Process for the removal of impurity elements from solutions of valuable metals
AssigneeHenkel Kommanditgesellschaft auf Aktien
InventorsWerner Schwab, Ralf Kehl
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Abstract
A process is disclosed for removing impurity elements, such as arsenic, and if necessary antimony, iron or bismuth, from valuable metal containing, such as copper containing, strongly mineral acid solutions by way of solvent extraction with organic solutions of hydroxamic acids, and for selectively stripping the impurity elements therefrom. Antimony, iron or bismuth are stripped with complexing acids, and arsenic is stripped with an aqueous solution containing valuable metal ions at a pH value in the 1.5 to 5 range, a higher pH than the original valuable metal containing aqueous acid solution.
Claims33
A process for removing impurity elements selected from the group consisting of arsenic, antimony, iron, bismuth and mixtures thereof, from valuable metal containing aqueous acid solutions comprising:
- (a) contacting the valuable metal containing aqueous acid solution with an organic solvent solution of a hydroxamic acid having the formula (I) ##STR4## in which R is an alkyl and/or alkenyl radical containing 6 to 22 carbon atoms, a cyclo-alkyl radical or an aryl radical containing up to 19 carbon atoms for a sufficient time to transfer said impurity elements and the valuable metal from the valuable metal containing aqueous acid solution to said organic solvent solution of the hydroxamic acid, which forms an aqueous phase and an organic phase containing the impurity elements and the valuable metal;
- (b) separating the organic phase from the aqueous phase;
- and
- (c) contacting the organic phase from step (b) with an aqueous solution to strip the impurity elements from the organic phase, wherein the aqueous solution to strip the impurity metal elements selected from the group consisting of antimony, iron and bismuth comprises an aqueous solution of a complexing acid which complexes with one or more of the antimony, iron or bismuth impurity elements to remove the antimony, iron or bismuth from the organic phase and wherein the aqueous solution to strip any arsenic impurity element from the organic phase comprises an aqueous valuable metal containing solution having a higher pH value relative to the aqueous acid solution in stage (a) containing a valuable metal to remove the arsenic from the organic phase, in which the removal of the arsenic impurity element is carried out simultaneously with or subsequent to the removal of the metal elements of antimony, iron or bismuth;
- (d) recovering the impurity elements from the aqueous stripping solutions of step (c) after separation of the stripping solution from the organic phase;
- and
- (e) recovering the valuable metal from the organic phase.
A process as defined in claim 2 wherein the valuable metal containing aqueous acid solution is a copper containing electrolyte solution.
Dependencies are inferred from the claim text.