Mica process characteristics and main uses
    1. Process characteristics
    (1) Physical properties. The physical properties of mica mainly depend on the size of mica crystals, the stripping properties determined by cleavage and hardness, and the color transparency and elasticity of mica. Industrial mica is mostly in the form of a plate or a book-like crystal, and the crystals vary in size from a few millimeters to several tens of centimeters. Generally, as long as the effective area of the crystal is greater than or equal to 4 cm2, it has direct use value. Of course, the larger the crystal area, the higher the value. The stripping performance of mica is determined by the cleavage and hardness of mica. Mica's unique crystal structure gives it a very complete set of bottom cleavage, which is an important property of industrial mica technology 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 of flat sheets of any thickness according to industrial requirements to meet the mica of electrical and electronic industries. Requirements. The hardness of mica is low, the muscovite is 2-2.5, the magnesia-silica muscovite is 2.37, and the phlogopite is 2.78-2.85. The harder the mica is, the more difficult it is to peel. Muscovite and magnesium-silica muscovite have better stripping performance, and phlogopite is slightly worse. The color characteristics of mica are often used to characterize the insulation properties of mica. Industrial mica is generally preferred to light-colored muscovite, followed by phlogopite, which has the worst insulation performance. Muscovite has a modulus of elasticity of 15346-21760 bar and phlogopite of 14500-19480 bar. When industrial mica is used as an insulating material, its elasticity is strictly required.
    (2) Electrical performance. The advantages and disadvantages of mica insulation performance are the most important factors determining the value of industrial use. 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 test results of mica in various mining areas in China, when the mica sheet thickness is 0.015 mm, the average breakdown voltage is 2.0-5.7 kV, and the breakdown strength is 133-407 kV/mm.
    (3) Optical properties. The optical properties of mica are listed in Table 2. muscovite:
    The industry mainly uses mica natural crystals directly to process the desired products. The larger the mica crystal without defects, the higher its economic value. Therefore, in the process of beneficiation of mica ore, it is necessary to protect the natural crystals of mica from damage as much as possible.