碘量法测定铜冶炼分银渣中铜

铜冶炼分银渣中含有较高含量的砷、锑、锡等元素,对碘量法测铜产生干扰,并且样品较难溶解完全.实验采用盐酸-硝酸-高氯酸-硫酸分解样品,用氢溴酸除去砷、锑、锡等干扰元素.控制溶液pH值为3～4,用氟化氢铵掩蔽铁,加入碘化钾与铜(Ⅱ)作用,析出的碘以淀粉为指示剂,用硫代硫酸钠标准滴定溶液滴定,建立了硫代硫酸钠碘量法测定铜冶炼...

Determination of copper in silver separating residue from copper smelting by iodometry

The silver separating residue from copper smelting contains high content of arsenic, antimony, tin and other elements, which have interference with the determination of copper by iodometry. Moreover, the sample is difficult to be dissolved completely. The sample in experiments was decomposed with hydrochloric acid-nitric acid-perchloric acid-sulfuric acid. Then, the interference elements including arsenic, antimony and tin were removed by hydrobromic acid. The pH of sample solution was controlled at 3-4. Ammonium hydrogen fluoride was added to mask iron. Potassium iodide was added to react with copper (Ⅱ), and the iodine precipitated was titrated with sodium thiosulfate standard titration solution using starch as the indicator. Consequently, the determination method of copper in silver separating residue from copper smelting by sodium thiosulfate iodometry was established. The experimental conditions such as sample dissolution method, addition amounts of glacial acetic acid and saturated ammonium hydrogen fluoride were optimized. The experimental method was applied for the determination of copper content in silver separating residue from copper smelting. The relative standard deviations (RSD, n=11) of determination results were 0.30% and 0.85%, and the recoveries were between 99.6% and 101.8%.