Non-ferrous metals extracted from pyrite roasting residues - by the fluidized bed method and oxidation

摘要

The parent patent discloses treating the roasting residue in a fluidized state with O2, SO2 and water or steam. In order to extract the non-ferrous metals when present in much smaller particle size, the residue is treated in the fluidized state in an atm. contg. SO3, pref. in the first stage. The SO3 atm. is provided by addn. of substances which form SO3 by thermal dissocn. such as sulphuric acid, wash acid of final roasting gases, aryl- or alkyl sulphonic acid, ammonium sulphate, Fe sulphite singly or together.