| 摘要 |
Disclosed is a process for recovering substantially all platinum group metals using a dry carbochlorination process. The feed material is amended with NaCl and subjected to the action of chlorine and carbon monoxide gases in an open furnace at temperature varying from about 250 .degree.C to about 720 .degree.C. The platinum, palladium, rhodium, ruthenium and iridium values remain in the solid material while the osmium values are carried in the gas phase exiting the reactor. Osmium is recovered from the gas phase, containing also FeCl3, by the separate condensation of FeCl3 in a condenser and the percolation of the exhaust condenser gas in water or HCl solutions. The platinum, palladium, rhodium, ruthenium and iridium are recovered from the solid material after the carbochlorination step by digestion in water or in diluted HCl solutions. The dissolved platinum group metals are extracted from the leached solutions by cementation or ions exchange resins. The process can be run simultaneously with the removal of iron from the feed as gaseous FeCl3. Advantageously, where the feed is chromite rich, the recovery of the platinum group metals by the present process also conducts to an increase in the chromium to iron ratio of the feed, this ratio being directly related to the commercial value of chromites.
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