Method of controlling the crust in an electrolysis cell

摘要

In the event of a short-term change in the energy supplied by the electric mains, the thickness of the crust in a molten-salt electrolysis cell for producing aluminium is altered and has to be monitored. If the ohmic bath resistance (R) differs from a basic value (R0) by more than a value ( DELTA R) specified for each electrolysis cell, the interpolar distance is corrected by altering the cross-arm position by computer control. To do this, use is made of the product of the square of the current level (I) and the ohmic bath resistance (R) as control variable. The corrections are carried out so that the thermal equilibrium of the electrolysis cell is maintained during and after a change in the energy supplied from the electric mains. <IMAGE>