离子交换树脂分离富集-分光光度法测定铜金精矿及尾矿中银

研究了732型阳离子交换树脂柱分离富集银的条件，建立了光度法测定铜精矿、金精矿及其尾矿中银的方法。实验表明，在pH 2~4的条件下，样品溶液中的银与硫脲络合以［Ag(SCN₂H₄ )₃］⁺形式被树脂吸附后，采用10 mL 0.5 mol/L的硫代硫酸钠溶液可定量洗脱，从而消除了绝大部分共存离子的干扰；树脂柱分离-富集后，硫代米蚩酮光度法测定银的检出限为5.0 μg/L。将本方法用于实际样品分析，测得结果与火焰原子吸收光谱法测定值一致，相对标准偏差(RSD，n=5)小于或等于14%，加标回收率为96%～102%。

Spectrophotometric determination of trace silver in copper concentrate, gold concentrate and tailings after separation and enrichment with ion exchange resin

The conditions of separation and enrichment of trace silver with 732 type cation exchange resin column have been studied.A method for spectrophotometric determination of silver in copper concentrate,gold concentrate and tailings was proposed.The experiment results indicated that silver could be absorbed by the ion exchange resin in the form of [Ag(SCN2H4)3]+ through reacting with thiourea at pH 2-4,and it could be eluted quantitatively with 10 mL of 0.5 mol/L sodium thiosulfate solution,which eliminated the interference from most of coexisting ions.After the separation and enrichment with resin column,the detection limit of thio-michler’s ketone spectrophotometry was 5.0 μg/L.When this method was applied to the determination of actual samples,the determination results were consistent with those obtained by flame atomic absorption spectrometry.The relative standard deviations(RSDs,n=5) were not more than 14% and the recoveries were between 96% and 102%.