合金精炼提纯过程中金属Sn的电解回收研究

Study on recovery of metallic Sn by electrolytic method

Al-Si-Sn 三元合金精炼方法能够显著提高太阳能级多晶硅的提纯产率,但添加的金属 Sn 与 Si难以分离的问题限制了它的实际应用.选用 SnCl2（60 g/L）作为电解液,Al-Si-Sn 合金（58．14％（原子分数）Al-31．86％（原子分数）Si-10％（原子分数）Sn）作为阳极,高纯 Sn（99．99％）作为阴极,在室温下进行恒电流沉积实验.通过讨论电流密度、电解液 pH 值、沉积时间、搅拌速度等参数对电流效率及 Sn 沉积层形貌的影响,优化电解回收金属 Sn 实验工艺.研究结果表明,在室温下,当磁力搅拌速度为800 r/min,电流密度为0．4～0．5 A/cm2,沉积时间为3～6 min,pH 值为3～4时,电流效率达到最大值.

Al-Si-Sn ternary alloy refining method can significantly improve the purification yield of solar grade polysilicon,but the main problem of separating added metallic Sn and Si limits its practical application.The gal-vanostatic deposition experiment of Al-Si-Sn alloy at room temperature in SnCl2 (60 g/L)electrolyte solution was studied in this research.Al-Si-Sn alloy for the anode electrode and high purity Sn (99.99%)for the cathode electrode were used.The effects of current density,electrolyte pH value,deposition time and other parameters on the current efficiency and the morphology of deposited tin were discussed to optimize the experimental process of electrolytic recovery of metal Sn.The results show that at room temperature,current efficiency rea-ches maximum when magnetic stirring speed was 800 r/min,current density was 0.4-0.5 A/cm2 ,deposition time was 3-6 min,and pH value was 3-4.