Removal and recovery of Cu and Pb from single-metal and Cu-Pb-Cd-Zn multimetal solutions by modified pyrite: Fixed-bed columns

Modified pyrite (MPy) with submicrometer particle sizes and porous polycrystalline structure, which was obtained by calcining pyrite, was used to remove and recover Cu, Pb, Cd, and Zn from the single- and multimetal fixed-bed columns. Results showed that the removal capacities of Cu and Pb were 77.42 and 73.68 mg/g MPy for single-metal solutions, and they were 30.79 and 10.86 mg/g MPy for the Cu-Pb-Cd-Zn multimetal solution. The Cu and Pb contents in the used MPy collected from the saturation zone of the single- and multimetal sorption columns were 17.4% and 15.37% and 6.8% and 2.5%, respectively, high enough to extract Cu and Pb from the used MPy particles by means of direct extractive metallurgy. This research shows that MPy is able to remove and recover Cu and Pb from wastewater even with the presence of Cd and Zn. Sequential extraction of the metals, XRD, and TEM analyses evidenced that the major mechanism for Cu and Pb removal by MPy was precipitation and dissolution reactions by formation of covellite and galena.