Patent ID: 7378009

Claim:
A method for controlling operation of an aluminum reduction cell having automatic alumina feed, the method comprising the following steps: maintaining alumina concentration by alternating base, underfeed and overfeed modes, measuring cell voltage and potline amperage, calculating current normalized voltage value and a rate of changing thereof over time comparing the calculated values of said normalized voltage with preset values thereof and correcting anode-cathode distance when passing from said base mode to said overfeed or underfeed modes, measuring a number of alumina feed doses in said underfeed mode and overfeed mode over a time period sufficient to evaluate conditions of alumina dissolutions and taking corrective actions including changing base constant of the point-feeding modes by changing coefficients K1 defining said overfeed mode and coefficient K2 defining said underfeed mode of alumina feeding system, changing cell voltage settings and changing aluminum fluoride additions in to the cell.