Mica Definition

Ground mica is used in the well drilling industry as an additive to drilling fluids. Coarsely ground mica flakes help prevent circulation loss by sealing the porous sections of the borehole. Well drilling muds accounted for 15% of mica consumption in dry soil in 2008. The plastics industry used crushed dry mica as an extender and filler, especially in automotive parts as lightweight insulation for noise and vibration suppression. Mica is used in plastic car covers and fenders as a reinforcement material that provides improved mechanical properties and increased dimensional stability, rigidity and strength. Horizontally reinforced plastics also have high dimensional stability, reduced distortion and the best surface properties of all filled plastic composites. In 2008, the consumption of dry ground mica in plastic applications accounted for 2% of the market. The rubber industry used crushed mica as an inert filler and release compound in the manufacture of molded rubber products such as tires and roofs. The platy texture acts as an anti-block non-stick device. Rubber moulding lubricants accounted for 1.5% of dry-ground mica used in 2008. As a rubber additive, mica reduces gas permeation and improves elasticity. [20] Micas other than glauconite tend to crystallize as short pseudohexagonal prisms.

The lateral surfaces of these prisms are usually rough, with some appearing striped and blunt, while the flat ends tend to be smooth and shiny. The frontal surfaces are parallel to the perfect division that distinguishes the group. Dry mica is used in the manufacture of rolled roofs and asphalt shingles, where it is used as a surface coating to prevent adhesion to adjacent surfaces. The coating is not absorbed by freshly manufactured roofs, as the structure of the mica plate is not affected by acid present in the asphalt or weather conditions. Mica is used in decorative coatings on wallpaper, concrete, stucco and tile surfaces. It is also used as an ingredient in flux coatings on welding wires, in some special greases and as coatings for core and mold release compounds, roofing agents and mold washes in foundry applications. Dry phlogopit mica is used in brake linings and clutch discs of motor vehicles to reduce noise and vibration (a substitute for asbestos); as sound-absorbing insulation for coatings and polymer systems; in the reinforcement of polymer additives to increase strength and stiffness and to improve stability against heat, chemicals and ultraviolet (UV) rays; in heat shields and thermal insulation; in the industrial coating additive to reduce the permeability of moisture and hydrocarbons; and in polar polymer formulations to increase the strength of epoxies, nylons and polyesters. [20] Wet ground mica, which retains the shine of its low-cut surfaces, is mainly used in pearlescent paints in the automotive industry. Many metallic-looking pigments consist of a mica substrate coated with another mineral, usually titanium dioxide (TiO2). The resulting pigment produces a reflective color, depending on the thickness of the coating. These products are used to produce automotive paints, shimmering plastic containers, high-quality inks for advertising and security applications. In the cosmetics industry, its reflective and refractive properties make mica an important ingredient in blush, eyeliner, eye shadow, foundation, hair and body glitter, lipstick, lip gloss, mascara, moisturizing lotions and nail polish.

Some brands of toothpaste contain powdered white mica. This acts as a mild abrasive to help polish the surface of the tooth, giving the paste a cosmetically appealing and sparkling sparkle. Mica is added to latex balloons to achieve a colorful shiny surface. [20] Some lightweight aggregates such as diatomite, perlite and vermiculite can replace ground mica when used as a filler. Ground synthetic fluorophlogopite[48], a fluorine-rich mica, can replace ground natural mica for applications requiring thermal and electrical properties of mica. Many materials can replace mica in many electrical, electronic and insulating applications. Substitutes include acrylate polymers, cellulose acetate, fiberglass, fish paper, nylon, phenols, polycarbonate, polyester, styrene, PVC vinyl and vulcanized fibers. Mica paper from mica waste can replace sheet mica in electrical and insulating applications. [19] In 2008, mica fission accounted for most of the mica wafer industry in the United States.

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