金精矿、铅精矿中铅量的测定方法改进

Improvement of Determination Method of Lead in Gold Concentrate and Lead Concentrate

金精矿国标方法测定铅量,滤液中会有少量铅损失,结果偏低,铅精矿国标方法测定铅量步骤过多、耗时较长,实验使用硝酸-氯酸钾饱和溶液溶解样品,加入浓硫酸使铅形成硫酸铅沉淀,过滤分离硫酸铅后以醋酸铵溶解沉淀,使用EDTA滴定得主量铅;过滤分离的沉淀中有少量铅不溶于醋酸铵,使用碱性熔剂溶解,滤液中也含有少量铅,合并滤液与滤渣,使用火焰原子吸收测定两项总含铅量,与主量铅加和可得样品中总铅量。该方法测定结果的相对标准偏差0.045%~0.12%,结果的准确度为0.01%~0.11%,实验流程短,极大提高了铅量测定的准确度。

The national standard method for determining lead content in gold concentrates will cause a small amount of lead loss in the filtrate,which will lead to a low result.The national standard method for determining lead content in lead concentrates has too many steps and takes a long time.In the experiment,a saturated solution of nitric acid-potassium chlorate is used to dissolve the sample,concentrated sulfuric acid is added to form lead sulfate precipitate,after filtering and separating lead sulfate,ammonium acetate is used to dissolve the precipitate,and EDTA is used to titrate the main amount of lead.A small amount of lead in the precipitate separated by filtration is insoluble in ammonium acetate.After dissolution with alkaline flux,the filtrate also contains a small amount of lead.After the filtrate and filter residue are combined,the two total lead contents are determined by flame atomic absorption spectrometry,and the total lead content in the sample can be obtained by adding the two total lead contents to the main lead content.The method has a relative standard deviation of 0.045%~0.12% and an accuracy of 0.01%~0.11%.The experimental process is short,which improves the accuracy of lead determination greatly.