Back to results
US 4,889,695 AGranted
Reclaiming spent potlining
AssigneeAluminum Company of America
InventorJ. Finley Bush
Life of this patent
Estimating the term…
Abstract
Disclosed in a process for recovering aluminum flouride, caustic, and carbon from spent potlining retrieved from an aluminum electrolytic reduction cell. Spent potlining is treated by leaching with a caustic solution to produce a fluoride-rich basic liquor and carbonaceous solid residue followed by contacting the carbonaceous solid with an acid bath of aluminum sulfate and sulfuric acid to produce a fluoride-rich acid liquor.
Claims13
The process for recovering halogen from carbonaceous material comprising:
- (a) leaching carbonaceous material containing halogen with a caustic solution to produce a halogenrich basic liquor and a carbonaceous solid;
- and
- (b) contacting said carbonaceous solid with an acid bath of aluminum sulfate and sulfuric acid to produce a halogen-rich acid liquor.
The process for recovering fluorine from spent potlining from an aluminum electrolytic reduction cell comprising:
- (a) grinding the potlining to a particle size less than about 100 microns,
- (b) leaching the ground spent potlining with a caustic solution to produce a fluoride-rich basic liquor and a carbonaceous residue,
- (c) filtering, returning a portion of the filtrate for grinding,
- (d) contacting said carbonaceous residue with an acid bath of aluminum sulfate and sulfuric acid at a ratio of about 0.75 to 1.0,
- (e) deironing, and
- (f) separating carbon from insulation materials from the acid leaching.
3 more elements
Dependencies are inferred from the claim text.