The leaching characteristics of Cu, Ni, Ag, Au, Pd, Rd and Pt with aqueous ozone were investigated. The Metalozon process consists basically of three consecutive steps: 1) Cu and Ni are recovered from a first step by leaching in O{sub}2/H{sub}2SO{sub}4.2) Ag is leached in O{sub}2/O{sub}3/H{sub}2SO{sub}4.3) Au and Pd are recovered by leaching in O{sub}2/O{sub}3/H{sup}+ in presence of dilute Cl{sup}-(～0.1M). Rh and R remain in the final residue. The main characteristics are: a) All steps can be carried out at ambient temperature and normal pressure or moderate overpressure; b) Kinetics are basically controlled by mass transfer; c) The main by-product of the steps 2 and 3 is O{sub}2 which is recycled to step I; and d) Recovery of the metals by electrolysis or by HI reduction regenerates the acidity consumed. The process can be cost-effective and of very low environmental impact for a wide range of raw materials: Including radiographic plates, gold concentrates, anode slimes from copper electro refining, electronic scrap, etc. Laboratory-scale results on these raw materials are reported.
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