Extraction of metals from their sulfide minerals without emitting SO₂ could realize an environment-friendly metallurgical route. Here we demonstrate an electrochemical pathway to reduce solid copper sulfide to copper powder in a 50 wt.% NaOH solution. Unlike oxides, most sulfides are semiconductors or electrical conductors and have less formation energy than that of oxides, resulting in a small polarization during electrolysis and less theoretical dissociation potentials. The use of the strongly alkaline solution suppresses the generation of H₂, and the electrolyte could dissolve S²⁻ and then shuttle the S²⁻ between cathode and anode. Moreover, a transparent cell was assembled to directly observe the reduction process of solid copper sulfide. On the anode side, the irreversibility of anodic reactions prevents the parasitic reactions, thereby ensuring a current efficiency over 90%. This electrochemical pathway could be employed for extracting various metals from their sulfides without SO₂ emissions.

从其硫化物矿物中提取金属而不释放SO ₂可以实现环境友好的冶金路线。在这里，我们展示了一种电化学途径，可以将固体硫化铜在50％（重量）的NaOH溶液中还原成铜粉。与氧化物不同，大多数硫化物是半导体或电导体，比氧化物具有更少的形成能，从而导致电解过程中的极化较小，理论上的解离电位也较小。使用强碱性溶液可以抑制H ₂的产生，并且电解质可以溶解S ²⁻，然后使S ²⁻穿梭。在阴极和阳极之间。此外，组装透明电池以直接观察固体硫化铜的还原过程。在阳极方面，阳极反应的不可逆性阻止了寄生反应，从而确保了超过90％的电流效率。该电化学途径可用于从其硫化物中提取各种金属而无SO ₂排放。