TALC 



621 



O 200 



1 r 



1 r 



Figure 69.— Talc and soapstone produced and used by major consuming industries in the United States, 1950-1970. Other 

 uses include asphalt filler, crayons, exports, fertilizer, floor and wall tile, foundry facings, electrical insulation, joint 

 cement, plastics, rice polishing, textile coating, toilet preparations, and miscellany. 



The United States has abundant reserves and re- 

 sources of talc, but is deficient in certain grades 

 such as block steatite used for high-frequency insu- 

 lators, and cosmetic talc. In 1970, imports of talc 

 were 29,988 short tons, and exports were about 

 105,000 tons. Use of flotation and magnetic separa- 

 tion methods in the processing of talc has made us 

 less dependent on imports for cosmetic-grade talc, 

 although in 1970 imports of cosmetic-grade talc 

 from Italy were markedly increased. Phosphate- 

 bonded synthetic "lava" talc and die-formed steatite 

 is being increasingly substituted for block steatite 

 for ceramic insulator needs; however, a residual 

 demand for block steatite for high-frequency insu- 

 lators will probably continue. 



COMPETITIVE MINERALS 



Many minerals are competitive with talc for 

 ceramic and filler uses. Kaolin is commonly used as 

 a base for wall tile, but such clay-base tile absorbs 

 water and expands causing the glaze to craze (Gas- 

 kins, 1952) . Addition of a certain amount of talc to 



the base material alleviates this condition and im- 

 proves translucency and toughness of the tile. An- 

 other important competitive use of kaolin is as paper 

 filler and coater. Ground limestone is substituted 

 for talc as a paint pigment extender, but it is 

 reactive and does not have the scaly and fibrous 

 particle shape of talc that aids in both coating 

 and holding pigment in suspension. Wollastonite 

 (CaSiOs) has most of the good qualities of talc and 

 is directly competitive in the ceramic and paint in- 

 dustries (Andrews, 1970). However, reserves of 

 wollastonite are relatively small in the United 

 States, and this mineral is now mined only in Essex 

 County, N.Y., and in Riverside and Inyo Counties, 

 Calif. Synthetic molded laboratory work surfaces 

 are increasingly being used as a substitute for 

 sawed soapstone slabs. Some of the synthetic ma- 

 terial probably contains talc as a filler, and the 

 overall tonnage of talc consumption may therefore 

 not be seriously decreased, but a much less expen- 

 sive form of industrial talc will be consumed. 

 Pyrophyllite, a mineral with physical properties 



