Canadian Patents & Development Ltd.

Bernard H Lucas

Gordon M Ritcey

Kazi E Haque

James M Skeaff

David Y Shimano

Kenneth T Price

The present invention relates to an aqueous ferric chloride leach process for the extraction of metal values from a metal-sulphide bearing material, the leach being carried out in the presence of a leaching aid chosen from among salts of diesters of sulphodicarboxylic acids. It, in particular, relates to the enhanced recovery of metal values from complex, metal-sulphide bearing materials such as, for example, fine grained, polymetallic sulphide ores, their concentrates or the like.

Ferric chloride leach of a metal-sulphide bearing material

Uranium ores, concentrates, calcines or tailings are processed to remove radium and thorium as well as uranium. Selected ores, concentrates or tailings, or if more appropriate, chlorination calcines thereof, are leached by selected aqueous chlorine-containing media (preferably in two stages) until uranium, radium and thorium are substantially all dissolved, with the insoluble residual solids being suitable for disposal. The leach solution is treated to recover sequentially uranium, usually thorium, and radium by selected techniques. The radium recovered can be disposed of in any environmentally-acceptable manner. The amount of iron in the residual leach liquor should be controlled to avoid iron build-up, with the barren leach solution being suitable for recycle.

Uranium ore processing

The solvent extraction separation and recovery of copper and zinc from complex chloride liquors; e.g. those resulting from the low temperature chlorination and leach of a copper-lead-zinc sulphide ore or concentrate; are described, including the selection of sequence, conditions, extractants, scrubbing and stripping media and adaptations for electrowinning and recycle. High purity copper sulphate and zinc chloride electrolytes are produced for subsequent direct electrowinning. Lead may also be recovered.

Recovery of copper and zinc from complex chloride solutions

Chromium and vanadium can be co-extracted from alkaline solutions or leach liquors containing these metals using quaternary amine solvent mixtures. The alkaline leach liquors usually are derived by leaching of calcined ores or concentrates. The loaded solvent mixture is scrubbed with chromium solution to remove all metals except chromium, and the chromium is then recovered from the solvent phase. The vanadium can be recovered from the scrub liquor. Recovery of aluminum is also possible.

Solvent extraction of chromium and vanadium

In solvent-in-pulp extractions where aqueous leach slurries containing dissolved metal values and gangue particles of the silica, sericite or sulphide types are contacted with organic amine extractants, the loss of amine extractant to the solids is decreased sharply by pretreating the slurries with organic non-ionic hydrophilic material which is adsorbed by the gangue solids and decreases the affinity of the gangue solids for the amine. A combination of inexpensive materials has been found to be most effective. Crud formation is substantially avoided and the separation of phases is facilitated.

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Nepean, Canada

Bernard H Lucas