2D finite element analysis of thermal balance for drained aluminum reduction cells

Abstract

Based on the principle of energy conservation, the applicable technique for drained cell retrofitted from conventional one was analyzed with 2D finite element model. The model employed a 1D heat transfer scheme to compute iteratively the freeze profile until the thickness variable reached the terminating requirement. The calculated 2D heat dissipation from the cell surfaces was converted into the overall 3D heat loss. The potential drop of the system, freeze profile and heat balance were analyzed to evaluate their variation with technical parameters when designing the 150 kA conventional cell based drained cell. The simulation results show that the retrofitted drained cell is able to keep thermal balance under the conditions that the current is 190 kA, the anodic current density is 0.96 A/cm², the anode-cathode distance is 2.5 cm, the alumina cover is 16 cm thick with a thermal conductivity of 0.20 W/(m·°C) and the electrolysis temperature is 946 °C.

Keywords

drained cell / thermo-electric field / thermal balance / finite element analysis

References

[1] STEDMAN I G, HOUSTON G J, SHAW, R W, et al. Aluminum smelting cells: US, 5043047[P]. 1991-08-27.

[2] TOWNSEND D W. Supersaturation plating of aluminum wettable cathode coatings during aluminum smelting in drained cathode cells: US, 5028301[P]. 1991-07-02.

[3] de NORA V. Cell for aluminum electrowinning employing a cathode cell bottom made of carbon blocks which have parallel channels therein: US, 5683559[P]. 1997-11-04.

[4] BERCLAZ G, de NORA V. Aluminum production cell and cathode: US, 6358393[P]. 2002-03-19.

[5] LiQ.-y., LaiY.-q., LiJ., et al.. The effect of sodium-containing additives on the sodium-penetration resistance of TiB₂/C composite cathode in aluminum electrolysis[C]. TMS Light Metals, 2005, San Francisco, Minerals, Metals and Materials Society: 789-791

[6] FengN.-x., QiX.-q., PengJ.-p., et al.. Electrolysis test of 1350 A drained cathode reduction cell with TiB₂-coated cathode[C]. TMS Light Metals, 2006, San Antonio, Minerals, Metals and Materials Society: 505-509

[7] ZhouN.-j., XiaX.-x., BaoS.-zhong.. Effect of electromagnetic force and anode gas on electrolyte flow in aluminum electrolysis cell[J]. Journal of Central South University of Technology, 2006, 13(5): 496-500

[8] ZhouN.-j., XiaX.-x., WangF.-qiang.. Numerical simulation on electrolyte flow field in 156 kA drained aluminum reduction cells[J]. Journal of Central South University of Technology, 2007, 14(1): 42-46

[9] LiX.-p., LiJ., LaiY.-q., et al.. Influences of gas discharging grooves at bottom of prebaked carbon anodes on bath flow pattern in aluminum reduction cells[J]. Chinese Journal of Nonferrous Metals, 2006, 16(6): 1088-1093

[10] ZhouN.-j., MeiC., JiangC.-w., et al.. A method of determining and designing the drained slope in drained aluminum reduction cells[J]. Journal of Central South University of Technology, 2003, 10(1): 74-77

[11] LiX.-p., LiJ., LaiY.-q., et al.. Freeze profile heat balance calculation of the 160 kA drained cell[J]. Acta Metallurgica Sinica: English Letters, 2004, 17(2): 215-220

[12] PEI Hai-ling, ZHOU Nai-jun, ZHOU Zheng-ming. Research on the performance of resisting heat disturbance of the drained cell[J]. Light Metals, 2005(3): 26–29. (in Chinese)

[13] YangZ.-yu.Light Metals Metallurgy[M], 1991, Beijing, Metallurgical Industry Press

[14] ZhouP.Continuously monitoring the shape of the ledge of aluminum electrolysis cells[D], 1991, Changsha, Central South University

[15] HauglandE., BorsetH., GiklingH., et al.. Effects of ambient temperature and ventilation on shell temperature, heat balance and side ledge of an alumina reduction cell[C]. TMS Light Metals, 2003, San Diego, Minerals, Metals and Materials Society: 269-276

[16] HuoQ.-fa.Technologies and Equipments of the Aluminum Reduction Industry[M], 2002, Shenyang, Liaohai Publishing House

[17] DupuisM.. Thermo-electric analysis of the grande-baie aluminum reduction cell[C]. TMS Light Metals, 1994, San Francisco, Minerals, Metals and Materials Society: 339-342

[18] BrownC. W.. Wettability of TiB₂-based cathodes in low-temperature slurry-electrolyte reduction cells[J]. JOM, 1998, 50(5): 38-40

[19] WelchB. J.. Aluminum production paths in the new millennium[J]. JOM, 1999, 51(5): 24-28

[20] KeniryJ.. The economics of inert anodes and wettable cathodes for aluminum reduction cells[J]. JOM, 2001, 53(5): 43-47