With high quality anthracite, coke, graphite as raw materials made of carbon block. Used as cathode of aluminium electrolytic cell. It is built at the bottom of the electrolytic cell, also known as the bottom carbon block. The cathode carbon block plays a dual role of conducting electricity and forming the inner lining of the electrolytic cell.
The cathode carbon block is required to have high temperature resistance in aluminum electrolysis production, resistant to molten salt erosion, good electrical and thermal conductivity, high mechanical strength, good thermal shock resistance and strong corrosion resistance of sodium, which is conducive to energy saving and tank life improvement in the production of aluminum electrolysis.
According to the quality requirements of the products, the raw materials selected and the technological conditions used, the cathode carbon blocks in China are basically divided into three categories: ordinary cathode carbon blocks, semi-graphitic carbon blocks and graphitic carbon blocks. Anthracite calcined at 1250 ~ 1350℃ is used as the main raw material for common cathode carbon block. The half graphite carbon block is divided into two kinds according to the different production process.
One is high quality high temperature electric calcination of anthracite or, with more graphite fragments or even all graphite fragments as aggregate, the green products after molding only after roasting (roasting temperature does not exceed 1200℃) no longer into graphitization furnace heat treatment, this kind of carbon block is called half graphitic carbon block.