EDTA滴定法连续测定铅精矿中铅和锌

Successive Detemination of Lead and Zinc Contents in Lead Concentrates by EDTA Titration Method

建立了EDTA滴定法连续测定铅精矿中铅和锌的方法。试样用盐酸、硝酸、硫酸和氯酸钾分解。铅通过硫酸铅沉淀与其他干扰元素分离,沉淀溶解于乙酸-乙酸钠溶液中。在滤液中加入氨水、氟化钾使铁等干扰元素沉淀并与锌溶液分离。用二甲酚橙作指示剂,EDTA分别滴定溶液中的铅和锌。研究中测定了能力验证NILPT(2010)-0211铅精矿样品10-1和10-2中铅和锌,结果满意。

A new EDTA titration method was established to successively detemine lead and zinc contents in lead concentrates. The samples were dissovled by hydrochloric acid, nitric acid, sulfuric acid and potassium chlorate. Lead was separated from other interfering elements by forming the lead sulfate precipitate, and the precipitate was dissolved in acetic acid - sodium acetate solution. By adding ammonia and potassium fluoride to the filtration solution, the interfering elements such as iron were precipated and thus separated from zinc containing solution. Xylenol orange was used as titration indicator, and EDTA was used to titrate lead and zinc in the solution, respectively. This method was used to determine the lead and zinc content in lead concentrate samples 10-1 and 10-2 which are designated for the NILPT（2010）-0211 Proficiency Testing. The results are satisfactory.