METHOD OF LEAD RECOVERY FROM LEAD-CONTAINING RAW MATERIALS Russian patent published in 1999 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: method includes of molten potassium hydroxide, lead-containing raw material and oxygen-containing gas to reaction zone with temperature of 600-700 C. Process results in obtaining black lead and melt including potassium hydroxide, potassium sulfate, potassium carbonate, sulfides of zinc, copper, iron and barren rock. Melt is withdrawn from reaction zone and subjected to the first aqueous leaching which results in suspension in the form of mixture of solid particles of potassium sulfate, potassium carbonate, sulfides of zinc, copper, iron and barren rock and aqueous solution containing potassium hydroxide. The suspension is filtered to obtain solution containing potassium hydroxide and solid residue. Solution of potassium hydroxide is directed for evaporation and melt of potassium hydroxide resulted from evaporation is supplied to reaction zone. Solid residue, after the first stage of leaching and washing, for instance, on filter is subjected to operation of the second aqueous leaching. Supplied for the second aqueous leaching is reusable solution and sulfuric acid, and pH is maintained within 6-8. The second aqueous leaching results in obtaining suspension which is filtered to produce cake containing solid particles of sulfides of zinc, copper, iron and barren rock. Cake is subjected to washing with water and withdrawn from process. Saturated aqueous solution of potassium sulfate is used for producing crystals which are also withdrawn from the process. Mother solution from crystallization of potassium sulfate is combined with water after washing of cake and directed for the second leaching. EFFECT: simplified process, reduced energy consumption and higher efficiency. 2 cl, 2 tbl