A less magnitude of liquid aluminum deformation is required to shorten the anode-cathode distance so as to lower the electric energy consumption of the aluminum reduction cell. A mathematical model aimed to describe the electrolyte/aluminum two-phase flow in reduction cells, based on the computational fluid dynamics method, was developed to study the impacts of the cathode convexes on the electrolyte/aluminum interface deformation. The results showed that the magnitude of the two-phase interface deformation was reduced for about 17.2% with the novel cathode convexes; while at the same time, the washout of the melt on the ledge was also enhanced. 1. Introduction Aluminum and its aluminum material is the second large metal materials in the world whose consumption is only next to the steel. Aluminum metal was produced by the electrolysis of aluminum oxide dissolved in an aluminum-electrolyte fluoride mixture, which requires large amounts of electrical energy. Therefore, there is an urgent demand to lower energy consumption in the process of aluminum production. To decrease the energy consumption, the anode-cathode-distance (ACD) in reduction cells needs to be cut down [1]. However, due to the electrolyte/aluminum interface instability, the ACD cannot be too small to avoid reduction cell voltage fluctuation which may result in cell failure [2]. The instability between the layer of molten aluminum and a slightly lighter electrolyte plays a defining role in the energy saving of aluminum reduction cells. Consequently, many researchers have focused on uncovering the mechanism of this instability. By using particle image velocimetry, Cooksey and Yang [3] experimentally investigated the onflow caused by anode gas and its bubble behavior in a full-scale, three-anode liquid model aluminum reduction cell. Pedchenko et al. [4] proposed a new solution for experimental modeling of the interfacial instability in which a tiny electrode stick was immerged into liquid metal of In-Ga-Sn on substitute of molten aluminum overlaid by electrolyte. Due to the difficulty to experimentally study the complex fluid flow phenomenon including molten aluminum, bath, and bubble agitation in aluminum reduction cells, most researchers focused on numerically modeling the magnetic fluid flow in reduction cells. Based on the nonlinear shallow water model, Kadkhodabeigi [5] built up a two dimensional model to study the electrolyte/aluminum interface instability and this model is superior to the linear model because linear model cannot determine the flow mode of the electrolyte and aluminum.
References
[1]
Y. Tian, “Discussion on Best Polar Distance of Industrial Aluminum Cell,” Non-Ferrous Mining and Metallurgy, vol. 25, pp. 23–25, 2007.
[2]
O. Zikanov, A. Thess, P. A. Davidson, and D. P. Ziegler, “A new approach to numerical simulation of melt flows and interface instability in hall-héroult cells,” Metallurgical and Materials Transactions B, vol. 31, no. 6, pp. 1541–1550, 2000.
[3]
M. A. Cooksey and W. Yang, “PIV measurements on physical models of aluminum reduction cells,” in Light Metals, pp. 359–365, 2005.
[4]
A. Pedchenko, S. Molokov, J. Priede, A. Lukyanov, and P. J. Thomas, “Experimental model of the interfacial instability in aluminium reduction cells,” Europhysics Letters, vol. 88, no. 2, Article ID 24001, 2009.
[5]
M. Kadkhodabeigi, “Two dimensional model of melt flows and interface instability in aluminum reduction cells,” in Light Metals, vol. 4, pp. 443–448, Wiley, New York, NY, USA, 2008.
[6]
V. Bojarevics and K. Pericleous, “Shallow water model for aluminium electrolysis cells with variable top and bottom,” in Light Metals, vol. 2, pp. 403–408, 2008.
[7]
J. Li, W. Liu, Y. Lai, and Y. Liu, “An improved finite-element model for electromagnetic analysis in aluminum cells,” JOM, vol. 60, no. 2, pp. 58–61, 2008.
[8]
M. Li and J. Zhou, “Numerical simulation of busbar configuration in large aluminum electrolysis cell,” Journal of Central South University of Technology, vol. 15, no. 2, pp. 271–275, 2008.
[9]
V. Bojarevics and K. Pericleous, “Solutions for the metal-bath interface in aluminium electrolysis cells,” in Light Metals, pp. 569–574, TMS, 2009.
[10]
V. Bojarevics and K. Pericleous, “Time dependent MHD models for aluminium reduction cells,” in Jim Evans Honorary Symposium: Proceedings of the Symposium Sponsored by the Light Metals Division of The Minerals, Metals and Materials Society (TMS), pp. 199–206, 2010.
[11]
Z. Liu, W. Li, Q. Zhao, J. Zhou, and Y. Wang, “Current efficiency predictive model and its calibration and validation,” in Light Metals, pp. 935–938, 2012.
[12]
J. Bruggeman, “Technical contributions of late Warren Haupin—a review,” in Light Metals, pp. 495–500, 2008.
[13]
J. P. Peng, N. X. Feng, Y. L. Jiang, Y. W. Wang, and J. You, “Test of drained aluminum electrolysis cell with TiB2/G graphitized cathode at high current density,” Chinese Journal of Nonferrous Metals, vol. 18, no. 4, pp. 738–744, 2008 (Chinese).
[14]
N. Feng, “Low energy consumption aluminum reduction cell with novel cathodes,” China Patent, ZL200710010523.4, 2007.
[15]
B. E. Launder and D. B. Spalding, “The numerical computation of turbulent flows,” Computer Methods in Applied Mechanics and Engineering, vol. 3, no. 2, pp. 269–289, 1974.
[16]
D. S. Severo, V. Gusberti, A. F. Schneider, E. C. V. Pinto, and V. Potocnik, “Comparison of various methods for modeling the metal-bath interface,” in Light Metals, pp. 413–418, 2008.
