Abstract: This invention relates to refining platinum group metal concentrates and the separation therefrom of silver and of the majority of base metals with which they naturally occur. In more detail the process comprises the steps of:(a) contacting a solid particulate mixture of base, silver and precious metal components, any of which components may be in metallic or chemically combined form, with a halogen-containing gas at a temperature which is sufficiently high for the base metal and silver components to form their halides and for the said halides substantially to volatilize from the said solid mixture, and(b) removing the said volatilized halides from the solid precious metal-containing component which remains.

Abstract: This invention relates to refining platinum group metal concentrate and the separation therefrom of silver and the majority of base metals which are present in them. In more detail, the process comprises the steps of:A. contacting a solid particulate mixture of base, silver and precious metal components, any of which may be in metallic or in chemically combined form, with substantially anhydrous sulphuric acid at a temperature which is sufficiently high for most of the base metal and silver components to form water soluble sulphates andB. separating the said water soluble sulphates from the solid precious metal-containing components by contacting the product from step (a) with a dilute aqueous solution or water and dissolving therein the said water soluble sulphates formed in step (a).

Abstract: This invention relates to refining platinum group metal concentrates and the separation therefrom of silver and of the majority of base metals which are present with them. In more detail, the process comprises reacting together gaseous hydrogen and chlorine so as to produce a flame and passing into the reaction zone of the said flame the said mineral concentrate in finely divided particulate form.The specification also describes an apparatus for carrying out the above process comprising a tubular burner having a hydrogen-chlorine flame discharging into an inner heat resistant tube and means for maintaining the inner tube at an elevated temperature up to at least 2500.degree. C.