Electrolysis: processes – compositions used therein – and methods – Electrolytic synthesis – Utilizing fused bath
Reexamination Certificate
2005-03-15
2005-03-15
Valentine, Donald R. (Department: 1742)
Electrolysis: processes, compositions used therein, and methods
Electrolytic synthesis
Utilizing fused bath
C205S380000, C205S393000
Reexamination Certificate
active
06866766
ABSTRACT:
Methods and apparatus are disclosed for reducing sulfur impurities in aluminum electrolytic production cells in order to significantly increase current efficiency of the cells. An impurity reduction zone may be created in the bath of an inert anode cell by submerging a purifying electrode in the bath. In another embodiment, an oxygen barrier tube may be disposed in a portion of the bath. In a further embodiment, reductants such as aluminum, CO and/or CO2are added to the bath. In another embodiment, electrode current is interrupted or electrodes are removed from selected regions of the cell in order to allow gaseous impurities to escape from the bath. Sulfur impurity levels may also be reduced in inert anode cells by scrubbing bath emissions from the cell before they are reintroduced into the cell, and by controlling sulfur impurity contents of materials added to the cell.
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Kozarek Robert L.
LaCamera Alfred F.
Liu Xinghua
Ray Siba P.
Roddy Jerry L.
Alcoa Inc.
Beiriger Tracey D.
Eckert Seamans Cherin & Mellott , LLC
Valentine Donald R.
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