Inert anode technology in the concept of green aluminum metallurgy

An analysis is made of the traditional and advanced electrolytic technology for producing metallic aluminum from the point of view of environmental friendliness of production. A brief description is given of the use of Soderberg anode cells and pre-baked anodes combined by a common carbon anode material oxidized into gaseous oxide and carbon dioxide during aluminum reduction. In order to reduce (eliminate) the carbon footprint, the concept of an inert anode is proposed, the material of which does not enter into the aluminum reduction reaction, and therefore is not consumed (almost), while the release of oxygen in the status of the final gaseous “waste” is allowed. The basis for the development is an electrolytic cell with a self-baking Soderberg anode of the S-8BM type, which characterizes the oldest technology and has a large geography of representation in Russia. As a result of comparing the operating conditions and technological possibilities for obtaining anodes of similar sizes from composite and ceramic materials (cermets) when replacing the carbon anode array, it was decided to use the classic copper-nickel alloy CuNi44Mn1, which has a minimum iron content (reducing the grade of aluminum) and characterized by thermal stability at electrolysis temperature. Based on the electrical characteristics of the basic process and taking into account the recommendations of “RUSAL Laboratory” specialists, the dimensions of the metal inert anode are determined and recommendations are given for the reconstruction of the above-mentioned electrolyzer when switching to a new aluminum production technology.