Graphite soft, black gray; Greasy and can contaminate paper. The hardness is 1 ~ 2, and the hardness can be increased to 3 ~ 5 along the vertical direction with the increase of impurities. The specific gravity is one. 9 ~ 2. 3. Scope of specific surface area is focused on the 1-20 m2 / g, under the condition of starvation, its melting point above 3000 ℃, is one of the most heat-resistant mineral. It conducts electricity and conducts heat.
According to these characteristics, graphite products are commonly used in the following industries:
1. Refractory: graphite and its products have the properties of high temperature resistance and high strength. In the metallurgical industry, graphite is mainly used to make graphite crucible. In steelmaking, graphite is commonly used as the protective agent of ingots and the lining of metallurgical furnace.
2. Conductive materials: used in the electrical industry to manufacture anode of electrode, brush, carbon rod, carbon pipe and mercury current rectifier, graphite washer, telephone parts, and coating of TV picture tube, etc.
3. Wear resistant lubricating material: graphite is often used as a lubricant in the mechanical industry. Lubricating oil can not be used in high speed, high temperature and high pressure conditions, and graphite wear-resisting material can be in 200 ~ 2000 ℃ temperature under high sliding velocity, no lubricating oil. Many devices for transporting corrosive media are made of graphite into piston cups, sealing rings and bearings. Graphite milk is also a good lubricant for many metal processing (wire drawing, tube drawing).
4. Graphite has good chemical stability. Specially processed graphite, with corrosion resistance, good thermal conductivity and low permeability, is widely used in the production of heat exchangers, reaction tanks, condensers, combustion towers, absorbers, coolers, heaters, filters and pumps. Widely used in petrochemical industry, wet metallurgy, acid and alkali production, synthetic fiber, papermaking and other industrial sectors, can save a lot of metal materials.
5. casting, aluminum casting, molding and high temperature metallurgical materials: due to the small thermal expansion coefficient of graphite, and ability to the change of thermal shock, can be used as glass mold, after using graphite black metal casting dimension precision, smooth surface high yield, without processing or make a little processing can use, thus saving a large amount of metal. The production of cemented carbide and other powder metallurgy processes, usually made from graphite materials die and sintering porcelain boats. The crystal growth crucible of monocrystalline silicon, regional refining vessel, bracket clamping device and induction heater are all made of high purity graphite. In addition, graphite can be used as graphite heat insulation board and base for vacuum smelting, high temperature resistance furnace tube, rod, plate, lattice shed and other components.
6. Used in the atomic energy industry and defense industry: graphite has good neutron moderator used in atomic reactors, and uranium - graphite reactor is one of the most widely used atomic reactors at present. The deceleration material in a power reactor should have high melting point, stability and corrosion resistance. Graphite can meet the above requirements. Graphite, used as an atomic reactor, has high purity requirements and should contain no more than a few parts per million of impurities. In particular, the boron content should be less than 0.5PPM. Graphite is also used in the defense industry to make nozzles for solid fuel rockets, nose cones for missiles, components for space navigation equipment, insulation and radiation protection materials.
7. Graphite can also prevent the boiler from scaling. Relevant unit tests have shown that adding a certain amount of graphite powder (about 4-5 grams per ton of water) to water can prevent the boiler from scaling. In addition, graphite can be anticorrosive and rust-proof on metal chimneys, roofs, Bridges and pipelines.
8. Graphite can be used as pencil core, pigment and polishing agent. After special processing, graphite can be made into various special materials for the relevant industrial departments.
9. Cathode materials.
10. Modification agent to improve the abrasion resistance of rubber.