锑试金-电感耦合等离子质谱法测定铬铁矿中铂族元素  

Determination of platinum group elements in chromitite ores by inductively coupled plasma mass spectrometry after antimony fire assay

作　　者：李可及[1] 赵朝辉[1] LI Ke-Ji and ZHAO Chao-hui(Institute of Multipurpose Utilization of Mineral Resources C. A. G. S, Chengdu 610041)

机构地区：[1]中国地质科学院矿产综合利用研究所,成都610041

出　　处：《分析试验室》2018年第4期428-431,共4页Chinese Journal of Analysis Laboratory

基　　金：国土资源部川西稀有金属矿集区技术经济评价项目资助(121201016000150017-6)资助

摘　　要：建立了一种可定量富集铬铁矿中6种铂族元素的锑试金-电感耦合等离子体质谱分析方法。针对铬铁矿难溶的问题,选择硼酸、碳酸钠与六偏磷酸钠的熔剂组合,将取样量与熔剂用量等比例缩小(10:1),以XRF用熔样机开展预实验,以确定熔剂配比、熔融温度及时间等参数,而后以标准物质验证,相比试金条件实验省时省力,且易于判断溶解效果。因铬铁矿样品还原性弱,选择锑试金,经灰吹可同时预富集全部6种铂族元素,配料中加入锑粉作为捕集剂,即简化配料又避免了试金过程中熔体溢出。锑扣经灰吹获得合粒,而后经微波密闭消解,ICP-MS KED模式分析。各待测元素检出限在0.03~0.88 ng/g间,重现性RSD为4.5%~13%,铬铁矿标准物质分析结果与认定值吻合,适用于不同品位的铬铁矿样品。An antimony fire assay-ICP MS method for the determination of 6 platinum group elements in chromitite ores was established. As chromitite ores are refractory,a flux recipe containing boric acid,sodium carbonate and sodium hexametaphosphate was proposed. The weight of sample and flux were both reduced to one tenth of the normal ones. The experiments were conducted in a fusing machine designed for sample pretreatment in XRF analysis. The parameters such as flux composition,fusing temperature and time et al. were optimized,then verification tests were carried out with 5 g reference materials. Comparing with fire assay experiments conducted with a combination of sample and flux over 50 grams,this new method was faster and more productive（ the beads obtained weighted around 9 gram）,and it＇s easy to find whether the sample was completely dissolved. As the chromitite ores are of poor reducibility,the antimony fire assay method is most fitted,which keeps all PGEs intact after cupellation. Antimony powder was added to the flux instead of antimony oxide and flour,which not only made the recipe simple,but also prevented the melt overflow during fusing. After cupellation,the antimony button was reduced to a bead,which was then microwave digested,the solvent obtained was analyzed by ICP-MS under kinetic energy discrimination model. The detection limits are between0. 03 and 0. 88 ng/g and the reproducibility（ RSDs） is between 4. 5% and 13%. Analytical results of chromitite ore reference materials are in agreement with certified values,which proved this method could be applied to chromitite ores of different grades.

关 键 词：锑试金 铬铁矿 铂族元素 

分 类 号：TF03[冶金工程—冶金物理化学]