硫酸铅分离-EDTA滴定法测定铜闪速冶炼烟尘中的铅

建立了用硫酸形成硫酸铅沉淀加以分离,再用EDTA络合滴定法测定铜闪速冶炼烟尘中铅量的方法。试样用盐酸、硝酸、硫酸、氟化氢铵和高氯酸溶解,用硫酸沉淀铅与其它干扰元素分离,沉淀溶解于乙酸-乙酸钠缓冲溶液中,以巯基乙酸掩蔽铋,抗坏血酸掩蔽铁,二甲酚橙作指示剂,用Na2EDTA标准滴定溶液滴定溶液中铅含量,采用火焰原子吸收光谱法测定滤液中铅含量加以补正。实验结果表明,沉淀时硫酸(1+24)加入量为50 mL,无水乙醇加入量为10 mL,乙酸-乙酸钠缓冲溶液加入量为30 mL。方法相对标准偏差(RSD)在0.35%~1.5%,加标回收率为在99.0%~101%。完全满足生产控制分析的要求,同时也可以作为类似物料中铅分析的参考方法。

Determination of Lead in Copper Flash Smelting Dust by Lead Sulfate Separation -EDTA Titration

A method was established for the determination of lead in copper flash smelting dust by EDTA complexometric titration after the precipitation of lead sulfate formed by sulfuric acid was separated. The sample was dissolved with hydrochloric acid, nitric acid, sulfuric acid, ammonium bifluoride and perchloric acid, lead precipitated with sulfuric acid was separated from other interfering elements, the precipitate was dissolved in acetic acid-sodium acetate buffer solution, bismuth was masked with mercaptoacetic acid, iron was masked with ascorbic acid, xylenol orange was used as indicator, lead content in the solution was titrated with Na2EDTA standard titration solution, and lead content in the filtrate was determined by flame atomic absorption spectrometry to correct it. The experimental results showed that the addition of sulfuric acid (1+24) was 50mL, anhydrous ethanol was 10mL, and acetic acid-sodium acetate buffer solution was 30mL. The relative standard deviation (RSD) of this method is between 0.35 and 1.52, and the recovery rate of standard addition is between 99.0% ~ 101.3%. It fully meets the requirements of production control analysis and can also be used as a reference method for lead analysis in similar materials.