蒸馏分离-电感耦合等离子体原子发射光谱(ICP-AES)法测定氰化样品中砷的含量

Determination of Arsenic in Cyanide Samples by Inductively Coupled Plasma Atomic Emission Spectrometry with Distillation Separation

砷是黄金选冶过程中常见的元素之一,选冶过程中砷的存在在一定的程度上影响了黄金等贵金属的氰化浸出效果。选冶样品中砷含量的准确分析可以为黄金选冶提供可靠的数据,并且采用一定的方法避免选冶过程中砷存在的影响。采用饱和溴水-硝酸-硝硫混酸强氧化剂处理含氰样品,一方面分解氰化物,另一方面将各种形式的砷氧化为五价离子;再通过加入溴化钠催化剂,用硫酸亚铁将五价砷还原为三价砷,在108℃条件下,通过蒸馏方式将三价砷蒸馏出来,利用电感耦合等离子体原子发射光谱仪测定砷的含量。通过实验得出方法的检测限为0.0019%;方法的相对标准偏差(RSD)小于2%;方法的加标回收率为99.8%～101%;通过与溴酸盐滴定法的结果对比,结果准确、可靠。

Arsenic is one of the common elements in the selection process of gold.The existence of arsenic in the process of smelting influences the result of cyanidation leaching of gold and other precious metals.The accurate analysis of the arsenic content in the selected samples can provide reliable data for the selection of gold,and help to adopt certain methods to avoid the influence of arsenic in the process.In this method,the cyanide samples were decomposed by treating with saturated bromide,nitric acid,nitric-sulfur mixed acid,and on the other hand,various forms of arsenic were oxidized to five valent ions.Then adding sodium bromide catalyst,the pentavalent arsenic was reduced to trivalent arsenic by ferrous sulfate,under 108℃,trivalent arsenic was distilled,determined the content of arsenic by inductively coupled plasma atomic emission spectrometer.The detection limit of this method is 0.0019%.Method precision RSD〈2%;the range of accuracy-additive recovery was 99.8%-101%.The accuracy of the results is reliable comparing with the bromate titration method.