The best quality is artificial graphite.

The main raw material for the manufacture of artificial graphite is powder of high quality calcined petroleum coke, in which asphalt is added as a binder, and a small amount of other auxiliary materials. After a variety of raw materials with good, it will be pressed into shape, and then in 2500 ~ 3000℃, non-oxidizing atmosphere treatment, so that the graphitization. After high temperature treatment, ash, sulfur, gas content are greatly reduced.

Petroleum coke is a widely used carburizing agent. Petroleum coke is a by-product of refining crude oil. Residual oil and petroleum bitumen obtained from pressure distillation or vacuum distillation of crude oil can be used as raw materials for manufacturing petroleum coke. After coking, petroleum coke is obtained. The production of petroleum coke is less than 5 percent of the crude oil used. Annual production of crude petroleum coke in the United States is about 30 million tons. The impurity content in petroleum coke is high, can not be used directly as a carburizing agent, must be calcined first.