Process for recycling spent pot liner
AssigneeClemson University
InventorDenis A. Brosnan
Life of this patent
Estimating the term…
Abstract
The process includes the steps of combining silica with the spent pot liner in order to convert a majority of the spent pot liner into silicon carbide. Specifically, the silica reacts with carbon in the spent pot liner to form silicon carbide. In order to form the silicon carbide, the materials are heated, such as in an electric resistance heater. The formed silicon carbide is free of contaminants and can be used for many useful purposes.
Claims19
A process for recycling spent pot liner obtained from an aluminum electrolytic cell comprising the steps of:
- comminuting spent pot liner, said spent pot liner containing carbon;
- combining said spent pot liner with silica, said silica being added in an amount such that the molar ratio of silica to carbon present in said pot liner is from about 1:3 to about 1:5;
- heating said spent pot liner and silica in an electric resistance furnace in a reducing atmosphere to a temperature sufficient for said silica to react with said carbon to form silicon carbide;
- and
- separating said formed silicon carbide from the remaining heated spent potliner.
A process for recycling spent pot liner comprising the steps of:
- providing spent pot liner, said spent pot liner containing carbon;
- combining said spent pot liner with silica, said silica being added in an amount such that the molar ratio of silica to carbon present in said pot liner is from about 1:3 to about 1:5;
- heating said spent pot liner in a reducing atmosphere to a temperature sufficient for said silica to react with said carbon to form silicon carbide, said temperature also being sufficient to decompose any compounds containing fluorine and any cyanates present within said spent pot liner;
- and
- cooling and collecting said produced silicon carbide.
A process for recycling spent pot liner comprising the steps of:
- providing spent pot liner, said spent pot liner containing carbon, a fluorine compound and a cyanate;
- combining said spent pot liner with silica, said silica being added in an amount such that the molar ratio of silica to carbon present in the spent pot liner is from about 1:3 to about 1:5;
- heating said spent pot liner and silica in an electric resistance furnace in a reducing atmosphere, said spent pot liner and silica being heated to a temperature sufficient for said silica to react with said carbon to form silicon carbide, said temperature also being sufficient to decompose said fluorine compound and said cyanate, said fluorine contained in said fluorine compound being released as a vapor in flue gas exiting said electrical furnace;
- collecting said fluorine in said flue gas;
- and
- separating said formed silicon carbide from the remaining heated spent pot liner.
Dependencies are inferred from the claim text.