Top-blowing technology in copper pyrometallurgy

CIM Bulletin, Vol. 73, No. 818, 1980

K.B. CHAUDHURI, Head, and F.E. RACHOR and I.D. WEBB, Senior Metallurgists, Department of Process Metallurgy, F.A. SAUERT, Senior Metallurgist, Department of Research and Development, KHD Humboldt Wedag AG Federal Republic of Germany

A characteristic of all methods of copper concentrate smelting is that slags with a high copper content are produced at some phase of the operation. Recirculation to the smelting unit, electric furnace reduction or flotation are at present used on an industrial scale to recover the copper from these slags.This paper describes the application of the top-blowing technique, originally developed by KHD Humboldt-Wedag AG for refining of metallic copper, for the treatment of copper-containing slags. By this method, a mixture of a reducing gas and commercial oxygen is blown onto the melt at velocities which can be supersonic from the tip of a water-cooled lance. The impingement of the reaction gas mixture on the surface of the slag forms a depression in the molten phase and a deflection of the jet which brings the slag into a rotating motion. This causes high rates of heat and mass transfer. Results of pilot-plant tests for batch and continuous treatment of slags are presented, and the potential applications of top blowing for industrial-scale operation are indicated. In combination with the cyclone as a smelting unit, this process appears to be economic for smelters of very low capacity.
Keywords: Pyrometallurgy, Non-ferrous pyrometallurgy, Copper pyometallurgy, Top-blowing reactors, Cyclones, Slag conditioning, Smelting.