Controlling anode effect during electrolytic mfr. of aluminium - where computer fed with anode voltages operates hoist raising or lowering anodes

摘要

During the prodn. of Al in an electrolysis cell contg. molten cryolite and alumina, the normal voltage is 3.8-4.5 but this can rise to more than 30 V if the melt becomes low in alumina. This voltage increase is known as the anode effect, and wastes energy while also increasing anode consumption. The invention measures the anode voltage, and raises the anodes to create the anode effect, and lowers the anodes to eliminate the effect. When the voltage attains 8 V, the anodes are pref. raised until a max. of 28 V is reached; and the anodes are lowered to obtain te desired operating voltage. The vertical movements of the anodes are pref. controlled by an electronic computer fed with the anode voltages. The anode effect can be created and eliminated at prescribed times to assist completely automatic operation of the electrolysis cell.