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采用硝酸溶解试样,加入过量的硫酸沉淀分离Pb2+,用溴水挥发除去砷锑的干扰,用氟化氢铵掩蔽铁,在弱酸性溶液中,加入KI,Cu2+与I-作用生成CuI沉淀,并析出等当量的碘,以淀粉为指示剂,用Na2S2O3标准溶液滴定法测定Cu2+。该方法对铜含量在1.0%~10.0%范围内的铅及铅合金中铜含量的测定准确度高,测定结果的相对偏差为0.8%~2.0%,铜的回收率大于99.70%。
Using nitric acid to dissolve the sample, adding excess sulfuric acid to precipitate and separate Pb2 +, volatilizing with bromine water to remove the interference of arsenic and antimony, masking iron with ammonium bifluoride, adding KI, Cu2 + and I- in weak acid solution to form CuI precipitate, Equivalent iodine to starch as an indicator, with Na2S2O3 standard titration titration Cu2 +. The method has high accuracy in determining the copper content in lead and lead alloys with the copper content in the range of 1.0% to 10.0%, the relative deviation of the determination results is 0.8% to 2.0%, and the recovery rate of copper is more than 99.70%.