电感耦合等离子体原子发射光谱法测定金精矿中铊

Determination of thallium in gold concentrate by inductively coupled plasma atomic emission spectrometry

目前在黄金行业,金精矿冶炼过程中环保元素如铊、砷等的检测受到越来越多的关注,而金精矿中铊的检测尚无标准可依。采用盐酸、硝酸、氢氟酸、高氯酸分解金精矿样品,在王水介质中,在过氧化氢、三氯化铁存在下,使用聚氨酯泡沫富集铊,与杂质元素分离,并在沸水浴中使用硝酸(1+99)进行解脱,选择Tl 190.801nm为分析线,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定铊,建立了金精矿中铊的测定方法。通过试验,确定了最优分离富集参数,即为15%(V/V)王水、3%(V/V)过氧化氢、0.5g/L铁盐介质。铊的质量浓度在0.10~500μg/mL范围内与其发射强度呈线性,相关系数为0.999 9;方法的测定下限为6.5μg/g。金精矿中共存元素由于泡沫的分离富集作用而不影响测定。实验方法用于测定4个金精矿样品中铊,结果的相对标准偏差(RSD,n=11)为2.1%~5.0%;按照实验方法对金精矿样品中铊进行加标回收试验,回收率为92%~101%。

At present,the detection of environmental elements such as thallium and arsenic in melting process of gold concentrate has attracted more and more attention.However,there is no standard about the detection of thallium in gold concentrate ore.The gold concentrate sample was decomposed by hydrochloric acid,nitric acid,hydrofluoric acid and perchloric acid.The thallium was enriched using polyurethane foam in aqua regia medium in presence of hydrogen peroxide and ferric trichloride,realizing the separation from impurities.Then,it was eluted with nitric acid(1+99)in boiling water bath.Tl 190.801 nm was selected as the analytical line.The determination method of thallium in gold concentrate ore by inductively coupled plasma atomic emission spectrometry(ICP-AES)was established.The optimal separation and enrichment conditions were obtained by experiments:15%(V/V)aqua regia,3%(V/V)hydrogen peroxide and 0.5g/L ferric salt.The mass concentration of thallium in range of 0.10-500μg/mL was linear to the corresponding emission intensity with correlation coefficient of 0.999 9.The low limit of determination was 6.5μg/g.The coexisting elements in gold concentrate did not influence on the determination due to the separation and enrichment effect of foam.The proposed method was applied to the determination of thallium in four gold concentrate ore samples.The relative standard deviation(RSD,n=11)was2.1%-5.0%.The recovery test of standard addition was conducted according to the experimental method,and the recoveries were between 92% and 101%.