What is Pitch Coke?
Pitch coke is a solid, combustible product obtained by coking coal tar pitch. It is a good quality coke with low sulfur and low ash content, and it is graphitizable.
Characteristics and Applications
Pitch coke has low volatile content, a dense structure, and high particle mechanical strength and wear resistance. Chinese carbon manufacturers often incorporate a certain proportion of pitch coke—typically 15–25%—into formulations for RP graphite electrodes to enhance the mechanical strength of the finished products. In addition, pitch coke serves as a raw material for producing carbon products used in electrochemical applications, such as carbon anodes or anode paste in aluminum electrolysis.
Production Method of Pitch coke
Pitch coke is a high-quality carbon material obtained from coal tar pitch. It is widely used in the production of graphite electrodes, anodes, and other advanced carbon products due to its low sulfur, low ash content, high density, and excellent graphitization performance. There are two methods for producing pitch coke: delayed coking and medium-temperature carbonization.
1. Delayed Coking Method
- Raw Material: Refined coal tar pitch.
- Process: In this method, coal tar pitch is processed in a delayed coking unit, where it undergoes thermal cracking and polycondensation at high temperature. During this stage, volatile components are removed, and the residue solidifies into dense coke blocks.
- Features: Mature and widely applied technology, high production yield, dense structure, and low impurity content.
2. Medium-Temperature Carbonization / Calcination Method
- Raw Material: Refined coal tar pitch.
- Process: Coal tar pitch is first subjected to dry distillation at medium temperature (approximately 600–800 °C) to gradually eliminate volatiles. It is then calcined at high temperature (1200–1400 °C) to produce pitch coke with improved purity and crystallinity.
- Features: The resulting coke has higher crystallinity and superior graphitization properties, making it suitable for advanced carbon and graphite applications. However, the yield is relatively lower compared to delayed coking.
