Chemico:physical treatment of residues contg. lead - by washing with water or brine, then roasting so lead can be recovered by hydrometallurgical treatment

摘要

The residues contain PbSO4, and are washed with water or salt water at 10-80 degrees C., using a ratio water:residue of 10:1 to 100:1, followed by filtering under vacuum, but esp. in a filter press, to obtain a filter cake, using a filtering pressure of 9-30 kg/cm2. The cake is then subjected to simultaneous agglomeration and oxidn. by roasting at 200-750 degrees C. to obtain a prod. which can be used in a hydrometallurgical process for winning lead. The residues are moist or dry, and are pref. obtd. in the mfr. of zinc by a hydrometallurgical process; they are not directly suitable for the recovery of Pb, and they are therefore treated so the Pb can be recovered economically. The residues contain PbSO4, ZnSO4, jarosite, hydrated silica, gypsum, metal sulphides, sulphur H2SO4, and water.