滴定法快速测定多金属矿石中的铜铅锌铁

Rapid Determination of Copper,Lead,Zinc and Iron in Polymetallic Ore By Titrimetry

采用盐酸、硝酸、硫酸等试剂分解试样,铅形成硫酸铅沉淀,过滤洗涤使硫酸铅沉淀与铜、锌、铁等金属离子分离,沉淀加NaAc-HAc缓冲液溶解,用EDTA标准液滴定测铅。滤液以水定容至100mL,用移液管分别分取2份部分溶液,1份溶液用碘量法测定铜。另1份溶液加过量氨水使锌离子与铁离子等分离,过滤洗涤,滤液用EDTA标准液滴定测锌;氢氧化铁沉淀加HCl溶液溶解,用重铬酸钾法测定铁。试验测定结果与传统单独测定方法的测定结果相吻合。

Mineral sample was dissolved in HNO3,HCl and H2SO4,lead reacted with H2SO4,and the deposit of PbSO4 was produced,which was filtered and dissolved with NaAc-HAc buffer solution,then lead was determined by EDTA standard solution.The filtrate was diluted with water to 100 mL in volumetric flask,and two sample solution of which were accurately put into different conical flask,then copper in the first sample solution was determined by iodometry.The second sample solution was accurately put into a beaker with excess NH3·H2O-NH4Cl solution added.In the ammonia medium,zinc ion reacted with ammonia to form a complex [Zn（NH3）4]2＋,iron was precipitated and separated after filtration,zinc was determined by EDTA standard solution in the filtrate.The Fe（OH）3 sediment was dissolved with HCl solution,iron was determined by titration with potassium dichromate.All the determination results were consistent with those determined by the traditional methods.