Method of Processing Fly Dusts Containing Sulphur, and Smelter mixed Oxides or other mixed Oxides Containing Zinc and Lead

摘要

1,173,251. Extracting metals. UNTERHARZER BERG-und HUTTENWERKE G.m.b.H. Jan. 4, 1968 [Feb. 2, 1967], No.589/68. Heading C7D. Fly dusts, smelter mixed oxides and/or other mixed oxides containing sulphur, zinc and lead are processed to give a crude lead, a slag rich in zinc and sulphur and a secondary fly dust which can be sintered, by mixing them with barium sulphate and excess reducing agent (e.g. coke) and melting the mixture in a furnace at 820‹ -1000‹ C. The process may be carried out in a rotary tube furnace supplied with a counter-current flow of combustion air at 200‹ -300‹C. using, as the source of barium sulphate, barytes or a lead-zinc ore containing barium sulphate. The crude lead is preferably tapped in the presence of air so that zinc can evaporate therefrom and be oxidized: further zinc may be removed by tapping the lead into a pot containing solid lead so that the molten lead cools whereupon zinc dross forms on its surface, this dross being removed and purer lead being tapped from the bottom of the pot.