铜-钢复合材料中锌含量的测定

Determination of zinc content in copper-steel composite material

采用先加盐酸、分步滴加过氧化氢及补加硝酸的方式溶解铜-钢复合材料,然后在溶解液中加入氟化铵、硫脲以掩蔽大部分的铁离子及铜离子,在稀酸介质中锌与硫氰酸铵形成络阴离子后用4-甲基-2戊酮萃取分离,除去溶解液中的铬离子、锰离子、镍离子和铝离子后,用六次甲基四胺缓冲溶液反萃取锌离子到水相中,再加入氟化铵、硫脲以掩蔽残留的铜离子、铁离子和铝离子,以二甲酚橙为指示剂,用乙二胺四乙酸标准滴定溶液滴定,就此建立了铜-钢复合材料中锌含量测定的试验方法,并用该方法测定铜-钢复合材料中锌含量.结果表明,该法准确度及精密度较高,其中RSD为0.45%~1.85%,加标回收试验的锌回收率为96.0%~103.5%.

The copper-steel composite materials were dissolved by adding hydrochloric acid first, and dropped the hydrogen peroxide step-by-step, adding nitric acid when the materials can not be dissolved. In the solution by adding ammonium fluoride, thiourea mask most of the iron and copper ions. In dilute acid medium,zinc and ammonium thiocyanate formed complex anions, extraction separation with 4-methyl-2- pentanone. The chromium, manganese, nickel and aluminum ions in solution were removed. Adding six methyl four amine buffer solution, the zinc ions were stripped back into the aqueous phase, added ammonium fluoride, thiourea masking residues, iron, aluminum, copper ions, with xylenol orange as the indicator,titration with EDTA standard titration solution. The determination method of zinc content in copper-steel composites was established, and the content of zinc in copper-steel composites was determined by this method. The results show that the accuracy and precision of this method are high, among which RSD is 0.45%-1.85%, and the recoveries of zinc are 96.0%-103.5%.