锍镍试金-微波消解-高分辨率连续光源石墨炉原子吸收光谱法测定岩石矿物中超痕量铂钯钌铑铱  

Determination of ultra-trace platinum,palladium,ruthenium,rhodium and iridium in rocks and minerals by high resolution continuum source graphite furnace atomic absorption spectrometry with nickel sulfide fire assay enrichment and microwave digestion

作　　者：毛香菊[1,2,3,4,5] 刘璐 肖芳[1,2,3,4,5] 张宏丽 高小飞[1,2,3,4,5] 倪文山 MAO Xiang-ju;LIU Lu;XIAO Fang;ZHANG Hong-li;GAO Xiao-fei;NI Wen-shan(Zhengzhou Institute of Multipurpose Utilization of Mineral Resources,CAGS,Zhengzhou 450006,China;China National Engineering Research Center for Utilization of Industrial Minerals,Zhengzhou 450006,China;Key Laboratory for Polymetallic Ores′Evaluation and Utilization,MNR,Zhengzhou 450006,China;Key Laboratory of Comprehensive Utilization of Gold Resource in Henan Province,Zhengzhou 450006,China;Northwest China Center for Geosience Innovation,Xi′an 710054,China)

机构地区：[1]中国地质科学院郑州矿产综合利用研究所,河南郑州450006 [2]国家非金属矿资源综合利用工程技术研究中心,河南郑州450006 [3]自然资源部多金属矿评价与综合利用重点实验室,河南郑州450006 [4]河南省黄金资源综合利用重点实验室,河南郑州450006 [5]西北地质科技创新中心,陕西西安710054

出　　处：《冶金分析》2020年第3期1-8,共8页Metallurgical Analysis

基　　金：中国地质调查局地质调查二级项目(DD20189263,DD20190573,DD20190186)。

摘　　要：Pt、Pd、Ru、Rh和Ir属于铂族元素,它们物理化学性质接近,是一组重要的地球化学和环境化学元素。然而,铂族元素在自然界矿石中丰度很低且分布不均匀,具有块金效应,准确测定其含量一直是分析化学中的难题。实验采用锍镍试金法对样品中Pt、Pd、Ru、Rh和Ir进行分离和富集,用微波消解法处理Pt、Pd、Ru、Rh和Ir这些金属的硫化物沉淀以及滤纸,用高分辨率连续光源石墨炉原子吸收光谱法(HRCS-GFAAS)对样品溶液中这些元素进行测定,建立了岩石矿物中超痕量Pt、Pd、Ru、Rh和Ir的测定方法。实验表明:运用传统的锍镍试金富集岩石矿物中Pt、Pd、Ru、Rh和Ir时,用实验制备提纯的NiCO 3代替商品试剂NiO作为捕集剂,可大幅度降低锍镍试金流程中待测元素Pt、Pd、Ru、Rh和Ir的空白值,且空白值非常稳定;采用微波消解仪在优化的加热消解程序下以10 mL王水(1+1)溶解Pt、Pd、Ru、Rh和Ir这些金属的硫化物沉淀以及滤纸,Pt、Pd、Ru、Rh和Ir可被完全溶解在溶液中,Ru不会形成RuO 4挥发;采用连续光源原子吸收光谱仪的高分辨率分光系统,各待测元素的连续光源原子吸收光谱分辨率均不大于0.00223 nm/pixel,可将Pt、Pd、Ru、Rh和Ir的原子吸收谱线与干扰谱线完全分开,故样品中共存元素对Pt、Pd、Ru、Rh和Ir所测谱线的干扰可忽略。在选定的实验条件下,Pt、Pd、Ru、Rh和Ir的吸光度与其对应的质量浓度运用二次方程最小二乘法拟合校准曲线,各元素校准曲线的相关系数分别为0.9999、0.9998、0.9998、0.9999、0.9997;特征浓度分别为2.98、0.47、0.98、0.48、2.76 ng/mL。将实验方法应用于铬铁矿原矿中Pt、Pd、Ru、Rh和Ir的测定,测定结果的相对标准偏差(n=5)介于4.2%~13.4%之间。按实验方法测定土壤和岩石(橄榄石、辉石)等标准物质中的Pt、Pd、Ru、Rh和Ir,测定值与标准值吻合良好。Pt,Pd,Ru,Rh and Ir belonged to platinum group elements with similar physical and chemical properties.They were a group of important elements in geochemistry and environmental chemistry.However,the abundance of platinum group elements in rocks in nature was very low and the distribution was non-uniform.Due to the nugget effect,the accurate determination of their contents was always a problem in analytical chemistry.After the elements including Pt,Pd,Ru,Rh and Ir in the samples were separated and enriched by nickel sulfide fire assay method,their sulfide precipitates and the filter paper were treated by microwave digestion.Then the contents of these elements in sample solution were determined by high resolution continuum source graphite furnace atomic absorption spectrometry(HRCS-GFAAS).Thus,a determination method of ultra-trace platinum,palladium,ruthenium,rhodium and iridium in rocks and minerals was established.The experiments showed that when Pt,Pd,Ru,Rh and Ir in rocks and minerals were enriched by traditional nickel sulfide fire assay method,the blank values of Pt,Pd,Ru,Rh and Ir could be greatly reduced in the process of nickel sulfide fire assay with commercial reagent NiO replaced by the purified NiCO 3 as the trapping agent.Moreover,the blank values were very stable.The sulfide precipitates of Pt,Pd,Ru,Rh and Ir as well as filter paper were dissolved with 10 mL of aqua regia(1+1)in microwave digestion system with optimized heating procedures.The results showed that Pt,Pd,Ru,Rh and Ir could be fully dissolved in solution,and Ru would not form volatile RuO 4.The high resolution beam splitting system of continuum source graphite furnace atomic absorption spectrometer was adopted.The resolutions of continuum source graphite furnace atomic absorption spectra for test elements were all not more than 0.00223 nm/pixel.The atomic absorption lines of Pt,Pd,Ru,Rh and Ir could be fully separated from interference lines.Therefore,the interference of coexisting elements in sample with the spectral lines of Pt,Pd,Ru,Rh

关 键 词：锍镍试金 铂 钯 钌 铑 铱 碳酸镍 微波消解 高分辨率连续光源石墨炉原子吸收光谱法(HRCS-GFAAS) 

分 类 号：O657.31[理学—分析化学]