Ground talc

Steamic OOS, OOS D - micronized and finely ground talc for PP dashboards and bumpers IN, Extra 5/O-MlO, Prever, M8, MIOC, M8C, M30 - talc from Val Germanasca mine in Italy for rubber and plastics Paint grades... 

Glacier. [Cyprus Industrial Min.] Coarse ground talc for fertilizers and insecticides. 

Be cautious about using ground talc on your body... 

Figure 8.6 Scanning electron microscopy photomicrograph of typical ground talc. 

Talc is the name given to hydrated magnesium silicate, which has the theoretical formula 3Mg0-4Si02 H20 and it occurs in several ores from which talc products can be made. The form of most use in plastic formulations is finely ground talc, which consists of thin platelets. It is considered to be a reinforcing filler in many compound applications, although it can also be described as an extender because of its low cost. 

Because of talc s lubricity characteristics and the concomitant improvements in a rubber compound s flow characteristics in extrusion or injection molding, there could be problems in directly substituting it for clay or whiting. Also, talc does a better job of imparting reduced air permeability than the other economic diluents. It has been reported that ground mica and clay together can sometimes be used to substitute for ground talc. 

Talc milling is largely a grinding operation accompanied by air separation. Most of the industrial talcs are diy-ground. Diyers are commonly employed to prediy ahead of the milling operation because the wet material reduces mill capacity by as much as 30 percent. 

The mills in the western United States, in which generally are ground softer talcs than those of New York, have simple flow sheets. Single-stage crushing is employed, and the talc is merely ground in Raymond roller mills in closed circuit with air separators. 

For electrical insulation china clay is commonly employed whilst various calcium carbonates (whiting, ground limestone, precipitated calcium carbonate, and coated calcium carbonate) are used for general purpose work. Also occasionally employed are talc, light magnesium carbonate, barytes (barium sulphate) and the silicas and silicates. For flooring applications asbestos has been an important filler. The effect of fillers on some properties of plasticised PVC are shown in Figure 12.21 (a-d). 

Traditionally ceramic raw materials have been dug out of the ground and used with little or no treatment or purification. Sand, fireclay, talc, and gypsum are examples. The energy expenditure for producing these materials is therefore small. Some of these materials can be found naturally in high purity. Silica sands (SiO,) with less than 100 ppm (parts per mil-... 

Talc is a soft, large-molecule phyllosilicate mineral having a characteristic waxy luster. Ground to a floury texture, it used as bath powder and as a base for cosmetics. It is also used as a filler in food, as a dry lubricant, and in the manufacture of some kinds of paper. 

There are three formulations of sulfur used predominantly today. The first is finely ground sulfur mixed with 1 to 5 percent talc or clay to assist in the dusting effectiveness. The sulfur in this form may be used as a carrier for additional pesticides. The second form is colloidal sulfur that is so fine that it must be formulated as a paste to enable it to be mixed with water. The third form is wettable sulfur. In this formulation the sulfur is finely ground with a wetting agent so that it will mix readily with water for spraying. 

---