Carbon Cathode for Aluminium Electrolysis

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Carbon Cathode for Aluminium ElectrolysisLow carbon anthracite, bituminous coke, metallurgical coke, natural and artificial graphite and coal asphalt are the m

Carbon Cathode for Aluminium Electrolysis

Low carbon anthracite, bituminous coke, metallurgical coke, natural and artificial graphite and coal asphalt are the main Raw materials for side cathode carbon block, side carbon block, tamping carbon paste and carbon glue.  These Raw materials are first calcined. The anthracite and bituminous coke are calcined in a tank calciner or rotary kiln at high temperatures of 1473-1623K to improve their densification and thermal stability and reduce their resistivity.  Anthracite can also be calcined in the calcination furnace, the calcination temperature is generally 2073~2173K.  Calcination can further improve the thermal stability of anthracite and reduce its specific resistance.

The calcined coke and dehydrated metallurgical coke and graphite are crushed and ground to make carbon paste according to certain particle size ratio, and then mixed and kneached together with binder coal pitch in intermittent or continuous kneaching machine.

The roasting of raw carbon blocks is carried out in a closed or open multi - chamber ring roaster.  Small and medium-sized carbon plants in China often use inverted flame kilns or multi-chamber side-by-side kilns for roasting, which has low thermal efficiency.  The cathode carbon blocks can be calcined at 1123-1423K, and the lower calcination temperature can be used for the graphite or semi-graphite coke cathode carbon blocks.  Graphitized or semi-graphitized cathode carbon blocks require higher calcination temperatures, typically 1073-1123K. Roasting is to make binder asphalt pyrolysis, coking, so that the green has higher mechanical strength, better thermal stability and higher electrical conductivity. Roasting curve and loading operation have great influence on the quality of finished products.

The cathode steel rod has a rectangular section. According to the selected size of the steel rod, grooves (dovetail grooves) are processed on the cathode carbon block to load the steel rod.  The cathode steel rod is joined to the carbon block by casting cast iron or carbon paste tamping。