摘要
稀土电解过程中阳极侧壁产生的气泡会改变阴阳极极间电场分布,引起极间电阻增大、电压升高、电解效率降低,从而影响电解槽的稳定运行.所以,系统分析阳极侧壁气泡的成核、长大、聚并及脱离等生长行为和规律对稀土金属的提取具有十分重要的意义.本文根据相似原理,进行水电解低温实验,按照与稀土电解槽1:2的几何比例设计,通过铂丝嵌入环氧树脂的方法制备微电极.实验结果表明,垂直微电极侧壁面气泡成核、生长和脱离过程符合经典的气泡生长规律公式D(t)=βt1/3;为观察气泡之间的聚并、脱离行为,在微电极表面设计三个间距为500 μm的成核点位,通过高速摄像机拍摄发现,微电极表面下方和中间的两个气泡率先发生聚并变为一个气泡,聚并时间为 0.05 s,随后吸引上方的气泡与之发生聚并,最终三个气泡合并为一个大气泡脱离微电极,气泡的脱离时间为 5.06 s,脱离直径约为1352.03 μm.结合数值模拟的方法,进一步解释气泡之间的聚并过程,结果表明,电极表面的缺陷大小会影响气泡的脱离时间,气泡下侧与电极表面的三相接触位置会产生一个向上的涡旋,加速气泡的脱离,正确利用气泡的聚并行为可以减小稀土电解槽的槽电压,从而提高电解效率.
Abstract
The bubbles generated on the anode side wall during the rare earth electrolysis process will affect the stable operation of the electrolytic cell.According to the similarity principle,the low temperature experiment of water electrolysis was designed according to the geometric ratio of 1:2 to the rare earth electrolytic cell,and the microelectrode was prepared by the method of platinum wire embedded in epoxy resin.The experimental results show that the process of bubble nucleation,growth and detachment on the side wall of vertical microelectrode conforms to the classical formula of bubble growth law.In order to observe the coalescence and detachment behavior between bubbles,three nucleation sites were designed on the surface of the microelectrode.Through high-speed camera shooting,it was found that the two bubbles below and in the middle of the microelectrode surface first coalesced into a bubble,and then attracted the bubbles above to coalesce with it.Finally,the three bubbles merged into a large bubble and detached from the microelectrode.Based on the numerical simulation method,the coalescence process between bubbles is further explained.
基金项目
国家重点研发计划(2020YFC1909102)
内蒙古自治区自然科学基金(2022MS05024)
NETL
NSTL
万方数据