Henkel Kommanditgesellschaft Auf Aktien

Yokogawa Electric Corporation

Kanegafuchi Kagaku Kogyo Kabushiki Kaisha

Ralf Kehl

Werner Schwab

Willi Buchmeier

Robert B Sudderth

Gary A Korkosky

Process for working up ammoniacal metal solutions including treating the

Process for the removal of impurity elements from solutions of valuable

Process for the two-phase extraction of metal ions from phases

Prior art processes for removal of one or more contaminant elements, including at least one of antimony, bismuth, and arsenic and optionally including iron, from electrolyte solutions of primary metals by solvent extraction with an organic phase including a hydroxamic acid, then precipitating at least part of the contaminant elements from the organic phase as sulfides, are improved by an additional step of re-extracting the organic phase with water before precipitating the sulfides from it. At least part of any arsenic present and, if desired, part of any antimony as well, may be re-extracted in this manner and subsequently recovered if desired, so that the overall process is made more economical.

Process for selective extraction of contaminant elements from mixtures

A process for the common or simultaneous separation of arsenic, antimony, bismuth and iron from electrolyte solutions of valuable metals by solvent extraction and subsequent recovery of the contaminating elements, which process is characterized in that aqueous mineral-acidic electrolyte solutions of valuable metals are admixed with a sparingly water soluble organic solvent containing at least one hydroxamic acid, the aqueous and organic phases are thoroughly mixed, the contaminating elements arsenic, antimony and bismuth are precipitated from the organic phase by direct sulfide precipitation, the sulfides are separated, and the extracted iron is subsequently reextracted with a water soluble iron-complexing agent into an aqueous phase and recovered.

Common separation of contaminating elements from electrolyte solutions

Citric acid partial esters corresponding to the following general formula ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 represent hydrogen or a straight-chain or branched C.sub.4 -C.sub.20 alkyl radical or a metal atom, with the proviso that at least one but at most two of the substituents R.sup.1, R.sup.2 and R.sup.3 represent such an alkyl radical, or mixtures of the citric acid partial esters corresponding to general formula (I), are used for the extraction of iron from aqueous solutions.

Use of citric acid partial esters for the extraction of iron

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Duesseldorf, Germany

Ralf Kehl