The leaching behaviour of electrostatic precipitator dust from the Mufulira Cu smelter was studied using a 48-h pH-static leaching experiment. The release of metals (Cd, Co, Cu, Ni, Pb and Zn) and changes in mineralogical composition were investigated in the pH range of 3-7.
The highest concentrations of metals were released at pH 3-4.5. Chalcanthite, magnetite and delafossite represented the principal phases of the studied dust.
In contact with water, chalcanthite was dissolved and hydrated Cu sulphates precipitated at pH 4-7. Serious environmental impact may occur in dust-contaminated soil systems in the vicinity of the smelting plants.