TALC — natural magnesium silicate; mineral from a subclass of layered silicates (chemical structure 4SiO • 3MgO • H 2 O).
Very small white or inodorous slightly grayish powder and taste, fat and slippery to the touch. Practically we will not dissolve in water, to-takh and other solvents. Crystals of T. soft (hardness on a mineralogical scale 1), give double refraction, are visible in the polarizing microscope, density of 2776 — 2824 kg/m 3 .
T. apply in various industries, including in medical and perfumery and cosmetic. For the medical purposes T. use in the form of the smallest powder (sieve No. 1) which is carefully purified of impurity. Will sterilize a hot air at t ° 180 or 200 °.
In the medical practician T. apply as the adsorbing means (see) at burns, dermatitis, an intertrigo, the becoming wet ulcers, and also at massage, in pharmaceutical practice as aid for tabletting, pelleting, during the sprinkling of pills, production of fragrant waters (as cleaning agent), pastes and ointments, and also as a basis of compound powders for external use, hairremovers, powders and powders (e.g., children's powder from perspiration). Powders from talc unlike the powders containing organic matters (starch, vegetable sulfur) are the adverse environment for development of microorganisms.
Locally T. makes mechanical and chemical impact on fabrics and in this regard can sometimes cause hron. proliferative inflammation and development of so-called talc granulomas. At the persons occupied with production and processing of T., emergence of a talcosis is possible, to-ry is a version pneumoconiosis (see). The main measures of prevention of a talcosis same, as at other pneumoconiosis (mechanization and automation of work, dust suppression and a pyleulavlivaniye, use of respirators).
A. I. Tentsova.