Simultaneous Preheating and Fast Restart of 50 Aluminium Reduction Cells in an Idled Potline

Abstract

Due to the global economical crisis a significant amount of primary aluminium production capacity has been shutdown. A number of different strategies to restart idled aluminium reduction cells have been discussed in the literature [1, 2]. This paper describes the successful development and execution of the start-up of 50 cells simultaneously in one potline. The procedure is based on restarting reduction cells using a cold metal plate. Contrary to electrical preheating of new cells with use of cokes or graphite, these cells have been prepared with anodes positioned in direct contact and on top of the cold metal plate. The rate of preheating of the cells and associated melting of metal is controlled by a gradual line current increase. The actual start-up of the cells is performed sequentially by the addition of liquid electrolyte and moving the anode beam upwards. In this respect 50 cells have been preheated and restarted in 8 days.