Solvent extraction of platinum group metals

Abstract

This invention relates to the separation and purification of the platinum group metals; more particularly it relates to the separation of mixtures of Pt and/or Pd from Rh and/or Ru. In more detail, the present invention relates to a process for the separation or purification of platinum group metals in which either platinum, iridium (IV) and/or palladium (II) are present in aqueous solution together with one or more other platinum group or base metals comprising the steps of: (a) adjusting the acidity, if necessary, to provide a pH less than 7; (b) contacting the said aqueous solution with an organic phase containing at least one nitrogen containing organic compound selected from the group consisting of primary, secondary and tertiary amines and quarternary ammonium compounds and at least one oxygen containing organic compound selected from the group consisting of alcohols, phenols and carboxylic acids; (c) removing from contact with the said solution the said organic phase now containing the platinum, iridium (IV) and/or palladium (II) extracted together with the nitrogen- and oxygen-containing organic compounds; and (d) contacting the organic phase obtained at stage (c) above with a strongly acidic solution and thus stripping the platinum, iridium and/or palladium from the said organic phase and obtaining an aqueous solution of the said metals.

Dependencies are inferred from the claim text.