Abstract: A process for the dissolution of precious metal values in a concentrate thereof wherein the concentrate is caused to alloy with aluminum and the alloy is then leached in at least two steps, the first of which is to remove base metals and in the second of which the precious metals are dissolved using hydrochloric acid and chlorine gas or nitric acid as an oxidant.

Abstract: A process for the recovery or purification of rhodium wherein:(i) a solution of a soluble anionic rhodium complex is treated to precipitate insoluble pentammino-chloro rhodium dichloride;(ii) the rhodium is redissolved in the form of the equivalent hydroxo complex cation;(iii) the solution is treated to precipitate the nitrate salt of the pentammino-nitro rhodium complex;(iv) the precipitate is converted to pentamminochloro rhodium dichloride; and,(v) the latter is calcined to form rhodium metal.

Abstract: A method of recovering iridium from a solution thereof containing rhodium and impurities in the form of base metals comprising; oxidizing the iridium to the Ir(IV) oxidation state in an acid solution in the presence of chloride ions; removing the iridium chlorocomplexes formed using a suitable anion-exchange resin; washing the resin; treating the iridium with an aqueous solution of sulphur dioxide which is substantially free of chloride ions; and thereafter eluting the iridium complex formed from the resin using a suitable eluant.

Abstract: A process for the separation of platinum and/or palladium from acid starting solutions containing the chlorocomplexes thereof together with other platinum group metals and/or base metals in 0.01 to 2M acid solutions comprises contacting the starting solution with a suitable solvent extractant; the solvent extractant being substantially water insoluble, carried in an organic phase and comprising functional groups of the formula R.sub.2 N--CH.sub.2 --COOH wherein R is a long-chain alkyl group and thereafter separating the two phases and recovering the extracted platinum or palladium or both from the loaded solvent extractant.

Abstract: A process for the separation or purification of ruthenium from solutions thereof comprising conversion of the ruthenium to nitrosylruthenium complex with the ruthenium in the Ru.sup.+2 oxidation state; conversion of the nitrosylruthenium complex to a nitrosylruthenium chlorocomplex and any other platinum group metals to chlorocomplexes; and the removal of the nitrosylruthenium chlorocomplex from solution using a suitable liquid or resin anion exchanger.