Supercritical Fluid Extraction of Metal Values from Selected Minerals.
Magyar MJ; Godoy FE; Haynes BW
Metall Soc AIME Warrendale, Pennsylvania, 1986 :1019-1027
Supercritical fluids (scf) are being studied by the Bureau of Mines to determine the feasibility of selective metal extraction from various minerals and spent catalysts. Because supercritical fluids are dense gases rather than liquids, they offer the potential for high permeability and selective dissolution of mineral values. Supercritical so2, nh3, h2o, and h2o2 have been investigated as solvents. Static and flowthrough reactor systems were used at temperatures up to 500 deg c and pressures up to 10,000 psig to investigate metal extraction. Results showed limited extraction of metal values from manganese nodules, laterites, and sulfide minerals using anhydrous so2 or anhydrous nh3 in the scf state. Supercritical nh3, modified with 30 pct h2o2 in h2o, enhanced copper extraction from chalcocite. Using supercritical h2o2 solutions, selective chromium extraction was obtained from chromite and from chromium-bearing spent catalysts. Experimental procedures are discussed.
Metall. Soc. AIME, Warrendale, Pennsylvania, 1986, PP. 1019-1027