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Bonded-particle model calibration using response surface methodology

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Particuology 2017年第3期15卷 141-152页

作者： Sajjad Chehreghani Mohammad Noaparast Bahram Rezai sied ziaedin shafaei School of Mining University College of Engineering University of Tehran. 14395-515. Tehran Iran Department of Mining and Metallurgy Engineering. Amir Kabir University of Technology Tehran Iran

The bonded-particle model （BPM） is commonly used in numerical analysis of the mechanical behavior of rock samples. Constructing a BPM model requires specification of a number of microstructural parame- ters, including the parallel-bond tensile strength, parallel-bond cohesion strength, parallel-bond effective modulus, parallel-bond friction angle, and parallel-bond stiffness ratio. These parameters cannot be eas- ily measured in the laboratory or directly related to either measurable or physical material parameters. Hence, a calibration process is required to choose the values to be used in simulations of physical systems. In this study, response surface methodology along with the central composite design approach is used to calibrate BPMs. The sensitivities of the microparameters related to the uniaxial compressive strength （UCS） and elasticity modulus （i.e., the macroscopic responses of the models） are thoroughly scrutinized. Numerical simulations are performed to carefully assess the performance of the model. It is found that the elasticity modulus is highly correlated with the parallel-bond effective modulus. In addition, the parallel- bond tensile and cohesion strengths are the two most significant microparameters with a considerable effect on the UCS. The predicted values determined by the proposed approach are in good agreement with the observed values, which verifies the applicability of the proposed method.

关键词： Bonded-particle modelCalibrationResponse surface methodologyUniaxial compressive strength

Kinetics of magnetite oxidation under non-isothermal conditions

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International Journal of Minerals,Metallurgy and Materials 2017年第5期24卷 486-492页

作者： Aref Sardari Eskandar Keshavarz Alamdari Mohammad Noaparast sied ziaedin shafaei Department of Mining Engineering Science and Research BranchIslamic Azad University Department of Mining and Metallurgical Engineering Amirkabir University of Technology School of Mining Engineering University of Tehran

Oxidation of magnetite concentrates, which occurs during the pellet induration process, must be deeply understood to enable the appropriate design of induration machines. In the present paper, the kinetics of the magnetite oxidation reaction was studied. Primary samples were obtained from the Gol-e-Gohar iron ore deposit. Magnetic separation and flotation decreased the sulfur content in the samples to be approximately 0.1wt%. Thermogravimetric analysis was used to measure mass changes during the oxidation of magnetite and, consequently, the conversion values. The aim of this study was to use isoconversional methods to calculate the kinetic parameters. The Coats-Redfern method was also used to obtain the activation energy. Thermogravimetric analyses were run at three different heating rates. The Coats-Redfern results were too ambiguous for a meaningful interpretation. In the case of the isoconversional method, however, the mean activation energy and pre-exponential factor of the oxidation reaction were obtained as 67.55 kJ and 15.32 × 108 min−1, respectively. Such a large activation energy implies that temperature strongly affects the reaction rate. The oxidation reaction exhibits a true multi-step nature that is predominantly controlled by chemical reaction and diffusion mechanisms.

关键词： magnetite kinetics oxidation thermogravimetric analysis

Effects of nanobubble and hydrodynamic parameters on coarse quartz flotation

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International Journal of Mining Science and Technology 2019年第2期29卷 289-295页

作者： Sabereh Nazari sied ziaedin shafaei Mahdi Gharabaghi Rahman Ahmadi Behzad Shahbazi Fan Maoming School of Mining Engineering College of Engineering University of Tehran Department of Mining Engineering Imam Khomeini International University Mining Engineering Department Tarbiat Modares University EFD Eriez Manufacturing Co.

Quartz, the second most abundant mineral in the earth's crust, is a gangue mineral in practically every flotation process. Coarse quartz flotation has been a long standing problem in various mineral processing plants to reduce milling cost and increase valuable mineral recovery. Based on this, the effects of nanobubbles(NBs) and hydrodynamic parameters on coarse quartz particle flotation were systematically investigated. Mechanical flotation experiments were carried out using the 7 cm and 9 cm diameter impellers in order to produce different hydrodynamic conditions. 900–1300 rpm impeller speeds were used for the 7 cm diameter impeller and 554–786 rpm for the 9 cm diameter impeller. The results show that the presence of NBs increased the flotation recovery of à425 + 106 lm quartz by up to 21%. For the7 cm diameter impeller, the maximum flotation recoveries of 86.4% and 98% were obtained in the absence and presence of NBs at Reynolds number(Re) of 81,000 and 66,000, respectively. For the 9 cm diameter impeller, the maximum recoveries of 86.3% and 97.5% were obtained in the absence and presence of NBs at Re of 90,000 and 75,000, respectively. NBs increased the flotation rate constant up to 36%.

关键词： Flotation Nanobubbles Coarse particle Quartz Hydrodynamic parameters

Removal of copper from molybdenite concentrate by mesophilic and extreme thermophilic microorganisms

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International Journal of Mining Science and Technology 2013年第6期23卷 827-834页

作者： Abdollahi Hadi Manafi Zahra shafaei sied ziaedin Noaparast Mohammad Manafi Moorkani Navid School of Mining College of EngineeringUniversity of Tehran Sarcheshmeh Copper Complex Research and Development Centre

Mixed mesophilic and extreme thermophilic bioleaching were evaluated to remove copper from the molybdenite *** tests were carried out in shake flasks and in a 50-L *** shake flask tests were performed with different inoculum size,solids density,*** temperature in order to identify optimum *** highest amount of copper elimination,75%was obtained with extreme thermophilic microorganisms(at 12%inoculation,10%solids,65℃and a pH of 1.5).The highest copper elimination by mesophilic microorganisms was 55%(at 12%inoculation,5%solids,30℃at pH 2).The optimum conditions in shake flask tests were applied to 7 days batch tests in a50-L *** thermophilic experiment gave the best copper elimination of 60%(at 12%inoculation,10%solids,65℃and pH 1.5).Mesophilic test removed 50%of the copper(at 12%inoculation,10%solids,35℃at pH 2).

关键词： Bioleaching Molybdenite concentrate Copper removal Mesophilic and extreme thermophilic microorganisms

Extraction and stripping of Cu and Ni from synthetic and industrial solutions of Sarcheshmeh Copper Mine containing Cu, Ni, Fe and Zn ions

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Transactions of Nonferrous Metals Society of China 2020年第2期30卷 518-534页

作者： Amirhossein SOEEZI Hadi ABDOLLAHI sied ziaedin shafaei Esmaeil RAHIMI School of Mining engineering College of EngineeringUniversity of TehranTehranIran Department of Mining Engineering Islamic Azad UniversitySouth Tehran BranchTehranIran

The extraction and stripping of Cu and Ni ions from synthetic and industrial solutions of Sarcheshmeh Copper Mine containing Cu(770 mg/L),Ni(3200 mg/L),Fe(800 mg/L)and Zn(200 mg/L)were comprehensively investigated using D2 EHPA,LIX 984,Cyanex 302,Chemorex CP 150 and Acorga 5774 diluted in *** influential parameters such as mixing speed and time,concentration of extractant,p H and temperature were considered in extraction ***,stripping of Cu and Ni was examined using different inorganic and organic acids(sulfuric,hydrochloric,nitric and citric acids)with different *** results indicated that the highest extractions of Cu and Ni occurred within 3 min,with the mixing speed of 500 r/min,28℃and A/O ratio of 1:***,Cu was extracted by LIX 984 at the concentration of 10%(v/v),whereas Ni was extracted by Cyanex 302 at the concentration of 30%(v/v),*** optimal p H for Cu and Ni extraction is in ranges of 2-3 and 4-5,*** and Ni were selectively extracted with the recoveries of 85%,93%and 77%,82%from synthetic and industrial solutions containing Ni,Cu,Zn and Fe ions,*** results of optimal condition showed that 96%of Ni and 93%of Cu were stripped from the synthetic and industrial ***,four elements Zn,Fe,Cu and Ni were extracted in three stages with D2 EHPA,LIX 984 and Cyanex 302 extractants respectively with the least impurities.

关键词： solvent extraction nickel copper D2EHPA LIX 984 Cyanex 302

Modeling and optimization of low-grade Mn bearing ore leaching using response surface methodology and central composite rotatable design

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Transactions of Nonferrous Metals Society of China 2012年第9期22卷 2295-2305页

作者： Dariush AZIZI sied ziaedin shafaei Mohammad NOAPARAST Hadi ABDOLLAHI School of Mining University College of EngineeringUniversity of TehranTehranIran

The application of leaching process to extracting Mn from a low-grade manganese ore was investigated using a software based design of experiments. Four main parameters, i.e. sulfuric acid concentration, oxalic acid concentration, time and temperature were considered in a central composite response surface design. The recoveries of Mn and Fe were selected as response of design. The optimum conditions under which the Mn and Fe recoveries were the highest and the time and temperature were the lowest were determined using statistical analysis and analysis of variance （ANOVA）. The results showed that Mn and Fe recoveries were 93.44% and 15.72% under the optimum condition, respectively. Also, sulfuric acid concentration was the most effective parameter affecting the process. The amounts of sulfuric and oxalic acid were obtained to be 7% and 42.50 g/L in optimum condition and the best time and temperature were 65 min and 63 ℃.

关键词： response surface methodology leaching manganese optimization modeling

A mathematical model to simulate Heap(bio)-leaching process:An exact conceptual model,Homotopy theory and comparative insights with conventional methods

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International Journal of Modeling, Simulation, and Scientific Computing 2017年第1期8卷 271-296页

作者： M.Yaghobi Moghaddam S.Z.shafaei tonkaboni M.Noaparast F.Doulati Ardejani School of Mining College of Engineering University of TehranP.O.Box 14395-515TehranIran

This paper attempts to address some nonlinear differential equations which describe main mechanisms governing heap(bio)leaching process as an important metallurgical facility in mining and mineral processing *** Homotopy Perturbation Method(HPM),Finite Volume Method and Analytical(Laplace)Method have been employed to provide proper solutions for these *** was made between the methods and agreement was close;considering the fact that the proposed solution in comparison with the others provided a remarkable accuracy in dealing with nonlinear problems associated with mining and mineral processing *** maximum error of HPM in relation to the analytical solution was *** numerical finite volume method incorporating a computational fluid dynamics model termed PHOENICS provided rational and accurate results;describing that many chemical and biological processes extremely affect the transportation mechanism of the aqueous compounds in a heap structure and subsequently on the process ***,all solution methods presented to simulate heap leaching process provided valuable information related to the time dependence concentrations of dissolved *** results obtained from this study can be effectively applied to manage the heap leaching costs to make the process feasible.

关键词： Diffusion-advection-reaction equations nonlinear problems Homotopy perturbation method finite volume method analytical solution Heap(bio)-leaching