The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 15, 2005
Filed:
Aug. 05, 2002
Alfred F. Lacamera, Trafford, PA (US);
Siba P. Ray, Murrysville, PA (US);
Xinghua Liu, Murrysville, PA (US);
Robert L. Kozarek, Apollo, PA (US);
Jerry L. Roddy, Knoxville, TN (US);
Alfred F. LaCamera, Trafford, PA (US);
Siba P. Ray, Murrysville, PA (US);
Xinghua Liu, Murrysville, PA (US);
Robert L. Kozarek, Apollo, PA (US);
Jerry L. Roddy, Knoxville, TN (US);
Alcoa Inc., Pittsburgh, PA (US);
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 COare 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.