Potassium Balance and Its Distribution in Commercial Aluminum Reduction Cells—When Potassium-containing Alumina Is Used as the Raw Material for Aluminum Electrolysis

Abstract

China is short of high grade bauxite for the production of smelting grade alumina. With the massive exploitation of potassium containing bauxite in China, the produced Bayer alumina contains a non-negligible content of potassium oxide. When this kinde of alumina is used as the raw material for aluminum electrolysis, the potassium would cause multiple effects to the cell performance. In this paper, the potassium concentrations of fresh alumina, secondary alumina, aluminum fluoride, anode, electrolyte, anode cover, cathode block, carbon lining, silicon carbide block and product aluminum et al. in 160 kA and 200 kA prebaked aluminum reduction cells were tested and a potassium balance model was preliminarily given. Initial results showed that most of the potassium was brought into the cell by the potassium containing impurities in the fresh alumina. The only effective way for potassium removal from the cell was through the carbon residue though nearly 80 wt% of the potassium would stay and enrich in different positions of the cell.

Keywords

• aluminum electrolysis
• prebaked aluminum cell
• potassium balance
• alumina impurities