摘要
铝土矿是极端风化作用的产物,也是锂的重要载体,由于其资源量巨大,对铝土矿中锂的富集机制和分布规律的研究将有利于找矿预测。锂同位素的高效准确分析是深入认识矿物中锂的富集机制和分布规律的基础。铝土矿样品由于化学稳定性较强,溶样过程较为复杂,且Al、Na、Ca、K等基体元素含量远高于锂,给锂的纯化增加不少难度。本文采用内径5mm、柱长190mm的聚四氟乙烯离子交换柱和AG50W-X12阳离子交换树脂,以0.5mol/L硝酸为淋洗液淋洗34mL,收集最后的12mL,即可完成对铝土矿中锂的完全纯化回收。该纯化方法减少了淋洗液的使用量,提高了实验效率。采用该方法对国际标样L-SVEC、RGM-2、GSP-2进行锂的纯化,通过多接收电感耦合等离子体质谱仪(MC-ICP-MS)测试锂同位素组成,得到的δ7Li测试值分别为-0.26‰±0.09‰(2SD,n=3)、3.19‰±0.37‰(2SD,n=3)、-0.78‰±0.22‰(2SD,n=3),与前人报道一致,验证了该方法的可靠性。此外,采用本方案对铝土矿国家标样(GBW07182)进行锂的纯化,δ7Li测定值为10.16‰±0.21‰(2SD,n=3)。
BACKGROUND: Bauxite is a product from extreme weathering, an important carrier of lithium. Due to its huge resources, the study on the mechanism and distribution of lithium in bauxite will be beneficial to the prospecting and prediction of bauxite deposits. Efficient and accurate analysis of lithium isotopes is the basis for deep understanding of the lithium enrichment mechanism and distribution driplines in the ores. The bauxite samples are more chemically stable and the sample dissolution process is more complicated. The content of matrix elements such as Al, Na, Ca and K is much higher than that of Li, which makes it difficult to purify Li.OBJECTIVES: To establish a method for separating and purifying lithium in bauxite for Li isotope analysis.METHODS: On the basis of previous studies, the separation, purification, and measurement scheme of Li in bauxite were investigated by leaching experiment.RESULTS: In this scheme, polytetrafluoroethylene exchange column with an inner diameter of 5 mm and a column length of 190 mm, and AG50 W-X12 cation exchange resin were used. 34 mL of 0.5 mol/L nitric acid was used as the eluent and the final solution was 12 mL, resulting in complete purification and recovery of Li in bauxite. At the same time, the method was used to purify the Li in international standard samples, L-SVEC, RGM-2 and GSP-2, and the values of δ7Li were measured by MC-ICP-MS, which were-0.26‰±0.09‰(2 SD, n=3), 3.19‰±0.37‰(2 SD, n=3),-0.78‰±0.22‰(2 SD, n=3). The analytical results were consistent with the previous results obtained by other methods, verifying the reliability of this method. The proposed method was used to purify bauxite standard sample, GBW07182, which yielded δ7Li of 10.16‰±0.21‰(2 SD, n=3).CONCLUSIONS: The purification method reduces the amount of eluent used and improves experimental efficiency.
作者
严爽
黄康俊
付勇
包志安
马龙
龙克树
叶远谋
陈蕤
陈满志
YAN Shuang;HUANG Kang-jun;FU Yong;BAO Zhi-an;MA Long;LONG Ke-shu;YE Yuan-mou;CHEN Rui;CHEN Man-zhi(College of Resource and Environmental Engineering,Guizhou University,Guiyang 550025,China;Key Laboratory of Karst Georesources and Environment,Ministry of Education,Guizhou University,Guiyang 550025,China;State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2020年第1期41-52,共12页
Rock and Mineral Analysis
基金
国家重点研发计划深地资源勘查开采专题(2017YFC0602701)
中国地质调查局中国矿产地质志项目(DD20160346,DD20190379)
贵州省人才基地项目(RCJD2018-21)
