A novel method for selective extraction of pure antimony via electrolysis of molten arsenic-alkali residues

Antimony is a globally scarce strategic metal critical to new energy technologies, defense, and aerospace. In crude antimony smelting, arsenic removal generates large quantities of arsenic-containing hazardous waste (arsenic-alkali residues), in which substantial antimony remains due to its similar physicochemical properties to arsenic. Recovering antimony from this residue is both economically and environmentally significant. Herein, a molten salt electrolysis process is developed for one-step recovery of pure antimony directly from additive-free arsenic-alkali residues (AAR). Thermodynamic analysis shows that the decomposition voltage of NaSbO 3 is lower than that of NaAsO 3 and Na 2 CO 3 , enabling selective cathodic reduction of antimony. Optimization experiments identified the optimal electrolysis parameters as a temperature of 800 °C and a cell voltage of 2 V, After electrolytic treatment of the AAR for 10 h, metallic antimony with a purity of 99.59 % was obtained, with an arsenic removal yield of 98.72 %. Through deep extraction, a direct antimony direct yield of 74.39 % was achieved. This process not only achieves one-step direct extraction of pure antimony from AAR, but also eliminates wastewater generation and delivers a high arsenic removal yield. • A novel molten salt electrolytic process was proposed for selective extraction of pure antimony from AAR. • A single-step electrolysis selectively separated As and Sb while simultaneously recovering metallic Sb. • Achieved 99.59 % Sb purity, 98.72 % As removal yield, and 74.39 % Sb direct yield. • This process provides an innovative pathway for industrial-scale treatment of AAR.