TN951 : Feasibility investigation of copper recovery from oxide part of Nasim copper mine using acid leaching and solvent extraction
Thesis > Central Library of Shahrood University > Mining, Petroleum & Geophysics Engineering > MSc > 2020
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Abstarct: This research is focused on the feasibility of leaching process of copper from the oxide section of Nasim copper mine (Bardaskan) and its recovery from the leaching solution using solvent extraction process. In the leaching step, firstly the influence of operating important parameters including sulfuric acid concentration, liquid/solid ratio, pulp mixing rate, temperature, and contact time was investigated on the recovery of copper and then the optimum conditions of parameters and their interaction effects were determined using response surface methodology. In addition, the dissolution kinetics of copper baxsed on the shrinking core models was studied to further investigate the behavior of leaching process. The results demonstrated that the dissolution time and temperature had the largest influence and the linear impact of stirring speed had the least degree of importance on the recovery of copper. Also, the recovery of copper was strongly influenced by the interaction effects of liquid to solid ratio with temperature and stirring rate with leaching time. Process optimization was performed utilizing the desirability function approach and it was found that more than 88.17% copper was recovered at the optimum conditions: ~ 17% acid concentration, ~ 11.3 mL/g liquid/solid ratio, ~ 390 rpm stirring speed, 50 °C temperature, and 60 min leaching time. Under these conditions, the sulfate solution with copper content of 2083 mg/L was achieved. The leaching kinetic study indicated that diffusion through product laxyer was the dissolution rate controlling step with the activation energy of 28.92 kJ/mol. In solvent extraction stage, the extraction behavior of copper from sulfate leaching solution was investigated using Acorga M5640 commercial extractant in kerosene diluent. The effects of important factors such as the extractant concentration, extraction time, solution pH, and temperature were examined on the separation factor Cu/Fe and the extraction efficiency of copper. The findings indicated that about 92.32% copper was extracted from the leach liquor at 10% (v/v) Acorga M5640 concentration, 1:1 aqueous/organic phase ratio, 20 min contact time, pH 2.5, and 25 °C temperature. Also, the further increase in the values determined had no positive impact on the extraction of copper. In these conditions, the separation factor Cu/Fe was obtained about 29.64. The extraction mechanism was studied applying the plot of log(D) – 2 pH against log [extractant] and it confirmed the association of two moles of Acorga M5640 for the extraction of one mole of copper. McCabe–Thiele diagram was constructed and a single-step extraction process was found to obtain the maximum extraction. Additionally, thermodynamic data were investigated and it was distinguished that the extraction process was endothermic and non-spontaneous at 298 K. Ultimately, the loaded organic phase was stripped and 80.94% copper was recovered after 20 min using 10% sulfuric acid concentration.
Keywords:
#Copper recovery #Leaching kinetics #Response surface methodology #Extraction efficiency #Separation factor #Acorga M5640 extractant #Thermodynamic studies Keeping place: Central Library of Shahrood University
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