风化壳淋积型稀土矿浸取过程的模拟计算研究Ⅲ:考虑级间离子扩散的液-固萃取模型  

Simulation on Leaching Process of Weathered Crust Elution-Deposited Rare Earth Minerals Ⅲ:Liquid-Solid Extraction Model Considering ion Diffusion Between Stages

作　　者：程福祥 冯凯[1] 吴声 廖春生 严纯华[2] Cheng Fuxiang;Feng Kai;Wu Sheng;Liao Chunsheng;Yan Chunhua(China Minmetals(Beijing)Research Institute of RE Co.,Ltd.,Beijing 100085,China;College of Chemistry and Molecular Engineering of Peking University,State Key Laboratory of Rare Earth Materials Chemistry and Applications,Beijing National Laboratory for Molecular Sciences,Beijing 100871,China)

机构地区：[1]五矿(北京)稀土研究院有限公司,北京100085 [2]北京大学化学与分子工程学院,稀土材料化学及应用国家重点实验室,北京分子科学中心,北京100871

出　　处：《中国稀土学报》2022年第6期1032-1044,共13页Journal of the Chinese Society of Rare Earths

基　　金：国家重点研发计划项目(2019YFC0605005)资助。

摘　　要：风化壳淋积型稀土矿物的柱浸过程可视作一种多级连续的液-固萃取操作,并通过其中的萃取平衡和物料平衡关系建立其模拟计算方法。在稀土矿物的液固萃取过程中,浸矿液中离子除所在矿柱级内部扩散并进行离子交换反应外,还将发生邻级矿柱间的浓差扩散,从而改变浸矿剂和稀土离子在矿柱中的浓度分布。基于菲克扩散定律建立了一种考虑级间离子扩散的风化壳淋积型稀土矿液固萃取模拟计算模型。计算结果显示,矿土渗透系数减小,扩散作用效果增大,浸矿剂利用效率下降;矿土中存在的滞留水可阻滞浸矿液中离子向前的扩散进程,但可促进浸矿液中离子向后方顶水中的运移;对于具有不同渗透性的等柱高矿土,渗透系数越小,可因增加矿柱级数提升浸矿剂利用效率,但也将因级间扩散作用更显著而产生相反的影响效果;浸矿剂浓度较高时级间扩散作用更显著,但仍可保持较高的浸矿剂利用效率,并增加浸出母液稀土浓度,减少浸矿液注液量。Column leaching of rare earth(RE)adsorbed to weathered crust elution-deposited rare earth ore can be considered as a multi-stage continuous liquid-solid extraction process,and a simulation method of the process can be developed on the basis of extraction equilibrium and involving mass balance. During leaching of the ore,the ions in leaching solution not only diffuse inside a stage and participate ion exchange reaction,but also diffuse between adjacent stages driven by concentration difference,which will change ion distribution in the column. According to Fick’s law of diffusion,a calculation model of considering the outside-stage ion diffusion is developed for column leaching process of weathered crust elution-deposited rare earth ore. The calculation results indicate that effect of outside-stage diffusion becomes significant and efficiency of leaching solution decreases with the decrease of permeability coefficient of ores;the immobile water in ores can retard the forward diffusion of the ions in the leaching solution,but advance their migration backward to discharging water;for the ore columns with an equal length butdifferent permeability,the efficiency of leaching solution will increase owing to increase of stage number,but decrease due to more significant outside-stage diffusion with decrease of permeability coefficient of ores;the leaching solution with higher concentration will enhance outside-stage diffusion,however can lead to its high leaching efficiency and high RE concentration of the leachate,and therefore decrease total required volume of it.

关 键 词：风化壳淋积型稀土矿 柱浸 液-固萃取模型 离子交换机制 级间离子扩散 

分 类 号：O614.33[理学—无机化学]