EP 0814181 B1 20011128 - Process for regulating the alumina content of bath in cells for producing aluminium
Title (en)
Process for regulating the alumina content of bath in cells for producing aluminium
Title (de)
Verfahren zur Regulierung des Tonerdegehalts im Bad einer Elektrolysezelle zur Aluminiumherstellung
Title (fr)
Procédé de régulation de la teneur en alumine du bain des cuves d'électrolyse pour la production d'aluminium
Publication
Application
Priority
FR 9607712 A 19960617
Abstract (en)
[origin: EP0814181A1] Regulating the alumina content in the cryolite-based bath of an electrolytic aluminium production cell comprises varying the alumina supply rate, as a function of the value and change of cell resistance (R) calculated from the cell terminal potential difference, in alternate phases of under-supply with slow rates (CL) of alumina introduction (phase 1) and phases of over-supply with rapid (CR) or very rapid (CUR) rates of alumina introduction (phase 2) w.r.t. a reference or theoretical rate (CT) corresponding to the mean theoretical alumina consumption of the cell. Each regulation cycle of duration (T) comprises: (a), at the end of each regulation cycle 'i', calculating the average resistance 'R(i)', the resistance change rate or slope 'P(i)', the rate of change of the resistance slope or curve 'C(i)' and a forecasted value of the resistance slope at the instant 't(i+1)' or the extrapolated slope 'PX(i)' (= P(i) + C(i) x T) which is an estimate of the future resistance slope 'P(i+1)' at the end of regulation cycle 'i+1'; (b) comparing the value 'R(i)' with a target value 'Ro' to ascertain whether the anodes require displacement for reducing or for increasing the anode-to-metal distance; and (c) regulating the alumina supply as a function of the values of the slope 'P(i)', the curve 'C(i)' and the extrapolated slope 'PX(i)' to compensate anticipated alumina content changes.
IPC 1-7
IPC 8 full level
C25C 3/20 (2006.01); F21V 25/12 (2006.01); F21V 37/00 (2006.01); F23D 3/26 (2006.01); F23Q 25/00 (2006.01); G02F 1/133 (2006.01); G09G 3/36 (2006.01); F21V 25/02 (2006.01)
CPC (source: EP US)
C25C 3/20 (2013.01 - EP US)
Designated contracting state (EPC)
DE ES FR
DOCDB simple family (publication)
EP 0814181 A1 19971229; EP 0814181 B1 20011128; AR 007606 A1 19991110; AU 2495097 A 19980108; AU 719053 B2 20000504; BR 9703604 A 19981027; CA 2208913 A1 19971217; CA 2208913 C 20040210; DE 69708513 D1 20020110; DE 69708513 T2 20020718; ES 2165010 T3 20020301; FR 2749858 A1 19971219; FR 2749858 B1 19980724; IN 192205 B 20040313; NO 317186 B1 20040913; NO 972723 D0 19970613; NO 972723 L 19971218; NZ 328095 A 19981125; RO 119240 B1 20040630; SA 97180273 B1 20051112; SI 9700163 A 19971231; US 6033550 A 20000307; ZA 975324 B 19980625
DOCDB simple family (application)
EP 97420090 A 19970616; AR P970102646 A 19970617; AU 2495097 A 19970617; BR 9703604 A 19970617; CA 2208913 A 19970616; DE 69708513 T 19970616; ES 97420090 T 19970616; FR 9607712 A 19960617; IN 1096CA1997 A 19970610; NO 972723 A 19970613; NZ 32809597 A 19970613; RO 9701109 A 19970616; SA 97180273 A 19970802; SI 9700163 A 19970617; US 87633597 A 19970617; ZA 975324 A 19970617