Abstract：:The sample was dissolved by adding 15 mL of HCl and 15 mL of HNO3 in sequence. Coexisting element such as Fe, Mg and Pb was separated through forming zinc amine complex when the sample was rapidly cooled in water after ammonium chloride was added. In the buffer of acetic acid-ammonium acetate at pH 5.5, the content of zinc was titrated by EDTA standard solution by masking interference ions such as Cu2+, Hg2+, Al3+ and Ca2+ with saturated thiourea, ascorbic acid and potassium fluoride and with xylenol range as indicator. It was found that the sample was dissolved faster when HCl and HNO3 was used instead of HCl, HNO3 and H2SO4 in national standard. Besides, both dissolution methods needed to separate interfering elements through precipitation. Though thermal fluid filter adopted in national standard method could avoid liquid transfer process, but sample dissolution and boiling time was too long. While the cooling filter adopted in the proposed method could avoid secondary filter, which could simplify the analytical procedure. In precision test, the relative standard deviation of the determination results of both standard samples were 0.23% and 0.12% (n=10). Different zinc concentrates were determined with national standard method and the proposed method. The results were basically consistent.
李颜君. EDTA滴定法测定锌精矿中锌含量方法的改进[J]. 冶金分析, 2014, 34(7): 47-50.
LI Yan-jun. Method improvement on the determination of zinc in zinc concentrate by EDTA titrimetry. , 2014, 34(7): 47-50.
