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Bakhtiari F.,Shahid Bahonar University of Kerman | Zivdar M.,University of Sistan and Baluchestan | Atashi H.,University of Sistan and Baluchestan | Seyedbagheri S.,Hydrometallurgy Research Unit
Journal of the Chemical Society of Pakistan | Year: 2010

Bioleaching of the copper flue dust of the smelting furnaces of Sarcheshmeh Copper Complex has been investigated. At present, the dust is recycled to the smelters, which reduces their efficiencies and increases the required energy for the smelting process. In this study, the bioleaching performance of two continuous systems consisting of a two-stage aerated stirred tank, and a series of two-stage airlift bioreactors were compared. Comparison has also been made with shake flask tests. The parameters which have been studied include oxidation-reduction potential (ORP), pH, copper and iron concentration, and the effect of pulp densities and time on the bioleaching of copper dust. With the pulp densities of 20 g/L and 40 g/L, both reactor systems have shown a stable redox potential. Copper recoveries for the pulp densities of 20, 40 and 70 g/L in the stirred tank series with retention times of 2.7, 4 and 6 days, were 91.8%, 90.3% and 87.6% respectively. Copper recoveries for the airlift series with the same pulp densities, and with retention times of 2.7, 4, and 5 days, were 90.1%, 89%, and 86.1%, at 32 °C, respectively. The shake flask recoveries for the same pulp densities after 23 days were 85.5%, 85.2% and 70.1%, respectively. The results show that the performance of the two bioreactor systems is nearly similar, and both series of bioreactors had better performance than shake flasks.

Mahmoudian A.R.,Sharif University of Technology | Sadrnezhaad S.K.,Sharif University of Technology | Manafi Z.,Hydrometallurgy Research Unit
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2014

A heat-transfer model was formulated to determine the distribution of temperature within a bioheap of chalcopyrite of Sarcheshmeh copper mine. Bioleaching employs mixed mesophilic and thermophilic microbes for Cu extraction. Thermophiles are better than mesophiles to dissolve CuFeS 2. The solution irrigation and aeration rates were taken into account as the main operational factors. The model was validated by comparing the temperature profiles of test columns with those of bioheap. The model was used to find the optimal ratio of irrigation to aeration. It was found that when the solution was fed at a flow rate of 5 kg/m2 h and air was blown at a flow rate of 7.5 kg/m2 h, the transition from a mesophilic to thermophilic state inside the heap was possible. In this situation, the maximum temperature rise inside the heap was about 332 K (59 °C) after 60 days. © 2014 The Minerals, Metals & Materials Society and ASM International.

Vakylabad A.B.,Shahid Bahonar University of Kerman | Schaffie M.,Shahid Bahonar University of Kerman | Naseri A.,Sarcheshmeh Copper Complex | Ranjbar M.,Shahid Bahonar University of Kerman | Manafi Z.,Hydrometallurgy Research Unit
Hydrometallurgy | Year: 2016

The present research work describes a facile and industrial-friendly procedure for producing high quality CuO nano-powder from a PLS of a low-grade chalcopyrite-ore bioleaching. The PLS containing lower than about 1 g Cu/L (obtained from the ore bioleaching) was used as the feed for the procedure in which firstly the iron and other impurities was removed from the PLS, and next the pure copper-ammonia complex was selectively formed from the PLS. Then, the complex was transformed to the precursor (Copper Hydroxide Sulfate Hydrate (Cu2.5(OH)3(SO4)·(H2O)2)) at the room temperature. Finally, the precursor was dried at 60°C overnight to obtain pure CuO nano-powder (average crystalline size of about 19 nm). The results were confirmed by the characterization analyses: XRD, SEM/EDS, elemental mapping, TEM, FTIR, chemical analyses, and XRF. © 2016 Elsevier B.V. All rights reserved.

Yaghobi Moghaddam M.,University of Tehran | Ranjbar M.,Shahid Bahonar University of Kerman | Manafi Z.,Hydrometallurgy Research Unit | Schaffie M.,Shahid Bahonar University of Kerman | Jahani M.,University of Tehran
Minerals Engineering | Year: 2012

Modeling and optimizing process parameters, initial pH, pulp density, and initial concentration of ferrous ions by bacterial leaching to increase copper extraction from a low-grade ore of Sarcheshmeh Copper Complex was studied as an empirical model. Optimum conditions to achieve maximum total copper extraction were initial pH 2.0 and pulp density 1.59% without adding ferrous ions. In these conditions, model prediction for total copper extraction was 85.98%, higher than any value obtained in conducted experiments. © 2012 Elsevier B.V. All rights reserved.

Lotfalian M.,Kerman Graduate University of Technology | Ranjbar M.,Shahid Bahonar University of Kerman | Fazaelipoor M.H.,Shahid Bahonar University of Kerman | Schaffie M.,Shahid Bahonar University of Kerman | Manafi Z.,Hydrometallurgy Research Unit
Minerals Engineering | Year: 2015

A continuous bioleaching process was developed for the dissolution of chalcopyrite concentrate with electrochemically redox control. Therefore, using a flotation concentrate containing 46% chalcopyrite and 23% pyrite, bioleaching tests were carried out at 47 °C with 15% pulp density under controlled and uncontrolled redox conditions. To increase the copper recovery in contrast to the conventional bioleaching (∼39.62%), the effect of redox potential on the chalcopyrite bioleaching was investigated by electrochemically controlled bioleaching. The results showed that by controlling the redox potential, faster copper leach kinetics could be achieved. At last, reducing the redox potential from high levels to optimum window (420-440 mV SCE) caused an increase in copper recovery from around 39% to higher than 69% (over 25 g/L Cu2+). © 2015 Elsevier Ltd. All rights reserved.

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