Graphite is broadly classified into two main categories: natural graphite and synthetic graphite. Natural graphite is derived from graphite deposits and can be further subdivided into flake graphite, amorphous graphite, and massive graphite. Naturally mined graphite typically contains a high level of impurities, necessitating beneficiation to reduce these impurities before it can be used. The primary applications of natural graphite include the production of refractories, carbon brushes, flexible graphite products, lubricants, and anode materials for lithium-ion batteries; in some cases, a certain amount of natural graphite is also added during the manufacture of carbon-based products. In the carbon industry, the largest volume of production consists of various synthetic graphite products. These are generally manufactured using graphitizable petroleum coke and pitch coke as raw materials, undergoing a series of processes—including batching, kneading, molding, baking, graphitization (high-temperature heat treatment), and mechanical machining—resulting in a production cycle that can extend over several dozen days. Synthetic graphite encompasses a wide range of types, such as single-crystal graphite, polycrystalline graphite, pyrolytic graphite, highly oriented pyrolytic graphite, polyimide-derived graphite, and graphite fibers; most synthetic graphite products fall under the category of polycrystalline graphite. The principal product among synthetic graphite items is the graphite electrode used in electric arc furnaces for steelmaking and in submerged arc furnaces for smelting. Graphite electrodes are high-temperature– and corrosion-resistant conductive materials. Synthetic graphite also finds extensive applications in many other industrial sectors, including the machinery industry—for motor brushes, precision casting molds, electrical discharge machining molds, and wear-resistant components; the chemical industry—for conductive elements or corrosion-resistant equipment used in electrolytic cells; and the nuclear industry—for reactor structural materials made from high-purity, high-strength synthetic graphite, as well as for components in missiles and rockets. In addition, graphite can be processed into heat-dissipating materials, sealing materials, thermal-insulating materials, and radiation-shielding materials. Graphite functional materials are widely employed across industries such as metallurgy, chemical engineering, mechanical equipment, new-energy vehicles, nuclear power, information electronics, aerospace, and national defense. In its report “Critical Raw Materials for the EU,” the European Commission has listed graphite among 14 strategically important mineral resources facing supply shortages.

Electrical and thermal conductivity Graphite’s electrical conductivity is a hundred times higher than that of most nonmetallic minerals. Its thermal conductivity surpasses that of metallic materials such as steel, iron, and lead. The thermal conductivity coefficient decreases with increasing temperature; in fact, at extremely high temperatures, graphite behaves as an insulator. Graphite’s ability to conduct electricity stems from the fact that each carbon atom in graphite forms only three covalent bonds with neighboring carbon atoms, leaving one free electron per atom to carry electric charge.

High-temperature resistance Graphite has a melting point of 3850±50℃; even after exposure to ultra-high-temperature electric arcs, its weight loss is minimal, and its coefficient of thermal expansion is also very low. Moreover, graphite’s strength increases with rising temperature, doubling at 2000℃.