| 摘要 |
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. The invention also relates to an apparatus for carrying out the above process and comprises: (a) a gas-tight means for feeding particulate solid into a tubular vessel; (b) a vertical shaft reaction chamber connected to the tubular vessel and having an inlet for the introduction of halogen-containing gas and an outlet for exhaust gases including volatilized halides; (c) heating means, disposed around the shaft reaction chamber, and (d) a discharge system whereby precious metal-containing residue may be ejected from the reaction vessel.
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