Aluminum Extraction by Al–Si–Fe Alloy Electrolysis

With the rapid development of the aluminum industry, the contradiction between the supply shortage of bauxite and alumina has become more prominent. If aluminum can be extracted from the aluminum-containing waste produced by the factory, especially Al–Si–Fe alloy, the problem of insufficient aluminum resources in China can be alleviated. In this paper, metal aluminum was extracted by electrolysis with Al–Si–Fe alloy as a soluble anode in NaCl–KCl–Na₃AlF₆ low temperature melts. The liquidus temperature and conductivity of the electrolyte were measured, and the influencing factors of current efficiency during electrolysis were discussed. The results show that when the molar ratio of NaCl–KCl–Na₃AlF₆ is 0.48:0.48:0.04, the liquidus temperature of the electrolyte was relatively low and the conductivity was high. When the electrolysis experiment was conducted in the above electrolyte with a current density of 0.2 A cm⁻² at 690 °C for 1.5 h, a high current efficiency of 77.6% can be reached.