Needle coke is a key raw material for producing high-power or ultra-high power graphite electrodes

Needle coke is a high-quality coke with a clear fibrous texture, a particularly low coefficient of thermal expansion, and easy graphitization. When the coke block ruptures, it can split into thin and elongated particles (usually with an aspect ratio of 1.75 or above) according to the texture. The anisotropic fibrous structure can be observed under a polarizing microscope, so this type of coke is called needle coke. The anisotropy of the physical and mechanical properties of needle coke is very obvious, and it has good conductivity and thermal conductivity parallel to the long axis of the particles. The coefficient of thermal expansion is low, and during extrusion molding, most of the long axes of the particles are arranged in the extrusion direction. Therefore, needle coke is a key raw material for manufacturing high-power or ultra-high power graphite electrodes. The graphite electrodes produced have low electrical resistivity, low coefficient of thermal expansion, and good thermal vibration resistance.

Needle coke is divided into oil-based needle coke produced from petroleum residue and coal based needle coke produced from refined coal tar pitch raw materials.