Non-metallic mineral powder I - mica

Mica is the general name of the mica group minerals. It is an aluminosilicate containing potassium, aluminum, magnesium, iron, lithium and other metals. Its structure is layered. From the perspective of formation, it can be divided into natural mica and artificial mica.
Natural mica mainly includes biotite, phlogopite, muscovite, lepidolite, sericite, chlorite, ferrolepidolite, etc. The mica ore is a shallow ore, and generally distributed in large mountains and plateaus, and its hardness is in direct proportion to the altitude of the origin, that is, the higher the sea level of the ore vein, the higher the purity and hardness of natural mica, the better the mechanical properties, and vice versa. The whiteness is related to the distribution of other metal ores in the original ore area. For example, if there is iron ore near a mining area, the whiteness of the natural mica produced in the mining area will be slightly poor. If there is calcium carbonate or talc ore near the mining area, the whiteness of the mica produced in the mining area will be better.
Muscovite, sericite and phlogopite are the most widely used in industry. Muscovite is an important industrial raw material, and its hardness is excellent in the natural mica category. It can be used as a reinforcing filler, toughening agent, physical ultraviolet reflector and other applications in the coating field; In the field of cosmetics, it can play the role of increasing slippery, reducing costs, sunscreen, etc; It is an extremely excellent filler in the field of plastics, which can greatly reduce costs and enhance the physical properties of plastics. It is an excellent filler necessary for many important engineering plastics. The structural composition of sericite is close to that of muscovite, but its hardness is weak due to its low altitude, but its powder has excellent processability. It can be superfine ground with ordinary dry process equipment. It is a high-quality filler for wood paint, cable and other industries. The abrasion resistance of phlogopite is the best of all natural mica, and it is generally used as the raw material of high-end wear-resistant materials (such as brake pads). Lithium mica is an important mineral raw material for lithium extraction.
Due to the influence of geographical distribution, the composition, quality and batch product stability of natural mica are not very stable, causing great inconvenience to customers' application. In addition, China's high-quality natural muscovite resources are mainly concentrated in Sichuan and Xinjiang, and the mining and transportation are subject to environmental restrictions. At present, the main source of high-quality muscovite in China is imported from India or Pakistan. As an important strategic mineral, the country has carried out the research and development of artificial mica in the 1970s, and now it is ready for mature industrial production. The existing synthetic mica is mainly divided into fluorogold synthetic mica, wet lithium-based synthetic mica and special functional synthetic mica. Among them, fluorogold synthetic mica is the most industrialized synthetic mica product with the widest range of application. Compared with natural mica, it has great advantages in various physical and chemical properties.
Processing technology of mica:
Because mica is a peelable sheet structure, its processing technology is generally divided into dry method and wet method.
As the name implies, the dry method is the process of direct crushing by mechanical force in the anhydrous environment. At present, domestic low-end filler grade mica powder is produced by this method.Features of dry processing products:
1. Low price
2. Uneven distribution of mica powder by relative specific humidity method
3. The ratio of diameter to thickness is uneven, which can only be used for low-end products
4. The whiteness is worse than that of wet method
5. High impurity content
6. High production efficiency
Wet grinding, as the name implies, takes water as the medium to grind mica for a long time in a grinder. Its principle is to use the mechanical force generated by the relative motion of the grinding wheel to crush mica. High-end mica powders are all wet grinding.
Features of wet processing products:
1. Higher price
2. The particle size distribution is uniform and controllable
3. Good diameter-thickness ratio, high mica transparency
4. Good whiteness
5. Low impurity content after repeated washing, suitable for high-end scenarios