Document gayJ3bLN1YDyERa9BdDy0ZMe

PLAINTIFF'S EXHIBIT w.y. UC-2248 te^: , Upon PHysicaf-.P^rd^j^^ BByy MM.. Sa.. MBAADUOULLBMTl * - ' ,>'. (Annual General Meeting, Toronto, Ont., April, 1900) (Transaction* Volume LIU, 1980) '&.*?? .-'' /'' Introduction mand for a particular fibre gTade handle the fibre. Since many man is great enough to warrant special ufacturers of asbestos products pur ASBESTOS as received by the milling techniques. In such a case, manufacturer of asbestos prod- the mill places this specially pre . ucts is in the form of either erodpeasred fibre in itB regular produc chase their asbestos from more than one source -- Canada United States, . Africa Russia, and Aus or milled fibres processed to differ tion line. Each time it decides to tralia -- it is important for them, ent degrees of texture. Frequently, produce a special fibre, several im "to know how to handle the several the manufacturer finds that the fi portant points must be considered, fibres properly. This is particular bres as he buys them are not adapt such as: (1) Will this special fibre ly true when fibres of the same able to bis plant processes, and, require new . processing equipment . grade- are purchased from two or therefore, it is necessary for him or can existing equipment be used? more different, sources and couse- either to contact the mine supply (3)- Will the- over-all: capacity of quently^may have entirely different ing the material and request a spe the miff be reduced? (0), Does this1 physical' 'characteristics. cific texture for the fibre or to re special fibre-hare specific physical process the fibre in his own plant: properties that-canmOt be matched'. When the mine or mill manager ia by present fibres offered .to', the, requested to change his milling public? and (*) Cun tbe uxtra pro equipment to produce a special duction dost be_ recovered? grade of fibre with a specific tex-< tare, he would like to comply. How ever, if he began to make special fibre grades for each customer, he would be in the position of con stantly rearranging his milling tech nique, adding more equipment, or building a new mill. In the end, his mill would be producing hum dreds of different fibre grades of ' Fibre milling- is A technique that: differs somewhat with- each. plant/ All' producers- arecpniinually, mak ing miteWnlCAK-phaagflfct- in order. tB> improvetheit, products while spam-; tabling; . their production-- schedules. This problenirlk po easy <mc, and h, requires - full co-eperadiuk between . the Sales staff and the Milt Depart varying degrees of texture, which, mentdifficult accomplishment if he, . 'i: ";V- ' desires to maintain any quantit.Lof: i production. .............. To illustrate some of the ptbIems facing the manufacturer oflas hestos products, typical shipments of asbestos hove been obtained from different, sources and the effects of wiUowtog upmt the physical propesdes of thesb fibres have been in- Al>AidAi*.~BfceA. (CsOcabtrrx)' ' Th^-FSriety pf'asbestos would be1 difficult to use in its raw condition, as received In the. United States, be cause f itoctndy. pattree, quantities ofunopened bandits of fibres, and the preacBf* ofpiit* of rock of. : vacyuig si^f'tiiejefort, times* - ^h* custontfAi'hnw'ast.estahllshedb, tomer oiuit-eilbcf-vbave some lype, of 'prdeeksing: cqnlpmentto convert - VIEWPOINT or TH -'"Wgls .wfasbestos; products 'and- probably - ' thirf' faito . to- tito-gyopef condithorTy ' It is well known tl^Al.sshrvfSti'^R^iaC one ttaid he set- Up biA plant'7 fut rose,dhbi produetsoc he muster';,.-, bres as productd&dlffjj|j|; Csnsffl^;*~Vfth thf> iTlirTBriTrm of equipment ng.' try- to doaviiice tbemtoet in Africa*- .'T'7' ' mines fall into dgHHSMfemiDa, smt|A:^8ry for utilisation- ofitha regor .topr*oesa hisfibre to the customer as crudes and iiidBjjt$$E2c:: Each- lar grades of fibre prodocedat specifications.' Years of-experience;' . of these Af~ tfieminea! Affer a dumper of'years-- have stown that the easiest answer'; sub-divisions, and>35g5 of- the fi of' competition, and new. develop-' to this'problem is toy tkfe.customer''' bres have differertC fefihlits such as mentBy his products possibly did not*, to n-pneto the- fibre himself^ ber ' crudy, semi-crudy, open,, and well . meet- the Bewer specifications, and canse. lto. knows, exactly: what be'-; /' opened. No doubt these-Several do- the first question that came up for* ^.:Cr' [ "' greea of texture have been estab dUcnaakm was Asbestos fibre. Was "'' AfriAap Bhte>ffltee is strong bat. lished after many years of- expert be using the proper flbte,OT should harsh,: and- bji: snscessiva wiUpwing ence based upon the general demand he install' equipment to.re-prOefcso aetwUs^n^.^bme.becom^r,. balky and-' - .r of the customer. Therefore the mill the fibre in ordexTto- changedits ' tries to maintain a set of standard eliaracterUticsF At- this?, point, tips- ~ fibre mixtures, with gaps between Research and ` Development Engfc. .ter one-wilbAriiiig,^shows that the different grades for future ex neer should stepson and review the spprosiiqatofy' K; bnnees of the total pansion if the demand is sufficient. entire problem , with tha prodoctioa 19; onpetUL remain-pn the top screen. In some instances, the customer de- department mid decide whether the Suceesive;.wlUo^ng. stages do not fibre must be ebanged- to fit epjt^' -change''Vfits; resu%U-sufficiently to "Research Centre, Johns-Manville ing equipment, or whether the show what is Happening to the phys Corporation, Manviile, NJ. equipment should be modernised to ical properties of this fibre. , . . .P-- -- 10 -- UCC.004669 ; . .. .i'.. By a careful water elutriation method, a definite indication can be obtained of reduction in fibre length after each willowing action. Figure 1 shows that, for five willowing ac tions, the -f-14 mesh fibre dropped from 52.6 per cent to 30.6 per cent, a length reduction of 40 per cent. Coincident with decrease in fibre length, there is also an increase of fines ( --200 mesh) from 30.4 per cent to 15A per cent or an increase of 19 per cent. Therefore, to wil low this fibre successfully, a mini mum amount of willowing action should he used in order to avoid a loss in length of fibre and the for mation of fines which would be lost in later stages of processing or product formulation. In the production of asbestos products by wet methods, the den sity of the opened fibre as well as its ability to remain in suspension are important factors. The buoy ancy of a fibre can be determined from a slurry of fibre in water, with a definite weight of fibre in a constant and definite volume of wa ter. After thorough mixing, the slurry is allowed to settle, and the rate of settling is read in cubic cen timeters for a given time. In most rases* the settling reaches equili brium after one hour. The density can be determined by filling a stand ard measure with a capacity of say. a cubic foot, and obtaining the weight of its contents. The results are then expressed as pounds per cuh ic foot. Figure 2 shows that the buoyancy of the Blue fibre increases rapidly for the first willow pass, and that after the second pass the slope of the curve decreases. Conversely, the curve for the density values shows that the density decreases rapidly for the first pass and after the sec ond pass changes only slightly. An interpretation of the buoyancy and density curves indicates that this particular Blue fibre reached a high degree of opening at two pass es through the willow and that further willowing, at added expense, would effect relatively little im provement in the quality of the fibre. During the process of willowing a fibre there is another important change taking place in its surface area. This change, also, is indi rectly reflected in the buoyancy and the density measurements. Samples of the Blue fibre were measured for surface area by the air permeability method, using the Bowen apparatus and following the Lea and Nurse technique (1). A number of methods have been advo cated for determining the surface area of solids and each has advan tages and disadvantages. However, after considerable experimentation, it is thought that the method used in this investigation, while not giving absolute values, shows the general trend and indicates physical changes to the fibre after each processing action. Since it is known that wil lowing action on a fibre will open bundles into thinner cross-sections, reduce length, and create fines, there should result a cumulative measure of these effects by obtain ing the surface area measurements. Figure .1 shows the surface area measurements of the Blue fibre in its original state and after each willowing action. The results are expressed in square centimeters per gram of fibre, and the data, ex pressed graphically, yield a curve which shows that: (I) the surface area is increased after each willow action; and (2) this measurement shows a gTeater change per willow pass than the tests for buoyancy and density, because of the change in fibre length and the formation of fines. The conclusions that can be drawn from these test data on open ing African Blue are: (I) the fibre length decreases after each wiliowing pass, with resulting increase of fines; (2) the buoyancy and density values of the fibre show only small changes after two passes through the willow; (3) surface area meas urements show that, after each wil low pass, the area is increased; (4) a total of two passes through this particular willow would be the maxi mum treatment to produce a fibre for use in a plant; (5) one willow pass would be acceptable, since it produced a fairly open fibre with the minimum of length loss and creation of fines. Rhodesian Fibre (Chrysotile) This particular grade of fibre as received in the United States would also be difficult to use in most wet processes for the production of as bestos products, because of the pres ence of crudy fibre bundles. The same procedure has been ap plied to this fibre as was used with the African Blue. The same equip ment and rates of feed were adopt ed for all tests, so that the mechan ical processing was constant in all cases. This particular fibre was given a total of eight passes through the willow in order to determine the maximum opened condition of the fibre. The Quebec-screen tests increased slowly to the maximum value of 12.0 ounces on the second screen at four passes, and then decreased to 11.7 ounces on this screen at the eighth pass. The water elutriation procedure for length indicated a decrease in fibre length (-(-14 mesh) after each pass, and a small increase in fines (--200 mesh). Figure 4 shows the two curves, which are entirely dif ferent from those for the African Blue fibre and which do not inter sect at any point. The slope of the curve for the + 14 inesh fraction begins to level off after six passes while the curve for the --200 mesh fraction shows only a small increase in fines after six passes. In other words, the +14 mesh fibre decreased in length 01 per cent, but increased only 24 per cent in the objectionable --200 mesh fines. The buoyancy of the fibre con tinues to increase rapidly after each pass. Figure 5 indicates that the slope of the buoyancy curve would begin to level off at some point after eight passes. Density measurements show that the density of the Rhodesian fibre decreases rapidly for the first two passes and thereafter at a lesser rate, with indications that it would probably reach its minimum density after eight passes. Surface area measurements made on this fibre show that it has less surface area than the African Blue after each pass through the willow. The curve (Figure fi) has a lesser slope than that for the Bine fibre, which would indicate that this fibre does not break down into shorter fibre lengths as rapidly as the lat ter. In other words, it resisted de structive action better than the Afri can Bine under identical tests ro*ditions. Canadian Chrysotile -- S smi-Harsh A quantity of Canadian semiharsh fibre was obtained and sub jected to numerous willowing actions to determine its resistance to fibre length destruction. This particular fibre contains considerable quanti ties of crudy fibre bundles that should be opened before it is usable in an asbestos product; therefore, it was subjected to a total of ten wil low treatments. The Quehec-screen test indicated -- 11 -- UCC 004670 a large Increase on the second screen for the first pass, and only small increases for each succeeding pass up to six. From that point up to ten passes, the test, indicated minor changes only. - The water elutriatfoa test indi cated an 18% per cent decrease in length for the -(-It mesh fibre for the first two passes. Examination of the curve (Figure 7) reveals that the remaining widowing actions from two passes to ten had only minor effects upon the destruction of the fibre length. The fines (--200 mesh) show a 14 per cent increase for the first two passes and only a slight increase for the re maining treatments. From these data it can be concluded that this fibre resists destructive action and remains in good condition even after ten passes through the willow. The buoyancy value of this fibre, as shown by Figure 8, increases rapidly for the first four passes, and then the slope of the curve begins to decrease. The density values (Figure 8) show a large change for the first two passes and only minor changes for the remaining tests. Surface area measurements are not increased os rapidly as in the case of either the Rhodesian or the Blue fibre. Figure 9 illustrates the increase in surface area and, as will be noted, the slope of the curve is less than fur the two African fibres. From the test data obtained on this Canadian fibre, it can be stated that willowing action is not detri mental to its physical properties and that it resists destructive action bet ter than the African Blue or the Rhodesian fibre. Canadian Soft Chhtsotii,* Fibs* A typical Canadian- soft, silky fi bre was willowed a. total of sixteen times in order to dgjOnn&ie Us re sistance to the action-of * willow. The Quebec-screen teat indicated a change on the second screen after the first pass. This same screen began to indicate a decrease after nine passes and, at sixteen passes, had decreased to a value slightly above that at the starting point. The water elutriation curves (Figure 10) show that this fibre, although it lost length and some pul verizing took place, did not disin tegrate; therefore, it can be con sidered highly resistant to process ing equipment. It would probably be satisfactory for use in its orig inal state unless an increased fibre buoyancy was desirable for some specific usage. The +14 mesh fibre decreased 20 per cent after sixteen passes, and the --200 mesh fines increased 14% per cent for the same nnmber of passes, a further proof that this fibre resisted the destructive action of the mechanical equipment. The buoyancy of this fibre, as il lustrated by Figure 11, shows a rapid increase for the first two to three willowings and only a gradual increase by subsequent treatments. However, the buoyancy values are all lower than those for the three fibres previously discussed, which shows that this fibre is relatively free from crudy fibre bandies and is fairly well opened. The density values decrease for the first two to three passes and then practically level off, with only minor changes brought about by further procesaing. A total of two willow passes wonld probably be snfficient to place this fibre in good open condi tion. From the curve obtained (Figure 10), it can be concluded that this number of willowing ac tions did little harm as regards de stroying fibre length or pulverizing tbe fibre. The curve also indicates that the quantity of unopened bun dles was small and that the fibre was fairly well opened at the asbes tos mill prior to shipment to the customer. Therefore, this fibre can be used in its original condition as received from the mine, without farther processing on tbe part of the purchaser. Surface measurements on the Canadian soft fibre are given in Figure i2. The fibre, in its condition as received presents a greater sur face than any of tbe other fibres discussed in this investigation. This would indicate that the combination of - fibres of various lengths and fines created a large surface area. The surface area of this fibre at any given pass is greater than that of any of the other fibres so far dealt with. Therefore, if a manu factured product requires a fibre of great surface %rea, this one should fit the specification. However, since this physical property is only one of many to be recognized, we must balance it against the other factors before reaching a final conclusion. Canadian Ckbybotti,* Harsh Fibks This harsh fibre of the chrysotile variety has some interesting char acteristics from the viewpoint of its physical properties. It was subjected to a total of six passes through a willow, and, in the Quebec-screen test, each pass indicated an increase on the second screen. The crudy fibre bundles opened easily and became fairly bulky, so that most of the fibre re mained on tbe second screen. Water elutriation tests indicated a definite length loss in the +14 mesh fibre after each pass through the willow (see Figure 13). After six passes, this decrease in length amounted to 81 per cent and the quantity of fines (--200 mesh) showed an increase after each wil low action. However, the amount of this increase is only 22 per cent, which would not be considered alarming. These data indicate that the long fibre will not resist flexing ation by willowing, and that shorter lengths were produced without pul verizing to dust. Therefore, any mechanical re-processing of this fi bre after shipment to a customer should be extremely mild, or the fibre should be used without addi tional processing. The buoyancy value of this fibre (see Figure 14), while showing Bn improvement after each pass, does not equal that of the other fibres discussed ap to this point. The density shows a rapid im provement for the first two willow passes and only minor changes after subsequent passes. Therefore, for re-processing of this fibre, from tbe viewpoint of buoyancy or density, a minimum of two passes, or even one pass, would be considered sufficient. However, there is an important loss of length after one or two passes, and it might be advisable to avoid any farther processing of this fibre. Surface area measurements on this harsh fibre, shown graphically in Figure 13, indicate a smaller in crease in area than for any of the other fibres tested in this invest!-, gation. In other words, this fibre maintains low surface area and low buoyancy, although it loses length, in processing. For certain products these properties are important and should not be overlooked; for other products, great care must be exer cised in handling tbe fibre before and during its use. The surface areas of all fibres tested sre charted in Figure 10, which enables a direct comparison to be made between the several fi bres for the same number of passes through the willow. The two ex treme fibres are the soft, silky chrysotile of large surface area, and -- 13 -- UCC 004672 bir o^:Test Danes The Research- of Dfcyefl __ y-.r*'?" ' In general, were is good correla tion between buoyancy and surface : area values at a given number of willow passe*. ' When the surface area data, and buoyancy values are expressed graphically, most of the points fall upon a straight line, in dicating that either test can be used as a guide for determining the de gree of opening of a given grade of Engineer should make a thorough study of the available fibres. Th knowing the fibre specifications qnired-for'a giTeir .asbestoa , act, he- should makfcidefihlte mendstirms tw tk*- i to the kind of fibrk;j processing neeesairy to obtain maximum value of. the.fibre; fbr'4 specifie utilisation., V fibre. Figur* 16a--Effect of willowing on purface area, variou* fifete*. When the surface area measure ments and the decrease in -J--14 mesh the harsh cbrysotile,' haring- small surface area. fibre expressed in percent are shown graphically for each willow pass for each' kind of fibre, there ap Effects or Willowiho Upon Fii.tiuubu.itt or Fibre pears to be a fairly good correlation, since most of these points also fall' upon a- straight line. This is an When a fibre is opened by mech indication that the surface area of anical means, a fibre of greater processed .fibres - is greatly influ surface area results. Figure IT enced by. the. destructive action of shows, for each of the fibres inves willow hammers. tigated, the effects of four willow passes upon its filterability. . Application or Test- Data. The soft, silky chrysolite fibre rapidly becomes more difficult to The manufacturers of some as de-water after each opening process, bestos products require that asbes with the result that plant produc tos fibres meet certain specifications tion is retarded. as to date of filtration, fibre- The Rhodesian fibre remains fast strengtlr, length, buoyancy, density, filtering up to four passes through and surface area. In a previous pa the willow, at which point it begin# per on filtration, presented at' the.. to show a trend toward more diffi- 1946- Anngadr General Meeting of cult filtration. However,. after thir this Instituto-fa-H ib.. wan pointed . number of willow pasafs; the. fi^rq.- ouCthat^hy^opEnfeg a fibre, the. would still be considen^^tisfito rid* oliiltiationU. decreased. In- tory for any wet process. all oftbe investigation* discussed in Of all the investigation, fibres tested*- in.'thbt the filtration charae- ' the present paper, . a trend to become each more fibre show*: difficultto teristics of the two. identified; a*-: filter after, each willowing action.. "semi-harsh' and'hartb'aftrttawtl- Therefore,, some decisiou must be affected by the wittowiitgpjoceto _ made' oprthetbasiS; of: -the general Both would be coasideT*dia&f<i!^ . trtjWrall; effect : a ^willowing. action Goncldsioics (1) Asbestos fibres as received the manufacturer of asbestos pr nets usually require some type re-processing before they can used to best advantage in a prodoetj (2) Any fibre re-processing od adopted by a manufacturer will produce changes in physical prop ertiea, such as a lowering of fibi strength, loss in length, formatic of fines, different degrees of bunjfcl ancy, changes to density, increase a surface area, and' a tendency to. bn come more difficult to filter. (8) The soft cbrysotile fibigi 1 sist the destructive action of low fairly well, but have the! esf surface area and axe thews difficult to filter at any givenfim her of willow passes. ' (4) African; Blue fibre ' length, increase* rapidly, to area, becomes relatively ' buoy after each willow, pass; apcT.j rapidly.' - -*f. " (5) Rhodeiian fibro loses increases in bnoyamry has las* , face area than, either' the Cat soft fibre or the African Bloch 1 and its filtration 'dwscteriit^j main good. even after ,four- tjj sweetening poor fiiterii even if they had been by mechanical pi .^ .r - .> baa .up$' py4ealpropertiea of the passes. ' `-Jr' (6) The' semi-harsh ^ Fibre steen^ii. (a) is important, the destructive. action of The filterabil fibre is only the willowing passes it is s( " '" filtering fibreL.j^^g^ggji;^;- .; 'SM. Boft^silky,, fibres retain their 'Strength* bqtte* than harsh fibres ''when.: /processed.' by mechanical ; eqnipnmbti,'- ,';i If' ^bsttn- a the most impor tant- fsetot government the produc low fairly well,' hist is lest to willowing. action, than:' titoj dian soft fibre, increases ra- " buoyancy,,is rapid- filtering; Ettt'1 leas surface area- titan- tfcftW! Rhodesian, or Canadian soft.'-) tion rate . of. an asbestos product, (T) The, harsh fibre lose#! then, given a. fibre of satisfactory rapidly, increases In buoyant}*^ ip Strength, a minimum amount'of wib ly, has the'lowest-surface "l "* lowing, shouldj be' useth ' aU. fihres studied-in this-, . if a low density or, a high buoy tion, and remain* fast' 1 ancy value is. required, and' filtra- - each willow stage/- ' tion is hot' important, then the fibre should be well opened to obtain its- - - - - RKraiulNcxs maximum' fluffing condition.. . If . a fibre is required- to- have strength and high- surface area, with (1) Lea, F. IS., and ?fOT*tij'; Speeifie Sirrfaea- of fnk era; So*. ChetHs Imb/r-3 a minimum loss of fibre length and Sept-, 1038, fu, 297-288. r Figure 17.--Effect of willowing cm fiiterabilitv of various fibre*. minimuih formation of fines by a willowing action, then it is neces sary to select a fibre or a blend of fibres that will meet these require ments. UCC 004673 (21 BADDtunr, M. Asbsstoa Fibre*; C.LM^v* Vol. LBT1848 pp. 260-2* (3) Badollet, Nu a., Research Asbestos Fibres; Can. Min. Jo April 1948, pp. 213-216. -r-U --