Method for the recovery of fluorides from spent aluminum potlining and the production of an environmentally safe waste residue

Patent · Tue Apr 24 04:00:00 EST 1984

OSTI ID:6308657

Snodgrass, J B; Cambridge, E L

A method for recovery of fluoride values from spent potlining and fluoride containing insulating materials associated with the potlining is disclosed. Spent potlining and the insulating matericals are reduced to a fine particle size and incinerated. The ash residue is leached with a dilute caustic and the leachate is treated with a calcium compound to precipitate calcium fluoride. The calcium fluoride is dried to a moisture content of less than 0.1 percent and is treated with about 93 to 99 percent concentration of sulfuric acid to produce hydrogen fluoride gas and a metal sulfate. The hydrogen fluoride gas is fed into an alumina dry scrubber to produce alumina with absorbed fluorides to be used as feed material to reduction cells used in the manufacture of aluminum by electrolytic reduction. The metal sulfate residue is treated with lime and constitutes an environmentally safe product which can be disposed of as landfill material.

• Assignee: Atlantic Richfield Company
• Patent Number(s): US 4444740
• OSTI ID: 6308657
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CARBONATE ROCKS
CHEMICAL REACTORS
DISSOLUTION
ELECTROLYSIS
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROFLUORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
LAND POLLUTION ABATEMENT
LEACHING
LIMESTONE
LINERS
LYSIS
MANAGEMENT
METALS
POLLUTION ABATEMENT
PRECIPITATION
PROCESSING
PRODUCTION
RECOVERY
ROCKS
SANITARY LANDFILLS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SORPTION
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTE PROCESSING