风化壳淋积型稀土矿浸取过程的模拟计算研究Ⅱ:存在“返混”的液-固萃取模型  

Simulation on Leaching Process of Weathered Crust Elution-Deposited Rare Earth Minerals:ⅡBack-Mixing Involved Liquid-Solid Extraction Model

作　　者：程福祥 吴声[1,2] 廖春生 严纯华[2] Cheng Fuxiang;Wu Sheng;Liao Chunsheng;Yan Chunhua(China Minmetals(Beijing)Research Institute of RE Co.,Ltd,Beijing 100085,China;College of Chemistry and Molecular Engineering,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3期438-449,共12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中稀土元素的浸取可视作一种液-固萃取过程,可通过其中的萃取平衡和物料平衡关系进行浸取行为的模拟计算。前文介绍了一种基于一定假设的风化壳淋积型稀土矿柱浸过程液-固萃取模型计算方法。本文基于土壤水动力学中关于土体水份的形态分类原则,对前文假设进行了适当修正,进而建立了考虑“返混”的风化壳淋积型稀土矿液-固萃取模型计算方法。修正的模型将土体中存在的水份分为滞留水和流动水两类。通过模拟计算探讨了不同滞留水比例,以及考虑滞留水时离子交换反应系数、浸矿剂浓度、原矿稀土品位、矿土饱和含水率等因素对于浸矿效果的影响。计算结果显示:较大的滞留水比例、较高的原矿稀土品位、较小的离子交换反应系数和较低的浸矿剂浓度均会使所需注入的浸矿液体积增加,但所需顶水体积变化不大,始终与矿土饱和持水量相近;而矿土饱和含水率的不同对于浸矿剂硫铵的消耗需求影响不大,但线性改变顶水量需求;先浓后淡注液方式使浸矿剂的浸取效率降低,并增加所需浸矿液注入量,未显现更为优异的工艺效果;滞留水所占比例越大,浸出液中稀土峰值浓度越低,但浸矿液中的初始硫铵浓度应仍为浸出液中稀土浓度峰值的主要决定因素。Leaching of the rare earth elements(RE)in weathered crust elution-deposited rare earth minerals can be considered as a liquid-solid extraction process and therefore simulated accordingly by extraction equilibrium and mass balance.Aprevious article presented a simulation method of column leaching process of weathered crust elution-deposited rare earth minerals based on some hypotheses.The present article then further developed a back-mixing involved liquid-solid extraction model with a hypothesis modification according to the classification principle of water in the minerals as described in soil hydrodynamics.The water in the minerals is divided into two types:immobile and mobile as the modification.The influences of immobile water ratio and reaction constant,leaching agent content,RE grade and saturation water rate of mineral,etc.on leaching efficiency have been discussed by simulation calculation based on the modified model.The results show that the larger ratio of immobile water,the higher RE grade of mineral,the smaller reaction constant and the lower leaching agent content shall require larger volumes of leaching solution butalmost stable volumes of discharging water that are close always to saturated water capacity of the respective mineral;variation of saturation water rate of mineral changes the volume of leaching solution sightly but that of discharging water linearly;the dilute-after-dense injection mode decreases the efficiency of leaching agent as well as increases the volume of leaching solution,hence behave no good performance;a larger ratio of immobile water may lower the peak RE content in leaching solution to some extent;the initial content in leaching solution still dominates the theoretical peak content of RE in leaching solution when considering the immobile water.

关 键 词：风化壳淋积型稀土矿 柱浸 液-固萃取模型 离子交换机理 稀土穿透曲线 

分 类 号：O614.33[理学—无机化学]