基于力场调控机制的离子分离数值仿真

Numerical simulation of ion separation based on force field modulation mechanism

为了解决高镁锂浓度比例下离子分离困难的问题,提出一种基于力场调控的离子分离数值仿真系统。该系统引入呈特定位置关系的水平障碍,来调节系统的流场分布,依据锂离子和镁离子电泳迁移率的差异,在电场力和流场力的作用下将2种离子以与水平方向不同夹角的路径扩散,实现镁、锂离子的分离;采用计算流体力学方法对离子分离系统进行数值模拟,通过分析离子在流场调节下的行为,探索该系统对电压、流速和障碍参数的响应规律;水平障碍将通道分为中间宽、边界窄的区域,在离子出口处稳定流场,缩小离子采样空间,控制来流方向接近锂离子分离轨迹,使离子分离质量更高,稳定性更好;采用稀释后的盐湖卤水溶液进行数值仿真模拟。结果表明:在电压为11.5 V、水流速度为990μm/s时,该系统可以回收93%的锂离子,并将镁离子回收率提高至95%,基于力场调控机制的离子分离系统可以实现对化学性质相似的锂、镁离子的高效分离。

In order to solve the problem of difficult ion separation under high Mg^(2+)-Li^(+)concentration ratio,a numerical simulation system for ion separation based on force field modulation was proposed in this paper.The system regulated the flow field distribution of the system by introducing horizontal barriers in a specific positional relationship.Based on the difference in electrophoretic mobility of lithium and magnesium,the separation of magnesium and lithium ion was achieved by diffusing the 2 ions in a path with different angles to the horizontal direction under the action of electric field forces and fluid flow forces.This study used computational fluid dynamics methods for numerical simulation,and explored the response law of the system to voltage,flow rate and barrier parameters by analyzing the behavior of ions under the flow field regulation.The horizontal barrier divided the channel into a region with a wide middle and a narrow boundary.The flow field was stabilized at the ion outlet to narrow the sampling space for ions,and the direction of the inlet flow was controlled to be close to the lithium ion separation trajectory,resulting in higher quality and stability of ion separation.In this study,numerical simulations were carried out using diluted salt lake brine solutions.The results show that the system can recover 93%of lithium ions and increase the recovery of magnesium ions to 95%at a voltage of 11.5 V and a fluid flow velocity of 990μm/s.The ion separation system based on the force field modulation mechanism can achieve efficient separation of chemically similar lithium and magnesium ions.