High-Temperature Cyanide Leaching of Platinum-Group Metals from AutomobileCatalysts-Laboratory Tests

摘要

The U.S. Bureau of Mines investigated leaching automobile catalysts with NaCNsolutions at elevated temperatures to recover platinum group metals (PGM). The feed was virgin monolith rejects, used monolith, and used pellet catalysts. Leaching with a 5-pct NaCN solution for 1 h at 160 C dissolved over 97 pct of the PGM contained in the virgin monolith, over 85 pct of the PGM contained in the used monolith, and over 90 pct of the PGM contained in the used pellet catalyst. Over 99.8 pct of the dissolved PGM was recovered as a precipitate by heating the solution to 250 C for 1 h in an autoclave. The cyanide complexes were decomposed and free cyanide destroyed.