What are the raw materials for carbon additives?

There are many raw materials for carbon additives, and their production processes also vary, including charcoal, coal, coke, graphite, etc. Under various classifications, there are many subtypes. High-quality carbon additives generally refer to those that have undergone graphitization. Under high-temperature conditions, the arrangement of carbon atoms is in the microscopic form of graphite, thus they are called graphitized.

At present, most of the carbon additives on the market, including graphite electrodes and graphitized oil coke, are produced from raw petroleum coke. Crude petroleum coke is obtained by coking the residual oil distilled from crude oil under normal pressure or vacuum and the petroleum asphalt. Raw petroleum coke has a high impurity content and cannot be directly used as a carbon additive. It must be calcined or graphitized. High-quality carbon additives generally need to be graphitized. Under high-temperature conditions, the arrangement of carbon atoms takes on the microscopic form of graphite, thus it is called graphitization. Graphitization can reduce the content of impurities in carbon additives, increase the carbon content of carbon additives, and lower the sulfur content. Carburizing agents used in casting can significantly increase the amount of scrap steel used, reduce the amount of pig iron used or even eliminate the need for pig iron.

Commonly used carburizing agents include carburizing pig iron, electrode powder, petroleum coke powder, charcoal powder and coke powder. When smelting medium and high carbon steel grades in a converter, petroleum coke with very little impurities is used as a carburizer. The requirements for the carbon additive in top-blown converter steelmaking are high fixed carbon content, low impurity content such as ash, volatile matter, sulfur, phosphorus and nitrogen, dryness, cleanliness and moderate particle size.