五酸微波消解——钡沉淀——电感耦合等离子体质谱法测定岩石矿物中稀土元素

Fiveacid Microwave DigestionBarium PrecipitationInductively Coupled Plasma Mass Spectrometry (ICPMS)

摘要:

稀土元素是国家重要的战略资源，为了能够更加精准高效的勘探稀土矿，建立一种便捷可靠，高灵敏度，适用性广泛的岩石矿物中稀土元素的分析技术势在必行。本文建立的方法：五酸（硝酸、盐酸、氢氟酸、硫酸、高氯酸）微波消解钡沉淀电感耦合等离子体质谱（ICPMS）法测定岩石矿物中的稀土元素，即先采用硝酸、盐酸、氢氟酸作为消解酸微波消解样品，消解后加入硫酸和高氯酸赶酸，再以王水复溶，最后再加入氯化钡沉淀硫酸根，借助电感耦合等离子体质谱仪（ICPMS）完成定量分析。本文尝试了采用氯化钡沉淀去除溶液中大部分的硫酸根的方法，有效降低了稀释倍数，提高了测试的灵敏度。结果表明，该方法检出限为0.0009~0.0192 μg/g，相对标准偏差（RSD，n=11）低于总体上3%，相对误差RE总体上低于5%，优于或接近于目前常用的氢氧化钠过氧化钠碱熔法。 对GBW 07185、GBW 07186、GBW 07188标准物质测定结果与标准值相符，其中部分重稀土元素如Yb、Lu尤其是Eu的准确度优于氢氧化钠过氧化钠碱熔法。本方法操作简便、安全性高、成本较低，适用于大批量岩石矿物样品中稀土元素的快速准确测定。

Abstract:

Rare earth elements (REEs) are important national strategic resources. In order to enable more precise and efficient exploration of rare earth deposits, it is necessary to establish a convenient, reliable, highly sensitive and widely applicable analytical technique has been set up for determining REEs in rare earth ores. In this paper, five acids (nitric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid and perchloric acid), followed by barium precipitation and inductively coupled plasma mass spectrometry (ICPMS)for the determination of REEs in rare earth ores. First, using nitric acid, hydrochloric acid and hydrofluoric acid as digestion acids for microwave digestion of samples. After digestion, sulfuric acid and perchloric acid are added to remove the acid, and then dissolved in aqua regia. Finally, barium chloride is added to precipitate sulfate ions, and quantitative analysis has been performed by using an inductively coupled plasma mass spectrometer (ICPMS). Barium chloride precipitation has been tried to remove most of the sulfate ions in the solution. It can effectively reducing the dilution factor and improve the sensitivity of the test. As showed by the results, the detection limit of this method is 0.000 9~0.019 2 μg/g, the relative standard deviation (RSD, n=11) is lower than 3%, and relative error RE is lower than 5%. The result is better or close to the commonly used sodium hydroxide peroxide alkali melting method. The determination results of GBW 07185, GBW 07186 and GBW 07188 standard substances are consistent with the standard values, and the accuracy of some heavy rare earth elements, such as Yb, Lu, especially Eu is better than that of sodium hydroxide and sodium peroxide alkali melting method. This method is easy to operate with high safety and cost-effeciency. It is suitable for rapid and accurate determination of rare earth elements in large quantities of rock mineral samples.