EP 0201438 B1 19890621 - PROCESS FOR ACCURATELY REGULATING THE LOW ALUMINA CONTENT OF AN IGNEOUS ELECTROLYSIS CELL FOR ALUMINIUM PRODUCTION
Title (en)
PROCESS FOR ACCURATELY REGULATING THE LOW ALUMINA CONTENT OF AN IGNEOUS ELECTROLYSIS CELL FOR ALUMINIUM PRODUCTION
Publication
Application
Priority
FR 8507319 A 19850507
Abstract (en)
[origin: US4654129A] A process is disclosed for accurately maintaining a low alumina content of between 1 and 4.5% in a cell for the production of aluminum by electrolysis in the Hall-Heroult process. According to the invention, a control parameter P=-1/D(dR1/dt), is determined, wherein D is the variation in the alumina content of the electrolytic bath in % weight per hour, R1 is the internal resistance of the cell, and t is the time. A series of operations is then carried out in a repeated cycle, starting with the cell being fed alumina at a nominal rate which is substantially equal to the quantity consumed by electrolysis. At periodic intervals, an over-supply of alumina is added in order to enrich the bath, and the over-supply is continued for a preset time during which dR1dt is negative. The feed rate is then reduced to less than the nominal feed rate, during which time dR1dt passes through zero to become positive and the regulation parameter P, the value of which tends to rise, is measured often. The successive values of P are compared with a required preset value Po. As soon as P equals Po, the feed rate is returned to the nominal feed rate and a new cycle is recommenced.
IPC 1-7
IPC 8 full level
C25C 3/20 (2006.01)
CPC (source: EP US)
C25C 3/20 (2013.01 - EP US)
Designated contracting state (EPC)
AT CH DE GB IT LI NL SE
DOCDB simple family (publication)
EP 0201438 A1 19861112; EP 0201438 B1 19890621; AT E44165 T1 19890715; AU 5715786 A 19861113; AU 576152 B2 19880811; BR 8602039 A 19870106; CA 1251417 A 19890321; CN 1006307 B 19900103; CN 86103165 A 19861105; DE 3664058 D1 19890727; ES 554683 A0 19871116; ES 8800733 A1 19871116; FR 2581660 A1 19861114; FR 2581660 B1 19870605; GR 861139 B 19860821; HU 205632 B 19920528; HU T45102 A 19880530; IN 164906 B 19890701; IS 1347 B6 19890320; IS 3095 A7 19861108; JP S61261490 A 19861119; MY 101644 A 19911231; NO 172192 B 19930308; NO 172192 C 19930616; NO 861806 L 19861110; NZ 216051 A 19891027; OA 08324 A 19880229; PL 144950 B1 19880730; TR 22683 A 19880303; US 4654129 A 19870331; ZA 863380 B 19870225
DOCDB simple family (application)
EP 86420118 A 19860505; AT 86420118 T 19860505; AU 5715786 A 19860506; BR 8602039 A 19860506; CA 508520 A 19860506; CN 86103165 A 19860506; DE 3664058 T 19860505; ES 554683 A 19860506; FR 8507319 A 19850507; GR 860101139 A 19860429; HU 189386 A 19860507; IN 321CA1986 A 19860424; IS 3095 A 19860502; JP 10459186 A 19860507; MY PI19870457 A 19870409; NO 861806 A 19860506; NZ 21605186 A 19860505; OA 58855 A 19860507; PL 25935486 A 19860506; TR 2503086 A 19860507; US 85990786 A 19860505; ZA 863380 A 19860506