Document dQ2wR3Gbj9nZKVoB7ajYkoO26

s*:v?-^ Y'-T- r ` .`>:YV-^- ` - . Asbestos Fibres: Production and Usage By M. S. BADOLLET* (Annual General Meeting, Kdmonton, April, 1953) (Transactiont, Volume LV1, 1953, pp. 237-239) DURING the past five years, grade, and quantities of rock, dust, production of asbestos fibres and such foreign materials as wood lias increased in all countries thant d wire. Comparisons are made list asbestos as one of their mineral with standard Canadian grades, or, resources. Despite the many small if the fibre is of some other variety, mines that have been opened in comparison is made with shipments Canada, United States, Mexico, of that grade received during the Chrysotile Chrysotile asbestos is the most popular variety for industrial pur poses and probably accounts for 1)0 per cent of all asbestos fibres used in industrial products. South America, Italy, South Africa, past five years. If the sample is The quantity of chrysotile im Australia, Yugoslavia, and Rho only a small quantity, such as a few ported by United States industry in desia. the supply still does not meet grams, it is placed between two 1952 was approximately 734,500 the demand. It is estimated that glass plates and reflected against tons (2), 668,800 tons of which total 1952 world production of as a white wall, where the lengths may came from Canada. When available, bestos fibres of all varieties ap he measured and the impurities some Rhodesian and Arizona chry proximated 1,000,000 tons, with counted. When large samples are sotile fibres are used in textiles, Canada supplying 966,382 tons (1), available they are given special special papers, and asbestos-cement or 60 per cent of all fibre mined. tests to evaluate the fibres for use products. Last year the textile in Asbestos fibre brokers continu ally are offering odd-lot samples of chrvsotile. amosite, crocidolite, tremolite, and anthophyllite fibres to manufacturers, quoting fantastic prices for. tonnages varying from just a few to 50 or more in a month. In many cases, the samples are not properly graded and con tain quantities of rock impurities and finely ground dust. When vendors submit samples of asbestos fibres, the manufacturer should consider them in terms of price, quality, quantity, and as pos sible substitutes for fibres current ly used in his products. Grading of these odd-lot fibres in most eases has been poorly done, with resultant non-uniform fibre lengths. In some instances, a num ber of miscellaneoua lot* of fibres have been blended for sale. This blending produces a fibre that is difficult for the manufacturer to ac cept as a substitute for the wellstandardized Canadian fibres. All fibres offered to the pur chasing departments of most manu-facturers usually are forwarded to in regular products. These special dustry in the United States im tests include air separation and ported 26,145 tons (2) of chryso- screening in a pilot plant to deter tile fibres, including No. 1 and mine impurities ranging from large No. 2 crudes and Group 3 fibres. -j-4 mesh fragments of rock to --35 This amount includes 21,631 tons mesh granular material. Then the of spinning fibre from Canada, and clean fibres as well as the original 1,824 tons of C.&G. No. 1 and fibres are combined separately with No. 2 from Rhodesia. These fibres the necessary ingredients to produce usually are re-processed by the a commercial-product. Physical tests, . consumer and .then carded and on the product furnish further fac formed into blankets, rovings, tors for evaluating the fibre. threads, cords, ropes, and yarns of Should a sample of fibre pass laboratory tests, it is customary to request three to ten tons for a plant test before final approval is given. When the large shipment of fibre arrives it is thoroughly sampled and re-tested, and the data com pared with those of the original sample. If both sets of data are comparable and the plant tests are satisfactory, fibre specifications are drawn up for future purchases of this grade and variety of asbestos. In some cases, the quality of the fibre is so poor that anyone accus tomed to fibre examinations will realize that it is worthless before various classifications depending on demand. Asbestos cloths, tapes, wicks, and braided tubing all are made to meet particular specifica tions. Fibres prepared in the textile plant (3) are used in such products as awnings, brake linings, blankets, conveyors, curtains, clothing, gloves, bag filters, draperies, coverings for electrical and power plant equip ment, flexible metal tubings, pack ings, chemical filters, thermal in sulating materials, friction mate rials, clutch facings, gaskets, elec tric blankets, ironing board covers, joint fillers, turbine jackets and blankets, and plastics. their research units, where they are tests are made. The shortage of spinning fibre carefully examined for length.* 1 The three varieties of asbestos has resulted in off-grade so-called used in large quantities industrially Research Center, Johns-Manville Corporation, Manville. New Jersey, U.S.A. (1) Preliminary estimate by In dustry and Merchandising Division, Dominion Bureau of Statistics, Ot tawa. are chrysotile, amosite, and crocido lite. Although actinolite occasional ly appears on the market, no pub lished records show how much is used, and we may consider it of minor importance. (2) Bowl.ES, Oliver, U.S. Dept, of Interior, Washington, D.C., private communication. (3) A Primer on Asbestos Textiles, prepared by the Asbestos Textile In stitute, 1946. -- 30 -- UCC 004653 I * vfe-fr ' ;'textiie*r fibre*.' Being* offered1" to customers. Most of these fibres come from sources other then Canada and often are poorly graded. They .sometimes are brittle and contain high percentages of non-fibrous ma terials. On several occSSJoSs, small sam ples of textile fibres from foreign countries have been submitted and found to be satisfactory in length, strength, and in quantity of such impurities as magnetite, limestone, rock, and dust. An order of a ton of the fibre, however, proved en tirely different and resulted in large card drops because of brittle ness and non-uniformity of fibre length. Brokers submitting samples uf textile fibres should get a guaran tee from the miners that shipments of fibres will be equal to samples submitted to prospective customers. For papers and millboards, most manufacturers use fibres of Groups :l to 6, depending upon the kind of products being made. The longer fibres are used in special papers or diaphragms requiring sufficient length to give reinforcement. The types of paper products manufac tured by a paper mill are numerous and may be mentioned briefly as electrolytic ceil or diaphragm, wick, pipe covering, millboards, roofing papers, laminated roll-board, roof ing felts, pipe line felts, welding paper, and similar materials. Fibres for asbestos-cement prod ucts vary from Groups 4 to 7, in clusive. depending upon the methods of manufacture. This group of prod ucts includes shingles, pipes, jackets, flat sheets, corrugated sheets, wall boards, and electrical panels. Asbestos asphalt roof coatings usually contain fibres of Grenpa A and 7. and floats, depending upon the particular codtibg. being manu factured. The wiiyjp; floats was dis cussed in A*be*tfjtRf6St* (4) pre sented at the Ottowis'General Meet ing of the Institote in January, 1952. In this presentation, many of the physical properties and uses of floats were discussed. The popularity of flour tiles made from organic resins and as bestos fibres has resulted in ex ceedingly large sales. Group 7 fibres used in floor tiles by all lead ing United States manufacturers amounted to approximately 170,000 tons in 1952. * Asbestos-cements contain fibres of Groups 6 and 7, as well as floats, the fibre used being governed by the cement. The quantity of fibres nsed in these products in the United States in 1952 was approximately 30,000 tons. Amosite United States industry imported 18,319 tons of amosite fibres (5) from-South Africa last year. This was approximately 30 per cent of the total African production. Samples of amosites are being offered by many vendors and brokers. In some cases, the same samples appear under different identification numbers. These en velope samples actually are too small for evaluation and many times appear to be of good quality, al though larger samples of the same fibre, contain high percentages of rock and are rejected. In many cases-, the fibre length is so short that it falls into the filler classifica tion. When properly processed, this variety of asbestos is bulky and light, in density, and frequently is suitable for insulations. Amosite imported into the United States gradually is becoming short er in length and dirtier, and con tains considerable rock. It is neces sary, therefore, for the consumer to reprocess the fibre to remove the non-fibrons material which should have been removed in Africa. This additional processing cost plus loss of the non-fibrous material has raised the cost of this fibre to a point where substitutes will be given consideration. It is not known what kind of control tests are maintained an the production of amosite fibres in Africa, but it is suggested that, whatever they are, they should be reviewed in terms ' of consumer needs. Amosite is not as strong as chrysotild or crocidolite, nor does it have the good flexing properties of thesefibres for use in textiles. Occasional samples of amosite, however, possess sufficiently high strength and* good flexing properties to be tise<J in textiles, if they were avail able in quantity. Products requiring light weight and not needing high strength' can be greatly improved by the use of this variety of asbes tos. Amosite fibres, with or without other varieties of- fibres, will exhibit - ,,. ----------- _ and good insulation properties,'and; when properly processed, can be formed into magnesia blocks and pipe coverings of low density and good insulating properties. Amosite, combined with- other; fibres and fillers, is used to prexfohe. ' lightweight asbestos-cement wallboarda that are attractive,, easy toinstall, and possess good insulation properties. A most recent installa tion of this construction is found in. the fireproof walls of the new American ship, Untied State*. Crocwoute Crocidolite asbestos is fonnd in commercial quantities in South Africa and also in Austria. Small er mines in other countries do not produce mnch fibre of this variety. Africa produced 44,734 tons of crocidolite last year. United States industry imported about 7,100 tons, including 274- tons of Australian Blue fibre (6). That the quality of crocidolite fibre has decreased during thejst - five' years is evidenced by a*, de crease in length and an increase In rock and extreme fines in the form of finely gronnd ironstone. Many vendors and brokers are offering,. , samples of crocidolite as odd lots. Some fibres are so short that they fall' into the filler class. If the - quality of this variety of- fibre con tinues to decrease, it will be uat- ; oral for customers to investigate substitutes. ` .- Because of its physical proper ties, crocidolite lends itself to some special applications that are not practical for chzysotile. For, exam-1 pie, this type of fibre has very high tensile strength, has good- addi-xl,!. resisting properties, will gWe good porosity when farmed into * Bites mat, and will. Biter oat small pat- .V-T' ,f tides of dusts, smokes, apd: strict pended particles in gases, " '- Crocidolite can be converted-into- ' textiles with some difficulty bifc ' it does not lend itself to carding and N weaving as easily as does' cbtySotile. - Probably its greatest application Is in . asbestos-cement products ' where its properties of strength and , increased porosity improve mano- ,. factoring processes and boost pro- c. . dnetion- rates. Crocidolite Is ex- - ; tremely effective in acid-resisting gaskets and the so-called service (4) Bajjollet, M.S., Trans., Vol. LV, 1952, pp. 185-189. (6) Bowles, Oliver, U.S. Dept, of Interior, Washington, D.C., private communication. (6) Bowles. Oliver, U.S. Dept of Interior, Washington, D.C., private communication. -31 -- UCC 004654. & .ssizSi