摘要
传统观点认为,风化壳淋积型稀土矿床(即离子吸附型稀土矿床)中,稀土主要以吸附态赋存于风化壳黏土矿物表面,其他赋存形式占比较少。但近年来的同步辐射研究显示,稀土元素也同时以内层络合物形式存在,而内层络合物的存在可能会抑制稀土元素的离子交换。如何将风化壳淋积型稀土矿中各种形态的稀土元素有效地溶出,对于提高稀土资源利用率十分重要。本文选取南岭地区风化壳淋积型稀土矿石样品,选择混合酸(五酸)消解、盐酸消解、硝酸消解、硫酸铵浸提的前处理方式,采用电感耦合等离子体质谱(ICP-MS)测定,探讨样品中稀土元素的溶出情况。结果表明,采用混合酸(五酸)能够溶出样品中的全相稀土;盐酸或硝酸能够溶出以离子状态吸附于黏土矿物或铁锰氧化物中的稀土元素,以及以碳酸盐、磷酸盐等形式存在的稀土元素;硫酸铵浸提则只能将离子相的稀土元素置换出来。采用硝酸、盐酸溶出的稀土量,占混合酸(五酸)消解溶出稀土量(全相稀土)的71.7%~97.5%,硫酸铵浸提溶出的稀土量(离子相稀土)最低,仅是全相稀土量的9.1%~75.5%。Sc^(3+)的离子半径明显小于其他稀土元素,其提取率也明显低于其他稀土元素;铈(Ce)不同于其他稀土元素的分异-富集特性,使其在硫酸铵浸提中提取率与其他稀土元素不一致。
BACKGROUND:Weathered crust elution-deposited rare earth ores are the dominant mineral resources in China[1-5].The occurrence of rare earth elements(REEs)in weathering crust elution-deposited is very complicated.At present,the“ionic”rare earth extraction process can only use the“exchangeable adsorption state”rare earth elements,that is,the“ionic phase”rare earth elements,and other phase rare earth elements cannot be effectively recycled[6].How to effectively dissolve various forms of rare earth elements in ion-adsorbed rare earth ore is very important to improve the utilization rate of rare earth resources.OBJECTIVES:To compare the extraction efficiency of REEs in weathered crust elution-deposited rare earth ores by different pretreatment methods and discuss the influencing factors.METHODS:Five pretreatment methods,being open mixed acid digestion(HCl+HNO3+HF+HClO4+H2SO4),nitric acid digestion with or without hydrogen peroxide,hydrochloric acid digestion with hydrogen peroxide and ammonium sulfate leaching,were used to extract REEs in six rare earth samples from the Nanling area.The content of REEs in samples was determined by ICP-MS.For ion-adsorbed rare earth minerals,the open digestion method of five acids can replace the complicated alkali melting method for the determination of REEs in samples under certain conditions.Nitric acid,hydrochloric acid digestion or ammonium sulfate leaching can only dissolve part of REEs in ion-adsorbed rare earth samples.RESULTS:The amount of REE extracted by different pretreatment methods is quite different.The results of mixed acid digestion(five acids)are the highest;the results of nitric acid with or without hydrogen peroxide digestion,hydrochloric acid and hydrogen peroxide digestion are similar.The amount of REEs dissolved by nitric acid or hydrochloric acid digestion is slightly lower than mixed acid digestion.The amount of REEs dissolved by ammonium sulfate leaching is the lowest.The amount of REEs dissolved by 50%nitric acid,hydrochloric acid and other digesti
作者
朱云
郭琳
于汀汀
芦苒
张磊
屈文俊
丁竑瑞
马生凤
ZHU Yun;GUO Lin;YU Tingting;LU Ran;ZHANG Lei;QU Wenjun;DING Hongrui;MA Shengfeng(National Research Center for Geoanalysis,Beijing 100037,China;School of Earth and Space Science,Peking University,Beijing 100871,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2023年第5期877-887,共11页
Rock and Mineral Analysis
基金
国家重点研发计划项目(2021YFC2903000)课题“战略性多元素同时分析技术和标准化”。
