Graphite electrode is made of petroleum coke, needle coke and coal pitch.
Petroleum coke is a combustible solid product obtained from petroleum residue petroleum pitch after coking. It is dark and porous, and the main element is carbon. Ash content is very low, and less than 0.5%. Petroleum coke is easily graphitized carbon, it is widely used in chemical metallurgy and other industries, it is the main raw material for producing man-made graphite products and electrolytic aluminum carbon products.
The needle coke is a kind of high quality coke with obvious fibrous texture with low thermal expansion coefficient and easy graphitization. When a chunk breaks, it can be split into long, thin strips of grain, Anisotropic fibrous structure can be observed under polarized light microscope, so it’s called needle coke.
The orientation of physical and mechanical properties of the needle coke is very obvious, and it has good electrical and thermal properties parallel to the long axis of the particle, low thermal expansion coefficient. When extruding, the long axes of most particles are arranged in the direction of extrusion, so the needle coke is the key material for manufacturing high power or ultra high power graphite electrode. The graphite electrode made of needle coke has low resistivity, low thermal expansion coefficient and good seismic performance.
Coal bitumen is one of the main products of coal tar deep processing. It is the mixture of various hydrocarbons, black semi-solid or solid with high viscosity at room temperature, no fixed melting point. After being softened by heat, it melts, density is 1.25-1.35g/cm³. Coal pitch is used as binder and impregnant in carbon industry, and its performance has great influence on the production process and quality of carbon products.
Graphite electrode has Good electrical conductivity, Strong thermal shock resistance, High mechanical strength. Through the electric energy is input to the electric furnace, the high temperature generated by the electric arc between the electric extreme part and the furnace material is used as a heat source to melt the furnace material for steel making.