勃姆石对稀土离子的吸附性研究  

Adsorption Properties of Rare Earth Cations by Boehmite

作　　者：周宗可 覃宗华[1] 万泉[1] 聂信 于文彬[1] ZHOU Zongke;QIN Zonghua;WAN Quan;NIE Xin;YU Wenbin(State Key Laboratory Ore of Deposite Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地球化学研究所,矿床地球化学国家重点实验室,贵阳550081 [2]中国科学院大学地球与行星科学学院,北京100049

出　　处：《硅酸盐通报》2023年第5期1688-1695,共8页Bulletin of the Chinese Ceramic Society

基　　金：贵州省省级科技计划(黔科合基础[2019]1460号);中国科学院战略性先导科技专项B类项目(XDB41000000);矿床地球化学国家重点实验室领域前沿项目(SKLODG-2018-01)。

摘　　要：稀土元素在铝(氢)氧化物矿物表面的吸附过程对铝土矿中稀土元素的富集和以吸附态存在的稀土元素的提取回收均具有重要影响。本文选择勃姆石作为研究对象,La和Y分别作为轻稀土和重稀土元素的代表,以批实验的方法,探究吸附时间、溶液pH值和背景电解质对勃姆石吸附稀土离子的影响。研究发现:勃姆石吸附稀土离子在72 h内能够接近平衡,对La^(3+)和Y^(3+)的吸附率分别约为45%和35%;在所选pH值范围内吸附率随pH值增加而升高;同时,吸附率随背景电解质浓度增加而升高。由于质子化效应,在弱酸性条件下,勃姆石表面携带正电荷,与稀土离子之间存在静电斥力,稀土离子与勃姆石之间可能形成内圈络合物。通过对比轻稀土和重稀土的吸附行为发现,勃姆石对轻稀土有更强的吸附能力。此外,通过热力学和动力学模型拟合分析发现,勃姆石对稀土离子的吸附更符合Langmuir单层吸附模型和准二级动力学模型。The adsorption process of rare earth elements on the surface of aluminum(hydrogen)oxide minerals has an important impact on the enrichment of rare earth elements in bauxite and the extraction recovery of rare earth elements in the adsorbed state.In this research,boehmite was selected as the model mineral,and La and Y were chosen as the representatives of light and heavy rare earth elements,respectively.The effects of adsorption time,solution pH value and background electrolyte concentration on the adsorption of rare earth ions on boehmite were investigated by batch experiments.The results show that the adsorption of rare earth cations by boehmite approaches equilibrium within 72 h,and the adsorption rates of La^(3+)and Y^(3+)are about 45%and 35%,respectively.In the selected pH value range,the adsorption rate and the background electrolyte concentration rise with the increase of pH value.Due to the protonation effect,the surface of boehmite possesses positive charges under weakly acidic conditions,and electrostatic repulsion occurs between rare earth cations and the surface.So it can be speculated that inner-sphere complexes may be formed between rare earth elements and the surface of boehmite.Compared with heavy rare earth cations,boehmite is more likely to uptake light rare earth cations.The adsorption behavior of rare earth elements by boehmite is fitted better by Langmuir monolayer adsorption model and the pseudo-second-order kinetic model.

关 键 词：勃姆石 稀土元素 吸附 电位滴定 铝(氢)氧化物 批实验 

分 类 号：TQ424[化学工程]