Abstract
It has been demonstrated that the traditional hydrometallurgical method is still economically viable in several industrial applications. The conventional extraction technique of valuable metals from their ores using aqua medium has several challenges. The following can be listed for the illustration: (1) inorganic acids used during the leaching process have been proven non-environmentally friendly and ready to lead to non-selective processes in general, except in rare cases used in alkaline environments. (2) special linings are required in the material due to their corrosiveness and render all processes costly. (3) practically, using inorganic acids while leaching samples containing amorphous silicate phases leads to gel formation. Therefore, this work addresses the above by investigating the possibility of applying the solvometallurgy methods to leach copper directly from a chalcopyrite ore, avoiding problems associated with silica gel formation. Therefore, oxidative and complexing solvoleaching was performed with LIX 984 N as a chelating extractant solvent associated with ethylene glycol, HCl and H2O2 diluted in the kerosene in place of water. The approach consisted of selectively recovering copper from chalcopyrite ore (80% <75 μm) while collecting Cu ions simultaneously in the organic phase. The thermodynamics and kinetic investigations were performed to assess the impact of ethylene glycol, HCl, and H2O2 addition successively to the solvent phases for Cu recovery efficiency while checking the selectivity through the entrainment of Co and Fe fractions when working in (1) the presence of Ethylene glycol alone, (2) Ethylene glycol associated with HCl and Ethylene glycol associated with HCl and H2O2 working at different temperatures. Results revealed that the successive addition of Ethylene glycol, HCl, and H2O2 directly impacted Cu's recovery, while the temperature effect led to the best Cu recovery.
About 88.11% of Cu was recovered after 150 min when leaching with 2.5 M H2O2 at 45℃ with 50% ethylene glycol/Lix 984N-C and 2.5 M HCl with low entrainment of Fe (1%) as a sign of selective process throward Fe. However, the process was deemed less selective for Co since about 12.04% was entrained in the PLS. The outcomes of the kinetic investigation revealed that the limiting step in the optimum operating conditions was diffusion-controlled through the ash layer. The apparent activation energies were found to be 43,81, 31,68 and 137,7237 kJ/mol at 298 - 318 K for Cu recovery and the Co and Fe entrainment leading.
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Furthermore, experimental data were compared to theoretical data for validation to ascertain the kinetic investigation's outcomes. Based on the correlation R2 values of 0.8366, 0.7556 and 0.9221 for Cu dissolution and, Co and Fe entrainment, respectively, the experimental outcomes were considered satisfactory and indicated that the generated empirical equations could be used to forecast the leaching rate.