离子型稀土饱和-非饱和原地浸矿动力学与注液优化

The use of in-situ leaching technology for extract ion adsorption rare earth resources cause a large amount of ammonium sulfate to remain in the leaching field, and to significantly elevate ammonia nitrogen levels in the mining area as well as its drainage basin. It is a cost-effective means to reduce the ammonia nitrogen residue in leaching field through optimizing the liquid injection parameters and controlling the simultaneous transport of ammonium ions and rare earth ions. The project select the yttrium-moderate europium-rich ion adsorption rare earth ore as the research object, and main research works are as follows. The ion-exchange model is determined by batch experiments, the relationship between the ammonium ion concentration and the rare earth ion concentration at the reaction interface is quantized, the ion diffusion in the liquid film layer is simplified, the leaching rate equation of rare earth ions is established, and the relationship between the rare earth grade and the maximum adsorption/desorption amount of ammonium ions is obtained. The law of desorption hysteresis of ammonium ions in ore bodies is studied, and the source and sink rate equation of ammonium ions was established. The effect of the pore structure of ore body on the hydrodynamic process of solute transport is investigated, the differences of the solute diffusion paths in the non-dehydrated pores and dehydrated pores is analyzed, and the solute transport equations for saturated-unsaturated leaching processes are established. The in-situ test method for hydraulic parameters and solute transport parameters of the heterogeneous ore bodies is proposed, and the “simple constitutive, complex structure” idea is used to design the solute transport algorithm, analyze the solute transport law of the in-situ leaching, and optimize the injection parameters of leaching agent. The project research results will provide theoretical and technical guidance for optimizing in-situ leaching process parameters.

采用原地浸矿工艺提取离子型稀土资源造成大量硫酸铵残留在浸矿场，引发矿区及其流域氨氮严重超标，通过优化注液参数，控制铵离子和稀土离子同步运移是减少浸矿场氨氮残留的经济有效手段。本项目以中钇富铕离子型稀土矿体为研究对象，主要研究工作包括：试验确定离子交换模型，量化反应界面上铵离子和稀土离子浓度之间的关系，简化离子在液膜层的扩散过程，建立稀土离子的浸取速率方程，试验获得稀土品位与铵离子最大吸附量和最大解吸量的关系，研究铵离子在矿体的解吸滞后规律，建立铵离子的源汇速率方程；研究矿体孔隙结构影响溶质运移的水动力学过程，分析未脱水孔隙和脱水孔隙中溶质扩散路径差异，建立饱和-非饱和浸矿过程的溶质运移方程组；提出非均质矿体水力参数和溶质运移参数的原位测试方法，采用“简单本构，复杂结构”思想设计溶质运移算法，分析原地浸矿的溶质运移规律，优化注液参数。项目研究成果为优化原地浸矿注液工艺参数提供理论和技术指导。

采用原地浸矿工艺提取离子型稀土资源，造成大量硫酸铵残留在浸矿场，引发矿区及其流域氨氮严重超标，建立原地浸矿的数值模拟方法，优化注液工艺，是减少浸矿场氨氮残留的有效手段。项目重点研究了饱和-非饱和浸矿过程离子交换和溶质运移的机理、规律和数学模型，以及矿体水力参数测试和离子型稀土矿浸出过程溶质运移的数值模拟等内容，主要成果和结论如下：.（1）揭示了铝、钙等杂质离子对离子型稀土矿浸出过程的影响机制，阐明了影响规律，建立了双参数模型等3个源汇方程，并与信丰、寻乌、安远等稀土矿区的离子型矿浸出实验数据进行对比，双参数模型的误差小于5.00%，与Kerr模型进行比较，该模型的计算精度更高，该成果为建立离子型稀土矿浸出的源汇方程提供了依据。.（2）将浸矿剂的消耗分为离子交换、专性吸附和维持浸矿剂溶液浓度三部分，建立了浸矿剂用量计算方法，室内试验结果表明，该模型的误差小于1.14%，该成果为合理设计离子型稀土原地浸出的浸矿剂用量提供了方法。.（3）采用常数变异法建立了测试土壤水分扩散率的解析-修正法，试验结果表明，土壤水分扩散率的测试值与真实值的相关系数均大于0.90，室内试验不同测点间测试结果的相关系数均大于0.97，该成果为原位测试矿体水力参数提供了技术手段。.（4）在饱和-非饱和渗流条件下，采用顺序非迭代法解决了溶质运移数值解的弥散和振荡问题，建立了离子型稀土矿浸出过程的数值模拟方法，对比实验结果和数值模拟结果，稀土和铝两种离子穿透曲线的相关系数均大于0.7500，该成果为注液方案设计提供技术手段。.（5）分析了深潜式、浅伏式和表露式三种矿床类型的矿层厚度、渗透系数分布对注液方式的影响，结果发现，在相同稀土储量的情况下，深潜式矿床所需的浸矿剂用量最少，浅伏式其次，表露式所需的浸矿剂用量最多；渗透性越小的矿层，浸矿剂单耗就越大，该成果为注液优化提供指导。.