Abstract

Abu Gurdi area is located in the South-eastern Desert of Egypt which considered as volcanic massivesulfide deposits (VMS). The present work aims at investigating the ore mineralogy of Abu Gurdi region inaddition to the effectiveness of the hydrometallurgical route for processing these ores using alkaline leachingfor the extraction of Zn, Cu, and Pb in the presence of hydrogen peroxide, has been investigated. The factorsaffecting the efficiency of the alkaline leaching of the used ore including the reagent composition, reagentconcentration, leaching temperature, leaching time, and Solid /Liquid ratio, have been investigated. It was notedthat the sulfide mineralization consists mainly of chalcopyrite, sphalerite, pyrite, galena and bornite. Gold isdetected as rare, disseminated crystals within the gangue minerals. Under supergene conditions, secondary copperminerals (covellite, malachite, chrysocolla and atacamite) were formed. The maximum dissolution efficienciesof Cu, Zn, and Pb at the optimum leaching conditions i.e., 250 g/L NaCO3 - NaHCO3 alkali concentration,for 3 hr., at 250℃, and 1/5 Solid/liquid (S/L) ratio, were 99.48 %, 96.70 % and 99.11 %, respectively. Anapparent activation energy for Zn, Cu and Pb dissolution were 21.599, 21.779 and 23.761 kJ.mol−1, respectively,which were between those of a typical diffusion-controlled process and a chemical reaction-controlled process. Hence, the diffusion of the solid product layer contributed more than the chemical reaction to control the rateof the leaching process. High pure Cu(OH)2, Pb(OH)2, and ZnCl2 were obtained from the finally obtained leachliquor at the optimum leaching conditions by precipitation at different pH. Finally, highly pure Au metal wasseparated from the mineralized massive sulfide via using adsorption method.