风化壳离子吸附型稀土矿中稀土元素含量测定与赋存形态研究  

Rare Earth Element Contents and Occurrence Forms in Weathering Crust Ion Adsorption Rare Earth Ore

作　　者：肖细炼 郭敏 邵鑫 谭娟娟 王磊 邱啸飞[1,2] XIAO Xiian;GUO Min;SHAO Xin;TAN Juanjuan;WANG Lei;QIU Xiaofei(Wuhan Center,China Geological Survey(Geosciences Innovation Center of Central South China),Wuhan 430205,China;Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey,Wuhan 430205,China;Guangdong Institute of Geological Survey,Guangzhou 510080,China)

机构地区：[1]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205 [2]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205 [3]广东省地质调查院,广东广州510080

出　　处：《岩矿测试》2024年第6期866-879,共14页Rock and Mineral Analysis

基　　金：中国地质调查局花岗岩成岩成矿地质研究中心开放基金项目(PM202302);广东省地质勘查与城市地质专项“广东省重要成矿区稀土资源评价项目”(2024032)。

摘　　要：风化壳离子吸附型稀土矿床具有稀土元素(REEs)种类齐全、放射性活性低、重稀土含量高,且易开采等特点,是一种极为重要的稀土矿床类型。当前,有关该矿床中稀土元素的测定研究大都只测定了稀土元素全量及离子相分量,且有些方法操作流程较繁琐,对于稀土元素的各种赋存形态分析研究较少。但在研究风化壳离子吸附型稀土矿床的成矿规律时,不仅要分析其稀土元素全量,还需要分析影响该矿床中稀土元素的成矿背景、迁移、富集过程中移动差异性、长期性和可利用性的化学形态,因此,准确测定风化壳离子吸附型稀土矿床中稀土元素全量及各赋存形态含量非常必要。本文以五酸混合消解作为测定风化壳离子吸附型稀土矿样品中稀土元素全量的前处理方法,并将BCR法和Tessier法提取的稀土元素形态结果进行对比,以ICP-MS为检测手段,探讨了样品中稀土元素全量及各赋存形态含量分布情况。结果表明,五酸混合消解能将稀土矿样品中所有稀土元素完全溶出,且操作简便,方法精密度(RSD)为0.82%~5.19%,检出限为0.002~0.027μg/g,各元素测定值与认定值的相对误差为-4.70%~6.65%,∑LREEs/∑HREEs为1.25~16.50,涵盖轻稀土和重稀土富集。BCR法和Tessier法提取的稀土元素各形态结果的相对偏差(RD)为0.79%~8.07%,提取结果基本能相互对应吻合,∑REEs回收率为84.75%~107.13%,∑REEs测定值的相对偏差(RD)为0.62%~21.00%,相对误差(RE)小于40%。相较之下,BCR法前处理流程简单,但是划分的形态没有Tessier法直观、具体,无法获取更详细的各形态数据,在本文实验条件下,Tessier法对于稀土元素形态分析可能具有较好的适应性。风化壳全风化层样品中稀土元素主要以离子吸附态赋存在黏土类矿物表面,因而离子交换态含量最高,随着风化壳剖面深度增加,pH升高,稀土元素更容易与碳酸根或碳酸氢根结合,导致碳酸The weathering crust ion adsorption type rare earth deposit has the characteristics of complete REE types,low radioactivity,high heavy rare earth contents,and easy mining,making it an extremely important type of rare earth deposit.At present,most of the research on the determination of REEs in this deposit only measures the total amount and ionic phase components of REEs,and some methods have complicated operating procedures,while there is relatively little research on the analysis of various REE forms.However,when studying the mineralization laws of weathering crust ion adsorption type rare earth deposits,it is not only necessary to analyze the total amount of REEs,but also to analyze the chemical forms that affect the mineralization background,migration,enrichment process,long-term differences,and availability of REEs in the deposit.Therefore,it is necessary to accurately determine the total amount and contents of various occurrence REE forms in weathering crust ion adsorption type rare earth deposits.In this article,a five acid mixed digestion was used as a pretreatment method for determining the total amount of REEs,and the results of rare earth elements speciation analysis determined by BCR method and Tessier method were compared.ICP-MS was used as the detection method to explore the distribution of the total amount and various REE forms in the samples.The results show that the five-acid mixed digestion can completely dissolve all REEs in the rare earth ore sample,and the operation is simple.The precision(RSD)of this method was between 0.82%to 5.19%,the detection limit was between 0.002μg/g to 0.027μg/g,and the relative error between the measured value and the recognized value of each element was between−4.70%to 6.65%.TheΣLREEs/ΣHREEs was between 1.25 to 16.50,covering the enrichment of light rare earths and heavy rare earths.The relative deviation(RD)of rare earth forms extracted by the two methods of BCR and Tessier was 0.79%to 8.07%,and the extraction results correspond and match each other.The rate

关 键 词：BCR四步法 Tessier七步法 风化壳 离子吸附型稀土矿 稀土元素 形态 ICP-MS 

分 类 号：P618.7[天文地球—矿床学] O657.63[天文地球—地质学]