Process for control of so.sub.x emissions from copper smelter operations

Abstract

Process for control of SO.sub.x emissions from copper smelter operations involving pyrometallurgical reduction of copper ores to elemental copper in which the gases from reverberatory furnaces, roasters, and/or converters are scrubbed with a sodium alkali sorbent to produce sodium sulfate and sulfite wastes. The cleaned flue gases are exhausted to the atmosphere. The waste sodium sulfate/sulfite material is then reacted with excess acid from the smelter acid plant and ferrous ion-rich barren solution from the associated cement copper operations to produce co-precipitated double salts of sodium ferric hydroxy-disulfates and/or sulfites (SFH), having low water solubility and being suitable for landfill type disposal without posing serious water pollution problems. This disposes of the sodium sulfite/sulfate waste materials from the air pollution control process and also strips the barren solution of iron prior to its recycle to heap or dump leaching operations. The reduction of ferrous iron concentrations in the recycle barren solution tends to reduce the opportunity for iron hydroxides to be formed in the dump thereby increasing production of copper from aqueous sulfuric acid type leaching operations.