火试金法测定铅冶炼渣中的金、银含量

建立了铅冶炼渣中的金银含量的测定方法,采用火试金法富集铅冶炼渣中的金、银,铅扣经灰吹后,形成金银合粒,合粒中除有金银外,还残留微量的铅铋杂质,合粒经硝酸分金后,实现金银分离,得到金粒和分金溶液。合粒中杂质保留在分金溶液中,分金溶液经酸处理,采用电感耦合等离子体发射光谱(ICP-OES)法测定其中杂质量和微量的金量。金粒质量补正分金溶液中微量金量即为样品中的金量,合粒质量减去金粒质量和杂质量即为银量。ICP-OES法测定杂质解决了合粒中铅铋残留和分金失误造成微量金进入分金溶液现象。方法精密度较好,加标回收率分别为银98.6%～100%,金96.2%～102%。方法准确、方便、快捷,能很好地满足铅冶炼渣中金、银含量的测定。

Determination of Gold and Silver in silver separating residue from lead smelting by Fire Assay

A method for determination of gold and silver in silver separating residue from lead smelting. Fire assay method was used to enrich the lead button. After cupellation, the gold and silver composite grains were formed. In addition to gold and silver, trace lead and bismuth impurities remained in the composite grains. After separation of gold and silver by nitric acid, gold particles and solution were obtained. The impurities are retained in the solution. After acid treatment, the impurities and trace amounts of gold in the solution were determined by ICP-OES. The trace quality of gold in the solution added gold particles is the quality of gold in the sample. Silver content is the quality of composite grain minus the quality of gold and impurities. The method is accurate, convenient and fast. The determination of impurities by ICP-OES solves the problem that trace gold enters into solution due to the residual lead and bismuth in the composite grains and the mistake . The accuracy of the method is good. The recoveries of standard addition are 98.6%-100% for silver and 96.2%-102% for gold, respectively.