Graphite is a crystalline form of carbon. Hexagonal crystal system, in iron ink to dark gray color. Density 2.25 g/cm3, hardness 1.5, melting point 3652 ℃, boiling point 4827 ℃. Soft in texture, with a smooth and conductive feel. Chemical properties are not active, corrosion-resistant, and not easily reactive with acids, alkalis, etc. Strengthening heat in air or oxygen can burn and generate carbon dioxide. Strong oxidants will oxidize it into organic acids. Used as an anti friction agent and lubricating material, making crucibles, electrodes, dry batteries, and pencil leads. High purity graphite can be used as a neutron moderator in nuclear reactors. It is often referred to as charcoal or black lead because it was previously mistaken for lead.

Main uses of graphite:

1. Used as refractory material: Graphite and its products have properties of high temperature resistance and strength, and are mainly used in the metallurgical industry to manufacture graphite crucibles. In steelmaking, graphite is commonly used as a protective agent for steel ingots and as a lining for metallurgical furnaces.

2. As a conductive material: used in the electrical industry to manufacture electrodes, brushes, carbon rods, carbon tubes, positive electrodes for mercury positive current transformers, graphite gaskets, telephone parts, coatings for television tubes, etc.

3. As a wear-resistant lubricating material: Graphite is often used as a lubricant in the mechanical industry. Lubricating oil often cannot be used under high-speed, high-temperature, and high-pressure conditions, while graphite wear-resistant materials can work without lubricating oil at high sliding speeds at temperatures of 200-2000 ℃. Many devices that transport corrosive media are widely made of graphite material to make piston cups, sealing rings, and bearings, which do not require the addition of lubricating oil during operation. Graphite emulsion is also a good lubricant for many metal processing (wire drawing, tube drawing).

4. Graphite has good chemical stability. Specially processed graphite has the characteristics of corrosion resistance, good thermal conductivity, and low permeability, and is widely used in the production of heat exchangers, reaction tanks, condensers, combustion towers, absorption towers, coolers, heaters, filters, and pump equipment. Widely used in industrial sectors such as petrochemical, hydrometallurgy, acid-base production, synthetic fibers, papermaking, etc., it can save a large amount of metal materials.

The variety of impermeable graphite varies in corrosion resistance due to the different resins it contains. Phenolic resin impregnators are acid resistant but not alkali resistant; Furfuryl alcohol resin impregnators are both acid and alkali resistant. The heat resistance of different varieties also varies: carbon and graphite can withstand 2000-3000 ℃ in a reducing atmosphere, and begin to oxidize at 350 ℃ and 400 ℃ respectively in an oxidizing atmosphere; The variety of impermeable graphite varies with the impregnating agent, and it is generally heat-resistant to below 180 ℃ by impregnating with phenolic or furfuryl alcohol.

5. Used for casting, sanding, molding, and high-temperature metallurgical materials: Due to the small thermal expansion coefficient of graphite and its ability to withstand changes in rapid cooling and heating, it can be used as a mold for glassware. After using graphite, black metal can obtain precise casting dimensions, high surface smoothness and yield, and can be used without processing or slight processing, thus saving a large amount of metal. The production of hard alloys and other powder metallurgy processes typically involves using graphite materials to make ceramic boats for pressing and sintering. The crystal growth crucible, regional refining container, support fixture, induction heater, etc. of monocrystalline silicon are all processed from high-purity graphite. In addition, graphite can also be used as a graphite insulation board and base for vacuum smelting, with high temperature resistance.

6. Used in the atomic energy industry and national defense industry: Graphite has excellent neutron moderators for use in atomic reactors, and uranium-graphite reactors are a widely used type of atomic reactor. The deceleration material used in atomic reactors for power should have high melting point, stability, and corrosion resistance, and graphite can fully meet the above requirements. The purity requirement for graphite used as an atomic reactor is very high, and the impurity content should not exceed dozens of PPMs. Especially, the boron content should be less than 0.5PPM. In the national defense industry, graphite is also used to manufacture nozzles for solid fuel rockets, nose cones for missiles, components for space navigation equipment, insulation materials, and radiation protection materials.

7. Graphite can also prevent boiler scaling. Relevant unit tests have shown that adding a certain amount of graphite powder (approximately 4-5 grams per ton of water) to water can prevent boiler surface scaling. In addition, graphite coating on metal chimneys, roofs, bridges, and pipelines can prevent corrosion and rust.

8. Graphite can be used as pencil lead, pigment, and polishing agent. After special processing, graphite can be made into various special materials for use in relevant industrial departments.

9. Electrode: Graphite has good conductivity and low resistance. Graphite electrodes can be produced for smelting furnaces and electric arc furnaces in steel and silicon factories.