg facilities are essentially the same as those that first vest into operation on Karch 12, 1?5iu Nore than twice as much slurry per day is being aixed now than it was then. The ultimate capacity of the system under the most efficient operation vas considered at that time to be about 32 batches per day of the same type of slurry# Not only has this alinatn been exceeded, but the plant has been called upon on certain days to mix three types of slurries instead of only one# The exact manner in which waste Kaylo products will be returned to the raw batch has not been determined as yet. Nor is it known how much of the material presently sent to the dump can be safely Incorporated In the batch. The quantity of dust that results from the trismlng, routing, and planing operations far exceeds the weight of the reject ware* This Kaylo dust is collected in dust arrestors, and usually amounts to more than 5 tons per day, or nearly 152 of the weight of the solids that go into the Kaylo-10 thermal insulation batches daily. laboratory results thus far indicate that it is likely that this much can be returned to the raw hatch without serious degradation of the quality of the product. In utilisation on a plant scale, this daat will probably be transferred from the collectors to a tank where it will be nixed with water at a definite vater/solids ratio. Plans call fear two such tanks. During any one day, the dust and water will be mixed in cos tank, and the dust-water sisrry prepared the previous day drawn off free the other as needed in the batching operation. 01 062 03M ( 33 Chapter Vlt FCKMINC** Casting Kethod With a forming method dependant upon the easting of a fluid slurry to shape, such, as usea for by far the most of the production at Berlin, a great many of the defects in the finished product originate at the pouring or casting station* The person who performs the task of filling the molds is a hey figure la determining the quality of the wars- A considerable amount of art is involved at this stage of the process* Accordingly, the plant has generally followed the practice of requiring that a man ``work up" to the 30b of pourer. Also, training manuals, emphasising the intricacies of the operation and describing in detail the procedure to be followed, are available and are required reading* The Shift Foreman Is directly responsible for the performance of his pourer and other members of his crew* In spite of all efforts to obtain uniform performance among the crevs, this objective is rarely attained for any one month. Quite typical is the record for Feoruary, 1959* Of the four crews, one was responsible for 364 of the off-ware, whereas another vas charged for only 164* This high offware crew, which poured a fourth of the production, was charged with more than one-half of the ware rejected for air holes, and had five times as much ware lost for this cause than did the best of the crevs in this respect. The answer to this problem seems to lie in eliminating as much of the bra&a ele&ent as possible in this operation. Efforts are sow being directed along these lines, as further discussion mil reveal. There are two pouring lines: No. 1 where all of the flat ware Is cast! No. 2 where only molded pipe covering is poured. Current demands for pipe covering era such that sei&e must also be poured on the No. 1 line. The pouring line actually begins at the station where the autoclaved ware is stripped from the molds- A summary follows of the operations per formed on the No. 2 or molded pipe covering line. A tier of filled molds (full car flight) is taken from a train that has been pulled frcm the cylinder and delivered by means of a lift truck to the end of the line, where the ware is stripped from the molds by the stripping gang of the crew. Here the processed ware undergoes its first inspection. A piece of ware with gross defects is discarded at this point. A report of the ware discarded is made on the Four and Strip Recap fora which originated when that particular train was poured and which accompanied that train throughout the complete process, with all pertinent data at each step being recorded thereon. As the ware is stripped, it is color coded to the proper pouring crew. 01 062 03ao ,3b A most significant control check is made by the weighing of a repre sentative saspic to determine its moisture content* One piece of each size ware in each car is weighed and the weight recorded os the Pour and Secap fora. By comparing with the preprinted maximum weight for "dry" ware of this sise, it is determined whether or not the ware has to receive supplementary drying. These data are also employed is establishing the proper cylinder cycles. It is the practice for a member of the Quality Control staff to make spot checks at the stripping station. Here the ware can be readily identified with a specific train, cylinder, and crew. Also of major importance is that faulty molds responsible for off-ware can be detected at this point and taken out for repair and/or cleaning. After the ware has been stripped from the mold, the cavity and core are coated with a mold releaae. This is an emulsion of about 3* of polyethylene la a fairly heavy petroleum oil compounded at the plant. The oiling of the molds is performed by hand, the oiler rubbing a rag that baa been dipped in the emulsion over the surface. All too often a poor job is done here. Incomplete coverage often results, as does deposition of excess oil in some parts of the mold. Mechanical application of the oil would, in all prob ability, provide a better job at a saving in manpower. This is one instance where the human element could be eliminated to an advantage. A project for the mechanical oiling of flat ware molds is now on the docket of General Engineering. This should prove to be a simpler arrangement than the osa which would be required for the Ho. 2 line. Following successful installation and operation of the equipment for the flat ware molds, work will undoubtedly begin on a mechanical oiler for the pipe covering molds. Following the oiling, the strippers reassemble the molds { that is, assure that the end spacers are is place, and reset the core into the cavity. This is done for all molds except those for g-segmeotal pipe covering. For this relatively flat ware the core is inserted by the poorer and his helper after the cavity has been filled with the slurry. The molds are moved along the line by a chain conveyor. On the Ho. 2 lice the pourer alone has control of the atop and go. He exercises this control by means of a pedal at his station. As the molds move along the line they pass under a blast of compressed air before they reach the poorer. The purpose is to ranore loose chips of old material that Invariably fall into the cavity frees sides and frames of the molds, etc. While the present arrangement accomplishes the purpose fairly well, it is costly to operate. It is estimated that the cost of the eaepresaed air runs about $800 per month. There appears to be an opportunity here for more efficient equipment with lower operating costs. When the molds arrive at the pouring station, the pourer adjusts the rate of flow for the slurry to a speed he considers proper for the size of the sold to be filled. The slurry is pumped from the pouring &ixsr through a hose with a pouring nozzle attached at its end. The pourer controls the 01 062 0341 35 rate of flow by adjustment of as outlet valve and by regulation of a variable speed pump. For ware of lesser thlcimess he employs a pouring nozzle 89 long and having a nominal slot opening of 3/8. For the thicker ware, he uses as 8 long nozzle with 5/8" wide opening. Use pourer has instructions to follow a certain prescribed pattern of operation during the filling. Sat there are* nevertheless, certain vari ations in node of operation characteristics of the Individual. This is, perhaps, typical of any field of activity where particular skills, coordi nation, and pride in the work being performed are concerned. Efforts are in progress toward the development of a full length (approx. 34*) pouring nozzle for pipe covering. There is reason to believe that a nozzle of this nature would eliminate much of the human.element from the pouring operation. Furthermore, it should reduce the incidence of air holes, slip planes, and folds which occur to acme extent when the much shorter nozzle Is employed by even the best 'pourer. For flat ware on the Ho. 1 line, the pouring nozzle is essentially' as elbow on the end of a 3 diameter hose, having a rectangular shape at the exit of about 70S of the area of that of the hose opening. Development of a 54" long pouring nozzle is the aim is this case. A gang of three molds could be poured at the same time with a nozzle of this length. Better alignment of the asbestos fibers is the ware should also result. As might be surmised, the first problem to be solved is the development of these ouch longer nozzles Is that of obtaining and maintaining uniform flow over the astire length. The presence of asbestos fibers Is the slurry makes the problem more difficult than if a perfectly homogeneous fluid were being dealt with. The second stage of development will be concerned with ease of handling on the line. Following the filling of the pipe covering molds, the overflow Is screeded off by tha pourer*s helper when he is available for the task or by the pourer himself when the helper is engaged with the hoist in lifting a gang of the molds off the line onto the car being loaded for entrance into the prehardener, the next step of the process. The excess slurry that is screeded from'the pipe covering molds on Ho. 2 line goea Into a sump and is pumped into the pouring mixer for the No. 1 line* There are always acne chips of hardened Zaylo material on the aides of the molds and frames which beceae loosened during the handling on the Ho. 2 line and then fall into the slurry in the sump. Formerly only flat ware was cast on the Ho. Inline, and the effect of the presence of ehlps in the slurry on the flat ware was negligible. But when the practice was begun of casting pipe covering also on this line, the clogging of the nozzles with the narrow openings "affected both predation and the quality of the ware. It is necessary, therefore, to pass the sump 'slurry through an attrition mill, such as a Bauer sill,* before re-use. The plant is planning an arrange ment whereby the sump slurry of both lines is emptied into a tank and then passed through a Bauer mill to the pouring mixer on either pouring line, depending on the slurry requirements at the time. 01 062 03&SL 36 AJTtar the car is loaded with the filled 53elds, it is the responsibility of the pourer's helper to move the car into the prehardener. In the case of the first and last cars of the train in schedule, this person records the of entry on the Pour and Strip Recap fora. He also positions an arpty car after a filled one goes into the prehardener. Is perhaps with any method of forming, there are advantages and dis advantages inherent In the method Just discussed. Among the advantages are*.. The actual casting is rapid; the molds are simple and. easily interchanged to meet demands of production; forming equipment is simple and compact; considerable latitude in batch formulation is possible. The major disadvantages are: The randaa orientation of the asbestos fibers that occurs is not as favorable as fibers oriented generally in the planes of the major axes, in respect to *k factor and to strength contributed to the product; the surface is not as hard and resistant to abuse, and of as uniform appeara&ee, as that obtained by certain other methods of forming; a large number of molds are required, ana an individual mold must acccaapany the vare through processing. Sntil recently, the casting method of forming did not permit the pro duction of sectional pipe covering in sizes greater than that for 12s pipe* The use now of a dispersing agent in the batch, and other batch aerifications that have been mads,, have resulted in changes in the pouring characteristics of the slurry such as to make possible the casting of sectional ware through 23s pipe sizes. The molds, which will be of the nested or piggyback type to avoid undue waste of space, are not yet available for production. When these sizes do go into production, it will be possible to eliminate all tri-segatntal vare froa the standard line of products. A disadvantage that has been reduced in significance to a great extent by the use of a dispersing agent in the batch and which should be even lass a factor when full length pouring nozzles are available, is the creation of air holes, folds, and slip planes in the ware. Air holes detract fren appearance, and adversely affect the nkn factor. Folds also mar the appearance of ware. Slip planes are discontinuities in structure and as such causa the vare to be more prone to breakage. There is another defect in many sizes of present production of molded pipe covering that is of, concern to the plant and to Sales. Too frequently the ends are not square. When detected the vare is given an end trim by hand. While vare corrected by this means is acceptable to most customers, it Is not to certain others, such as the ffavy for instance. The Havy has a specification calling for a length of 36 minus 0s. Detection of this defect in each and every piece is most difficult, and occasionally scae vare with out-of-square ends reaches the customer and is causa for complaint. Us casting method, itself Xa not responsible for this problem. The specific cause can be one of several. Among these are: Freesture and unequal drying of the vare, thin vare and small sizes in particular, while in the hot cylinder prior to the time that an atmosphere of . saturated steam obtains, resulting in excessive and uneven shrinkage; excessive build-up on, or Improper plscesezt cS, tfe. spacer*. qj gg^ gg/j^ The length of the mold cavity for pipe covering is only from 36-1/6" to 36-3/16*. This does not allow much for in process shrinkage (of which there must be acme to penait stripping), and for end trim, if a 36fl long finished piece with, square' ends, is to be obtained. At the time most of the molds were purchased, several persons, including the present Plant Manager at 3erlin, argued for longer molds with end trimming of all M.P.C., hut the decision was Bade to use the shorter lengths. It is generally agreea now that this was the wrong decision. The same mistake should not be mads again in the design of equipment for a new plant. Of the various types of imperfections that cause rejection cf pipe covering as off-ware, ^broken corners has almost always constituted the greatest percentage of the total. As would be expected, large sectional sites of the lesser thicknesses are particularly susceptible to this damage during strinping and subsequent handling in the plant. The sizes 6s x 1" ana 12 x li" are examples. Had molds of greater lengths been available, such of the ware with oanaged ends could have been saved by end. trimming. In an effort to get out of the difficulty caused by out-of-square ends without going to the very great expense of replacing the present molds with longer ones, the plant la trying out three different thicknesses of stainless steel spacers as replacements for the old and thicker black iron spacers. The lightest gauge that will stand up will be used. The additional length that will be gained is free 1/9" to 3/8*. General Engineering has the project for a conveyor to carry all molded pipe covering from the trim save to the wrap end pack area. On this conveyor all pipe covering will be md trimmed. Perhaps seme pieces will receive only a "kiss*, but even this would help some to correct the out-of-square ends condition. Bout**? Billets As the size of pipe covering decreases below that for 2" pipe, difficulties are experienced in forming it by the method discussed above. A major diffi culty lies in the tendency of the thin cores to deform during repeated runs. Accordingly, small sizes of pipe covering are now made at Berlin by cutting rectangular billets frem flat ware, trimming outer surfaces to give a hemi-cylindricai shape, and routing to the desired Inside diameter. This ware has a rough and unpleasing appearance, and is more susceptible to breakage than cast ware. For these reasons, there are serious objections to It on the part of sobs customers, and absolute refusal to buy by acme. Frcn the standpoint of manufacture, the routing method is a costly and wasteful operation. Plans are to abandon this method of forming if and when the method discussed below proves successful. Routing of I.D. in Solid SaifAbound Billets This method involves the casting of solid half-round billets and then form pipe covering by routing out the interior to the proper inside diameter. Thus the exterior has a cast surface end presents the same appearance as the other molded pipe covering being produced. Obviously, such less material Is wasted in routing to the interior dimensions only. 01 062 03SIH 38 The plant has demonstrated with trial aolds that solid half-round billets can be produced successfully. In principle, the mold is a rectangular pan vith a scalloped insert. Such an arrangement can be filled in the same manner as a flat ware oola. Studies are In progress at the plant on improvements that will make for easier stripping, handling of the ware, etc. But of major concern is the design and building of routing and triming equipment for billets of this nature. General Engineering has this project on its docket. After haring inspected a sample piece of ware that had had the I.D. routed by semi-mechanical means. Sales personnel have been pressing for the earliest possible production date. Vertical Casting or Tubular Holding For the past few Tears, and until January 21, 1959, certain small sixes were cast and prehardened in tubular form by means of original equipment developed for the purpose. The use of this equipment van discontinued as the result of conclusions reached in a study of the economics involved. There are three reasons why an unfavorable econemic picture was obtained: 1. An abnormally high percentage of off-ware resultea for production over extended periods of time; 2. Maintenance costs were high; 3. The equipment was designed primarily for demonstration, and not for production; accordingly only a single bank of molds was available for use. Conditions 1 and 2 above resulted because super-atmospheric pressures were involved.. Elevated pressures were employed to reduce cycle times and increase rate of production per mold cavity. But in so doing the problem of maintaining seals and preventing leakage, day in and day out, became a major one. A leak could be responsible for loss of slurry from the sold, and for boiling and blow-ups in the ware. Also because elevated pressures were involved, control and proper balance of pressures and temperatures throughout the system were critical. For exaaple, if at any stage the tesparature of the wire was such that the vapor pressure of the water within the ware exceeded the pressure being exerted externally on the ware, the ware would crack or blow up. When the equipment was in good repair, and the proper cycling, temper ature, and pressures were in effect, ware of excellent quality was proceed and the percentage of off-ware was exceptionally low. During the period it was in production, its behavior was similar to that of the little girl of nursery fame, "When she was good, she was very good; but when she was bad, she was horrid." Previous experience with vertical casting at the plant should not role out further consideration of the method vith certain modifications. Perhaps the use of elevated pressures is not feasible for production equipment. It may be better to east slurries at temperatures near the boiling point 01 062 03$5 29 of toter into vertical acids, saintain -than temperature in the cast piece t by means of hot water circulating around the sold and through the core, then eject the tubular piece after it has hardened sufficiently for safe handling. Equipment would be much simpler and easier to control than the former arrangement. Certain persons within the organization have seme definite ideas on a process of this nature. Pahco Caltemp Is made in all sizes by a saaswfcat similar method, so the principle is sot new and untried. The advantages of ary vertical casting- prehardening-ejection aethod ares low sold inventoryj and the fact that the sold does not accompany the molded piece through the cycle; with resulting saving of autoclave space and of heat that would otherwise be used in heating the sold steel. Press and Filter Method A press and filter method is employed by Johns-Manville for the pro duction of;?fcezmebe9tcs la this process a very dilute slurry (vater/aolida- approx. 18 to 20) is mixed, at a temperature of about 165F and then sent to tanks where the slurry is heated by the injection of live steam to about 20CF, and maintained at this temperature until a desired gel structure is obtained <2 to 3 hours). By the addition of the condensate from the steam employed in heating the vater/solids ratio of the gelled slurry at the end of the gelling period is about 2k or 2$ to 1. This slurry is then ready for the molding operation. At each press station there is a tank to receive the amount of slurry required for the piece being molded. The exact volume of slurry being received la determined by a probe for level control. This ancunt of slurry is then pressed and filtered in an elaborate mold at a pressure of 75 psi to the desired size and shape. Through the loss of vater by the press and filter action, the vater/solids ratio in the molded article is about 5 to 1. Since the solids are in a gal state, the molded ware possesses considerable cohesion and "green" strength. (Details of the J-H process is contained in the report, "Johns-Kanvllle D*.ernobeatos Plant Visitation", prepared by B. 5. Grant, July 10, 1958*) The advantage of this process is that it produces a product having excellent properties: low "k" factor, high strength and resistance to abuse, dimensionally' true, and pleasing appearance. Also, because of the high state of mechanisation, little of the human element is involved. The disadvantages are: 1. Offers little fieriM11 ty as to formulation; workable formulation is costly. 2. Formation of a gel of required properties is critical. 3. Molding stations are expensive and space consuming. it. Customer servicing is of concern because of the amount of labor and time required to make a acid change. 01 062 03A& ( kO Other Methods That Merit Further Study A number of other methods of forafng hare been tried ia the past to varying extents in the pleat laboratory and at the research laboratories. Certain ones, such as centrifugal casting, and continuous prehardening and forming, do net seen to merit further study for one reason or another. On the other hand, results vith others hare been sufficiently promising to afford reasons for further study. Among these ere? Filter press method (Denny) j extrusion of prehardened and plastic bodies to shape (similar to the forming of clay pipe)* pressing of prehardened light density flat ware to core material densities. Undoubtedly ideas as to other methods vlll occur as time goes on. 01 062 03S1) ^ { Chapter ?XXX a relieving the casting step in the Berlin operation, the slurry in the nolos Is partially reacted, and hardened to a state that considerable pressure with the iinger must be exerted to sake an impression. This is accomplished by exposing the ware to the conditions existing in one or the roar steam tunnels called Prehardeners. Temperatures of about 200F are maintained, which is near the optimum. Temperatures much in excess of this cause boiling of the slurry, and those lover than this decrease the rate or hardening to a point where it is slower than the pouring rate. Prehardener temperatures are controlled by means oT temperature recorders and controllers that actuate pneumatic steam values. Baffles prevent the direct impingement of the live steam on the molds, which would cause boiling of the slurry* The length of time required to preharden the ware varies with the thickness of the piece inasmuch as penetration of heat into the mass is involved* The extremes are a minimum of l.CC hour for ln thick ware to a minimum of 2.50 hours for 3n thicknesses* There are two malm reasons for prehardening the ware before it enters the cylinder. It reduces handling problems, and it makes the Interval of time between pouring and autoclaving much less critical. When the molds contain a fluid slurry, extreme care must be exercised In transporting them to, and loading them in the autoclave* The facilities at Berlin are not conducive to smooth and gentle handling of the molds between the time they are filled and the time they come to rest in the cylinder* Eaylo-20 slurries do not preharden, and with the smoothest handling possible under the conditions existing, a great amount of off-ware results because the slurry shifts freo one end of the mold to the other or actually spills from the mold. The defect appearing in the product is listed as BH*S*K*B (not enough material). On the other hand, idiea the slurry in the molds Is prehardened before the trip to the cylinder, it can withstand a reasonable amount of abuse. This is dona for all Kaylo-10 ware both pipe covering and flat ware. The other important reason for hardening the slurry soon after easting is to minimise bleeding of water from the cast piece and/or settling of the solids fra suspension. The extent of this action, of course, increases with time, and is more pronounced in large sixes in ifcich the head of the fluid slurry is high* Scheduling of the cylinders so as to have one available to receive a train of filled molds just as soon as it is ready for autoclaving is seldom possible if the cylinders are to operate at peak efficiencies without undue downtime. Accordingly, a train of filled molde may have to be held on the floor for periods up to about four hours before a cylinder is available for this train calling for a definite autoclaving cycle. Ware in a prehardened state can withstand this treatment without damage. In contrast, the length of time that noa-prehardaned ware in large sizes can 01 062 03as f ^ " t ( U2 rmnir\ outside tee cylinder without adverse effects is extremely limited. Within a relatively short time, discontinuities appear in the tors of reins of water, which cany ever into the finished product as cracks, and tears . or separations? or the slurry may subside to an extent that the prescribed dimensions are not met in the product. There is still a third advantage to he gained by prehardeoing. it peak rates of production, a fresh train of ware enters the cylinder within admites after a processed train has been pulled. Temperatures of the cylinder shell under these elrcmstances are in excess of hOOF. From the time of entrance until an atmosphere of saturated steaa is created within the sealed cylinder, the sold metal receives a great amount of heat by radiation. If the slurry Is still in a fluid state at this time, there is great danger of boiling occurring at the slurry-mold interfaces, resulting in pitted and rough surfaces of the product. When the slurry is prehardened, the risk of this happening is minimized. Surface boiling is sometimes experts* ed with the Kaylo-20 slurries, but the other problems which are attendant in the processing of a fluid slurry under existing conditions at Berlin are fax more serious. Every effort is made to get the cast slurries into the cylinder as soon as possible after pouring, but with the complications involved, too long a time fre quently elapses. Since the Kaylo-20 products are made on the same lines as Xaylo-10 ware, the latter in all stages of the process must be out of the way and not act as an obstacle in the path of the Kaylo-20 material. Working back from the time that a cylinder is scheduled to be available to receive a Kaylo-20 train, the following must be taken into consideration: the mixers and lines must be washed free of Kaylo-10 slurry, the batch weighed out and mixed, molds stripped end available on the pouring line, the Kaylo-10 ware in process ahead sufficiently prehardesed and moved out of the preharaener, ana the cylinder emptied and made ready to receive the cars of Kaylo-20 ware. Granting that all of this may be done effectively in proper sequence with perfect timing, the molds containing the fluid Kaylo-20 slurry must still be transported over a devious, rough, 150-foot-long path to the cylinder. If Ksyio-20 pipe covering is to be made consistently with low percentages of off-ware, a* separate line free mixer to cylinder is essential. As it is now, it is produced oa a line designed for a slurry of greatly different properties and behavior. Passage througn the prehardener is an example of the incongruity involved. Heating of the Kaylo-20 slurries in the prehardener not only does not accomplish the ends for which the treatment is designed, but actually has a detrimental effect. Beating to temperatures in the neighborhood of 200F results in more fluid slurries that are more prone to leak from the molds and also to slosh during movement of tne molds. Returning to the prehardening of Kaylo-10 pipe covering, this would sot be essential in the production of many of the small sizes if it were possible to autoclave the ware within about two hours after pouring. Sizes up to about 8 inches exhibit relatively slow rates of bleeding, and can be transported without damage with a reasonable amount of care. This is men tioned because tests have shown that ware which has not been prehardened exhibits about 251 higher strengths than ware which has undergone this treat ment. In a sense, then, preh&rdenlng is a necessary evil with conditions as they 01 062 0359 Probably because there is no alternative in view of the limited space available in the Berlin plant, a car of colds is pushed into the prehardaner as soon as it Is loaded* In this manner, the train is cabs op in the prehardener. This is had practice for several reasons.. In the first place, full advantage is not taken of the purpose for which the prehardener is designed* The capacity of the prehardener is governed fay tae time required to preharden the last car loaded* Therefore, it is serving merely as an accumulator for aXITpreceding cars. In as far as functioning as a prehardener, the time curing which it is being loaded is wastea. A second bad feature of car by car loading xs the loss of heat during the tiae the door is open to receive each and every car of the train. Third, it is not possible to achieve uniform prehardening throughout the train. Obviously, the -ware in the first car receives more heat than that in the last car* But perhaps of greatest significance is the bumping and Jarring which soft, partially prenaroened ware receives as each additional car meets and shoves those ahead of it in the prshardeser. At an intermediate stage of preharaening, tne ware has lost its plasticity and anility to move with and recover from mechanical shock, and does not yet possess sufficient strength to resist certain disruptive forces. Under forces that tend to move the partially prehardened slurry or to shift the core, cracks are apt to occur in the ware* Presently about 20% of the off-vare is due to cracks. There is every reason to believe that most of these originate in the prehardener. Katurally, the larger sizes of the lesser thicknesses are sore susceptible to damage. This cracking of the ware during the prehardening step woula not be the problem it is if means were available for smoother handling, such as perhaps a monorail system. The obvious way to overcome the several disadvantages inherent in present practice would be to accumulate an entire train outside the prehardener and to move the train as a unit into it. This does not appear possible with the restricted apace available at Berlin, but should be con sidered by all means in the design cf a new plant* Prehardener capacity pretty much controls the rate of production. An advanced state cf hardness must be. obtained| otherwise a high percentage of cracked ware results. Berlin has from time to time lengthened easting prehardenars to meet the ***/* of increased production* The limit as far as available space is concerned has been reached on 3 of the k units* In the design of a new plant, it should be made certain that prehardener capacity is in excess of expected demanda by a safe margin* The degree of latitude in formulation also la dependent upon prehardener capacity. The stiffening and hardening of the slurry at temperatures in the neighborhood of 200F is the result of chemical reaction between the dfatomaceous earth fraction and the lime of the batch. It follows that formulations containing less diatomaceous earth in proportion to crystalline silica, all other conditions being the same,.will preharden at a slower rate* Studies have shown that the limiting temperature the product can withstand is raised by a decrease in the proportion cf diatomaceous earth in the formulation. 01 062 03iO Presently Xaylo-10 thermal Insolation shews a shrinkage of about 1.3* after being heated for 24 hours at 1200F, The ratio of diatomaceous earth to total silica in the batch is 0.7. Available data indicate that if shrinkages of this magnitude are to. obtain at 150C instead of 1200*?, only anout k0% instead of 70S of the silica of the batch can be in the fora of diatcoaceeua earth. This change would reemee the rate of preh&rdening, with currently available raw materials at least, to a point that the output of the present prehardeners would be drastically curtailed. On the other hand, if the prehardeners were longer, or there were sore of them, making It possible for the ware to remain in the prehardeners for greater periods of tfcw, reductions could be made in amount of diatcsaaceoua earth without the pre hardening step becoming the bottleneck in the process. In determining prehardening capacity for a new plant, the prehardeners should be deliberately over designed, perhaps two fold, on the basis of the rate of prehardening of the present slurry. This would eliminate the restrictions on fonrolatioa now l&posed by esdatiog equipsest. 01 062 033J u5 Chapter H AUTCCIAVEJG AMD DHIITJC Autoclaving of Kayio predicts is accomplished In SID cylinders* 5H is a convenient term coined to designate a cylinder in which simultaneous induration and drying of hydrous calelea silicate products can be accoap] i shed. the strict meaning of induration is'hardening* la the processing of Kayio products, it is the step in which the lime, silica, and water are ccabined to fora the hydrous calcium silicate desired in the end product, the formation of this hydrous calcium silicate structure brings about the change from a soft, plia&le mass to a rigid body; hence tbs term induration* The reaction of the three cospeneat* to form the desired hydrous calcium silicate occurs under conditions of a steam atmosphere at elevated pressures and temperatures* Actually, it is the heat that brings about the combination of the eexponents, but since water is one of these, a steam atmosphere is required to conserve this ingredient in the reactive mixture. A ccaparison of the formulae of the two hydrous calcium silicates in question, uCaO.5SiO2.5H2O and.5CaO*5SiOg^O, with the batch formulations will reveal that the amount of water in the batch is greatly in excess of that present in either of the two compounds* This situation makes it possible to begin the drying phase of the autoclaving cycle before the combination of lime, silica, and vatdr is complete without any danger of insufficient water being present for the reaction* Thus it is possible to carry on the induration and drying simultaneously - a *5ZD* operation. Drying is accomplished by subjecting the ware to an atmosphere of super heated or unsaturated stems* Each cylinder Is equipped with radiators heated by a flow of Devtherm liquid at a temperature of about 600T or somewhat higher and a fan at one end to circulate the heat through the train of ware* At a given point in the specific cycle being employed, the fan is turned on* The heat being thus supplied raises the temperature of the atmosphere surrounding the ware, causing water to evaporate from the product* In a closed system, an equilibrium would soon be established. That is to say, for any given temperature the pressure would rise to the value equal to that of saturated steam at that temperature* When the equilibrium, or sat urated steam, condition was reached, evaporation of the water from the ware would cease. But in the SID operation, the pressure is maintained at a constant value by means of a control valve through which the additional steam being generated escapes frem the cylinder* In fact, the SID cylinder during the drying phase of the cycle functions as a boiler, the water for the generation of steam coming from the ware* This is literally true because the steam generated in the SHt cylinders is fed into a lew pressure system which serves to supply steam for the prehardeners, to heat the plant, etc* A SID cycle consists of four phasest time required to get up to pressure; time at pressure without the fan on (saturated steam atoosphere); drying time (superheated steam atmosphere); time required to bring the pressure down to atmospheric pressure* 01 062 033a U6 The first, er up to pressure, phase is fairly constant for a given cylinder and load and varies from 25 to 30 minutes for pipe covering, and is 1 hour for flat ware trains. A controlled rate of pressure rise is accomplished by a pneumatic control system composed of a time-pressure cam which operates the set point of the pressure controller. The pressure controller throttles the steam inlet valves to obtain the pressure rise cut on the time-pressure cam. The second, or indurating, phase is the period during which the ware is subjected to saturated steam at a constant and definite pressure and temperature. The length of this phase of the cycle is determined by a combination of many factors. Those that must be considered Includet Nature of the hydrous calcium silicate desired - Kaylo-10 or Zayio-20; the thickness of the ware; the type of product - core, pipe covering, or block; desired end moisture content - "wet" or adry*j the pj^sical structure of the train; the operating pressure and other characteristics of that particular cylinder. The indurating phase may vary in time from zero to 1 hour. In general if conditions are such that an artended drying period, the next phase of the cycle, is to be in effect, the indurating phase is shortened accordingly. This is because there is ample water present for the chemical reaction that produces the hardening or Indurating of the ware to continue far into the drying phase. The theory of SID autoclaving presumes that, at the start of the cycle, conditions are favorable for the reaction of lime, silica, and water to advance to the point at which a rigid structure of hydrous calcium silicate has been set up before there is any significant loss of water. Actually, this condition does not obtain with certain sines of pipe covering in 1 inch and 1-1/2 inch thicknesses under present plant practice and rate of production. Within a matter of 20 minutes to one-half hour, the processed train , is removed fros the cylinder, a fresh train put in place, and the cylinder door closed for the next cycle. During this time, the hot Dowtheim continues to circulate through the coils, and, of course, the cylinder vails remain very hot from the previous cycle. Although saturated steam is employed to bring the cylinder up to pressure, the temperature .of the atmosphere within the cylinder is considerably above that of saturated steam at the pressures existing at the beginning. Thus a saturated steam atmosphere is not created, and as a result, premature drying of the thin sections of pipe covering results. This often causes excessive in-process shrinkage, and sometimes soft ends, where drying is more pronounced. Attention is now being given to means of correcting or minimising this condition. It has been the practice to keep the steam trap at the bottcms of the cylinder open at all times. It is now proposed to close the trap during the up phase and the indurating phase of the cycle, and to open it when the drying phase begins. This is as added operation and must be given close attention, but it is hoped that the results will justify it. The theory is that the incomi ng steam will condense on the relatively cool molds and cars, and this condensate then held in the cylinder to contribute to the humidity instead of being allowed to escape through tbe trap. 01 082 03S3 r l " v ( k7 l great mount of attention must be given to the make-up of a train of ware going into a cylinder. Ware of the sane thickness, for the most part, goes Into the sane train. But drying characteristics depend upon the shape and other dimensions, as well as on the structure of the loaded car. Ware on cars near either end of the cylinder is in a position more conducive to rapid drying than that on cars near the middle of the train* Consequently, the cars of vare sore difficult to dry are placed at the ends of the train. Care oust also he exercised in the location of the cars in the train so as not to create undue obstruction to desired flow patterns within the cylinder. At the end of the prescribed Induration period, the fan at the end of the cylinder is turned on to carry heat free the radiators containing hot Bow-therm fluid over the vare. the length of this phase of the cycle is determined pretty such by the same factors as those for the length of the indurating phase, the Process Control Supervisor and the Quality Control Supervisor jointly evaluate the cylinder cycles each day from a mass of basis data accumulated in the operation. Changes are made in the cycles where and when indicated to be advisable.. Of particular importance in this connection are the moisture contents of the vare throughout the train and the strength and high temperature shrinkage of the product. The percentage of shrinkage shewn by ware after having been subjected to a temperature of 1200? for 2k hours is an excellent measure of whether or not it has received adequate processing in the autoclave. High shrinkages are evidence that an opportunity had not been afforded for sufficient reaction to occur, and are even more sensitive than strength data in this respect. The objectives in cycle design and adjustment are to produce vare of uniform high quality and of uniform moisture content. "Cry" cycles are employed for pipe covering in ln and 1-1/2 thicknesses, which means that all vare as it cernes fren the cylinder should have a moisture content very close to 25% Ware of greater thicknesses (except core material) is on vet" cycles, which are designed to yield vare having a moisture content near 65. Ware from "vet" cycles must receive additional drying in one of the four auxiliary driers. These are rooms In which a flow of air at about 300F is maintained by unit heaters. The sole purpose of this practice is to increase production from the cylinders that are available at Berlin. Crying Is not as efficient in the hot air driers as it is la a SID cylinder, but this scheme does pemit acme shortening of the cycles in the cylinders, resulting in more cylinder loads or cycles per day. The end achieved by the use of the four driers is about equivalent to that which would result from the addition of another cylinder with all operating on "dry" cycles. Were this additional cylinder available, there is little doubt that the production of the sane amount of dry vare could be accomplished more econom ically than Is now the case. Drying in the SID operation is acre efficient than drying by hot air for a number of reasons. In the first place, superheated steam has a much greater heat content than air at a gives temperature. It also has a great 01 062 033V thirst or affinity for water$ that is, it is the nature of steam to Hwant" to go to the saturated state. Also of great significance is that temper*, stares of 500 to OQC9? art sore feasible in the SID cylinder than in a hot air drier. High temperatures for the drying of Kaylo ware are advantageous because a lesser quantity of heat is required to evaporate a given amount of water (heat of vaporisation decreases with increase in temperature), and also because the viscosity of the water is less, thereby permitting the water frcn the interior of the piece to migrate more readily to the surface where evaporation occurs. Drying in the cylinder has the advantage also in that the ware is already hot throughout at the start of the drying operation and does not have to be brought up from room temperature. The mechanism by which Saylo ware dries is not generally understood* Practically all of the moisture is evaporated at or near the surface. Within the structure of Kaylo products is a network of extremely fine, continuous capillaries, which at the,start of drying are filled with water. The diameters of these capillaries are so small that the vapor pressure of the water in them is depressed.tremendously. Accordingly, the boiling point of the water in these capillaries is extremely high. Therefore, there is every reason to believe that water does not evaporate from the surface of the water deep down in one of these fine capillaries. To escape it must migrate through these narrow tubes to the surface, and evaporate at this point. This drying behavior explains why Sayle-2Q ware dries so much Taster than does Kaylo-10 ware uaoer the same conditions. The xonotlite structure of the former is more coarsely crystalline than the tobermcrlte structure of the latter. This results in capillaries of larger diameter that can deliver moisture to the surface more readily. Consequently, the aylo-20 product dries in frcmt 1/2 to 3/b of the time required for a comparable piece of K&yio-iO ware. The question has been raised as to why make-up air is not employed in the hot air, auxiliary driers at the plant to reduce the relative humidity of the drying atmosphere. The answer to this la it is more important frisa , the standpoint of drying to maintain as high a temperature as feasible than to bring about a reduction in relative humidity. In fact, the majdmua relative humanity that can obtain, in the driers operating at 300? and at atmospheric pressure is only about 20%. Under these conditions drying from the surface will be very rapid, and the time required to dry the piece as a whole depends upon the rate of migration of moisture from the interior to the surface. As mentioned earlier high temperatures speed up this migration. ?or the reasons Just discussed, a plant should not be designed to include aujti.ld.ary drying as an integral part of the processing. To be sere, provisions should be made for such drying in cases of emergencies, and for drying of a wet train or portions of a train that result occasionally for one reason or another. For cases of this nature, it does not appear feasible to re process a train in the cyl inder. On the other hand it should prove econom ical in the long run to have a spare or stand-by cylinder that could be put into service when another is down for repairs or cleaning, rather than attempting to make up the loss of production by going to *vet* cycles on all the other cylinders. When no spare cylinder is available and auxiliary ( 01 062 u9 driera are already being used to near capacity {as Is tie preset situation at Berlin), it is the natural tendency to continue using a cylinder long after a repair or cleaning job has been indicated* Prolonged operation of a cylinder that has lost much of its efficiency because of need of repair or cleaning, is, of course, costly. Returning to the SID cycles, after the dzying phase is cmpiete (the moisture of the we reduced to a prescribed amount), the timer starts the tine-pressure can which operates the vent to the low pressure syslen valve and starts to depressurize the cylinder. After the pressure reaches that of the low pressure system, the controls switch from the vent to the low pressure valve to the vent to the atoosphere valve to continue the lowering of the pressure in the cylinder. At this point the fan is also stopped. The pressure continues to decrease until atmospheric pressure is reached and the cycle completed. The standard down tines with pipe covering loads are 25 minutes for each of the three 175 psi cylinders, and 30 minutes for the two 200 psi and the seven 250 psi cylinders. The rapid rate at which the cylinder can be safely brought down from pressure is maos possible by the ware being in a dry state. Formerly when ordinary saturated steam autoclaves were in use, the rate at which the pressure was reduced was held at 1 psi/aimutej at faster rates the saturated ware would blow up. Herein lies another great advantage of the SID over ordinary autoclaves. With SID cylinders dry ware can be produced at a considerably greater rate than can wet ware by saturated steam vessels. Then, of course, provision has to be made to dry ail of the products frcsii the latter type of cylinders* As mentioned earlier, hot air drying is a prolonged and inefficient means of accomplishing this for hydrous calcium silicate products. It is of interest that the J-H plant at Hanville has 16 crying tunnels, 170 feet long, equipped with h tracks per tunnel, having a total capacity for 1,500 cars of ware. This plant has nine cylinders of the conventional type. The 250 psi cylinders at Berlin are such more efficient than the 175 psi ones* The latter are remnants of earoy operation which have bees con verted to the SID type. Os an average, the total cycles in the former are shorter by: 1 hour for 1-1/2" thick ware, 2 hours for 2-1/2" to 3" were, and 5 hours for 3-3/ha to u-l/h" thicknesses* Just what operating pressure would be the most favorable is plant practice remains to be determined. There is little doubt that it will prove to be higher than 250 psi, but how much in excess of this pressure Is a matter of pure speculation* As the operating pressures (and temperatures) increase, the rate of reaction lncresses, as should the rate of drying. While the degrees of superheat at 600F (difference between 600F and the te&perature of saturated steam at a given operating pressure) will decrease as the operating pressure increases, this should not in itself result In slower drying within practical ranges of pressures. The higher temperatures that will exist throughout the ware should more than offset the effect of fewer degrees of superheat. v 01 062 0336* 50 On the other aide of the Picture is the longer time required to bring the cylinder op to pressor* and to depressurise it at the end of the run. The tine consumed in accomplishing these two phases of the cycle could be appreciable at certain high pressures, and more than balance the gain in time possible for the indurating and drying phases of the cycle. The Research laboratory at Newark is obtaining an experimental SID cylinder capable of operating up to 500 psi. For the first tine equipment will be available to conduct experiments to determine optimum SID conditions and to obtain sane badly needed information. It is likely that the limiting factor in regard to operating pressures will prove to be the cost of the equipment designed to handle such pressures aa veil as certain other added costs involved is operating at pressures which are unccssoa for vessels of this sire. \ 01 062 0331 51 Chapter Z OPERATIONS SUBSEQUENT TO AUTCCLA7XN0 After the ware emerges frcs the autoclave, and is in a dry condition, it most undergo tramming and finishing, warping, packing, and storage in the warehouse. Of course, the ware Is inspected by Quality Control at all of these stations. If discolored or rough surfaces are detected at the trim saw, this vare is taken out of the line for hand cleaning and smoothing of the surfaces before it is sent on for wrapping. the handling of the vare after it leaves the aatoclsve Is the most inefficient of all of the operations at Berlin. This is probably the natural result of the plant haring evolved for the most part, from a sand-lime brink plant to one Saylo products. The inefficiency is strikingly evident vhes one considers that a given piece of vare coming from a cylinder on a vet" cycle is likely to be handled or removed frees one location to another, singly or la a container of acme sort, 16 separate times before It is on its vsy to the customer. A comparison of Berlin and Hanrille operations is this area reveals a startling contrast. It asst be said that management of Berlin Is aware of these deplorable conditions and has given GFB Engineering the project for conveyor and equip ment from trim saw to wrap and pack area. On the conveyor all pipe covering mill be end trimmed, if for only a kas to produce square ends. On the sane conveyor, the pipe covering will be brushed to raaeve discolorations and tops resulting trm dirty molds. The adhesive will be applied mechan ically. The wrapping will be done by hand, and carton sealing will be accasplished by top and bottcaa sealers. Ibis project is excellent as far as it goes, bat a material handling engineering study should be made of the cesplete operation to determine hew the general condition at Berlin could be improved, and to cose up with recommendations in this respect for a new plant. That there are 23 lift trucks continuously moving throughout the Berlin plant in an apparect helterskelter fashion, is illustrative of the problem. Aside from all other obvious undesirable aspects, a cor.siderable amount of damaged ware results frem this manner of handling. % 01 062 0338 \ ( 52 Chapter XI AUIILim OFSRATICtE Naturally, then are many supplementary operations connected with the proonetion of Kaylo products that are more or less ocanon ist the manufacture of any article. These vlll not he discussed. There is, however, one such operation that la peculiar to the subject process. That Is the cleaning of molds* The method now employed involvea the use of as inhibited acid to dissolve the adhering calcium silicate. Back in 1550, as part of the investigation of SIP possibilities, 0-1 Besearch conducted studies of various sold cleaning methods. The reooBBendation was made that acid cleaning he dropped from ary further consideration becanse of the many objections inherent is this sethod. For sou reason, probably because of a relatively high initial cost of an alternative sethod that was recommaded, this advice was unheeded by managesent and acid cleaning was put into operation. The result has prompted the Plant Manager at Berlin to write oa April 8, 1555: 9The cleaning of molds with the use of acid must be eliminated at the earliest possible time for two reasons: first, the mold equipment has now been subjected to acid attack for sufficiest years that the rate of deterioration is becoming greatly accelerated. Unless this is stopped, large replacement coats for molds will be encountered. Second, everyone is familiar with the aforementioned labor costs* incurred, which cause is based on the use of aeid for mold cleaning. Ve had a Fangbors** representative in last Friday, and all past work that was dene was covered in his files. This goes back . as far as 1550, when Research of 0-X conducted the experiments. The cleaning of the molds will be done by a soft abrasive blasting, using walnut shells. Faagbora has had mazy installations of this type of blast cleaning* They also have the design, which was designed long before and never followed through-- This reduces all of the etching of the shells (molds) and also eliminates the cost of acid and allied material cost. It will eliminate the manpower aforementioned, as well as reduce manpower in Mold Repair for cleaning and repairs necessary. It will increase the run life of the molds before gleaning is necessary* The blasting Is done with rotating wheels throwing the abrasive against the sold rather than using high pressure air, which calls for a large air compressor cost of installation and operation. Ve are sending out a shell (mold) for them to again check the buildup (deposit) to make sure that the machl ns will efficiently do the job. Cost of band cleaning stains and removing rough surfaces, both the result of acid cleaning of the molds, from a large portion of the ware. *?he method recommended by 0-1 Besearch* 01 062 0331? S3 This is a four-wheel job ana the cost 1a roughly $10,000 per wheel, which of course Includes the entire installation, however, it should be im the area of $35,000 or a little less* The machine has to be set la a pit and will hare conveyor holding of molds into, through, and out of the blast cleaning area* We will follow this project diligently and with dispatch, and as soon as design cost, tine of manufacture, installation time and cost are secured will follow through with a 901. Along with the acid cleaning, the other methods studies by 0-1 Research, and not recommended for one reason or another, were*. High pressure steam* high pressure water* mechanical brushing* supersonic vibration* The cleaning of molds would not likely be a problen of any consequence if they were to be mads of stainless steel* 1 few replacements have been constructed fairly recently of this metal, and the performance is respect to buildup and the surface of the ware has been remarkable* After about two months of service, the metal still exhibits a mirror-like appearance* If the present behavior continues over a prolonged period of time, the ecenemies involved should be evaluated. An unfavorable answer would probably result in the Berlin situation, in that it would likely be poor aconemy to merely replace the black iron shells with stainless steel, thus duplicating molds that are too short. But it may be a different story if new frames and new molds were to be fabricated for use at a different location* \ Oi 062 03VO Chapter XII INDICATED MODITXCATJCNS 0? FHS52NT PROCESS A2 EQUXrKSN? 5u At no comparable period Is the history* of the Kaylo operation hare ao many changes and improvements been Bade as is the past lev jaonths and weeks. Although the wilting: of this manual has been done at intervals over a period of no sore then six weeks up to this point, many of the changes indicated in previous chapters as being desirable have already been accom plished and in operation. Furthermore, several others are scheduled for early completion. On the assumption that these, too, will be In effect before this Manual is in the hands of the reader, no further aention will be Bade hare* The items that are listed in this chapter are those likely not to be in operation in the very near future because of the magnitude of the project, lack of manpower and/or space at Berlin, or other valid reasons for the delay. At the risk of appearing repetitious and redundant, mention will be &ada of certain subjects for the sake of esphasiting their importance. They should be considered from the standpoint of feasibility of incorporation at Berlin, and should by all aeans be takes into consideration in the design of any nsw plant* In this latter connection, Berlin experience is providing and will continue to provide, valuable information in respect to process and equipaent* Contrary to the situation in many plants, there is very little or no conserv atism,in the attitude of the management of Berlin* Bather than being averse to any change, there is an expression of desire to try anything new if it has at least a 50-50 chance of being favorable frcm the standpoint of cost savings, increased production, or quality of the product. With this foreword, further discussion of certain itmss follows. Separate Production line for Kaylo-20 Ware In the present set-up, Kaylo-20 ware is aace on the sene line as Kaylo-10 products. This all too frequently results in an excessive amount of off-*are. The Kaylo-10 line is designed to handle prehardened material. Kaylo-20 slurries do not preharden. The long route that the aolds filled with a fluid slurry smart follow - including passage through the prehardener - results in shifting of the slurry, causing the end product to be out of dimensions. Not only this, but the Kaylo-10 slurry and ware in all stages of the process, frcm mixer to cylinder, must be cleared out of way before Kaylo-20 production goes through* This results in waste of tine even under the best scheduling possible* The line for Kaylo-20 products should, of course, not include a pre hardener, but should provide a short, smooth passage frcm pouring station to the cylinder. Oi 062 03V/ 55 Separata mixers for Kaylo-20 slurries would eliminate the necessity for vashlng the mixers end piping free of Kayio-IG slurries when runs ere to be made, They would also make possible a reduction in the number of batching operations. Under the present practice, tfis size of the batch must be tailored to the volume of the molds in the particular train being processed at the time. Since Kaylo-20 slurries do not preharden and may be held indefinitely, a large quantity of Kaylo-20 batch could be mixed and drawn upon as needed. It was mentioned 1b a previous chapter that movement of materials ware throughout the Berlin plant Is acccaplished by a fleet of 23 lift tracks, . and that a materials handling engineering sta<$y is indicated* Discussion here is limited to the handling of the filled molds froa pouring to cylinder, because rough handling during this stage of the process contributes to offware. The sloshing of the fluid Kaylo-20 slurry was mentioned In the section above, but damage can also result to Kaylo-10 ware. At certain intermediate stages of prehardaaing, Ssylo-10 material has lost Its plasticity but has net yet attained any appreciable degree of cohesion and strength. Mechanical shock can easily cause cracking. Is the present practice, filled molds are loaded on cars with flanged wheels to run on a track through tne prehardensr. A train of cars is made up In the prehardeaer, and the ware receives bumping and jarring as each car is added to the train* Once the Kaylo-10 ware has been prehardened sufficiently, it can withstand a reasonable amount of mechanical shock, so smooth handling of the ware in the prehardener is of greater importance than on the way from there to the cylinder* But smooth handling of the fluid Kaylo-20 slurries Is required over the entire route. A different and smoother means of carrying both Kaylo-10 and Kaylo-20 ware through the prehardener to loading la the cylinder is indicated. A monorail system, for example, may be the answer to the problem. Accumulation of a Train Prior to PrehaMeni.^y The disadvantages inherent in the practice of *feiHng up the train of ware inside of the prehardener have been discussed In Chapter VIXX. The favorable results likely frost accumulating the train prior to entrance into the prehsxdener were also outlined* Prehardeners have in the past bees the governing factor affecting the Ate of production, and can also limit the latitude of batch formulations if the capacity for output is restricted. Under present conditions of formu lation and Ate of production, the prehardeners are in fairly good balance with the rest of the processing. But conditions could change and the pre hardener capacity could bscane a bottleneck. For reasons discussed in detail previously, a prehardener would function sore effectively if it were to receive an entire train of ware as a unit instead of one car at a time. That is to say, a given prehardener could preharden a given train of ware in a shorter period of time if means were provided for the make-up of the train before entrance into the prehardeser. 56 Along with as arrangement of this nature, means should be provided to pewit the by-passing of the prehardener if and when the else of ware and iifey q * cylinder indicate such is possible and advisable* This in itself would have the effect of increasing prehardener capacity in relation to the other production units* Reserve SIS Cy**der Capacity At present, la an effort to obtain the utmost in production frcas existing cylinders at Berlin, most of the ware is taken from cylinders when the moisture content is about b$%. Shin ware then must be dried further in the such less efficient atudliary driers. In addition to this loss in efficiency, the cost of extra handling of the ware oust be considered* If an additional S2L cylinder were available, the same amount of dry ware could be produced at less cost* It would likely prove to be good economy to have a spare cylinder availaole for use when one of the others is does for repair or cleaning* At present, the withdrawing of a cylinder frcm production is postponed as long as possible because of the production problems involved. In other words, it is kept in operation long after a decline in operating efficiency is evident* With a spare available, all cylinders could be maintained at top efficiencies without interruption of production* This spare cylinder need not be down all of the time it is not called upon to replace another, but could be used to receive at least a portion of the Kayl~20 ware poured on the separate Kaylo-20 line mentioned earlier* However, there should be a clear understanding among all concerned that its chief function is that of a spare, and should not be infle^bly tied In with production* Auirt 71 ary Driers It la sot the intention of the preceding section to imply that some auxiliary drying facilities are not necessary* The point is that it is not good practice to employ this type of drying as a routine matter* On many occasions some of the ware casing from a "dry41 cycle will have a higher moisture content than is permissible for dry ware end this ware will have to be given further drying* Mechanical failures, failures within the Dowtherm system, etc*, could seoetJaes result in as entire train of vet ware* Under conditions such as these, it is more feasible to dry in an auxiliary drier than to return to a SID cylinder. Mold Cleaning The present method of cleaning molds with acid is costly, and after a time results in serious dosage to the molds* An alternative method must be found* Studies of several years ago indicated that an effective and safe job could be done by blast cleaning with a soft, organic abrasive* The plant has just recently begun further investigation of this method* 01 062 Improvements on the louring Line There are several improvements indicated on the pouring line, and concerted aborts are being maos to put then into effect. Among these are: Keens for accomplishing couplets removal of Keylo chips and dust from mold cavities prior to filling; mechanical oiling of molds; full length pouring devices; mechanical screening* Perhaps the greatest benefit to be derived frees these items will be the elimination of much of the human element and the role it plays on the pouring Hn* in respect to rate of production ana the quality of the ware. Molds She major shortening of present pipe covering molds is that they are too short* If tbs molds vere longer (in the neighborhood of 3?*}# all pieces of pipe covering could be given an end trim* lees off-ware would result, and even passable ware would generally be improved in quality* The economics should be studied of constructing the shells and cores cf pipe covering molds of stainless steel* Trials in progress indicate 1agfr of attack and freedom free build-up* Preference of stainless steel over black iron may depend upon whether or not acid cleaning is continued* 01 062 03Vy iI K Chapur XXIX PBBTTMVTHT KSPQB2S Several detailed reports have been issued that ere pertinent to the subject setter of this manual* Those that ere seat closely related ere listed belotf* Copies are avail able et the desk of the author of this manual* end another set is on file at the Berlin plant* Title Author Date Developuest of and Experlaects vith the b1 x 21* 5S> Cylinders at Berlin Clawace D. Pavllnki 6--1--52 Development of Xaylo Batnh Mining Procedure at Berlin Plant Harold F. Zink 6-15-54 Effect of Asbestoa Variations on Physical Properties of Xaylo Thermal TnmilatiOT) Establishment of Cycles for 1** 2", and 3* Pipe Covering In the SXD Cylinder at Sayrrrille, V* J* D* L Bishop Harold ?. Zink CD1 U-h-55 Factors Affecting High Temperature Shrinkage of Kaylo Therms) Insulation D* L* Bishop Factors Affecting Thawnal Conductivity of Kaylo V* C* Taylor Factors Contributing to Off-ware at Berlin Harold F* Zink Investigation of the Effect of Variables In the PrehArdensr deration on the Quality of the Ware Harold F. Zink 4-6-56 8-20-5? 5-7-54 8-5-54 Johna-KanvlUe Tharnobesto* Rent Visitation B* S* Crant 7-10-58 Saylo Mold Design, Filling, Cleaning, Stripping, and Lubrication Clarence D. Pawilckl $-1-52 Kayla Manufacturing; Process and Operational Control Kayla Ban Materials and Processes C* F* Silbfood 6* L* Salousek 6-01-56 10-13-52 Observations of the Flat Van Process at the Berlin Plant During the Weeks of Hcveaber 9 and Hoveaber 30, 1953 Harold 7* Zink 12-22-53 01 062 03</5 *t 59 Physical and Chemical Properties of Saylo Products Qm L Kalousek No, 1 Production Line Training Manual A D. Denny So. 2 Production Line Training Manual A, B# Denny Renew of Berlin Plant Operations 0. V* Pfeifer SayrerUie SID Demonstration Plant; Backgrouna, Design, arid Performance Clarence D. Pavlicki Studies of the Effect of Reactivities of Various Diatoaitea in the Reactions of Formation of Sayl ana Kaylo-20 A. S. Ayiah Studies of Molded Pipe Covering Gff-wre at Berlin Plant 8* 24 Bishop Study of Molded Pipe Covering Off-ware at the Sayrevalle Plant W. C. Taylor Study of SID Cycles at Berlin Plant and Other Factors iffeoting the Quality of the Ware Joseph Scovronak The System Liae-Altanina-Silica^fatar ana Applications to Kaylo Products G* L. Kalousek The System Idae-Silica-Water Qm I. Kalousek Trial Runs of Zonotlite Eayl at the Berlin Plant, and Properties of the Product Om Taylor Vertical Casting, Prehardenlng, ana H. F# Zink Ejection of Xayle Molded Pipe Covering C, D. Fawlicld. Vertical Casting, Prehardening, and .Ejection of Kaylo Molded Pipe Covering C. D. Pavlicki Section II H. F. Zonotlite and Lepiali Zayio Products Qm tm Ealousek 10-13-52 5-l?-5h 2-22-5k 8-30-56 8-1-52 1-28-58 3-16-53 12-23-52 1-21-5U 10-13-52 10-13-52 3-5-55 5-T-53 10-19-53 10-13-52 01 062 Q34fe \