Uses of graphite
1. Refrachitetory materials include refractory bricks, crucibles, continuous casting powder, mold cores, mold detergents and high temperature resistant materials.
Magnesia-carbon brick magnesia-carbon refractories were successfully developed by the United States in the mid-1960s; magnesia-carbon bricks have been widely used in steelmaking worldwide and have become a traditional use of graphite. Aluminum-carbon bricks and aluminum-carbon refractories are mainly used for continuous casting, protective covers for slab self-positioning pipelines, underwater nozzles, and oil well blasting tubes.
Shaped and refractory crucibles and related products made of graphite, such as crucibles, retorts, stoppers and nozzles, have high fire resistance and low thermal expansion. During the process of smelting metals, they are exposed to metal infiltration and erosion. It is also stable, with good thermal shock stability and excellent thermal conductivity at high temperatures, so graphite and related products are widely used in the process of direct melting of metals.
Graphite and other impurity materials can be used as recarburizers when used in the steelmaking industry. The range of carbonaceous materials used in carburizing is very wide, including artificial graphite, petroleum coke, metallurgical coke and natural graphite. Graphite for steelmaking recarburizers is still one of the main uses of earthy graphite in the world.
3. As a conductive material
Graphite is widely used in the electrical industry as electrodes, brushes, carbon rods, carbon tubes, positive electrodes of mercury rectifiers, graphite washers, telephone parts, coatings for television picture tubes, etc. Among them, graphite electrodes are the most widely used. When smelting various alloy steels and ferroalloys, graphite electrodes are widely used. The graphite used in the electrical industry has very high requirements for particle size and grade.
4. As a wear-resistant and lubricating material
Graphite is often used as a lubricant in the machinery industry. Lubricating oil often cannot be used under high-speed, high-temperature, and high-pressure conditions, while graphite wear-resistant materials can work at a temperature of between 200°C and 2000°C and at a very high sliding speed (loom / s) without lubricating oil. Many equipment for transporting corrosive media widely use graphite materials to make piston rings, seals and bearings. When they are running, no lubricating oil is needed. Graphite emulsion is also a good lubricant for many metal processing (wire drawing, pipe drawing).
5. As corrosion resistant material
Graphite has good chemical stability. Specially processed graphite has the characteristics of corrosion resistance, good thermal conductivity, and low permeability. It is widely used in the production of heat exchangers, reaction tanks, condensers, combustion towers, absorption towers, coolers, heaters, and filters , Pumps and other equipment. These equipment are used in petrochemical, hydrometallurgy, acid-base production, synthetic fiber, papermaking and other industrial sectors, which can save a lot of metal materials.
6. Used in the atomic energy industry and national defense industry
Graphite has good neutron deceleration performance, and was first used as a moderator in atomic reactors. The "uranium-graphite" reactor is currently the most widely used type of atomic reactor. The deceleration material in the nuclear reactor used as power should have a high melting point, stability, and corrosion resistance. Graphite can fully meet the above requirements.
7. Used as anti-scaling and anti-rust material
Graphite can prevent boiler fouling. Tests have shown that adding a certain amount of graphite powder to the water can prevent scaling on the boiler surface. In addition, graphite coating on metal chimneys, roofs, bridges, and pipes can prevent corrosion and rust.
8. New uses of graphite
1) Flexible graphite products. Flexible graphite, also known as expanded graphite, is a new graphite product developed in the 1970s. In 1971, the United States successfully researched flexible graphite sealing materials and solved the leakage problem of atomic energy valves. Subsequently, Germany, Japan, and France also began to develop and produce. In addition to the characteristics of natural graphite, this product also has special flexibility and elasticity. Therefore, it is an ideal sealing material, widely used in petrochemical, atomic energy and other industrial fields, and the international market demand is increasing year by year.
2) Making semi-metal friction materials. Since the 1970s, semi-metal friction materials have been widely used in clutches and automatic linings. Semi-metal friction material is made by bonding graphite, metal powder, steel fiber, and clay powder with synthetic resin. These automatic linings are mainly used for high-speed equipment, such as brake devices and clutch plates for airplanes, trucks and off-road vehicles.