Hydrometallurgy Research Unit

Iranian, Iran

Hydrometallurgy Research Unit

Iranian, Iran
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Moghaddam M.Y.,University of Tehran | Shafaei S.Z.,University of Tehran | Noaparast M.,University of Tehran | Ardejani F.D.,University of Tehran | And 4 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2015

The copper extraction in shaking bioreactors was modeled and optimized using response surface methodology (RSM). Influential parameters in the mesophilic bioleaching process of a low-grade copper ore including pH value, pulp density, and initial concentration of ferrous ions were comprehensively studied. The effect of leaching time on the response (copper extraction) at the 1st, 4th, 9th, 14th and 22nd days of treatment was modeled and examined. The central composite design methodology (CCD) was used as the design matrix to predict the optimal level of these parameters. Then, the model equation at the 22nd day was optimized using the quadratic programming (QP) to maximize the total copper extraction within the studied experimental range. Under the optimal condition (initial pH value of 2.0, pulp density of 1.59%, and initial concentration of ferrous ions of 0 g/L), the total copper extraction predicted by the model is 85.98% which is significantly close to that obtained from the experiment (84.57%). The results show that RSM could be useful to predict the maximum copper extraction from a low-grade ore and investigate the effects of variables on the final response. Besides, a couple of statistically significant interactions are derived between pH value and pulp density as well as pH value and initial ferrous ion concentration which are precisely interpreted. However, there is no statistically significant interaction between the initial ferrous ion concentration and the pulp density. Additionally, the response at optimal levels of pH value and pulp density is found to be independent on the level of initial ferrous concentration. © 2015 The Nonferrous Metals Society of China.


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.


Lotfalian M.,Shahid Bahonar University of Kerman | Schaffie M.,Shahid Bahonar University of Kerman | Darezereshki E.,Shahid Bahonar University of Kerman | Manafi Z.,Hydrometallurgy Research Unit | Ranjbar M.,Shahid Bahonar University of Kerman
Geomicrobiology Journal | Year: 2012

Bacterially assisted heap leaching is an economical technology for treating low grade copper sulphides. In the present research, bioleaching of low grade chalcopyrite ore (1% chalcopyrite, and 3% pyrite) have been investigated using moderate thermophilic bacteria. The ore sample has low solubility in acid solution (about 5%). Experiments were carried out using column reactors and the effect of particle size (-12.7, -19.07 and -25.04 mm) and external addition of carbon dioxide to the induced air (10% v/v) have been investigated. Results have shown that the copper recovery increased with reducing particle size, and carbon dioxide addition improved bacterial activity and copper dissolution. In the optimum condition, i.e., particles finer than 12.07 mm and 10% (v/v) carbon dioxide addition, 69.68% of copper were extracted. © 2012 Copyright Taylor and Francis Group, LLC.


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.


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.


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.


Darezereshki E.,Shahid Bahonar University of Kerman | Darezereshki E.,Energy and Environmental Research Center | Schaffie M.,Energy and Environmental Research Center | Schaffie M.,Shahid Bahonar University of Kerman | And 3 more authors.
International Journal of Minerals, Metallurgy and Materials | Year: 2011

Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leachingof the ore. Sulfuric acid solution with a flow rate of 3.12 L.m-2.h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overallextractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and90 d, respectively. It was concluded that crushing and agglomeration of the ore using acteria could enhance the copper extraction considerably. © University of Science andTechnology Beijing and Springer-Verlag Berlin Heidelberg 2011.


Lotfalian M.,Shahid Bahonar University of Kerman | 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
Geomicrobiology Journal | Year: 2015

The main objective of the present study was to investigate the continuous bioleaching of chalcopyrite concentrate at a high pulp density by moderate thermophilic microorganisms. Using a flotation concentrate containing 46% chalcopyrite and 23% pyrite, bioleaching tests were carried out at a high pulp density (15%) and temperature of 47°C using a setup consisting of three continuous stirred tank bioreactors in series. A two-level full factorial design of experiments was used to assess the effects of residence time, particle size and acidity of the leaching solution on the copper recovery. From the results of these tests, we concluded that under the best process conditions (d80) = 30 μm, T = 47°C, and acidity of 130 (kg/ton) more than 54% of copper was extracted from the concentrate after 7 days. Also, the concentration of copper in the final solution was higher than 20 g/L. © 2015, © Taylor & Francis Group, LLC.


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.

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