DAVID STOFESKY
Engineering in Pittsburgh, PA

5538604, Jul 23, 1996

Jan 20, 1995

8/375790

Rudolf Keller - Export PA
C. Norman Cochran - Oakmont PA
David B. Stofesky - Pittsburgh PA

EMEC Consultants - Export PA

C25C 308

204243R

Disclosed is an improved carbonaceous material suitable for use as a liner in an aluminum producing electrolytic cell, the cell using an electrolyte comprised of sodium containing compounds and the carbonaceous material penetrable by sodium or nitrogen and resistant to formation or accumulation of sodium cyanide during operation of the cell. The carbonaceous material is comprised of carbon and a reactive compound capable of reacting with one of sodium, nitrogen and sodium cyanide during operation of the cell to produce aluminum, the reactive compound present in an amount sufficient to suppress formation or accumulation of cyanide compounds in the liner.

5683663, Nov 4, 1997

Jun 12, 1996

8/661920

Rudolph Keller - Export PA
C. Norman Cochran - Oakmont PA
David B. Stofesky - Pittsburgh PA

C01F 100, A62D 300

423111

A method of treating sodium cyanide in spent carbonaceous and/or refractory material, i. e. , spent potlining, from an electrolytic cell for producing aluminum from alumina dissolved in a sodium-containing electrolyte, wherein sodium cyanide forms in the carbonaceous material during operation of the cell. The method comprises grinding the spent carbonaceous and/or refractory material containing sodium cyanide to provide particles of spent carbonaceous material and adding a reactive material capable of reacting with the sodium cyanide to provide a mixture of reactive material and spent potlining material. Thereafter, the mixture is heated to a temperature effective in reacting the reactive material with the sodium cyanide to destroy the sodium cyanide in the spent potlining.