Document gEVQ5kqdy3xMVm5kBgoN7reJ

CAM-278 ),;,!II :: i- ;I /:i.!iiii Ii_'!II'; r I !I:II' ii i; I./,rIi: ! Table!. T:ilc liN:ral Composition5 Talc Tremolite " 92'(, '2 " U:!r 'J2' 0 Anthophyllile Serpenti Qu.tnz Chlorite Dolomite (I 2 Ii J l '. I 'I '' . 2 10 .) I Calcile \la,:nesite ', 0 . ) 2 I pure talcs have varying degrees of whiteness. Figure 4 depicts a crude rock from Montana. Ttrheme epusroefttnael;ssm, hinyedrraolpihsocbhiacns\cutrefraiczee<lprboypeitrstieexs, micaeous structure, and slippery !eel. Although pure talc is the standard of one on the Mohs Scale of hardness, some commercinl talcs ml\y exhibit more abrasive properties clue to the pres ence of impurities such ns dolomite, calcite, tremolite, and quartz. Cosmetic talc is lamellar in particle shape and this structure produces the slippery !eel. This occurs where the platy talc sheet slides over another sheet. This shearing action tends to <lelaminate the talc stacks. Commercial talcs are n1ined in a variety of ways, including straightforward drill, blast and North " ';12":0 '.0 ,) . 'I '. 2 ")l ,os. )0 'iO ) .2 ). I 2 0 2 I .) I " '1<)\, '12 "')()"., ' 'I ' ") . I . 10 Figure 5. Crude tole O!Mn pit mining. Figur 4. Montono tole en.rd rock. shovel, and open pit oper.itions such as shown . Figure 6. Talc mill in Th,.. Forks, Montana. in figure 5. Other deposits must be mined with using additional milling equipment and air chts complicated underground equipment. The sification. These products arc used in ,\erosol crude rock is then transported to the mill for and makeup applications. processing. In many industrial talc applications, f1ner par Figure 6 shows a talc mill which is situated in ticle size products with a median particle size of Three Forks, Montana. Traditional processing 1 .m are required. These products are not, how inv9lves crushing with a jaw-type crusher and ever, suitable for cosmetic applications. then milling in a roll-type mill. Figure 7 depicts Manv talc:s in their natural state are unsuitable a Raymond Roller Mill used for talc grinding. for cosmetic applications. If this is the case, up The product is collected in cyclones and bag gniding procedures must be used to make the ged. Dust is controlled by "bag house" dust talc acceptable to meet cosmetic spet'ific:ations. collectors. Conventional cosmetic talcs for Upgrading techniques include lloatation an,lior dusting and baby powder applications are usu acid leuchini: to the degree of dicmical purity n.lly manufactured in this manner. These mate an<l color needed. However, this ttpgrading is an rials are normally ground to specifications of expensive and energy-intensive additional 11ro 98% minimum through a 200 mesh (74 .m) cessin step which is avoided if at all po,sihle. screen. Other products are ground to a f1neness There are some high quality cosmetic tak de .I o!' 99.9% through a 325 mesh (44 .m) screen 30/Cosmetics & Toil,mies posits in the U.S. whit'h do not nt1.d lw11cL1t- Vol. 94, Februory 197C BASF EMTAL000005185