碱熔沉淀分离-电感耦合等离子体质谱法测定伴生重晶石稀土矿中的稀土元素  

Determination of Rare Earth Elements in Barite-associated Rare Earth Ores by Alkaline Precipitation Separation-Inductively Coupled Plasma-Mass Spectrometry

作　　者：董学林 何海洋[1,2] 储溱[1] 仇秀梅 唐兴敏 DONG Xue-lin;HE Hai-yang;CHU Qin;QIU Xiu-mei;TANG Xing-min(Hubei Province Geological Experimental Testing Center,Wuhan 430034,China;Key Laboratory of Rare Mineral,Ministry of Land and Resources,Wuhan 430034,China;School of Chemistry Engineering,Huazhong University of Science&Technology,Wuhan 430074,China)

机构地区：[1]湖北省地质实验测试中心,湖北武汉430034 [2]国土资源部稀土稀有稀散矿产重点实验室,湖北武汉430034 [3]华中科技大学化学与化工学院,湖北武汉430074

出　　处：《岩矿测试》2019年第6期620-630,共11页Rock and Mineral Analysis

基　　金：国家重点研发计划项目“重点领域急需化学成分量标准物质研究”(2016YFF020110308)

摘　　要：采用电感耦合等离子体质谱法(ICP-MS)测定伴生重晶石轻稀土矿中的稀土元素时,Ba以及轻稀土元素La、Ce、Pr、Nd、Sm等对中重稀土造成严重的质谱重叠干扰,因此在保证矿石完全消解的同时,若能选择合适的前处理方法实现目标元素与基体的有效分离,将有利于减少质谱干扰。本文采用过氧化钠-碳酸钠熔融分解伴生重晶石的稀土矿样品,熔融物用三乙醇胺溶液提取,将沉淀过滤去除硅、铁、锰、铝等大量基体元素,而稀土元素与钡、锶、钙等留存于沉淀中,沉淀经盐酸溶解后再用氨水进行二次沉淀,将稀土元素与伴生的高含量钡、锶、钙等元素分离,分离率超过96%,从而极大地降低了由钡的氧化物和氢氧化物对153 Eu等元素质量数的质谱干扰。轻稀土元素对中重稀土元素的干扰则通过测定高浓度的单元素标准溶液在m/z 138~175处的表观浓度来计算干扰校正系数,对干扰量进行扣除校正。该方法通过稀土矿石标准物质GBW07187、GBW07188验证,测定值与认定值的相对误差<10%;应用于伴生重晶石稀土矿石实际样品分析,相对标准偏差(RSD,n=12)为0.5%~4.6%,证明了本方法可用于分析高钡矿石中的稀土元素。BACKGROUND:When inductively coupled plasma-mass spectrometry(ICP-MS)is used to determine the rare earth elements(REE)in the barite-associated light rare earth ores,Ba and light rare earth elements La,Ce,Pr,Nd,Sm,cause severe mass spectral overlap interference to the medium and heavy rare earths.Therefore,under the condition that complete digestion of oress,if the appropriate pretreatment method can be selected to achieve effective separation of the target elements from the matrix,it will be beneficial to reduce mass spectrum interferences.OBJECTIVES:To reduce the mass spectrum interferences by establishing a simple and effective pretreatment method for separation of rare earth elements from barium and other coexisting elements in barite-associated rare earth ores.METHODS:The barite-associated rare earth ores samples were fused with sodium peroxide and sodium carbonate.After dissolution of the fusion cake,the target REE and the undesired barium were precipitated in triethanolamine solution,but some matrix elements like Si,Fe,Mg,and Al in samples,and most fusion agents,were separated by filtration.The target REE were secondly precipitated in ammonium hydroxide after dissolution of the precipitates by acid,so that Ba,Sr and Ca could be separated from REE.The separation exceeds 96%,so the mass spectrum interferences caused by barium polyatomic ions were effectively reduced.In addition,the interference correction coefficients by measuring the interference concentration at m/z 138-175 of the high concentration lighter rare earths standard single element solution were adopted to account for the oxide and hydroxide overlap problem for the determination of middle and heavier rare earth elements.RESULTS:The validity of the method was evaluated by analyses of rare earth ores certified reference materials and the results were in good agreement with certified values(|RE|<10%).For the actual sample analysis of the barite-associated rare earth ores,the relative standard deviations(n=12)were from 0.5%to 4.6%,which proved that th

关 键 词：重晶石 稀土元素 过氧化钠-碳酸钠熔融 沉淀分离 钡 电感耦合等离子体质谱法 

分 类 号：O657.63[理学—分析化学] P578.71[理学—化学]