Technological characteristics and main uses of mica
Sep 19, 2022
1. Process characteristics
(1) Physical properties. The physical properties of mica mainly depend on the size of the mica crystal, the exfoliation determined by cleavage and hardness, and the color transparency and elasticity of the mica. Industrial mica is mostly in the form of laminated or book-like crystals, with crystal sizes ranging from a few millimeters to tens of centimeters in thickness. Generally, as long as the effective area of the crystal is greater than or equal to 4cm2, it has direct utilization value. Of course, the larger the crystal area, the higher the value. The exfoliation performance of mica is determined by the cleavage and hardness of mica. The unique crystal structure of mica enables it to have a set of extremely complete cleavage of the bottom surface, which has become an important property of industrial mica technology for processing and stripping. In theory, muscovite can be stripped to about 10, and phlogopite can be stripped to about 5-10. Therefore, muscovite and phlogopite can be stripped and divided into flat sheets of any thickness according to industrial requirements to meet the requirements of electrical and electronic industries for mica.
requirements. The hardness of mica is relatively low, 2-2.5 for muscovite, 2.37 for magnesium-silica muscovite, and 2.78-2.85 for phlogopite. The harder the mica, the harder it is to peel. The peeling performance of muscovite and magnesium-silicon muscovite is better, but phlogopite is slightly worse. The color characteristics of mica are often used to characterize the insulating properties of mica. Generally, light-colored muscovite is better for industrial mica, followed by phlogopite, and biotite has poor insulating properties. The elastic coefficient of muscovite is 15346-21760bar, and that of phlogopite is 14500-19480bar. When mica is used as an insulating material in industry, there are strict requirements for its elasticity.
(2) Electrical properties. The pros and cons of mica insulation performance are the main factors that determine its industrial value. The mica insulation performance is determined by the electrical properties of mica. The electrical properties of mica are determined by testing the breakdown voltage and breakdown strength. According to the statistics of the test results of mica in various mining areas in my country, when the thickness of the mica sheet is 0.015mm, the average breakdown voltage is 2.0-5.7kV, and the breakdown strength is 133-407kV/mm.
(3) Optical properties. The optical properties of mica are listed in Table 2.
Muscovite: In industry, the natural crystals of mica are directly processed into the desired products. The larger the mica crystal without defects is, the higher its economic value is. Therefore, in the process of beneficiation of mica ore, it is necessary to protect the natural mica crystal from damage as much as possible.
