Numerical simulation and optimization of red mud separation thickener with self-dilute feed

ZHOU Tian(周天)^{1, 2}, LI Mao(李茂)^{1, 2, 3}, ZHOU Chenn-qian(周谦)^{1, 2, 3}, ZHOU Jie-min(周孑民)^1,

(1. School of Energy Science and Engineering, Central South University, Changsha 410083, China;
2. Hunan Key Laboratory of Energy Conservation in Process Industry, Changsha 410083, China;
3. Department of Mechanical Engineering, Purdue University Calumet, Hammond 46323-2094, United States)

Abstract:In order to acquire the flow pattern and investigate the settling behavior of the red mud in the separation thickener, computational fluid dynamics (CFD), custom subroutines and agglomerates settling theory were employed to simulate the three-dimensional flow field in an industrial scale thickener with the introduction of a self-dilute feed system. The simulation results show good agreement with the measurement onsite and the flow patterns of the thickener are presented and discussed on both velocity and concentration field. Optimization experiments on feed well and self-dilute system were also carried out, and indicate that the optimal thickener system can dilute the solid concentration in feed well from 110 g/L to 86 g/L which would help the agglomerates’ formation and improve the red mud settling speed. Furthermore, the additional power of recirculation pump can be saved and flocculants dosage was reduced from 105g/t to 85g/t in the operation.

Key words:separation thickener; self-dilute feed system; numerical simulation; optimization experiments; computational fluid dynamics