高砷废渣中锡的测定方法研究

Study on Determination Method of Tin in High-arsenic Waste Residue

碘量法在测定高砷样品中的锡时,在铝片还原锡的过程中,砷被还原成单质砷,使溶液呈现灰蓝色,使滴定终点较难判断,难以得到满意的结果。采用浓硝酸、硝酸铵溶解样品的方法,锡形成沉淀,而砷等干扰元素在溶液中,通过过滤使锡与元素砷等分离,消除干扰,该方法结果稳定、可靠,解决了碘量法不能准确测定高砷废渣里锡含量的问题。

In the determination of tin in high-arsenic samples by iodimetry,arsenic is reduced to elemental arsenic in the process of tin reduction by aluminum sheets,which makes the solution appear gray-blue,making it difficult to judge the endpoint of titration and obtain satisfactory results.In this paper,concentrated nitric acid and ammonium nitrate are used to dissolve the sample.Tin forms precipitation,while arsenic and other interfering elements are in the solution.the interference of arsenic will be eliminated.The results of this method are stable and reliable,which solves the problem that iodine quantity method can’t accurately determine the tin content in high-arsenic waste recidue.