湿法炼锌深度净化硫酸锌电解液中痕量锑的测定

采用孔雀绿分光光度法测定硫酸锌电解液(50～150 g/L)中的锑。在6.5 mol/L的盐酸介质中,用氯化亚锡将锑还原为三价,再用亚硝酸钠氧化为新生态五价,用尿素除去过量的亚硝酸钠,1.55mol/L的盐酸溶液中加入孔雀绿显色,用甲苯萃取有色络合物,于分光光度计波长640nm处测量吸光度。此方法对硫酸锌电解液(50～150 g/L)中0.02mg/L以上的锑进行定量测定时,锑的浓度与吸光度呈良好的线性,相关系数r为0.9994,标准偏差为0.12,相对标准偏差为5.63%,加标回收率为95.00%～105.00%。

Determination of trace antimony in deep purification of zinc sulfate electrolyte in zinc hydrometallurgy

The antimony in zinc sulfate(50~150g/L) electrolyte was determined by malachite green spectrophotometry. The antimony was reduced to trivalency by stannous chloride in hydrochloric acid(6.5mol/L) medium, and then oxidized to nascent state of quintavalent by sodium nitrite.The excess sodium nitrite was removed by urea,the malachite green coloration was added into hydrochloric acid(1.55mol/L) solution,the colored complex compound was extracted by toluene,and the absorbance was measured at 640nm wavelength of spectrophotometer. The antimony(over 0.02mg/L) in zinc sulfate electrolyte(50~150mg/L) was quantitatively determined by this method,the antimony concentration and absorbance had good linearity,the correlation coefficient r was 0.9994, the standard deviation was 0.12,the relative standard deviation was 5.63%,and the recovery of standard addition was 95.00%~105.00%.