Laboratory Tests on High-temperature Cyanide Leachng of Automobile Catalysts.
Atkinson-GB; Kuczynski-RJ; Walters-LA
Paper in Proceeds Precious Metals Recovery & Refining Seminar Sept 11-13 1991 :9 pages
The U.S. Bureau of Mines investigated leaching automobile catalysts with sodium cyanide (nacn) solutions at high 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 deg. C dissolved over 97 pct of the PGM in the virgin monolith, over 85 pct of the PGM in the used monolith, and over 90 pct of the PGM in used pellet catalyst. Over 99.8 pct of the dissolved PGM was recovered as a precipitate by heating the solution to 250 deg. C for 1 h in an autoclave. The cyanide complexes were decomposed and free cyanide was destroyed.
Paper in Proceeds Precious Metals Recovery & Refining Seminar (Sept. 11-13, 1991, Tempe, AZ)