摘要 |
Treatment of residues (I) comprising zinc ferrites and lead, silver, indium, germanium and/or gallium as oxides and sulfates involves (a) roasting (I) in an oxidizing medium at high temperature to give a desulfurized residue, (b) carrying out carbiding reduction-fusion in a reductive medium, (c) extracting carbided iron and slag in liquid form and (d) extracting non-ferrous metals in a vapor phase, followed by oxidation and recovery in solid form. |