Impurity Migrations in Aluminum Reduction Process and Quality Improvement by Anti-oxidized Prebaked Anode

Higher quality primary aluminum is increasingly required for high-performance alloy products. The influence of the impurity contents in such raw materials as prebaked anodes, alumina, etc. and impact of the process operations on the quality of primary aluminum are discussed in detail in this paper. The results show that Fe and Si are the major impurity components migrated in primary aluminum. The impurity Fe mainly comes from the cell covering material, prebaked anode, alumina, and operation process. The impurity Si mainly comes from the same sources as well as fluoride salts. Besides, a kind of anti-oxidized prebaked anodes with excellent reactivity to CO2 and air was studied and developed to reduce obviously Si content in primary aluminum and to improve aluminum quality.