逆王水微波消解 8-羟基喹啉沉淀-电感耦合等离子体质谱法测定 钨钼矿石中的铼. (Chinese)

Rock & Mineral Analysis; Sep2023, Vol. 42 Issue 5, p915-922, 8p

TUNGSTEN, MOLYBDENUM, RHENIUM, MICROWAVES, ORES

BACKGROUND: Rhenium (Re) is a key mineral resource widely used in the aerospace field. As one of the rarest elements in the earth, Re rarely exists as an independent mineral but is dispersed in various sulfide ores. Due to its low content and dispersed distribution, the highly sensitive and accurate quantification of Re (ng/g) in complex ore is one of the challenges of modern geological analysis. In order to solve the problem of incomplete decomposition and the great interference caused by co-dissolution of high abundance matrix elements, the existing “digestionseparation” method using 8-12h for one sample is complicated, time-consuming and labor-intensive. Therefore, the development of a simple, fast and low-cost method is urgently required. OBJECTIVES: To establish an analytical method based on Lefort aqua regia microwave digestion, molybdenum and tungsten precipitation, ICP-mass spectrometry for the determination of rhenium in ore. METHODS: Lefort aqua regia microwave digestion was used to fully decompose ore, and then the organic precipitator 8-hydroxyquinoline (8-HQ) was used to selectively precipitate high-abundance matrix interference elements molybdenum (Mo) and tungsten (W) in the acid-ammonium acetate buffer system (pH 4.5). The organic precipitator 8-HQ was used to precipitate Mo and W to produce stable hydroxyquinoline molybdenum [MoO2 (C9H6ON)2 ] and tungsten [WO2 (C9H6ON)2 ], thereby removing the high-abundance Mo and W in the digestion solution and reducing the interference of matrix on the quantitative analysis of Re. The relevant parameters of Lefort aqua regia microwave digestion and 8-HQ precipitation were systematically studied, and the digestion and precipitation properties were deeply studied by using national certified reference materials. RESULTS: The key parameters that influence ore digestion including volume of Lefort aqua regia and temperature of microwave digestion, were determined as 2.8mL and 130℃ for step 1 and 150℃ for step 2 separately. The addition amount of 8-HQ was also determined as 0.2mL (3%, w%) by comparing precipitation rates of W, Mo and W-Mo solution (25µg/mL) under different amounts, and results showed that the precipitation rate was greater than 95% in different ore digestion solutions. In the established method, the detection limit of Re was 6.9ng/g, the relative error was 0.71%-6.07%, and the RSD was less than 5%. CONCLUTIONS: The method established in this study can effectively eliminate the interference of matrix elements molybdenum and tungsten on Re quantification without introducing new interference elements. Compared with the existing “digestion-separation” process, the method is simpler and faster (shortened from 8-12h for one sample to approximately 1h) and the method has been successfully applied in molybdenum ore, rhenium molybdenum ore and tungsten-tin bismuth ore. This study proves that interfering instead of target element precipitation is feasible and provides a simple, fast and low-cost method for accurate quantification of Re in complex ore. [ABSTRACT FROM AUTHOR]

铼在地壳中的丰度低且分散，多伴生于钨钼矿中，现有方法常采用碱熔富集，流程长且繁琐，亟需开 发一种简便快捷的检测方法。本文建立了逆王水微波消解钨钼矿石样品，8-羟基喹啉沉淀分离钨钼元素， 与电感耦合等离子体质谱联用的检测方法。结果表明：0.0500g 样品，2.80mL 逆王水即可实现铼元素的全 部溶出，0.20mL 有机沉淀剂 8-羟基喹啉（3%）在乙酸-乙酸铵缓冲体系（pH 4.5）中可选择性沉淀钼、钨元素， 有效消除基体元素钼、钨（沉淀率>95%）对 Re 定量干扰，同时不引入新干扰元素。相比现有分离富集前处 理流程更加简便快捷，前处理时间缩短为现有方法的 1/4；该方法对 Re 的检出限为 6.9ng/g，采用国家一级 标准物质钼矿石（GBW07238）、钼矿石（GBW07285）、铼钼矿石（GBW07373）和钨锡铋矿石（GBW07369）对 方法的准确度进行了验证，测定值与推荐值吻合，相对误差为 0.71%～6.07%，RSD＜5%。本方法建立的 “消解-分离富集”处理流程所需时间从常规的 8～12h 缩短至 2h 左右，在准确定量矿石样品中 Re 的同时简 化了样品前处理流程，快速的样品处理及低廉的测试成本有助于关键稀有金属矿产的开发利用。 [ABSTRACT FROM AUTHOR]

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