Recovery process
AssigneeLI-Technology Pty Ltd.
InventorsGary Donald JOHNSON, Mark Daniel URBANI, Nicholas John VINES
Life of this patent
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Abstract
A process for the recovery of lithium from lithium bearing mica rich minerals, the process comprising passing an ore containing one or more lithium bearing mica rich minerals to at least one pre-treatment step, passing the pre-treated ore to an acid leach step thereby producing a pregnant leach solution, subjecting the pregnant leach solution to a series of process steps in which one or more impurity metals are removed, and recovering lithium as a lithium containing salt product.
Claims31
1-87. (canceled)
A process for the recovery of lithium from lithium bearing mica rich minerals, the process comprising passing an ore containing one or more lithium bearing mica rich minerals to at least one pre-treatment step, passing the pre-treated ore to an acid leach step thereby producing a leach slurry that is in turn passed to a solid liquid separation step, the separation step producing a leach residue and a pregnant leach solution, subjecting the pregnant leach solution to a series of process steps in which one or more impurity metals are removed, and recovering lithium as a lithium containing salt product.
A process for the recovery of lithium from lithium bearing mica rich minerals comprising the method steps of:
- (i) Separation of the lithium bearing mineral, lepidolite, from gangue minerals by a first pre-treatment step being froth flotation to produce a concentrate;
- (ii) Fine milling the concentrate in a second pre-treatment step;
- (iii) Leaching in sulfuric acid solution under atmospheric conditions to provide a leach slurry that is in turn passed to a solid liquid separation step, the separation step producing a leach residue and a pregnant leach solution containing soluble lithium, potassium, rubidium, caesium and aluminium sulfates and extracted fluorine;
- (iv) Selectively crystallising the mixed monovalent alum salts by cooling with or without evaporation;
- (v) Separation of the monovalent-alum salts from the liquor by filtration or decantation, whereby the resulting filtrate contains the large proportion of the lithium contained from the initial ore or concentrate;
- (vi) Impurities present in the lithium containing filtrate, including H2SO4, aluminium, chromium and iron, are removed by precipitation using a suitable base, including limestone, lime, or monovalent carbonate or hydroxide salts;
- (vii) Separation of the impurity metals and sulfate from the liquor by filtration or decantation whereby the resulting filtrate contains the large majority of the lithium contained from the pregnant leach solution, and washing the solids with water to recover entrained lithium;
- (viii) Precipitation of impurity base metals, including manganese and/or magnesium, using a base, which may be lime or a monovalent hydroxide salt;
- (ix) Separation of the impurity metals and sulfate from the liquor by filtration or decantation whereby the resulting filtrate contains the large majority of the lithium contained from the pregnant leach solution, and washing the solids with water to recover entrained lithium;
- (x) Precipitation of calcium ions by the addition of a monovalent carbonate salt;
- (xi) Separation of the precipitated calcium salt from the liquor by filtration or decantation whereby the resulting filtrate contains the large majority of the lithium contained from the pregnant leach solution;
- (xii) Precipitation of lithium carbonate by the addition of a monovalent carbonate salt and separation of the lithium salt from the liquor by filtration or decantation;
- (xiii) Crystallisation of monovalent sulfate salts from filtrate by salting out and/or evaporation;
- (xiv) Re-dissolving the mixed monovalent alum salts of step (iv) in water and subjecting same to selective precipitation using limestone, lime or monovalent carbonate or hydroxide salts, to precipitate Al(OH)3;
- (xv) Separation of the precipitated Al(OH)3 from the liquor by filtration or decantation whereby the resulting filtrate contains monovalent cation salts;
- and
- (xvi) Separating the monovalent cation salts by selective crystallisation.
Dependencies are inferred from the claim text.