China Nonferrous Metallurgy

In the process of aluminum production, the carbon anode participates in the electrolytic reaction. The theoretical carbon consumption is 333kg/t-Al, but the real consumption of the carbon anode often exceeds this theoretical amount. By analyzing the consumption mechanism of the carbon anode during aluminum electrolysis, it is found that the extra consumption of the carbon anode includes chemical and mechanical consumption. The oxidation of the carbon anode at high temperatures is the main cause of both types of consumption, either directly or indirectly. Currently, the main technologies to improve the oxidation resistance of carbon anodes include substrate modification, solution impregnation, and anti-oxidation coatings. Specific measures for substrate modification include altering the calcination temperature of petroleum coke and the baking temperature of the carbon anode, adjusting the sulfur and trace element content in the carbon anode, and using additives in the production of anode carbon blocks. Solution impregnation technology uses impregnating agents such as aluminum chloride and boron-containing compounds to enhance the oxidation resistance of the anode. Anti-oxidation coating technology involves using electrolyte coatings, carbon-based coatings, ceramic coatings, or aluminum coatings. Among these, coating protection is an important research direction for improving the oxidation resistance of carbon anodes. The cost, oxidation resistance effect, and adhesion to the carbon substrate are key research focuses for anti-oxidation coatings.