Petroleum coke is widely used as an accelerator at present.

Petroleum coke is a by-product of refined crude oil. The residual oil and petroleum pitch obtained by constant pressure distillation or reduced pressure distillation can be used as raw material for the production of petroleum coke, and then obtained raw petroleum coke after coking. The production of petroleum coke is less than 5% of the amount of crude oil used. The annual output of American petroleum coke is about 30 million T. The content of impurities in raw petroleum coke is very high and can not be used directly as carburizing agent. It must be treated by calcination.

Petroleum coke has spongy, acicular, granular and liquid state.

Sponge petroleum coke is prepared by delayed coking. Because of its high sulfur content and metal content, it is usually used as fuel for calcination and as a raw material for calcined petroleum coke. Calcined sponge coke; used primarily in making aluminum and as an agent for carburizing.

Needle petroleum coke is a kind of raw material with high content of aromatic hydrocarbon and low impurity content. It is prepared by delayed coking process. The coke has a needle like structure that is easy to break. It is sometimes called graphite coke. It is mainly used for making graphite electrodes after calcination.

Granular petroleum coke is hard granular and is a material with a high content of sulfur and asphaltene and is obtained by delayed coking. It is mainly used as fuel.

Flowing petroleum coke is obtained by continuous coking in fluidized bed. It is small granular, non directional in structure, low in sulfur content and low in volatility.

Petroleum coke is calcined to remove sulfur, moisture, and volatile matter. Calcined raw petroleum coke at 1200~1350 DEG C can make it essentially pure carbon.

The largest user of calcined petroleum coke is aluminum, and 70% is used to make anodes for the reduction of bauxite. Calcined petroleum coke produced in the United States; accounting for about 6% of the cast irons.