Fractional acid leaching of noble metals from various ores

Fractional ore opening with hydrochloric and hydrofluoric acids and aqua regia to recover noble and base metals is reported. Copper-nickel sulfide ores (low-grade disseminated and vein ores in pyroxenites, breccia ores, and massive ores), sulfide-oxide ores, oxide (titanomagnetite) ores, and sulfide carbonaceous shales were chosen to study. Leaching of noble metals occurs stepwise and terminates only when the silicate component has been completely decomposed. The noble metal recovery is affected by the nature of both the metallic and nonmetallic fractions, and the forms of noble metals in them.