Patent 7879220 was granted and assigned to Hydro on February, 2011 by the United States Patent and Trademark Office.
The present invention relates to a method of improving the current efficiency (CE) in an electrolytic aluminum production cell with an electrolytic bath, at least one anode and at least one cathode, and passing current between said anode and said cathode through said bath and feeding an aluminum containing feedstock to the cell. The CE is improved in that the aluminum containing feedstock is prepared in a manner where it contains substantially no humidity or water before it is fed to the cell, where the electrolytic process is carried out at conditions with reduced amount of hydrogen present.