Influence of cyanide on the extraction of transition elements from molten and aqueous thiocyanate with quaternary amines

The severe decrease in the extractability of nickel, zinc, iridium, osmium, silver and platinum with quaternary amines from molten thiocyanate containing small amounts of cyanide results from metal cyanide complex formation. Additional measurements on aqueous electrolyte systems show that these complexes cannot be extracted from aqueous solutions containing high concentrations of thiocyanate or iodide or from thiocyanate melts, as the activity of the extractant is highly reduced by structure-forced ion-pairing with thiocyanate or iodide ions.