Abstract:A comparative analysis of different molten salt systems was conducted, including NaCl-KCl, NaCl-CaCl₂, NaCl-Na₂CO₃, NaCl-KCl-CaCl₂, and NaCl-KCl-Na₂CO₃. The phase diagrams, thermal stability, and solubility of Sb₂S₃ in molten salt systems were investigated. Based on the distribution of the element antimony, current efficiency, energy consumption, and the characterization of the residue, the most suitable molten salt for the electrical reduction of Sb₂S₃ was verified. The results show that all molten salt systems have good thermal stability and can realize the electrolytic reduction of Sb₂S₃. The system with CaCl₂ is not conducive to the dissolution of Sb₂S₃, and the system with Na₂CO₃ can react with Sb₂S₃. In addition, the current efficiency of the NaCl-KCl system is the highest (75.68%), and the energy consumption ratio is the lowest (2.18 kW·h/kg).

Key words: antimony smelting; molten salt electrolysis; Sb₂S₃; eutectic system