Study On Preparation Inert Anodes Used In Aluminum Electrolysis By Two-steps Sintering

There are many problems in electrolytic production of aluminium in traditional Hall-Heroult aluminium-electrolytic cells such as high energy consumption, high carbon consumption, high cost and serious environmental pollution as a result of adopting consumable carbon anodes. Research groups in aluminium industry have been focusing on the investigation of inert anodes because they can overcome the problems mentioned above. A lot of research work and trials have been done to seek appropriate inert anode materials, which can be used in production aluminium.Considering the poor conductive properties of the oxides ceramics and difficulty in dynamically controlling the passivation film thickness of metal alloy inert anodes, in this work, the nickel ferrite-based cermets, which have better corrosion resistance and conductive properties, were selected as the research object.In the process of synthesizing NiFe₂O₄ spinel, additive of MnO₂,TiO₂, V₂O₅ was added to Fe₂O₃ and NiO powder as raw materials respectively. The effects of each additive on sintering and properties of NiFe₂O₄ spinel were investigated. The results show that additives can promote sintering and improve the properties of the materials. Adding MnO₂ can improve the overall properties, such as density, electrical conductivity, corrosion resistance property, bending strength and thermal shock resistance. TiO₂ can improve the electrical conductivity, bending resistance strength and thermal shock resistance greatly. V2O5 can strengthen the corrosion resistance remarkably. When the amount of V2O5 is 2.0%, the corrosion rate of the sample is 1/46 of that of the sample without additive.One-step sintering has many problems, such as lower percent of qualified finished products, poor bending strength, poor thermal shock resistance and crack problem of...