阳极开槽对底部阴极稀土电解槽气泡运动影响的数值模拟

Numerical Simulation of the Effect of Anode Slotting on Bubble Movement in Bottom-cathode Rare Earth Electrolytic Cell

针对底部阴极式稀土电解槽存在的阳极气体难以排出的问题,采用有限元的方法模拟了该电解槽内气液两相流动情况,研究了电解槽阳极开槽及开槽宽度对电解质流动和气泡运动的影响。在未开槽模型中,气泡主要从阳极斜面较高一端排出,大部分气体聚集在阳极凹面中心处,阻挡了电解质与阳极间的接触,导致电解效率下降。本设计在阳极底面中心对称处开宽度范围在20 mm~40 mm的窄槽,通过对比分析,阳极底部处气体体积分数平均值较未开槽的情况降低了10%~13%,同时流场的速度分布更加均匀。气泡能快速从开槽处直接排出,减弱了气泡堆积引起电阻升高和可能产生的阳极效应问题。降低电解电阻和减少阳极效应都有利于节约电能,其中减少阳极效应还可以减少非正常工况时间,提高稀土电解质量。此外,通过优化开槽宽度和位置,有效地调整气泡的生成和排放,还有利于温度场的稳定性,从而提高稀土电解过程的稳定性。本文通过综合开槽后阳极底部气泡体积分数、流场稳定性以及开槽去除阳极体量等因素分析,得出最佳开槽宽度为20 mm,为电解槽的优化设计提供了理论支持和数据参考。

In response to the issue of anode gas discharge difficulties in the bottom cathode type rare earth electrolytic cell, the finite element method was used to simulate the gas-liquid two-phase flow in the electrolytic cell, and the effects of anode slotting and slot width on electrolyte flow and bubble movement were studied. In the non-slot model, bubbles are mainly discharged from the higher end of the anode slope, and most of the gas accumulates in the center of the anode concave surface, blocking the contact between the electrolyte and the anode, leading to a decrease in electrolysis efficiency. This design opens a narrow slot with a width range of 20 mm to 40 mm at the center of symmetry of the anode bottom surface. Through comparative analysis, the average gas volume fraction at the bottom of the anode is reduced by 10% to 13% compared to the non-slot situation, and the velocity distribution of the flow field is more uniform. Bubbles can be quickly discharged directly from the slot, reducing the increase in resistance caused by bubble accumulation and possible anode effects. Reducing electrolysis resistance and reducing anode effects are beneficial for energy saving. In addition, reducing anode effects can also reduce abnormal operating time and improve electrolysis quality. Furthermore, by optimizing slot width and position, effective adjustment of bubble generation and discharge is also beneficial to temperature field stability, thereby improving electrolysis process stability. This paper comprehensively analyzes factors such as anode bottom bubble volume fraction after slotting, flow field stability, and slot removal of anode volume, and concludes that the optimal slot width is 20 mm, providing theoretical support and data reference for optimizing electrolytic cell design.