Recovery of alumina from siliceous minerals
AssigneeAlcan Research and Development Limited
InventorJohn E. Deutschman
Life of this patent
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Abstract
A process for the production of alumina from siliceous minerals containing substantial quantities of combined aluminium and calcium comprises the steps of treating the finely divided mineral with a hot acid liquor containing chloride, fluoride and calcium ions to extract alumina values from the mineral; recovering aluminium chloride from the liquid extract; recycling one fraction of the spent extract to the mineral extraction stage; and treating another fraction of the spent extract to regenerate hydrogen chloride gas for re-use in the process.
Claims7
A process for the production of alumina from siliceous materials containing substantial quantities of combined aluminium and calcium, comprising the steps of:
- (i) grinding the mineral to a fine particle size;
- (ii) treating the ground mineral with a hot acid liquor containing chloride, fluoride and calcium ions to extract alumina values from said mineral;
- (iii) separating the acid extract from the spent mineral residues;
- (iv) sparging the separated extract to precipitate aluminium chloride;
- (v) separating the precipitated aluminium chloride from the spent acid extract;
- (vi) recycling one fraction of the spent extract to the mineral extraction stage (ii);
- (vii) evaporating another fraction of the spent extract to dryness and heating the solid residue with active silica in the presence of water vapour to regenerate hydrogen chloride gas;
- (viii) recycling the regenerated hydrogen chloride gas directly to the extraction stage (ii) and/or sparging stage (iv) or absorbing said gas in water for recycling.
Dependencies are inferred from the claim text.