Patent Number: 6,183,620

Title: Process for controlling the A1F3 content in cryolite melts

Abstract: A process is provided for controlling the AlF.sub.3 content in cryolite melts for aluminum reduction, wherein the temperature of the melt is measured. In order to produce a very precise process which makes it possible to perform the aluminum reduction at the lowest posssible temperature, and thus as energy-saving as possible, the liquidus temperature of the cryolite melt is measured and compared with a first target value. AlF.sub.3 is added to the bath if the measured liquidus temperature is higher than the first target value. If the measured liquidus temperature is lower than the first target value, the measured liquidus temperature is compared with a second target value which is lower than the first target value. NaF or Na.sub.2 CO.sub.3 is added to the bath if the measured liquidus temperature is lower than the second target value.

Inventors: Verstreken; Paul Clement (Hasselt, BE)

Assignee: Heraeus Electro-Nite International N.V.

International Classification: C25C 3/00 (20060101); C25C 3/20 (20060101); C25C 003/08 ()

Expiration Date: 02/06/2018