Department of Mineral Processing (2010 - Present)
Metallurgy and Materials Engineering
, Laval University, Quebec, Canada
Mining Engineering - Mineral Processing
, University of Tehran, Iran
Mining engineering, mining exploration
, University of Tehran, Iran
Research field:
Expert:
Phone:
Address:
Dr Mohammad Reza Khalesi, born in Tehran, 1977, is a graduate of University of Tehran in Mining exploration (B.Sc.) and Mineral processing (M.Sc.) and hold a PhD in material and metallurgy from Laval University, Canada. He is a member of Iranian Society of Mining Engineering (vice president from 2016 to 2019) and a member of Canadian Institute of Mining, Metallurgy and Petroleum (CIM) from 2005. He is mostly focused on modeling, optimization and control of mineral processing and extractive metallurgy systems.
In the most important models of continuous tank leaching process, residence time distribution and particle size distribution are considered independently. While the studies by some researchers has shown that particle size distribution affect the residence time in the tank. However, no systematic study has been conducted on this issue yet. In this research, while studying the relationship between particle size and residence time, an empirical method for determining of residence time distribution based on inflow size composition to the agitated tank was presented. The relationship between average size of one size fraction of particles and its residence time was obtained by mean residence time and parameter (the slop of a fitted line to the da
In this study, precipitated calcium carbonate (PCC) has been produced using a semi-continuous carbonation process within Ca(OH)2(s)-CO2(g)-H2O system inside a bench-scale reactor. In order to understand the effect of temperature, solid percent of the milk of lime (MOL), CO2 gas injection rate, agitation rate on the conductivity, the specific surface area, microporous surface area (and subsequently agglomeration), and reaction termination time, an experimental procedure was used based on a central composite design (CCD). The conductivity and pH were applied as the parameters controlling the reaction termination time. Using the data obtained from the multiple regression analysis, the effect of the parameters on the above-mentioned responses w
In this study, a simplified dissolution model has been developed to evaluate the performance of continuous leaching reactors. The model considers continuous reduction of the surface area of particles using the distribution of their size and residence time. The model was validated by the bioleaching of a pyrite-arsenopyrite concentrate in the pilot plant scale, which resulted in good agreement between the experimental data and the predicted values. The developed model was also used to predict the outlet mass density function of particles, whose results showed that the mean particle size would not necessarily decrease as the mean residence time in the leaching process decreased. Using this model, the effect of operating parameters (e.g., part
This study aimed to introduce a new approach to determine the mass transfer rate constant in a laboratory column flotation through an analogy to a mass transfer process. The RTD of the column at two separate bubble sizes were modeled using both conventional N-mixer and N-mixer with back-mixing flow models. The number of perfect mixers (N) and the corresponding backflow coefficients (λ) were optimized using MINLP solver in MATLAB environment where N?=?5 with λ?=?0.567 at the bubble size of 1.8?mm and N?=?8 with λ?=?0.643 at the bubble size of 0.8?mm were obtained. The bubble active surface coefficient was introduced as a new parameter to study the flotation kinetics. Thus, the mass transfer rate constant was determined for various operati
In this study, the effect of various ions with different radius and charge such as aluminum, calcium, and iron on the selective ion flotation of neodymium using sodium dodecyl sulfate as a collector was investigated. Firstly, the optimum conditions of neodymium ion flotation were determined by evaluating the main factors on the process efficiency including collector dosage, air flowrate, and pH. The optimum conditions for ion flotation of neodymium are as following: collector dosage?=?21?× 10−4?M, air flow rate?=?100 mL/min, and pH?=?3 with 85.4% and 26.5% recovery for neodymium and water, respectively. Then, the effect of other ions on the ion flotation of neodymium was evaluated.
Multivariable nature of the flotation process compels advanced control strategies, including Model Predictive Controllers (MPC), leading to robust and effective compensation of disturbances. However, the complexity of calculations and implementation has limited their application in the industry. On the other hand, decoupling methods promise drastic reduction in computation time and complexity, while considering the multivariable relations between the inputs and outputs indirectly. Therefore, in this paper, an Adaptive Decoupling Controller (ADC) was designed and implemented on a pilot flotation column and its control performance was compared to MPC and SISO PID. Results showed that the weak coupling of variables in the studied case (and als
Copper oxide minerals such as malachite do not respond well to the traditional copper sulfide collectors, and require alternative flotation schemes. In many copper ore mines, significant copper oxide minerals, especially malachite, are associated with sulfide minerals. Considering that xanthates are most widely used in the flotation of sulfide minerals as well as copper sulfide minerals and, hydroxamate has shown a good selectivity for copper oxide minerals. Use of the synergistic effect of xanthate and hydroxamate can be an effective way to increase the flotation efficiency of copper oxide minerals along with sulfide minerals. In this work, we investigate the individual interactions of potassium amyl xanthate (PAX) and potassium alkyl hydr
Copper oxide minerals such as malachite do not respond well to the traditional copper sulfide collectors, and require alternative flotation schemes. In many copper ore mines, significant copper oxide minerals, especially malachite, are associated with sulfide minerals. Considering that xanthates are most widely used in the flotation of sulfide minerals as well as copper sulfide minerals and, hydroxamate has shown a good selectivity for copper oxide minerals. Use of the synergistic effect of xanthate and hydroxamate can be an effective way to increase the flotation efficiency of copper oxide minerals along with sulfide minerals. In this work, we investigate the individual interactions of potassium amyl xanthate (PAX) and potassium alkyl hydr
In the current research, isothermal experiments of kinetic analysis were performed at different temperatures (800–1050 C) and particle sizes (885 to 10,763 μm) to investigate the calcination kinetics of high-purity limestone. Thermal analyses were carried out in a zirconia crucible, 1 cm in height, for different temperatures and particle sizes. The reaction rate coefficients were varied in the 2.2? 10− 5-1.62? 10− 3-m 0.6. s− 1 range. Moreover, various isothermal kinetic analysis methods were applied to assess the decomposition mechanism and the calcination function governing the process. The modified shrinking core model was found as the best representation of the high-purity limestone kinetic data. The activation energy was evalu
Fluorescent powder contributes to almost 3% of CFLs, containing a big portion of Rare Earth Elements such as Yttrium and Europium. These lamps are not recycled for the REEs although they could be a secondary source. In this research, leaching and precipitation of Yttrium and Europium by Hydrochloric and Oxalic acid from the fluorescent powder was targeted. By measuring the pH variations, the optimized temperature, reaction time, acids’ concentrations and the ratio of solid to liquid were determined. Moreover, in precipitation stage, effect of gel rinse on purification of Eu and Y was investigated. Results showed that temperature of 70 0C, reaction time of 30 minutes, 15 g/L acid of 0.3 molar were optimum conditions in leaching stage. Maxi
Determination of liberation spectrums by using MLA and QEMSCAN techniques require polished sections and fine particles. These techniques cannot be performed in-situ and for coarse particles. Thus, the focus of this technical note is to investigate whether the image analysis method can be used for the determination of liberation spectrum for coarse particles. Two methods were used to determine the liberation spectrum. In the first method, the liberation spectrum was obtained using the small and large diameter of particles. In the second method, the liberation spectrum was determined using the small and large diameter of particles as well as the shape correction diameter. The results showed that the image analysis can be used to successfully
In mineral processing, liberation of valuable mineral from gangue minerals is the most important stage before the concentration process. Comminution, which leads to liberation, includes two types of random and non-random breakages. The contribution of random and non-random breakage is very important in modelling the liberation phenomenon. In this paper, a simulator based on 2D Voronoi tessellation is introduced which can simulate random, preferential and detachment breakages of binary ores (valuable and gangue mineral). This simulator has been validated by image analysis of fragmented artificial ores which were made in different grades and comminuted in different energy levels by a drop weight device. The data obtained from images of commin
Milk of lime (MOL) suspension is widely utilized in many industries; however, in some of the applications, such as the production of precipitated calcium carbonate (PCC), the suspension must be of high purity and quality. In other words, the amounts of iron and magnesium should be so little so that the final PCC product would be of high quality. The effects of initial temperature, quicklime particle size, amount of initial solid present, agitation rate, and time on the recovery of hydrated lime and iron/magnesium reduction efficiency were investigated through a central composite design (CCD) of experiments. The iron reduction efficiency and the weight recovery of hydrated lime were obtained as 91% and 98.5%, respectively. The reduction of m
Loading and hauling represent an important part of open pit mines production cycle and account for a considerable share of the total operating cost. The decision making during mine planning requires suitable and quick cost models. This paper intends to develop a model for estimating the capital and operating cost of major loading and haulage equipment used in the open pit mining, applying single (SRA) and multiple regression analysis (MRA). The MRA is based on Principal Component Analysis (PCA). The equipment include classical loading vehicles including hydraulic and cable shovels, wheel loader and backhoe along with rigid rear dump truck. Cost functions are classified on the basis of cost types; ie capital and operating costs. Furthermore,
Loading of particles on a bubble is the result of a successful collision, attachment, and balancing of the forces between particles and the bubble. In this study, a mathematical model to estimate the bubble loading was developed based on the force balance on the lowest particle attached to the bubble. Gravity, buoyancy, hydrostatic pressure, viscous drag, capillary, and capillary pressure induced forces were taken into account in the model. The resultant force of the tangential components of the normal force applied by particles on top of the lowest particle and the viscous drag exerted on the attached particles by the surrounding fluid is balanced with other forces to predict whether detachment of the lowest particle occurs or not. The mod
Abstract The synthesis of thorium silicate (thorite) was carried out to characterize the parameters affecting the process. A synthetic thorite with formula ThSiO4 was prepared by hydrothermal method with a mixture of 0.14 M thorium chloride (ThCl4) solution and sodium silicate containing 0.14 M SiO2. The effect of several experimental parameters on synthesis of thorite was investigated. The most important of these parameters were the pH of solution in hydrothermal process and volumetric ratio of SiO2 : ThCl4. The optimum pH in the hydrothermal process was 8–9, which was obtained by buffering with sodium bicarbonate. The increasing of volumetric ratio of SiO2 : ThCl4 led to gelatinization of synthetic mater
The consumption of cyanide during processing operations is a major economic cost in the extraction of gold from its ores, while the discharge of cyanide wastes may result in significant environmental pollution. Many factors influence the levels of consumption and discharge of cyanide, including ore mineralogy and lixiviant solution chemistry. This paper proposes a robust methodology to estimate leaching cyanide consumption due to oxidation and reactions with gold, chalcopyrite and pyrite minerals forming various cyanide complexes, cyanate, thiocyanate and hydroxide precipitates of copper and iron. The method involves concurrent modelling of both the oxidation and leaching kinetics of minerals and the chemical speciation of the lixiviant sol
Isobaric volumetric heat capacities of aqueous solutions of K4Fe(CN)6, K3Fe(CN)6, K3Co(CN)6, K2Ni(CN)4, and KAg(CN)2 have been measured at 298.15 K over the approximate concentration range 0.02 to 0.4 mol?kg–1 using a Picker flow calorimeter. These data were combined with measured densities to calculate the corresponding apparent molar isobaric heat capacities, Cpϕ. The values so obtained were fitted as a function of concentration using an extended Redlich–Rosenfeld–Meyer-type equation to provide the standard state (infinite dilution) quantities, Cpϕo, for each salt. The Cpϕ values for all the salts studied showed similar dependences on concentration, with a slight upward curvature at higher molalities, possibly due to anion aggreg
no record found