The general chemical composition of talc powder is 3Mgo, 4SiO2 and H20, or more easily magnesium silicate. About 30 to 32.5 percent is made of magnesium, also known as MgO. About 64 to 66 percent is made of silicate, or SiO2, and the rest is made of hydrogen or H20. Fe2O3 makes up 0.5 percent, CaO makes up 1.5 to 2.5 percent and Al2O3 makes up 0.6 percent.
Talc powder looks like and can be considered a white, fine and smooth powder. It has a special gravity of 2.7 to 2.9 and a bulk density of 0.5 percent. Ninety-four percent of talc powder is white and it has an oil absorption value of 35 to 40 percent. Its hardness is measured as 1 Mohs and it has a maximum of 5 percent water soluble matter. Talc powder has a 0.5 percent moisture and volatile matter at 221 degrees Fahrenheit. The powder has a minimum of 88 percent combined magnesium calcium silicate.
Talc powder can be used on paper to add smoothness and brightness as well as act as a pitch absorber. It can be used on paint jobs for wood finishes, primers, putties, architectural finishes and water-based coatings. The powder gives paint corrosion protection and improves the overall exterior durability of paint.
Talc powder can be used on ceramics to improve their resistance to thermal shocks and provide the ceramics with better electrical properties. The powder also adds resistance and toughness to spark plugs and switch boards. It is used for mold making and for the final finish of foundries. Talc powder is used as a filler in plastics and rubbers as well as a smooth, silky finish for cosmetics.
Talc powder should be stored in a dry area and has a shelf life of up to five years. it is a nonflammable and nonhazardous material.