Method for regulating an electrolytic cell

The regulation method for an electrolytic cell (1) for the production of aluminium by means of electrolytic reduction of alumina dissolved in an electrolyte bath (13) based on cryolite, said cell (1) comprising a pot (20), at least one anode (7), at least one cathode component (5,6), said pot (20) comprising internal side walls (3) and being capable of containing a liquid electrolyte bath (13), said cell (1) also comprising at least one setting means of said cell including a mobile anode frame 10 to which said at least one anode (7) is attached, said cell (1) being capable of circulating a so-called electrolytic current in said bath, said current having an intensity I, the aluminium produced by said reduction forming a pad referred to as the “liquid metal pad” (12) on the cathode component(s) (5,6), said cell comprising a solidified bath ridge (15) on said walls (3), said method comprising control operations of said cell including the addition of alumina and the addition of AlF3 into said bath and being characterised in that it comprises:

• the set-up of a regulation sequence comprising a series of time intervals of pre-determined length Lp referred to as “periods”;
• the determination of the value of at least one indicator B referred to as the “ridge variation” capable of detecting the variation of said solidified bath ridge (15);
• the determination of a quantity Qo(p), referred to as the “basic term”, corresponding to the net average AlF3 requirements of the cell;
• the determination of a corrective term Qi(p) including at least one term Qsol(p), referred to as the “ridge term”, which is determined from at least one or each ridge variation indicator;
• the determination of a quantity Q(p) of AlF3 to be added during the period p, referred to as the “determined quantity Q(p)”, by adding the corrective term Qi(p) to the basic term Qo(p), i.e. Q(p)=Qo(p)+Qi(p);
• the addition into said electrolyte bath, during the period p, of an effective quantity of AlF3 equal to said determined quantity Q(p).