稀土电解槽内杂质运动轨迹的数值模拟

发布时间：2018-02-28 04:11

本文关键词： 稀土电解槽气体碳颗粒运动轨迹　出处：《内蒙古科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：稀土作为新兴产业发展必需的关键性战略资源，广泛应用于电子、航空、环境保护、新能源汽车、风力发电，特别是清洁能源生产领域。最近几年国内的稀土金属产业发展越来越快，制取稀土金属的工艺技术熔盐电解法也得到了很快的发展。目前普遍使用的稀土电解槽为3kA上插式的稀土氟化物—氧化物体系电解槽，，因其结构简单，工艺纯熟，适合大规模生产的优点，得到业界的青睐。近年来，通过实验和数值模拟的手段，对3kA稀土电解槽的结构和电解工艺进行优化，极大的提高了电解效率和稀土金属的纯度；但是，对上插式电解槽还有些尚未解决的问题，比如在电解过程中，电解槽内会产生悬浮的碳颗粒，这些碳颗粒会致使电解槽内的电压降升高，影响溶液的导电率，缩短电解槽的使用寿命等。本课题主要是针对电解槽内电解过程出现的碳颗粒，采用FLUENT模拟软件，对流体采用欧拉方法进行处理，对碳颗粒运动轨迹采用拉格朗日法进行处理，模拟出不同粒径下碳颗粒的运动情况。气体在电解过程中起到一个很重要的作用，它可以促使熔盐进行流动，对碳颗粒的运动也起到间接的推动作用。通过不同条件下的模拟，可以对实际生产过程中的杂质进行比较有方向性的去除，对生产效率也有相应程度的提高。具体工作及结果如下：（1）在前人模拟电解槽的基础上，采用3kA最优模型，先用欧拉法模拟出熔体流场分布，再通过拉格朗日法模拟出不同粒径下的颗粒运动情况，对比各个不同粒径的颗粒的运动情况，发现粒径越大运动的幅度越大。（2）通过改变电解槽的槽型结构如电极插入深度，来模拟出颗粒的运动情况。发现电极插入深度越大，对颗粒运动的影响越小，颗粒运动偏离阳极的距离变小，但是电极插入深度过大，影响电解的正常进行。（3）改变电解槽阴阳两极的极间距，得到不同粒径的颗粒的运动情况，发现极间距对碳颗粒运动的影响不大。阳极内径相同时，颗粒的粒径越大，偏离阳极内表面的距离就越大。（4）改变电解的电流强度大小，发现颗粒运动远离阳极内表面的距离幅度不是很大，但是在电流强度比较大时，颗粒运动的相对远一些。颗粒的粒径越大，在液面的位置越远离阳极内表面。
[Abstract]:As a key strategic resource necessary for the development of new industries, rare earths are widely used in electronics, aviation, environmental protection, new energy vehicles, wind power generation, Especially in the field of clean energy production. In recent years, the rare earth metal industry in China has developed more and more rapidly. The technology of preparing rare earth metals by molten salt electrolysis has also been developed rapidly. At present, the commonly used rare earth electrolytes are 3kA type electrolytes of rare earth fluoride oxide system, because of its simple structure and perfect process. In recent years, by means of experiment and numerical simulation, the structure and process of 3Ka rare earth electrolysis cell are optimized, which greatly improves the electrolysis efficiency and the purity of rare earth metal. However, there are still some unsolved problems in the uppercut electrolyzer. For example, in the process of electrolysis, suspended carbon particles will be produced in the cell, which will cause the voltage drop in the cell to rise and affect the conductivity of the solution. Shorten the service life of electrolytic cell, etc. This paper mainly aims at the carbon particles in the electrolysis process in the electrolytic cell, adopts the FLUENT simulation software, uses the Euler method to deal with the fluid, and the Lagrangian method to deal with the moving track of the carbon particles. Gas plays a very important role in electrolysis, which can promote the flow of molten salt and indirectly promote the movement of carbon particles. The impurity in the actual production process can be removed in a more directional way, and the production efficiency can also be improved to a corresponding extent. The specific work and results are as follows:. 1) on the basis of previous simulation of electrolytic cell, using 3kA optimal model, the melt flow field distribution is simulated by Euler method, and then the particle movement under different particle size is simulated by Lagrange method. The larger the particle size is, the larger the movement is. (2) the movement of particles is simulated by changing the cell structure such as electrode insertion depth. It is found that the greater the electrode insertion depth, the smaller the effect on particle motion, and the smaller the distance from the anode to the particle motion. However, the electrode insertion depth is too large, affecting the normal process of electrolysis. 3) changing the polar distance between the anode and the anode of the electrolytic cell, the movement of the particles with different diameters is obtained. It is found that the distance from the inner surface of the anode increases with the increase of the diameter of the particles when the anode inner diameter is the same. 4) by changing the current intensity of electrolysis, it is found that the distance between the particles moving away from the inner surface of the anode is not very large, but when the current intensity is relatively high, the particle motion is relatively far away. The larger the particle size, the larger the particle size. The position of the liquid level is farther away from the inner surface of the anode.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ151;TQ133.3

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