摘要
离子型稀土矿自发现以来,由于其稀土配分元素以中重稀土为主、提取工艺简单而在世界上占据重要地位。系统总结了近年来离子型稀土矿粒度分布特征、粘土矿物类型及转化、盐基离子迁移及重金属在表生地球化学作用、原地浸矿及模拟浸矿等不同条件下的释放规律等。结果表明:化学蚀变指数(CIA)、酸雨淋溶、地形地貌及母岩岩性控制了稀土矿粒径的空间分布。X射线衍射(XRD)分析显示离子型稀土矿中粘土矿物主要类型有高岭石、埃洛石等,不同母岩风化形成的粘土矿物在扫描电镜(SEM)图像中呈现较大差异;透射电镜(TEM)扫描表明,粘土矿物出现堆垛晶格条纹、裂隙等,揭示原地浸矿及模拟浸矿作用下粘土矿物发生了含量及类型转化。稀土矿表层土壤中盐基离子含量受风化程度及母岩岩性双重控制,弱酸环境(pH=4.6~5.8)更有利于盐基离子淋溶。原地浸矿促进土壤酸化的加剧,不同层位稀土矿中盐基离子含量呈K^(+)>Na^(+)>Mg^(2+)>Ca^(2+),且在浸矿初期各离子含量大量淋失;模拟浸矿盐基离子的淋溶量随浸矿液pH的降低而增加,随浸矿液浓度的增加而增加,但注液强度降低盐基淋溶量越大,盐基的淋溶呈现一定的滞后效应。区域稀土矿调查及资料分析表明,稀土矿区表土层具重金属高背景值的特点,其来源与母岩风化密切相关。原地浸矿及模拟浸矿均表明,弱酸可溶态及可氧化态重金属随浸矿的持续发生迁移及释放,其迁移能力表现为Pb>Zn>Cu;重金属的迁移释放不是简单的扩散过程,而是由多个扩散机制控制及反应较为复杂的过程。在上述研究的基础上,对未来离子型稀土矿勘查标准、新型可控的池浸工艺及多孔介质稀土矿渗流模型等研究进行了展望,为稀土矿山可持续开发及矿山地质环境保护提供参考依据。
Since the discovery of ion adsorption type rare earth ore,it has occupied an important position in the world due to its medium and heavy rare earth elements and simple extraction process.In this paper,the particle size distribution characteristics,clay mineral types and transformation are summarized,and in different condi⁃tions of supergene geochemistry,in-situ leaching and simulated leaching,the migration of base ions and the re⁃lease of heavy metals in rare earth ores are outlined.The results show that the spatial distribution of grain size is controlled by chemical index of alteration(CIA),acid rain leaching,topography and parent rock lithology.XRD analysis shows that the main types of clay minerals are kaolinite and halloysite,and the SEM images of clay minerals formed by weathering of different parent rocks.In-situ leaching and simulated leaching revealed the content and type conversion of clay minerals under the action of the leaching solution,which was approved/supported by the appearance of stacked lattice stripes and cracks on the TEM scanning images of clay minerals.The content of base ions in surface soil of rare earth ore was controlled by weathering degree and lithology of parent rock.Weak acid environment(pH=4.6~5.8)was more conducive to leaching of base ions.In situ leach⁃ing promotes soil acidification.The content sequence of base ions in different layers of rare earth ore was pre⁃sented by K^(+)>Na^(+)>Mg^(2+)>Ca^(2+),and was shown a large amount of ions in the early stage of leaching.The simu⁃lated leaching showed that the leaching amount of base ions increases with the decreased of the pH of the leach⁃ing solution.But with the increase of the concentration of the leaching solution,the intensity of the injection de⁃creases.The leaching amount of base ions presented a certain hysteresis effect.The investigation and data analy⁃sis of regional rare earth ore showed that the topsoil of rare earth mining area had the characteristics of high background value of heavy metals,and it formed by the weathering of parent rock.Both in-situ leaching and sim⁃ulated leaching showed that weak acid soluble and oxidizable heavy metals had migrated and released with the continuous leaching,and showed migration ability with Pb>Zn>Cu.The migration and release of heavy metals was not a simple diffusion process,but a complex process by multiple diffusion mechanisms controlling.On this basis,the future ion type rare earth ore exploration standards,controllable new pool leaching process and po⁃rous media rare earth ore seepage model are prospected.This study provides a reference for the sustainable de⁃velopment of rare earth mines and the protection of mine geological environment.
作者
陈陵康
陈海霞
金雄伟
张恋
刘金辉
柳传毅
徐狮
吴开兴
何书
孙涛
刘卫明
Chen Lingkang;Chen Haixia;Jin Xiongwei;Zhang Lian;Liu Jinhui;Liu Chuanyi;Xu Shi;Wu Kaixing;He Shu;Sun Tao;Liu Weiming(College of Sciences,Guangdong Universi-ty of Petrochemical Technology,Maoming 525000,China;School of Resource and Environmental Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China;College of Petroleum Engineering,Guangdong University of Petrochemical Technology,Maoming 525000,Chi-na;School of Water Resources and Environment,China University of Geosciences,Beijing 100083,China;China Nerin Engineering Co.,Ltd.,Nanchang 330038,China;Sinohydro Bureau 9 Co.,LTD,Guiyang 550081,China;Guangzhou Holding Company of the China Railway Siyuan Survey and Design Group Co.,Ltd.,Guangzhou 510600,China)
出处
《中国稀土学报》
EI
CAS
CSCD
北大核心
2022年第2期194-215,共22页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金项目(41967038)
广东省基础与应用基础研究基金项目(2021A1515011487)
江西省自然科学基金面上项目(20171BAB203029)
广东石油化工学院人才基金项目(520130)资助。
关键词
粒度
粘土矿物盐
基离子
重金属PB
离子型稀土矿
particle size
clay minerals
base ion
heavy metal of lead
rare earth minerals
作者简介
通讯联系人:陈陵康(1973-),男,博士,副教授,研究方向:矿山地质环境、第四纪环境,E-mail:lkchen@gdupt.edu.cn。
