Electrochemical Reduction of Silicon Oxide and Codeposition of Al-Si Alloy from Cryolite Molten Salt

The preparation of high-purity and high-value alloys is of great significance to industrial production. The purpose of this study is to explore the process of producing aluminum-silicon (Al-Si) alloy by the electrochemical Al-Si eutectoid method. The electrochemical behavior of aluminum and silicon on tungsten electrode was studied by cyclic voltammetry and galvanostatic chronopotentiometry. The effect of SiO2 addition on the eutectoid behavior of Al and Si was studied. The results show that the precipitation potential of Al is about –1.35 V (versus Pt), and the initial precipitation potential of Si is about –0.8 V (versus Pt). The precipitation process of silicon includes two reduction stages. In addition, the precipitation of Si is a quasireversible reaction controlled by diffusion process. Finally, Al-Si alloy was obtained by potentiostatic electrodeposition at –1.8 V potential, indicating that Al and Si would codeposit at this potential.