Coke is a type of solid fuel. Obtained by dry distillation of coal at a high temperature of approximately 1000 ℃. The main component is fixed carbon, followed by ash, which contains very little volatile matter and sulfur. Silver gray in color, with a metallic luster. Hard and porous in texture.

Its calorific value is mostly 26380 - 31400 kJ/kg (6300 - 7500 kcal/kg). According to different uses, it can be classified into three major categories: metallurgical coke, foundry coke and chemical coke. It is mainly used in the smelting of steel and other metals, and can also be used as raw material for the manufacture of water gas, gasification and chemical industry, etc.