摘要
In the feeding process of aluminum electrolytic, feeding quantity of alumina affects eventually dissolved quantity at the end of a feeding cycle. Based on the OpenFOAM platform, dissolution model coupled with heat and mass transfer was established. Applying the Rosin-Rammler function, alumina particle size distribution under different feeding quantities was obtained. The temperature response of electrolyte after feeding was included and calculated, and the dissolution processes of alumina with different feeding quantities (0.6, 0.8, 1.0, 1.2, 1.4, 1.6 kg) after feeding were simulated in 300 kA aluminum reduction cell. The results show that with the increase of feeding quantity, accumulated mass fraction of dissolved alumina decreases, and the time required for the rapid dissolution stage extends. When the feeding quantity is 0.6 kg and 1.2 kg, it takes the shortest time for the electrolyte temperature dropping before rebounding back. With the increase of feeding quantity, the dissolution rate in the rapid dissolution stage increases at first and then decreases gradually. The most suitable feeding quantity is 1.2 kg. The fitting equation of alumina dissolution curve under different feeding quantities is obtained, which can be used to evaluate the alumina dissolution and guide the feeding quantity and feeding cycle.
在铝电解下料过程中,氧化铝下料量影响一个下料周期结束后氧化铝颗粒的最终溶解量。本文基于OpenFOAM 计算平台,开发了铝电解槽中氧化铝颗粒传热、传质耦合溶解计算模型;利用Rosin-Rammler 分布函数得出氧化铝在不同下料量下的颗粒粒径分布,考虑下料区温度响应,对实际300 kA 铝电解槽中氧化铝颗粒在不同下料量下(0.6, 0.8, 1.0, 1.2, 1.4, 1.6 kg)的溶解过程进行数值模拟。模拟结果表明:随着下料量的增加,氧化铝累积溶解质量分数降低,快速溶解阶段所需的时间逐渐加长。当投料量分别为0.6 kg 和1.2 kg 时,电解质温度下降至出现回升所需时间最短。随着下料量的增加,快速溶解阶段的溶解速率先迅速上升,后逐渐减少。最佳下料量为1.2 kg。通过拟合氧化铝溶解特性曲线,得到了不同下料量下氧化铝累积溶解质量分数的拟合方程,可根据此方程评估氧化铝溶解情况及指导氧化铝的下料量和下料周期。
基金
Project(2010AA065201) supported by the High-Tech Research and Development Program of China
Project(2018zzts157) supported by the Fundamental Research Funds for the Central Universities,China
作者简介
Corresponding author: HOU Wen-yuan, PhD Candidate;Tel:+86-18890095929;E-mail: zndxhwy@163.com;ORCID: 0000-0002- 5362-6678.
