敞开酸溶和偏硼酸锂碱熔ICP-MS法测定多金属矿中的稀土元素及铌钽锆铪  

Determination of Rare Earth Elements and Nb, Ta, Zr, Hf in Polymetallic Mineral Samples by Inductively Coupled Plasma-Mass Spectrometry Coupled with Open Acid Dissolution and Lithium Metaborate Alkali Fusion

作　　者：门倩妮[1] 沈平 甘黎明 冯博鑫 MEN Qian-ni;SHEN Ping;GAN Li-ming;FENG Bo-xin(No.5 Gold Geological Party,Chinese People’s Armed Police Force,Xi’an 710100,China;Gansu Zhiguang Geological Engineering Survey and Design Co.LTD.,Lanzhou 730010,China)

机构地区：[1]中国人民武装警察部队黄金部队第五支队,陕西西安710100 [2]甘肃智广地质工程勘察设计有限公司,甘肃兰州730010

出　　处：《岩矿测试》2020年第1期59-67,共9页Rock and Mineral Analysis

摘　　要：用电感耦合等离子体质谱法(ICP-MS)测定地质样品中的稀土及难熔元素,混合酸敞开酸溶法和碱熔融法是两种主要的溶样方法。但地质样品组分复杂,元素之间存在相互共生的现象,对于特殊元素、特殊样品用传统酸溶法会造成部分元素消解不完全,使测定结果不准确;而碱熔法的操作过程繁琐,且溶液盐度高,易产生基体干扰和堵塞仪器进样系统。本文改进了传统四酸和五酸体系,采用氢氟酸-硝酸-硫酸敞开酸溶体系,用国家一级标准物质制作标准曲线测定15种稀土元素,方法准确度(ΔlgC)为0.001~0.027。同时改进了偏硼酸锂碱熔法,样品用偏硼酸锂碱熔提取,加入氢氧化钠调节溶液至碱性条件,所测元素与偏硼酸锂共沉淀后过滤分离熔剂,再用硝酸复溶测定15种稀土元素及铌钽锆铪。两种溶样方法的测定值与认定值的相对误差为1.09%~9.30%。将混合酸敞开酸溶法测定稀土元素、偏硼酸锂碱熔法测定铌钽锆铪的结果与其他实验室密闭酸溶法相比,两组数据的相对偏差为0.13%~15.32%。本实验表明,混合酸敞开酸溶法适用于测定地质样品中的稀土元素,偏硼酸锂碱熔法不仅适用于测定地质样品中的稀土元素及铌钽锆铪,也适用于测定如古老高压变质岩石及铝含量高的样品中的铌钽锆铪。BACKGROUND: Mixed acid open acid dissolution and alkali fusion methods are the two main dissolution methods for determination of rare earth and refractory elements in geological samples by inductively coupled plasma-mass spectrometry(ICP-MS). However, the composition of geological samples is complex. For special elements and special samples, the traditional acid-dissolving method will cause incomplete digestion of some elements, which makes the measurement results inaccurate. The operation process of the alkali fusion method is cumbersome. The solution has high salinity, which can easily cause matrix interference and block the sample introduction system.OBJECTIVES: To improve the traditional four-acid and penta-acid systems in the determination of rare earth elements.METHODS: The hydrofluoric acid-nitric acid-sulfuric acid open acid solution system was used to determine the 15 rare earth elements by using the national standard material to prepare a standard curve. At the same time, the lithium metaborate alkali fusion method was improved. The sample was extracted with lithium metaborate alkali, and the solution was added to the alkaline condition by adding sodium hydroxide. The measured element was coprecipitated with lithium metaborate, and the flux was separated and filtered, and then reconstituted with nitric acid. Nineteen elements such as rare earth and lanthanum zirconium were measured.RESULTS: The relative deviations between the measured value and the certified value of the two dissolution methods were 1.09%-9.30%. The results of determination of Nb, Ta, Zr and Hf by mixed acid open dissolution method and rare earth element by lithium metaborate alkali fusion method were compared with those of another laboratory that used closed acid dissolution methods. The relative deviations between the two groups were 0.13%-15.32%.CONCLUSIONS: The mixed acid open dissolution method is suitable for the determination of rare earth elements in geological samples, whereas the lithium metaborate alkali fusion method is not

关 键 词：多金属矿 稀土元素 铌 钽 锆 铪 氢氟酸-硝酸-硫酸敞开酸溶 偏硼酸锂碱熔 氢氧化钠 电感耦合等离子体质谱法 

分 类 号：O614.33[理学—无机化学] O657.63[理学—化学]