Aluminum Company of America

Quyen C Nguyen

Herman J Hittner

A process for treating spent potlining from the electrolytic smelting of aluminum in cryolite includes incinerating the potlining to combust carbonaceous material to form an ash at a temperature low enough to maintain low fluorine vapor pressures, admixing siliceous material with the potlining either before of after the ash-forming stage, and heating the ash and siliceous material to form a glassy residue. The residue formed by the process of the present invention produces a spent potlining suitable for landfill characterized by a low leachability of fluorine in water.

Stabilization of fluorides of spent potlining by chemical dispersion

The present invention provides a process for treating spent potlining from the electrolytic smelting of aluminum in cryolite including burning the spent potlining to form an ash, mixing with a siliceous material either before or after the ash-forming step, and heating to form a residue suitable for landfill. The ash and siliceous material are mixed in a specified mole ratio of at least about 1.4 silicon to sodium. The process further includes cooling the residue rapidly. The residue formed by the process of the present invention produces a spent potlining suitable for landfill characterized by a low leachability of fluorine in water.

Growing community of inventors

Lower Burrell, PA, United States of America

Quyen C Nguyen