容量法测定方铅矿中高含量银

摘要

A method for KI volumetric determination of high content silver in galena was reported in this paper. Samples with high contents of silicon and lead were decomposed with HNO3-H2SO4-HF.Acidity for the KI volumetric determination of silver was also tested. The results show that in 1.6 mol/L HNO3 medium silver reacts with potassium iodide and forms silver iodide precipitate. The recovery of standard addition for silver by this method is 97.8%～100.4% with precision of 0.92% RSD (n=11). The method is suitable for the dissolution of silver in silicon-bearing silver ores and kerargyrite ores and has been applied to the determination of high content of silver in ores.%报道了采用HNO3-H2SO4-HF溶样，KI容量法测定硅、铅含量较高样品中高含量银的方法。试验了滴定反应的酸度条件。在1.6 mol/L"HNO3介质中，银与碘化钾反应，生成碘化银沉淀。银的标准加入回收率为97.8%～100.4%。精密度试验，相对标准偏差为0.92%(n=11)。该法可溶解含硅银矿及角银矿中的银。方法已被应用于测定矿石中高含量银。