常压酸溶-电感耦合等离子体质谱法测定地球化学勘查样品中的铌钽  

Determination of Niobium and Tantalum in Geochemical Exploration Samples by ICP-MS with Acid Solution at Normal Pressure

作　　者：邓长生[1] 李盛富[1] 张建梅[1] 王明力 勒孚河 牛芳红[1] DENG Chang-sheng;LI Sheng-fu;ZHANG Jian-mei;WANG Ming-li;LE Fu-he;NIU Fang-hong(No.216 Geology Party,China National Nuclear Corporation,Urumqi 830011,China;Xinjiang Institute of Measurement ＆ Testing Technology,Urumqi 830013,China)

机构地区：[1]核工业二一六大队,新疆乌鲁木齐830011 [2]新疆维吾尔自治区计量测试研究院,新疆乌鲁木齐830013

出　　处：《岩矿测试》2018年第4期364-370,共7页Rock and Mineral Analysis

基　　金：新疆军民结合产业发展专项资金项目“重点煤炭开发区放射性地质环境现状调查的关键技术研究”

摘　　要：常压酸溶法因溶矿效率高、成本低、检出限低,在地质实验室被广泛应用,但采用常用的氢氟酸-硝酸-盐酸-高氯酸四酸法处理样品,铌钽溶出率低,铌钽在容器壁发生水解和聚合反应导致其部分吸附或沉降,从而使测试结果偏低。因此,应用常压酸溶-电感耦合等离子体质谱(ICP-MS)分析地球化学勘查样品中的铌钽,需要解决的两个关键问题是铌钽的溶出率和试液中铌钽的水解。针对溶出率的不足,本方法在酸体系中引入硫酸,即氢氟酸-硝酸-盐酸-高氯酸-硫酸可以完全将铌钽溶出;针对水解,采用5%氢氟酸-5%硫酸-5%过氧化氢为提取剂,并采取与样品前处理相同分析流程的标准物质制作曲线,这两个方法相结合能有效抑制样品溶液中铌钽的水解,同时标准物质制作曲线法降低了ICP-MS分析中的样品溶液与标准溶液基体不一致引起的误差。本方法经国家标准物质验证,相对误差小于±7%,相对标准偏差在3.11%~6.27%之间(n=11),铌钽的检出限分别为0.04μg/g和0.03μg/g,相比于碱熔法检出限0.33μg/g具有明显优势,可以准确测定地球化学勘查样品中的铌钽。BACKGROUND： Due to its high digestion efficiency,low equipment cost and low detection limit,atmospheric acid dissolution is widely used in the geological laboratory. However,the commonly used four acid methods（hydrofluoric acid-nitric acid-hydrochloric acid-perchloric acid） is insufficient to dissolve niobium and tantalum.At the same time,niobium and tantalum would be partially adsorbed or would settle on the vessel caused by hydrolysis and polymerization reactions leading to the test results are lower than the real values.OBJECTIVES： To determine accurately the concentrations of Nb and Ta in geochemical samples,and to solve the two key problems of the dissolution rate and hydrolysis of Nb and Ta in the solution.METHODS： For the insufficiency of dissolution,sulphuric acid was introduced into the acid solution system. The acid solution system of hydrofluoric acid-nitric acid-hydrochloric acid-perchloric acid-sulphuric acid is used to completely dissolve niobium-tantalum in the sample. In view of the hydrolysis,extracting agent of 5% hydrofluoric acid-5% sulphuric acid-5% hydrogen peroxide was used. At the same time,the standard material curves were made using the same analytical process as the sample. The combination of these two methods effectively inhibited the hydrolysis of niobium-tantalum in sample solution. The method of standard material curves reduced the error caused by the matrix inconsistency between the sample solution and the standard solution in ICP-MS analysis.RESULTS： The relative deviation was less than ± 7% and the relative standard deviation was 3. 11%-6. 27%（n = 11）. The detection limits of niobium and tantalum were 0. 04 μg/g and 0. 03 μg/g,respectively. Compared with the detection limit of 0. 33 μg/g by alkali fusion method,it has obvious advantages.CONCLUSIONS： By changing the acid solution system,the extracting agent,and the method of standard material curves,the proposed method can be applied to measure niobium and tantalum in geochemical exploration samples.

关 键 词：地球化学勘查样品 铌 钽 电感耦合等离子体质谱法 常压酸溶 标准曲线法 

分 类 号：O614.512[理学—无机化学] O614.513[理学—化学]