Document Rj695R5582GoK5zKELrnZjRBa

L-l, *. v v_ ' ' 1 PLAINTIFF'S I VJ EXHIBIT ASA-150 Physical Properties end ! echoes! Applications of Asbestos Minerals M. S. EADOUET, Health Research Institute, fetfTtigh Dickinson University, Mafeonrfev.' Jersey, U.SA ABSTRACT The study of the physical properties of asbestos minerals requires a care ful isolation of tire fiber iron the "'all rock and, at a hv.cr. stage, a compari son of these physter.l properties with those of fibers that have passed through the .nilling and uoiicficiatiur, p: o.-csses. The effects of mineral impurities, low of fiber langlh and the formation of extreme fines (ashes! ir raid/or associated mnitial-) often show up in the formation of special asbestos products as veil aj in the commercial production of asbestos papers, millboards, aslirstos cc-mml products, plastics rr.d iusuiation materials, and in the filtration of blood j.lasina and trines. Xuraoiou", test iaolhe-ls have boon developed in Canada, and in England, for use in the asbestos industry. Spe cial treatments of asbestos fibers hr.to been used to improve Heir phy sical and vher.iir.al properties and to eliminate imparities. Numerous problems connected with the use of asbestos fibers are dis cussed, such us the effects of Asbestos on rillrulhui. surface area. Rurface treatment., Ls.iu" organic or inorganic materials, the surface charge cn the fiber, llic^ presence of magnetite ami air pollution elimination. biological studi'* on finely ground asbestos, when dispersed in 0.9 pgr cent sodium chloride .solution and then sterilized ar.d ir.juried into hamsters, sjio-.v that by reducing the di.se, the tissu- damage can be lrrgclv avoided. In th ..so exrsrira"rh, Ati.uv'r.a av.bes- tos fibers were carefully extracted from the wall reel:, finely ground, ami e::a ruined chemically ei.d micros copically for an., i.iincr:*.! impurities that :: igi.t he prestr.t that any affec! the lv..ixU-rs vi-uid he d\- rteii. to !: prc.v.-aee of the ..sbi's'no. The h-i-.ti Ari'.fib t ir.- c'.v.e'i a -ire c.\1..:':< o tis-r- rc..p ,v-a ih-.u th* soil fiber v.la 1, tv ted is ha v... Introduction - -- TlifS VAPKR is intended to offer comment on the physical proper ties' of asbestos minerals it. rela tion to the many diverse indusiiiatuses of these minerals. As the author is a chemical engineer, the material is presenio'J from r.-.r en gineer's point of view. However, in dustrial hygiene work in the' as bestos industry has ertaiitd work by many physician.-., ar.d blc'jgisls These medical scientists tend to focus their interests on the re sponse of tissues in mat. and in ex perimental iUiimal.:, but often have limited familiarity with the chem istry, physics -rid technical aspects of the minervori.-ai nuneria! with which they work, fiimiinriv, en gineer-.; familiar with the mr.'-wia::, often have limited undr-'tar.clii.g of the lauifurige and techniques of the medical scientists. This gap may delay asking the right ques tions to arrive at solutions for in dustrial hygiene problems. Al though the present paper is con cerned with the properties and SUBMITTED TO THE CU.M.: in Sep tember of lt"J8. 01:I('IXAI.1.Y rilESENTKD: in part at the Ciirfcverico on f-i-.ysm* and Chemistry of Asbestos Mineral:.. Ox- f-,r:i, July 20, lt'07. This v.-ork vas supported in part by U.S. Piil.oe Health Service r.-.'Ser.reb Grant UI- C913I fi-.m the Division of Urban and Industrial H-.a:,.li. l-'KY'*. Oltl'h: As!.As- l-.-stos c.i.t. l,;-..U..lUn. ''iter: li. a. Cr.'-yc*-fi;.`. I-ii. U.:i.,v, f_Y.. !'Mlt, A- 1 :n use.5 of the'material ;.. tire, author would -hope that it may V- r.-f some service in suggesting uteic to those investiga'ing questions as to how these mnferiais' behave in biological systems, how they me diate inuiogicai- responses and how such lespin-ic.s may b; minimized. The author d'-es noi propose to preseoi. theories - for hiologii-.d mccfjani>n'.s. and trusts that his colienTueu i'i industry will no stop reading at this point, ?.> the pai-er is ini ended primrri'y for them Jt might he .icte.I a! the out.-e. tha-:. in r.a IlLiou i,. iln cc.n?idm:iticii of differ.-prc.,'."*'.;*: of 'if ivier.t vaiir: of e--l-esi<*s. which influence their s .h i-ility rmi use for v.'.riot.:' im.:.1 ; itrp.vrv. tia reaevior. of . .-.bc-tos f'U :i r 5,-j*h inoi-runic or -/>.-i*ic ct*nir.ocnd can impro-.c I:br pvuportic-s for specin1 uses, such a. r-ci.ictng the Lyd-'cl''sis of chrysolite in water. Tirade.1 fillers can uffcci iexture r.u.J iiitra- tior. prcpt-vtic:. and ir.dcanc pro duction r.-Aoi. of asbestos ccii'ml .products, papers. milibnr.viU ar.d other v/ci jjrucoss products. SciOfiion ami Pro*s:'.raii.'n of Suinple, For fundament r.l studies on the physical m- hii.lcgii.'d prap.rlu-.- and tcchnieal. use of a--l...\<wv. min eral;., SPh-vtion it-:.,! i..ivp-.'. a`.i.`u of crude ores is the first .lap. This, should 1;; done by Someone nwi- il'ioJ to examine th-.: ore dwioate its ?r..'li'gicr.! fvrin.iiio:!. r r' t-> note tiie pi- vriiir: of dyb..-. in;;, `.in fio.oiti'r o.'i : .1 i.::i;; ra:s in tr-1! h - ." if p ' ... 431! HER 0000721 asbestos fibers. This type of exam The amount of extraneous mate ination often furnishes valuable rial in a bag of commercial asbes lends to the physical properties of tos fiber is rather surprising. From the crude asbestos and the com tin viewpoint of the quantity of mercial fiber, and its use in indus pure asbestos, it can vary from a try. fow per cent to 70 or 00 per cent, Asbestos fibers in the form of depending upon the grade. This ex crudes or in drill core should be traneous material Consists of opened by hand for laboratory teats broken pieces of wall rock, magne to avoid fractures. If further proc tite, brucitc, small sizes of asbes essing is necessary, they can be tos fibers, dusts and closely as opened by a very mild willowing sociated minerals ir. various forms. action. The method of mechanical Asbestos mill surveys have been opening of the crudes will vary, de made by checking the flow rates pending upon the variety of asbes throughout the mill and collecting tos. For example, soft chrysotile samples at each station for a pe may require more vigorous treat riod of several days. The samples ment than crccidolitc or amosite, arc composited, weighted and tested and anthophyliite and tremoiito re by the various test methods avail quire even milder treatment to able to obtain seme idea as to yield comparable fiber lengths. which milling unit is damaging the More research should be applied fiber and producing fines and dust. to the process of opening asbestos The McXctt wet classification''1 ores so that the maximum fiber method provided the best evidence length can be preserved and less of this. At the completion of the fines produced. survey, the mill foicman is told Although samples prepared di which equipment is damaging the rectly from ores are valuable for fiber. He can then regulate the fundamental studies, most tests in equipment to improve, change or industry are necessarily made with eliminate the trouble spots. commercially milled samples. These milled samples can, of course, con Fiber Testing tain a variety of associated min erals that can affect properties and Neutron activation analysis"1 has uses. been used on several occasions to identify trace elements in samples of chrysotile, amosite and crccido- a'iHiiig and Beneficiation . lite. For example, one series of examinations showed that ebry- In milling plants, large quanti sotilo, amosite and crocidoh'te all ties of ore, consisting of fiber, wall contained manganese 5G and sodi rock and many associated minerals, um 24; antimony 122 was present are crushed together. Some kind of in amosite; chromium i"l was pre mechanical separation i therefore sent in chrysotile and amosite. but necessary later in the milling not in crociuolite; iron 59 was process. Preliminary sorting of present in all three samples; anti crudes from the rock is helpful in mony 121 was present in all three 1 educing contamination. Water fibers; scandium 4G was present in washing processes have been in all three; and cobalt 69 was present stalled in some eases to reduce lion- only in chrysctile. Apparently the fibrous materials and to direct the radioactive sodium 24 was produ cleaner fibers to one milling line ced from the magnesium which i3 and the dirtier fiber and shorts to a normal constituent of asbestos, another milling line. In any case, `and the radioactive cobalt GO came a complete elimination of the as from the nickel which is an impu sociated minerals is extremely dif- rity in the chrysctile. These trace ficuit. They can be objectionable elements become important if the in the manufacturing of some prod samnte of asbestos is to be used in ucts. the filtration of wines, beers, blood The balkiness or degree of open plasma ami pharmaceuticals anti in ing of a fiber will govern the abil biological studies. Therefore, a pre ity to pressure-pack the fiber prod liminary acid treatment to remove uct for shipment. For purposes of trace elements would be desirable industrial hygiene, pressure pack before utilizing asbestos for such ing is of value in reducing dust in filtration purposes. Attention to the atmosphere ami on the packing trace elements in samples of asbes floor.' tos may be of particular importance The hooding of equipment where- in biological studies for effects of ever possible will also reduce at asbestos on tissue, particularly in mospheric dusts ami improve work tests for carcinogenicity. ing conditions. A set of samples taken bv the (Cll.i) Bulletin f;r April, 1B33 \ writer in an Arizona underground mine brings out an interesting point. The area containing soft fiber (chrysotlie) was free of faults and the fibers were well formed, with a strong flexing and I ensile strength. About 20 tTct away, where a series of faults oc curred, harsh cluysotile w:>s noted. These fibers were not wei! formed, showed a weak flexing and tensile strength and, after processing, lost length and produced a considerable amount of fines and dust. The soft fiber contained 13- p:*' cent mole cular water and the harsh fiber 12per cent. Filtration tests showed the soft fiber to be siimy and dif ficult to filter; the harsh liber was not siimy and filtered rapidly. This type of harsh fiber was re commended for the filtration of wines, either as straight fiber or in a blend with soft chrysotile or cel lulose fiber for filter pads. When the filter pads contain 103 per cent soft chrysotile asbestos, the fil trates are relatively tree from col loidal particles. As the quantities of cellulose or harsh chrysotile are increased in the -asbestos blend, the filtration rates inetesise and the fil trates are not as free of colloidal impurities. Test methods"* have been de veloped for determining the filter- ability, surface ;uea, colour, grit, dust, length, degree of opening, v.et classification. tensile strength, magnetic rating, volume resistivi ty and conductivity of asbestos. They do hot give the icioatuication methods for d..toi-!r.ini"g the as sociated minerals pr-sonl. These methods are printed in the form of a booklet and .ire avai'uble for dis tribution by the Quebec Asbestos Mining Association and by Tape Asbestos Flbcis Ltd., London. Some of the other tests ir.-.olve the use cf '.In5 oi-et'-e:-. ni'-.-rcscope. X-ray diffraction, different':-.! ther mal and infrared spectral data to show differences ir. the`fibers that are not shown by other test meth ods. The effect of opening asbestos fibers"' and measuring their pro perties as the fibers arc opened more and mere shows whr.t can happen in a factory where proces sing is accessary before the fiber can be made into a commercial product. For example, an African blue crocidolite, Rhodesian chryso tile, Canadian-semi-harsh clivyso- Determined by thermo-gravimetric analysis ur.iiig the Thcrmuanalyior. (Mettle:- Instrument Co:?., rrir.eeton. X.J.) HER 0000722 433 .( i i tile, Canadian soft chrysotile and a i Canadian harsh chrysoti'e show, as i the processing continues, that (1) J the length has a tendency to de crease, (2) the dust or fines con tent increases, {,") the buoyancy increases, (1) the density decreas es and (5; the surface areas in crease. Therefore, the plant fore man must know just what degree of opening is necessary to obtain the best workable slurry for his machine to produce a satisfactory product. The presence of magnetite can be a serious problem, depending up on the use of the fiber, especially in the electrical insulation field. Magnetic- rolls and a sudden flash j ! of high-intensity heat have not been too successful in removing or converting the magnetite to ferric oxide, which is non-magnetic. Methods of testing for magnetite iij have been proposed'''t:>but there is still room for more inves tigation. i i I| Fiber Treatment and Effects i>1 The field of son ics offers some interesting possibilities for opening asbestos fibers, laboratory tests show that it can be accomplished. The treatment of asbestos fibers, such as amositc or crocidolite, by inorganic or organic liquids may f alter the physical and chemical pro i I perties suffictenlly so that new ap plications may be found. By soften ?! ; i ing the stiff wiry properties of these two fi'oeis. their importance in textiles will be greatly increased. Adsorption ci organics by chry sotile asbestos was reported by T. J. Weeks and J. P. Leinwcbcr at the Oxford conference cn asbestos in July of 1967. They used a Brice- Fhoenix differential rofractometer 5 to measure the changes in the so lute concentration. i Opening in water using a Waring ' i blender'*' is a convenient method to prepare fibers for some types of tests in the laboratory. The sam 'I5 ples should bn washed with alcohol and ether to remove any polycyclic hydrocarbons and the benzo (a) pyrene sometimes found associated with asbestos. The reaction with soaps such as stearates or oleates'1*' can produce a water-repcllasii effect cn the sur face of the chrysotile -- in the form of a thin laser of magnesium stearate or o'.'a to. Textile clu-y.-o- tilc fibers .-i ore 'ime were treated by soap, with tin roving Inter used Co"-:rii!g : cleetrieul in- HER 0000723 Surface treatment of a slimy soft chrysotile can be accomplished by.the heat-treatment process, by an acid treatment or by the addi tion of sodium silicate'"' and flash drying'"'. Wetting agents'such as polyacrylainid (S^paran NP10) and aromatic sulfonate (Tamol N) have been used to floe the asbestos fines, improve filtration and re duce fiber losses.- In some cases, dispersing agents such as Soda Lig or B'.anccl are added to the tanks containing t.he asbestos slurries so as to keep the asbestos from soiling and present a well-dispersed suspension that can be picked up by the wet ma chine process. The amounts of these reagents are kept small -- just enough to accomplish the de sired effect. Excessive amounts can cause frothing at the pumping station and defeat the purpose of flocculating or dispersing. There are times when it is necessary to open the fiber by additional grind ing. In that case, such agents as Decerasol OT or Alkanol, when added in the proper amounts, can speed up the opening. There is one point that must be remembered. Does the use cf those agents in the presence of asbestos cement lower the strength of the finished asbestos cement products? If so. it may be necessary to avoid them entirely or-use lesser quanti ties. Asbestos fibers carry a surface charge -- either electropositive or electronegative. During the nine teen thi' ties, chrysotile, amosite, anthophyllite, c'-ocidolita, tremohte and. actir.olitc were ground to a fine powder and tested in a catapheresis cell using the ultramicro scope. Chrysotile was observed to have an electropositive charge in distilled water and all amnhiboks were electronegative'"'. It has been suggested that the electropositive charge on commercial chrysotile is due to aluminum or iron ions and that the charge on pure chrysotile approaches the electronegative side.- Chrysotile fines can be neutral ized or brought to the iso-electric' point by the addition of electro negative particles. This can. be fol lowed by the movement of particles, as observed in the cntaphorcsis ccli under a given potential. For exam ple, although dlatomaceous earth, cement and other particles wore all ciectroiwrativei the addition of Riddick. T. M.. "Control of Colloid Stability Through Zvta i'otw:* chrysotile fines to any one of them brought about complete flocculation in a short time and filtration was improved. In the early forties, a Swiss en gineer developed a method for the clarification of raw sewage in aera tion tanks. He added chrysolite as bestos to cause flocculation and, at the same time, increase t'nc surface area so that bacteria con'd grow rapidly and aid in the digestion of the sewage prior to filtration. Ac tually, with the chrysotile being electropositive and the sewage clec tronegr.tive, it was a case of using an appropriate amount of fiber to neutralize the negative charge and obtain a quick flocculation product that settled rapidly and was later removed by filtration. Oil-.veil drilling produces chips of rock particles and mud. In some cases, clays and/or asbestos fibers are added to form a viscous mud to coliect these iw.i tides so that they can he brought to the surface where they are removed by screen ing or filtering: the cleaned mud is returned to the well. In this case, the positive charged asbestos may have helped in forming large floes that hold the drillings. The colloidal properties of asbes tos'"' and zeta potential measure* ntents"*' have shown that the charges c.o exist and can be re versed by adding >me inorganic reagents or by changing in the pH. Hodgson"" measured the charges on crockicl'te and amositc. The crocidolite had a weak charge o! f-IOmV find amositc a weal: charge of --20iuV, vberras V.'avtinc;: and Zuei.er (131 -showed that chryscti!. had a strong positive charge of m-ICTuY, which may be r. rather high value. It: the production cf certain tvpc of celUdosic paper ',1 ''*', the addition of chryso lite asl.est.rs, with its electroposi tive charge;, was helpful in retain* ;iH: the negative-charged TiO.- and at the sane time furnished ?. high surface area. In the case of another type of paper, t'nc asbestos must hove the rubber latex deposited on it while in suspension. Here again, the negative-charged latex is held by the electropositive chrysolite during the sheet forming process. Physical Proper!ieo and Applications of Asbestos Chrysolite asbestos is the prin cipal fiber used in many product*-, because of its physical pr-ipm-ti; and availability. For some- pur poses, it i- Mji'pas.-.ed by sever.-! amphil.clcs that have y.!:ysi.al pr-j- vt. . ri - .. *?.. ................. pcrMc-s that give them particular icles, and metallic particles from advantages over clays;.tile. The ad metallurgical and smelting plants. vantages of chrysolite asbestos, Extremely fine asbestos fibers may however, are generally greater than be added as a procoal to the Lags its disadvantages and, consequent to increase the efficiency of re ly, chrysolite is used in most prod moval of particles polluting the air. ucts requiring asbestos. Chrysotile These fine particles of asbestos asbestos can nave a large surface may be precoated onto glass filter area, high strength, resistance to bags or cloth filter bags in the bag- elements of the air, and flexibility, house installation prior to placing and it mixes well with resins and them in use. cements and docs net support com bustion. The texture of asbestos fibers varies from very soft and silky to Miscellaneous semi-harsh, or even to a harsh, Technical Applications splintery, brittle type. Quite often, The presence of grit, whiskers, the fiber source of the ore will re fiber bundles (unopened), magne veal what has happened during the tite, brucito and micaceous mate original crystallization period. The rials in commercial fibers may be presence of dykes, faults, mineral impurities and crystal formation also furnish clues, Most harsh as objectionable when incorporated in a binder to be used in a spray gun, such as for sprayed under- bestos fibers have less water of coatings, and coatings for heat and crysta'lization, and this is partic sound insulation and fire protec ularly true of harsh chrysotiles. tion. The asbestos must have bulk The soft chrysotiles are slimy in and fluidity with the binder. water, hydrolyze slowly and are Caulking compounds are sensi extremely difficult to dewater; the tive to texture, foreign materials harsh fibers can be dewatered ra and changes in grades of asbestos, pidly. Advantage of this knowledge especially when applied by a gun. can be utilized in b'ending s. harsh or semi-harsh fiber with me strong Wall-joint fillets using asbestos must have good bulking value, good soft chrysolite, as in the produc coverage, a smooth texture and be tion of asbestos papers and asbestos cement products, hlends of emphiboles such ns amosite ov cvucidolitc free of whiskers, grit, magnetite and micaceous materials. Asbestos ir. paints must be free with slimy soft chrysotilc can be very effective in increasing produc tion rates, provided that the 1 of grit and whiskers, and must he uniform in texture fur ihe Vest ap plication. strengths of the end products con Plastics and molding powders are taining these blends arc not seri very sensitive to the. physical pro ously affected. perties of asbestos, even tu the Thin asbestos papers for elec presence of moisture, 1 iwiie, as trical insulation should be free sociated minerals, iron and off- from grit, unopened filer bundles, colour fibers. For example, the magnetite and brucite. If these im purities are present, they wiil ap fibrous structure will increase the impact strength, allow a wide pear on the surface of the paper range for adjusting the quantity of and produce weak spots whan the fiber, furnish good birder reten paper is wound or wrapped around a wire carrying electrical current. tion and good workability, impart hardness and toughness to the Air pollution is an important .moldings, increase heat and fire problem today. Its study involves resistance, reduce deformation, the collection of largo volumes of air in and around plants, mines, mill3, subways, tunnels and points of heavy traffic congestion. If as bestos is thought to be involved, then sufficient solids must be ob tained for tests by ail available make cold molding possible by con trolling the flow under pressure in the molds, permit the blending of mineral and organic fillers, impart a good finish, improve electrical properties and reduce the cost of molding. The presence of iron in procedures, including electron mi croscope, spectrographic, infrared and neutron activation analyses. New micro test methods must be developed to complete this type of investigation successfully. asbestos will produce off-colour plastic products, and a chelating agent may be necessary. A stabil izer for asbestos in plastics should function as a heat stabilizer, as an antioxidant and as an ultra-violet- Asbestos, glass, cotton or wool, light absorber to bo ideal. in the form of textile filter bags, The thermal insulation'1"' proper are sometimes used in plants to ties of asbestos have proved to be recover fly ash, radioactive part important in missiles and saf ' " and us special packings in atomic energy equipment. In asphalt paving1*"*', the strength, reinforcing and absorptive proper ties of asbestos have resulted' in an improvement in the plastic strength, tensile strength ami sta tic compression and a decrease in -the cracking properties of thin films of asphalt filler mixes. Other Applications of Asbestos In many asbestos products, it is the reinforcing effect of asbestos that is needed and not the non-fibrous materials, which would bo con sidered as expensive fillers. If fil lers are needed in a product along with asbestes, they can be pur chased at a lower price and under a manufacturing specification. The forunr-in in a plant that is using asbestos to produce a commercial product must have ?on;e idea of the quantity of pure asbestos that is a vail.tblo in a given grade of fiber. Then, he will know whether to use mo'2 or less fiber in his formula. Although it is tvur Ov.i the extra neous material may aid filtration, it will contribute lilt'd toward the strength of th- product, and is thus an expensive method of obtaining liiis effect. Tn the case or. manu facturing floor tile and plastics, it Is important to kuu'.v bow much true fiber is present to obtain the maximum vehiforeing effect. Toe much tiue fiber will dry up the mix and lequire more, expensive resine; on the ctne. hand, the fore man can reduce the qua nelly of fiber jr.d -ho tesr ivein to obtain the consistency desired. Commercial grades of asbestos fibers have been L-t.proved during the past tan yearn, so chat there is less extraneous material present in a bag of fiber today. In general, chrysocile asbestos has the widest use in commaicia! products such ns asbestos cement, flooring materials (asphalt and v'uyl tile), papers, millboards, roof ing felts, textiles, automotive prod ucts (brake linings, clutch, fru.ir.gs ami packing; and many miscella neous items. Fortunately, the phy sical properties of chrysotilc make this fibev ideal; however, some ara pidboles (croeidclite and nmosite) are becoming important and avo re placing chrysotile in some prod ucts. In the spinning and weaving of asbestos fibers the ."inter varieties -- >,, they do not break (CIH) Sslistia for A?ril, IS1-3 HER 0000724 <135 up in the processing: equipment. Soft chrysotile. causes the least trouble; harsh chrysotilc will show considerable loss due to its brittle ness. Crocidolite can.bc spun into yarns and cloths by modifying the textile equipment so that the stiff and wiry properties of crocidolite can be handled. Amosite is of low flexing strength and is usually formed into mats and later treated with resins, depending upon its use in industry. The tensile strength and flexibility of asbestos are also important in spinning and weaving applications. Where acid-resistant packings are required for acid pumps, cvocidolite, the most resistant of the fibers, can be made into all-blue yarn and impregnated with a re sin to form gaskets or, if required, it can be formed into millboards. Crocidolite and amosite fibers, when in the form of doth, pack ings, yarns ar.d baggings, and when treated with inorganic binders, can withstand temperatures higher than 4S0F. Reinforced plastics using croci- dolitc show good chemical and w&tev resistance. For heat insula tion, amosite is very useful due to its open volume and the fact that it contains air pockets. It is also used in reinforcing magnesium- or cal cium silicate ir.-ulation, where the filtration problem is greatly im proved by the presence of this fiber. Antnopliyllite asbestos has good heat resistance and acid resistance. It has bnon treated with resins and used in plastics. Although this fiber dors not have the strength of chrysotile. crocid.'Iite or amosite, it has good bulking properties. Some p.r.thcphyllites are mostly iron frea and almost, white in colour and are desirable in 3ome types of plastics. Tremolite, after an acid and caustic wash, is considered as a good fiber for -use in the chemical laboratory' for filtering chemicals and is sold for Hint purpose. The physical properties of ac- tinolitc- are not ioc attractive. It is ft weak fiber, usually associated with other minerals, and would be considered as a cheap filler in in dustrial use. Sumo Carry-oyer of Ir.duitrh'l -rirnre to Diologic.d E>:: itir.;rn tr ti o People in the asbestos industry have long 1/ei-ii familiar with the slimy suspensions formed by soft chrysotile in water in contrast to the rapid set! ling of harsh fibers. As indicated ir. the preceding dis cussion, it is this difference in physical properties that favours the use of harsh fibers in'certain products, such as asbestos cement, where it is desired to have water filter away rapidly for faster set ting. As also mentioned above, the author had taken a set of samples of harsh and soft chrysotile ores from a mine in Arizona. Fibers were hand-picked from these sam ples. The wall rock was cut away and the fibers were washed and processed to mean lengths of 30 microns in a Waring blender'". An aliquot of the processed soft fibers was heated untii it lest the property of forming slimy suspen sions in water. The samples were then turned over to Dr. V/m. L. Smith at Health Research Institute, Fairleigh' Dickinson University, Madison, New Jersey. Dr. Smith's group has found that the injection of sterilized saline suspensions of some preparations of asbestos into the pleural space, the space sur rounding the lumrs cf hamsters, elicited scar formation (fibrosis) and, occasionally, tumors (vieaot/icliows)<s". Working with the specially se lected and cleaned filers of Ari zona chrysolites, this group obser ved that tlie slimy character of sus. pensions of soft chrysotile in water carries over a.rd persists ir. depots of this material in the pleura! space of hamsters, whereas (.'.easts of harsh chrysotile become dry. There was much more CJ-tens'r-: scar formation and more rapid de velopment of tumors around the depols of harsh chrysot'lo than around the soft ones. The heated aliquot of soft chrysotile induced no more rapid development of. tu mors than the unheated aliquot, but tended to cause thicker scars than the unhealed soft chrvsotile,u'. In hamsters injected with a large (25 mg) dose of brush chrycotiin. tumors developed in 21 per cent of the animals. With a smaller (JO mg) dose, tumors arose in only 9 per cent of animals. Further reduc tion in dosage to 1 mg elicited no tumors at all'5". In hamsters injected with 10 ing of amosite. the yield of tumors was again 9 per cent. When only 1 my of amosite wals injected, none of the animals developed tumors'5". .The finding vhr.t hamster.- would ` ' injected with asbestos provided a test spe cies of demonsirared suseev>tibility. The follow-up experiments with graded doses afford evidence that tumor risks in operations where they may exist in the asbestos in dustry can be avoided by appropri ate measures to 1 educe the amount of exposure. Different varieties of asbestos fibers have been assembled and prepared as standard samples by Dr. R. E. G. Rend-iil, Pneumoconio sis Research Unit, Johannesburg, South Africa, in collaboration with Dr. V. Timbreii, Medical Research Council, Llandcugh Hospital, Pcnarth, Glamorgan, Wales. The Pneumoconiosis Research Unit is making these samples available to those interested in work on the biological effects of asbestos. CONCLUSIONS This review illustrates that any operator' using asbestos minerals must keep ir. mind many factors that may influence his fins! pro duct The undesirable effects er mineral impurities may need con trol. Fundamental studies an the changing pbys-cal and chemical properties of asbestos have de veloped new use:-, and undoubtedly will develop move. Improved milling technique: car. improve the quality cf asbestos fibcis by preserving the length and produci.-.g rV-.er fines. Treatments of asbestos with hu t or with inor ganic or crynnic compounds cr- o aice improve fibera Tor spoci.'l u.-.'-s. By taking advantage of the dif ferent texture-! of different asbes tos fibers, such as harsh, semiharsh or soft, Improvements can be made in wot processes. Many methods for physical antchemical tests of asbestos minerals have liter. proposed by the Quebec Asbestos Mining Association and by Capo Asbestos Co., Ltd., Lon don, and ai-o available from those sources. Electron microscopy, Xvay diffraction, and differential thermal and infrared spectral anal yses bring out differences not shown by the usual tost methods. Some biological differences in re sponse to harsh ar.d soft chrysotile were noted. Harsh fibres induce.! more extensive sear tissue forma tion in hamsters than, soft fibics. Tissue clamngo was proportions! to the amount of fibre injected. A2o HER 0000725 1 Tua t liinirw IM: (1) Manual of Testing Procedures for Chrysotile .-Utesfos Fibers, Asbestos Toil.ilc Institute, Que bec Asbestos Mining Associa tion, Thetford Asbestos-Cement Products Association. . (2) Private communication, Rny'oestos Manhattan Inc. (3) Test Methods for Bine and Amositc Asicstc-s Fibers, Cape Asbestos Fibers Ltd., London. (4) Badollet. M. S., "Processing As bestos Fibers -- Effect Upon Physical Properties," C.f-M. Transactions, VoL LIII, April, 1950. (5) Nicodomus, P. O.. "The Significunce of Iron in Asbestos Materiais Used for Electrical Insula tion Purposes," A-S.I'J./. Ball., Apr., 59, p. 62. (6) American Society for Testing Materials Test Method D 1118S7, Magnetic Rating of Asbes tos Used for Electrical Pur poses. (7) Badollet, M. S.'i and EJgerton, X. W., "The Magnetic Content of Asbestos by Magnetic Separa tion," C.I.M. Annual General Meeting. Quebec, March, 1961. (8) V/romsbi, J., "Magnetic Rating of Asbestos Fibers by a Magne tic Force Method," S.P.E. Jour nal, Vol. 19, Mo. 11, Nov., 1963. VV A., "Preparation of Asbestos Fibers for Experimental Use," A'cio York Academy of Sci ences, Vol. 132, (Art. 1), 451435, December 31, 19**5. (10) Badollet, M. S., U. S. Fatcnt 2,0(iS,219, Jan. ID, U'37. (11) Martinez, Edward, "The Effect of Sodium Silicate on Filtration Rate of Asbestos Fiber," C.i .!/. Bulletin, Vol. 57, rp. 1042-1044, Oct., 1064.. (12) Pundsack, F. L., and Reimshusel, G. P., "Method of Improving the Filtration Characteristics of Asbestos," U.S. Patent 3,173,831. March 18, 1065. (13) Badollet, M. S., "Asbestos -- A Mineral of Unparalleled Proper ties,'' CJAi. Transactions, Vol. LIV, pp. 151-160, 1951. (14) Pundsack, F. L., "The Proper ties of Asbestos, I. The Colloidal and Surface Chemistry of Chrysctilc," Jour. 1`hys. Chcm., Voi. 59, pp. 892-SC5, 1955. (15) Martinez, E., and Zucker, G. T,., "Asbestos Orcbody Minerals Studied by Zeta Potential Meas urements," Jour. Phys. Chcr.i., Vol. 64, pp. 924-923. 1060. (16) Hodgson, A. A., "The Surface Properties of Asbestos Fibers," Asbestos Mag., pp. 2-14, Nov, 1065. Hodgson, A. A., "Fibrous Sili- u;t nuyal In-fihuj of Chemistry, Lecture Scries, Number J, n;>. 23-30, 0-10, 2a, iOUS. (17) V/oilcrv, R. G,, "Effects of Chrysotile Additions to Cclluiosic Paper," 2'appi, Voi. IS, -.in. 92A-&6. 1065. (13) Xu cowan, A. 'V., "Properties of Asbestos Suitable for Use in Cellulosic. Paper," Tuppi, Vol. 43, Aug., 1965. 09) Feigiey, D. A., "Eenter Saturation of Asbestos Fibers," U.S. Patent 2,759,213, Aug. 21, 1C5C. (20) Badollet, M. 3., "Asbestos," En cyclopedia o' Chemical '"er-ltnology, 2nd Edition, p. 7-16, i'nterscience Publishers, New York, 1063. (21) Smith, V/. E.. Miller, I-., Elsasser, R. E., and Hubert. D. D., "Tests for Carcinogenicity of Asbestos," Ann. .Vein York Acad. Sci., 132, (Art 1), pp. 456-433, 1965. (2?) Smith, W. E., Badollet, M. S., Miller, L., Hubert, D. D., Lun ger, A. M., a.id Chur", J., "Com parison of Eiolo-jlcal Responses to Harsh and Soft Chrysotile," (in press). (23) Smith, W. E.. Hubert, D. D.. Mii'er, L.. B.nrlolhH, M. S., and Ckurg, J., '"Tests for Threshold Levels of Ca. cinoye.iicity of As bestos,'- (in press). tLii I di.l.iCi! I vf*%%V*>Li*'uflJ V*i .l"A\V WiU* .(lUlV AYy'/Jr,Ji a it t> S'*.1V*"'i JI Jl-'OC-Ct Sao i*au!o, July 7-12, 1239 The Gcmcresj of the Brazilian Society for Metai3 is to take place during the week cf July 7 to 12, 1969, and the program is to consist basically of the follow ing: I--Open Sessions, with subjects freely discussed. II--Technical Lectures, comprising specific technical subjects, delivered by world-wide experts. Ill--Technical Papers to be presented by the authors, followed by intensive discussion. These technical papers may cover any branch of metallurgy -- extractive or transforming, ferrous or non-fer rous rr.etah or physical metallurgy. At present, the program is still at a tentative stage and the following topics were suggested: For Open Sessions 1 -- Training personnel for the metallurgical industry. 2 -- Materials for cutting and forming tools. 3 -- Development in the production of topper and nickel and its alloys. 4 -- Problems and techniques relating to the operation (CiM) 3uli:tia for April, IC3 of blast furnace? aiming at the lowest possible coke rates. 5 -- Problems related to the supply o' cast iron, ar.ri m:licabie and nodular castings !o the automotive Indus lay. For Technical Lectures: 1 -- Six examples of rather startling research in physi cal metallurgy. 2 -- New developments in the extractive metallurgy of no.i-ferreus metals. 3 -- Investment and financing problems fev the metal lurgical industry. 4 -- Strategy cf research in the metallurgical industry. 5 -- Present slate of continuous processes ir. steel pro diiction. 6 -- Precipitation in steels. 7 -- New ceramics. S -- Solidification of metals and alloys. 9 -- New techniques ir. mechanical forming of metals. 10 -- Present status of techniques of continuous casting. Su far Prof. Robert 1*. Mel.l. Prof. Arthur G. Quar rel! and Prof. Kai Grjothein have already confirmed their presence and accepted the invitation to deliver lectures. Several technical papers from foreign au thors are expected. For additional information, contact the Organizing Committee: P*.lO. F.ox 15503, - Sao Paulo, Brazil, S.A. ^ . 437 HER 0000726