沉淀分离-EDTA滴定法测定铜闪速冶炼烟尘中的锌量

Determination of Zinc Content in Copper Flash Smelting Dust by Precipitation Separation EDTA Titration

称取0.5 g试样,用盐酸、硝酸、硫酸分解,铅以硫酸铅沉淀的形式分离。以过硫酸铵为氧化剂,氨性溶液中沉淀分离铁、锰等共存元素,加氟化物掩蔽铝、硫脲掩蔽铜,调节溶液pH=5.0~6.0,加入碘化钾消除镉的干扰,以二甲酚橙为指示剂,用EDTA标准溶液滴定。将沉淀物重新溶解,用原子吸收光谱法测定其中的锌量。在0.2%~10.0%范围内结果重现性良好,重复测定7次,相对标准偏差(RSD)在0.32%~0.76%,样品加标回收率为99.4%~100%。方法的准确度和精密度可以满足分析需求。

Weigh 0.5 g of sample,the sample was decomposed with hydrochloric acid,nitric acid and sulfuric acid.Separation of lead in the form of lead sulfate precipitation.Ammonium persulfate as oxidant,separation of coexisting elements such as iron,manganese and lead by precipitation,then adding fluoride to shield aluminum and thiourea to shield copper.In acetic acid-sodium acetate buffer solution with pH5.0—6.0,potassium iodide was added to eliminate the interference of cadmium,xylenol orange was used as indicator and titrated with EDTA standard titration solution.The filter residue was acidified and the zinc content was determined by atomic absorption spectrometry.The results showed good repeatability in the range of 0.2%—10.0%.When n=7,RSD was 0.32%—0.76%.The recovery of standard addition was in the range of 99.4%—100%.The accuracy and precision of the method could meet the needs of analysis.