New copper smelting technologies such as flash smelting - flash converting are replacing conventional ones, nevertheless, some limitations intrinsic to smelting still remain. Process based on solid-gas reactions rather than based in reactions between molten phases and gases could be a valid altetnative. Three differents options are proposed: A combined pyro hydro- process for standard copper concentrates, that considers a dead roast followed by two-stages leaching in which in the first one is dissolved the copper oxide and in a second and more energetic one is dissolved the copper ferrite. In a close loop, the resulting solution is then thermally decomposed to copper sulphate and hematite to further dissolve the copper in the first leaching. The copper is obtained finally as cathodes from the leach solution. A process for high-arsenic copper concentrates that consists of two concentric fluidised bed reactors: in the inner one is fed the high-arsenic copper concentrate which operates at 660-700 deg C and heated by heat by transfered through its wal from an outer annular oxidising reactor. The dearsenified calcine generated in the inner reactor overflow continuously into the outer oxidising reactor which operates at 780-820 deg C, where the remaining sulphur of the calcine is removed as SO_2. Finally, the copper oxide is reduced to metal with carbon and CO in a molten bath of oxides, reducing the copper oxide and ferrite to copper metal while slagging the iron with silica. As an alternative to conventional Peirce-Smith converters it is proposed a process that consists of the dead roast of the grinded matte or white metal in a fluidised bed roaster which operates at 780-800 deg C. The calcines generated are leached with spent electrolyte form the EW cells and the pregnant electrolyte, with very low levels of impurities, is send to the EW step to recover the copper as cathodes. The residue, which contains the ferrite and the precious metals is cyanided to recover these metals and the resulting ferrite residue is returned to the smelting furnace to recover the copper contained.
展开▼
