Mineral Processing
Zehra Khan; ABHISHEK SHARMA
Abstract
Due to rapid growth in infrastructure sector, the construction of high-rise buildings is becoming very popular among all the countries. Engineers face significant issues with high rise buildings, particularly in terms of structural and foundation aspects. Many old design approaches can't be used with ...
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Due to rapid growth in infrastructure sector, the construction of high-rise buildings is becoming very popular among all the countries. Engineers face significant issues with high rise buildings, particularly in terms of structural and foundation aspects. Many old design approaches can't be used with certainty since they involve extrapolation far beyond the domains of existing experience, hence structural and geotechnical engineers are being compelled to use more advanced analysis and design methodologies. The current study is an attempt to predict the bearing capacity and settlement behavior of piled-raft footing when embedded into cohesionless deposit. The numerical analysis has been carried out to examine the effect of numerous key parameters of pile and raft such as pile length (10, 15, 20 m), pile diameter (0.3, 0.4, 0.5 m), pile number (16, 20, 24), pile spacing (2D, 3D, 4D) (where “D” is diameter of the pile), raft thickness (0.4, 0.5, 0.6 m), and angle of internal friction of soil (25°, 30°, 35°) on load-settlement behavior of the piled- raft foundation using ABAQUS software. A constant spacing between the piles, i.e. 3D was used throughout the analysis. The results of numerical investigation revealed an improvement in bearing capacity and a reduction in settlement value on increasing length, diameter and number of piles and also with increasing angle of internal friction. The current study not only increases the bearing capacity of the foundation but provides a cost-effective foundation technique to engineers.
Mineral Processing
SATYA SAI SRIKANT; RAGHUPATRUNI BHIMA RAO
Abstract
The present paper deals with the development of process flowsheet for recovery of high-grade graphite from rougher graphite concentrate for use in industrial applications. In the present investigation, since the coarser graphite flakes have a higher demand, an attempt is made at every stage of comminution, ...
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The present paper deals with the development of process flowsheet for recovery of high-grade graphite from rougher graphite concentrate for use in industrial applications. In the present investigation, since the coarser graphite flakes have a higher demand, an attempt is made at every stage of comminution, and flash flotation experiments have been carried out, and the end product obtained by stage comminution followed by flotation has been further subjected to alkali pressure leaching followed by grinding and flotation to recover industrial grade graphite concentrate. During this stage grinding, an additive, a depressant that is being used for depression of silica during flotation, has been used as grinding aid. The data indicates that at any given time of grind, the effect of grinding aid is significantly better as far as the separation efficiency of graphite. Hence, it is concluded that excessive size reduction of graphite is minimised while using a grinding aid. Based on these observations, further studies have been planned for flash flotation using a comminution circuit with grinding aids. The results of the present study reveals that number of cleaning of rougher concentrate alone will not fetch more than 75% of fixed carbon (FC) with less than 8% yield and 41% recovery. The effect of four stage cleanings continued with starvation dosage in grinding circuit followed by flash flotation indicate that the end product achieved contains 97.8% FC with 11.6% yield and 78% recovery and the overall values loss in tailings contain 3.6% FC. The end product achieved by alkali digestion method from a flotation product [97.8% FC] contains 99.2% FC with overall 10.4% yield and 71% recovery. The process adopted in the present investigation is friendly environment and process flowsheet is an innovative. The end product obtained from this process is useful for various industrial applications.
Mineral Processing
Chol Ung Ryom; Kwang Hyok Pak; Il Chol Sin; Kwang Chol So; Un Chol Han
Abstract
Scheelite ore with heavy and magnetic minerals can be generally concentrated using shaking table centered gravity-magnetic processing. When magnetic field is formed by fixing magnetic bars on which permanent magnets are arranged at a constant interval, above the table desk, heavy scheelite particles ...
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Scheelite ore with heavy and magnetic minerals can be generally concentrated using shaking table centered gravity-magnetic processing. When magnetic field is formed by fixing magnetic bars on which permanent magnets are arranged at a constant interval, above the table desk, heavy scheelite particles can be concentrated by gravity, whereas heavy magnetic mineral particles can be floated off like light mineral particles by upward magnetic force. In this paper, concentration of scheelite and removal of pyrrhotite floated by magnetic force was simulated using CFD for the sample containing 1% scheelite and 2% pyrrhotite, and compared with the experiment. As a result, WO3 grade and separation efficiency of concentrate were 65.3% and 80.1%, respectively, in the new table equipped with magnetic bars, whereas 28.4% and 76.5%, respectively, in conventional table. The magnetic field formed by fixing magnetic bars above table could be significant in simplifying the sequential tabling-magnetic separation process and reducing the loss of scheelite.
Mineral Processing
nooshin navi; Mohammad Karamoozian; Mohammad Reza Khani
Abstract
Red mud is an important solid tailing with strong alkalinity that is obtained during the extraction of alumina in the Bayer process. The global reserve of red mud is more than 4 billion tons, and its disposal as tailing has always been a serious environmental problem. This tailing is considered as a ...
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Red mud is an important solid tailing with strong alkalinity that is obtained during the extraction of alumina in the Bayer process. The global reserve of red mud is more than 4 billion tons, and its disposal as tailing has always been a serious environmental problem. This tailing is considered as a potential source, due to its high content of valuable metal compounds including iron. In this research work, the extraction of iron in red mud is investigated by the method of reduction roasting. The main influencing factors are also investigated. These methods include reduction in muffle and tube furnace, and temperature, reduction agent, and additive type are as important factors. Reduction roasting of the samples in a tube furnace, with Argon gas and vacuum, a mixture of red mud, graphite, and sodium carbonate at 700–1000 °C results in the formation of Fe3O4. Magnetic measurements indicate that saturation magnetization increases from 0.239 to 38.205 emu/g due to the formation of Fe3O4. Applying the magnetic field intensity of about 1000 Gauss results in the iron recovery of 89.9%.
Mineral Processing
Pedram Ashtari; Saeid Karimi; Seyyede Atefeh Hosseini
Abstract
In this research work, the reductive leaching of pyrolusite in a sulfuric acid medium with the aid of orange peel as a reductant was investigated. The important parameters affecting the leaching process include temperature in the range of 25 to 95 °C, the weight ratio of reducing agent to pyrolusite ...
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In this research work, the reductive leaching of pyrolusite in a sulfuric acid medium with the aid of orange peel as a reductant was investigated. The important parameters affecting the leaching process include temperature in the range of 25 to 95 °C, the weight ratio of reducing agent to pyrolusite (R/P) in the range of 0 to 2 (w/w), and the concentration of sulfuric acid in the range of 0.05 to 0.25 M. According to the results, the parameters of temperature and the R/P are more significant in the reductive leaching process. With increasing temperature from 25 to 95 °C, Mn recovery increases from 0.5% to 52.5%. Also Mn recovery with a two-step increase in 0-0.1 and 0.1-1.5 of the R/P indicates a jump of 28.5% and 19.0%, respectively. Sulfuric acid concentration shows its effect by supplying sulfate and hydrogen ions in the leaching process. The successful use of orange peel as a reductant was confirmed by achieving a manganese dissolution efficiency of 98.1% under optimum conditions (temperature of 90 °C, sulfuric acid concentration of 0.1 M, and R/P ratio of 1.5 (w/w)). Kinetic investigations showed that the shrinking core model could not be used to determine the leaching mechanism of pyrolusite in the presence of fruit peel reductant. Avrami's kinetic model with very high fitting accuracy was used to determine the kinetic model of pyrolusite leaching.
Mineral Processing
Ali Nikouei Mahani; Mohammad Karamoozian; Mohammad Jahani Chegeni; Mohammad Mahmoodi Meymand
Abstract
Generally, mineral processing plants generate a large quantity of waste in the form of fine particles. The flotation speed of mineral microbubbles by coarse bubbles is dramatically higher than that of individual particles. The advantage of microbubbles is due to the increase of binding efficiency of ...
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Generally, mineral processing plants generate a large quantity of waste in the form of fine particles. The flotation speed of mineral microbubbles by coarse bubbles is dramatically higher than that of individual particles. The advantage of microbubbles is due to the increase of binding efficiency of conventional bubbles with fine particles coated with microbubbles. Here, the focus is on reducing chemicals consumption and improving recovery. After preparing a representative sample, XRF, XRD, and mineralogical analyses were performed. Then 50 experiments were selected by experimental design using the response surface method (RSM), and in the form of central Composite design (CCD) by (design expert) DX 13 software. The interactions of collector consumption, frother agent, pH, particle size, and solid percentage were investigated, and 25 experiments using typical flotation and without nano-microbubbles and others with nano-microbubbles were conducted. The laboratory standard limit of the collector used in the pilot plant of the Sarcheshmeh Copper copper complex is 40 g/t (25 g/t of C7240 plus 15 g/t of Z11). Here, by consuming 20 g/t of collector in the absence of nanomicrobubbles, a recovery of 79.96% and in the presence of nanomicrobubbles, a recovery of 80.07% was obtained, that is a 50% reduction in collector consumption and a 0.11% increase in recovery was observed. Also the laboratory standard limit of frother used in the pilot plant of Sarcheshemeh Copper Complex is 30 g/t (15 g/t of MIBC plus 15 g/t of A65). Here, by using 10 g/t of frother in the absence of nanomicrobubbles, a recovery of 78.12%, and in the presence of nanomicrobubbles, a recovery of 82.05% was obtained. In other words, a decrease of 66.6% in the consumption of frother and an increase of 1.93% in recovery was observed.
Mineral Processing
Aghil Haghdadi; Sima Mohammadnejad
Abstract
The presence of copper bearing minerals in cyanidation of gold ores may lead to several challenges in the CIP/CIL circuits. Many solutions have been proposed to address these problems, one being the use of glycine in the cyanidation process. Here, the experimental as well as molecular modelling studies ...
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The presence of copper bearing minerals in cyanidation of gold ores may lead to several challenges in the CIP/CIL circuits. Many solutions have been proposed to address these problems, one being the use of glycine in the cyanidation process. Here, the experimental as well as molecular modelling studies using Density Functional Theory (DFT) have been conducted to investigate the glycine role in cyanidation of copper bearing gold ores. The results show that in the presence of glycine in the solution containing copper-cyanide species and in very low or zero free cyanide content, the dissolution rate of gold is significantly improved (3.02 vs. 0.23 ppm), while no improvement is observed in copper free or cyanide enriched solutions. Molecular modeling has been performed to interpret the laboratory results as well as to identify the mechanisms. The modeling results demonstrate that in cyanide deficient solutions, cyanide complex of copper complexes (E = -319 kCal.mol-1) is replaced by glycine, and the free cyanide produced results in higher gold cyanidation as well as lower copper cyanide formation.
Mineral Processing
M. Diab; M. Abu El Ghar; I. Mohamed Gaafar; A. H. Mohamed El Shafey; A. Wageh Hussein; M. Mohamed Fawzy
Abstract
In this work we are concerned with the potentiality of using mineral processing for raising the grade of the valuable heavy minerals (VHMs) from the Quaternary stream sediments of Wadi and Delta Sermatai located on the southern coast of the Red Sea, Egypt. A rigorous understanding of the chemical and ...
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In this work we are concerned with the potentiality of using mineral processing for raising the grade of the valuable heavy minerals (VHMs) from the Quaternary stream sediments of Wadi and Delta Sermatai located on the southern coast of the Red Sea, Egypt. A rigorous understanding of the chemical and mineralogical characteristics of the studied samples is a prerequisite for the selection and development of the physical processing used in order to produce a high-grade concentrate. For this purpose, the grain size distribution analysis, heavy liquid separation tests as well as XRF, and SEM analysis are performed. The magnetite, ilmenite, garnet, zircon, rutile, apatite, sphene, pyrolusite, celestine, and heavy green silicates are the valuable heavy minerals recorded in the studied samples; but their quantity varies between Wadi and Delta. The upgrading experiments are performed via a shaking table in conjunction with the low and high-intensity magnetic separator in order to obtain the high-grade concentrates from the valuable heavy minerals, and after applying the optimum separation conditions, the total heavy mineral (THM) assay increase from 8.32% to 46.04% for Wadi Sermatai, while for Delta Sermatai increase from 8.37% to 50.13% into 8.89% and 9.59%, respectively, by mass yield. The THM recovery values reach 66.84% for Wadi Sermatai and 67.23% for Delta Sermatai. After the results of the chemical analysis of the concentrates, it is proved that the Sermatai area is considered as a potential source for some economic elements such as Fe, Ti, Zn, Zr, Cr, V, and Sr.
Mineral Processing
N. Khorasanizadeh; M. Karamoozian; H. Nouri-Bidgoli
Abstract
The bubble diameter effect on the bubble rise velocity profile in a flotation column is studied by the two-phase computational fluid dynamics (CFD) method. The simulations are done in the ANSYS® Fluent® software using a two-phase volume of fluid model. The computational domain is a square cross-section ...
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The bubble diameter effect on the bubble rise velocity profile in a flotation column is studied by the two-phase computational fluid dynamics (CFD) method. The simulations are done in the ANSYS® Fluent® software using a two-phase volume of fluid model. The computational domain is a square cross-section column with a 10 cm width and a 100 cm height, in which air is interred as a single bubble from the lower part of the column by an internal sparger. An experimental test is also performed, the hydrodynamics parameters are recorded, and the simulated results are validated using the values obtained for the bubble rise velocity. The simulation results obtained indicate that CFD can predict the bubble rise velocity profile and its value in the flotation column with less than 5% difference in comparison with the experimental results. Then the simulations are repeated for the other initial bubble diameter in the bubbly flow regime in order to study the bubble diameter effect on the rise velocity profile. The results obtained demonstrate that the larger bubbles reach the maximum velocity faster than the small ones, while the value of maximum velocity decreases by an increase in the bubble diameter. These results can be used to improve the flotation efficiency.
Mineral Processing
A.R. Javadi
Abstract
Carnallite, with the chemical formula KMgCl3.6H2O, is a mineral that was first discovered in the Urals Mountains in Russia. The reverse flotation has been established for carnallite processing in the current decades, and the alkyl morpholine collector is used for the removal of NaCl from carnallite using ...
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Carnallite, with the chemical formula KMgCl3.6H2O, is a mineral that was first discovered in the Urals Mountains in Russia. The reverse flotation has been established for carnallite processing in the current decades, and the alkyl morpholine collector is used for the removal of NaCl from carnallite using the reverse flotation. The carnallite processing method involves reverse flotation with the dodecyl morpholine collector, and then centrifugation and cold crystallization. In this research work, kimiaflot 619, as a new collector, is synthesized, and the bench-scale flotation shows that kimiaflot 619 reveals a better selectivity and affinity for the NaCl crystals at an acidic pH with a less collector dosages–only 1/2 of the Armoflot 619 collector. The flotation results indicate that the NaCl grade in carnallite concentrated by Armoflot 619 (200 g/t) is 2.86%, while the NaCl grade in carnallite concentrated by kimiaflot 619collector (100 g/t) is 2.75%. The frother’s stability of the Armoflot 619 collector after flotation is very high and uncontrollable, while kimiaflot 619 has solved this problem, and it is completely controllable.
Mineral Processing
S. Kolahi; M. Jahani Chegeni
Abstract
The number of lifters of mill shell liners, mill rotation speed, and filling percentage of grinding media are three of the most important parameters influencing the charge behavior and the trajectory of ball motion inside the SAG mills, and consequently, their performance. In this paper, the milling ...
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The number of lifters of mill shell liners, mill rotation speed, and filling percentage of grinding media are three of the most important parameters influencing the charge behavior and the trajectory of ball motion inside the SAG mills, and consequently, their performance. In this paper, the milling operation of pilot-scale SAG mills using the discrete element method (DEM) is investigated. First, a pilot-scale SAG mill with dimensions of 3.0 m × 1.5 m with no lifter is simulated. Then by adding, respectively, one, two, four, eight, sixteen, and thirty-two rectangle lifter(s), six other independent simulations are performed. The effects of the number of lifters on the two new parameters introduced by the authors, i.e. ‘head height’ and ‘impact zone length’ as well as on creation of cascading, cataracting, and centrifuging motions for balls at two different mill speeds, i.e. 70% and 80% of its critical speed (NC), are evaluated. Also in order to validate the simulation results, a laboratory-scale SAG mill is simulated. The results obtained indicate that the optimum number of lifters for pilot-scale SAG mills is between 16 and 32 lifters with medium thickness. Liners with the number of lifters in this range require less mill speed to create cataract motions. However, liners with the number of lifters less than this range require a higher mill speed. Also liners with the number of lifters beyond this range require less mill speed, and can cause centrifugal motions in the balls. Comparison of the simulations related to the laboratory-scale SAG mill with experimental results demonstrates a good agreement, which validates the DEM simulations and the software used.
Mineral Processing
S. Mohammadi; B. Rezai; A. A. Abdolahzadeh
Abstract
Geometallurgy tries to predict the instability the behavior of ores caused by variability in the geological settings, and to optimize the mineral value chain. Understanding the ore variability and subsequently the process response are considered to be the most important functions of an accurate geometallurgical ...
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Geometallurgy tries to predict the instability the behavior of ores caused by variability in the geological settings, and to optimize the mineral value chain. Understanding the ore variability and subsequently the process response are considered to be the most important functions of an accurate geometallurgical study. In this paper, the geometallurgical index is presented as a new tool to optimize the mining activities. Geometallurgical index is described as any geological feature that makes a footprint on the process performance of ores. In a comprehensive research work at the Sarcheshmeh porphyry copper mine, the geological features that affect the main process responses including the product grade and recovery and plant’s throughput are subjected to investigation. In the current report, the rock hardness variability in terms of semi-autogenous grinding power index (SPI) and its effects on the mill throughput and energy consumption are presented. Ninety samples are collected based on the geological features including lithology, hydrothermal alteration, and geological structures. The samples are mineralogically characterized using XRD, XRF, and electron and optical microscopy. The Starkey laboratory mill, commercialized by Minnovex, is used to perform the SPI comminution test. The SPI results show a wide range of hardness, varying from 12 to 473 minutes. The correlation between the SPI results and the geological features show that lithology is a key geological feature that defines the hardness variability. In addition, the hydrothermal alteration would be an effective parameter in the period that the plant is fed with a single lithology.
Mineral Processing
M. Jahani Chegeni; S. Kolahi
Abstract
The shell liner type, rotation speed, and ball filling percent are the key factors influencing the charge behavior inside the SAG mills, and consequently, their performance. In this work, the milling operation of industrial SAG mills is investigated using the Discrete Element Method (DEM). First, an ...
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The shell liner type, rotation speed, and ball filling percent are the key factors influencing the charge behavior inside the SAG mills, and consequently, their performance. In this work, the milling operation of industrial SAG mills is investigated using the Discrete Element Method (DEM). First, an industrial SAG mill with dimensions of 9.50 m × 4.42 m that has a Smooth-type liner is simulated. Then by changing the liner types, i.e. Wave, Rib, Ship-lap, Lorain, Osborn, and Step liners, six other independent simulations are performed. In order to investigate the impact mechanism and improve the mill performance, two new parameters called ‘head height’ and ‘impact zone length’ are introduced. Then the effects of the mill shell liner type on those parameters at two different mill speeds, i.e. 70% and 80% of its critical speed (CS), are evaluated. Also for validation of the simulation results, a laboratory-scale SAG mill with dimensions of 57.3 cm × 16.0 cm is simulated. The results obtained indicate that the Osborn liner, due to the angularity of its lifters and their proper number and thickness, performs best because it increases both parameters more than the other liners. Thus this liner is recommended as the best and optimal liner in this research work and is suggested for installation inside the industrial SAG mills. Also the Wave liner, due to its specific geometrical shape and its wavy lifters as well as their low number and inadequate thickness, provides the lowest charge ‘head height’. Therefore, it is not recommended to install this liner inside the industrial SAG mills. Meanwhile, comparison of the simulations related to the laboratory-scale SAG mill with the experimental results demonstrates a good agreement that validates the DEM simulations and the software used.
Mineral Processing
A.H. Rezaei; H. Abdollahi; M. Gharabaghi; A. A. Mohammadzadeh
Abstract
In the recent decades, water scarcity has become a major challenge for many reasons, especially the inadequate use of water resources. The mineral processing plant is among the most important water-consuming industries. Filtration, as one of the important processes in water recovery, is a process in ...
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In the recent decades, water scarcity has become a major challenge for many reasons, especially the inadequate use of water resources. The mineral processing plant is among the most important water-consuming industries. Filtration, as one of the important processes in water recovery, is a process in which the solid-suspended particles are removed from the liquid. In the present work, the effect of the additives affecting the filtration process upon the responses including the resistance to filter cloth (R), specific cake resistance (α), moisture content, water recovery rate, and cake formation rate by the vacuum top-feed method is investigated. The experiments are performed by two methodologies: one-factor-at-a-time and statistical analysis. The additives are the flocculant, coagulant, surfactant, and filter aid. According to the one-factor-at-a-time methodology, the optimal type and dosage of the variables are as follow: flocculant A25 with a concentration of 15 g/L, perlite as the filter aid with an amount of 2.5%, surfactant cop 20-101 with a concentration of 3 cc/L, and the coagulant CaCl2.2H2O with a concentration of 2.5 g/L. The usage of the flocculant, surfactant, and filter aid at the same time is also statistically analyzed with the aim of maximizing the cake formation rate and minimizing the moisture content of the filter cake. Under the optimal conditions and taking into account 11.68 g/t of the flocculant A25, 3.8% of perlite as the filter aid, and2.92 cc/L of the surfactant cop 20-101, the cake formation rate and the moisture content were obtained to be 0.297 mm/s and 12.7 %, respectively.
Mineral Processing
B. Nemati Akhgar; A. Fathzade; B. Golizadeh; S. Hajilou
Abstract
The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp ...
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The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp overflow to concentrate lander, maintenance and control problems. An attempt was exerted by implementing new helical static mixer in one of cleaner cells instead of old elliptical type to overcome the challenges. The changes resulted in proper performance of the column whereas burping phenomena due to choking was eliminated, finer bubbles were produced, and the boiling and overflow problems were solved. Also, the static mixers life time increased to 7 months in helical column cells from one month in elliptical column cells. In addition to 40% air consumption reduction and 20% solid percent increase in final product, the grade of Cu and Mo increased by helical static mixer replacement up to about 18.7% from 16.8% (11%) and to 511.1 ppm from 263 ppm (94%) in the cleaner step, respectively. Recovery of Cu and Mo were increased about 1.5% and 0.2%, respectively. Finally, the results proved the effectiveness of finer bubble generation on grade improvement is depend on minerals hydrophobicity as Mo grade increased more than Cu.
Mineral Processing
H. Jafari; H. Abdollahi; M. Gharabaghi; A.A. Balesini
Abstract
In this research work, solvent extraction and stripping of zinc ions from a Zn-Mn-Cd-bearing solution was investigated using D2EHPA as the extractant in a chloride medium. The efficiency of the extraction and stripping stages was evaluated separately, and different parameters such as the pH, extractant ...
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In this research work, solvent extraction and stripping of zinc ions from a Zn-Mn-Cd-bearing solution was investigated using D2EHPA as the extractant in a chloride medium. The efficiency of the extraction and stripping stages was evaluated separately, and different parameters such as the pH, extractant concentration, reaction temperature, and contact time were studied. Based on the results obtained, 97% of zinc, 14% of manganese, and 3% of cadmium were extracted at pH = 2.5, 10% (v/v) of D2EHPA, and 40 °C from the solution containing 5 g L-1 of each metal ion. The stripping isotherms of zinc, manganese, and cadmium at different pH values showed that manganese and zinc were stripped at two different pH values. Thus more than 70% of manganese and more than 90% of zinc were stripped at pH = 2.5 and pH = 0.5, respectively. Kinetic studies indicated that the extraction and stripping of zinc in the first 0.5-1 minute was high. The McCabe–Thiele diagrams showed that two stages of extraction and two stages of stripping in the continuous counter-current flow condition were adequate to separate zinc from Mn and Cd. The dominant Zn species extracted by D2EHPA was ZnCl+, and the values for the thermodynamic parameters ΔHo, ΔSo, and ΔGo were 25.65 kJ mol−1, 79.20 J K−1 mol−1, and 0.86 kJ mol−1, respectively, which showed that the reaction was endothermic at equilibrium.
Mineral Processing
P. Karimi; A. Khodadadi Darban; Z. Mansourpour
Abstract
Low-intensity magnetic separators are widely used in the research works and the industry. Advancement in the magnetic separation techniques has led to an expansion in the application of this method in different fields such as enrichment of magnetic mineral, wastewater treatment, and medicine transfer ...
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Low-intensity magnetic separators are widely used in the research works and the industry. Advancement in the magnetic separation techniques has led to an expansion in the application of this method in different fields such as enrichment of magnetic mineral, wastewater treatment, and medicine transfer in the human body. In the mineral processing industry, the main application of wet magnetic separation is via drum separators. The design of this separator is based on drum rotation inside a tank media, where a permanent magnet placed inside the drum as an angle form produces a magnetic field. In the present work, the magnetic variables involved (magnetic flux density, intensity of magnetic field, and gradient of magnetic field intensity) were simulated in the drum wet low-intensity magnetic separator using the finite element method and a COMSOL Multiphysics simulator; these variables were further validated through the measured data. A comparison between the simulation and laboratory measurements (of the magnetic field) showed that the mean value of the simulation error in 94 points in 2 sections was equal to 9.6%. Furthermore, the maximum simulation error in the middle of the magnets, as the most important part of the magnetic field distribution in the process of magnetic separation, was in the 6th direction and equal to 7.8%. Therefore, the performed simulation can be applied as a first step to design and construct more advanced magnetics separators.
Mineral Processing
S. Ghasemi; A. Behnamfard; R. Arjmand
Abstract
The Sangan processing plant consists of four consecutive low-intensity magnetic separation steps with the same magnetic field intensity of 1300 Gauss for upgradation of iron ore. Hence, the iron ore minerals with lower magnetic susceptibility or interlocked with gangue minerals have no opportunity for ...
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The Sangan processing plant consists of four consecutive low-intensity magnetic separation steps with the same magnetic field intensity of 1300 Gauss for upgradation of iron ore. Hence, the iron ore minerals with lower magnetic susceptibility or interlocked with gangue minerals have no opportunity for upgradation, and proceed to the tailing dam. Flotation is a powerful technique for upgradation of these materials, and it is the focus of this research work. A sample of 43.09% Fe and 12.1% FeO was taken from the tailings of second step of magnetic separation. The ore minerals of the sample were determined to be magnetite and hematite. A concentrate of 67% Fe and mass recovery of 50% was produced through the Davis tube test. A reverse flotation route was selected for upgradation of the sample. Fatty acid-based anionic collectors with trade names Alke and Dirol were used in the flotation experiments. The design of experiments was done by resolution IV fractional factorial design with nine factors at two levels per factor. A resolution IV design allows discrimination of all main effects and two-factor interactions. A concentrate of 53.92% Fe at a mass recovery of 60% was obtained at optimum flotation conditions of solid content 20%, pH 12, collector concentration of 1 kg/t, starch as depressant at a concentration of 5 kg/t, Alke/Dirol collector mass ratio of 30/70, conditioning time of 10 min., and concentration of Ca2+ as activator 1 kg/t. In this research work, the concept of natural depression of iron minerals in the reverse flotation was introduced and evaluated.
Mineral Processing
H. Ebadi; P. Pourghahramani; E. Dehgani; M. Ganjeh
Abstract
In this work, the effects of temperature, acid concentration, and mechanical activation on dissolution of ilmenite were studied using the statistical design of experiment technique. Mechanical activation was carried out using a planetary ball mill in dry mode, and the resulting structural changes were ...
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In this work, the effects of temperature, acid concentration, and mechanical activation on dissolution of ilmenite were studied using the statistical design of experiment technique. Mechanical activation was carried out using a planetary ball mill in dry mode, and the resulting structural changes were characterized by the particle size analysis, specific surface area measurements, and X-ray diffraction method. The results obtained indicated that intensive milling led to a significant decrease in the ilmenite particle size and that after 20 minutes, particles tended to agglomerate. However, after 90 minutes, the BET specific surface area increased to 9.36 m2/g. In addition to surface changes, mechanical activation led to intense changes and disorders in the crystal structure of ilmenite as amorphization degree increased to 94.30% and the volume weighted crystallite size and lattice strain changed from 346 nm and 0.13% to 14 nm and 1.44%, respectively. The results of the dissolution tests in the form of experimental design indicated that a suitable model could fit the experimental data in 95% confidence level. The coefficient factors for acid concentration, mechanical activation, and temperature were 3.75%, 33.04%, and 9%, respectively. Mechanical activation had the highest effect on titanium extraction in comparison to the other factors involved. Also in addition to its dominant effect on ilmenite dissolution, it also weakened the temperature effect. However, the results of the kinetic tests proved that mechanical activation led to promotion of the temperature effect on increasing the dissolution reaction rate in the initial stages. Finally, a dissolution yield of more than 98% was achieved through 90 minutes of activation at 95° C and 55 wt.% acid concentration.
Mineral Processing
K. Barani; M. Azghadi; M. R. Azadi; A. Karrech
Abstract
The influence of microwave treatment on the surface roughness, hydrophobicity, and chemical composition of galena was studied. The pure galena specimens and purified galena concentrate were used in this work. A conventional multi-modal oven (with a frequency of 2.45 GHz and a maximum power of 900 W) ...
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The influence of microwave treatment on the surface roughness, hydrophobicity, and chemical composition of galena was studied. The pure galena specimens and purified galena concentrate were used in this work. A conventional multi-modal oven (with a frequency of 2.45 GHz and a maximum power of 900 W) was used to conduct the experiments. The results obtained from the atomic-force microscopy analysis showed that the surface roughness of galena decreased after the microwave radiation. The results also showed that the surface hydrophobicity of galena increased with increase in the duration of the microwave radiation, which was in good agreement with the micro-flotation mass recovery results. The increased surface hydrophobicity may be attributed to the decreased surface roughness by microwave radiation or formation of sulfur on the surface. The results of the SEM/EDS analyses indicated that after microwave radiation, the amount of S increased, whereas Pb decreased on the surface of galena, indicating that the average atomic number of the galena surface changed due to microwave treatment.
Mineral Processing
M. R. Khani; M. Karamoozian
Abstract
In the present work, we investigated and optimized the digestion efficiency, A/S (Al2O3/SiO2 in red mud), and N/S (Na2O/SiO2 in red mud) of mixed bauxite in Iran Alumina Company using the Bayer process. Digestion experiments were carried out in an induction rotary autoclave on a mix of Jajarm, Yazd, ...
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In the present work, we investigated and optimized the digestion efficiency, A/S (Al2O3/SiO2 in red mud), and N/S (Na2O/SiO2 in red mud) of mixed bauxite in Iran Alumina Company using the Bayer process. Digestion experiments were carried out in an induction rotary autoclave on a mix of Jajarm, Yazd, Tash, and Shirin Cheshmeh bauxites. A 4-factor 3-level response surface methodology was applied for the design and analysis of the experiment with the optimization of Na2O concentration, digestion temperature, residence time, and amount of lime addition. Towquadratics and one linear model were derived for the prediction of digestion efficiency, and A/S and N/S responses. The results obtained showed that the optimum amounts for Na2O concentration, temperature, amount of lime addition and residence time were 180 g/L, 275°C, 7.73%, and 50 minutes, respectively, in which the digestion efficiency, A/S, and N/S reached 72.05%, 1.169, and 0.27, respectively. Validation experiment showed that the digestion efficiency, A/S, and N/S were 72.24%, 1.162, and 0.28% respectively, which meant a 2% increase in digestion efficiency and a 0.09 and 0.02 decrease in A/S and N/S, respectively, compared to the current operating condition.
Mineral Processing
A. Abbasi Gharaei; B. Rezai; H. Hamidian Shoormasti
Abstract
According to the classification of the nickel laterite, this paper describes mineralogy test is to reveal where valuable elements are located in the ore, in which mineralogical form. The purpose of the sieving test was to study if some specific particle size contains most of the valuable metals. Based ...
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According to the classification of the nickel laterite, this paper describes mineralogy test is to reveal where valuable elements are located in the ore, in which mineralogical form. The purpose of the sieving test was to study if some specific particle size contains most of the valuable metals. Based on its chemical composition nickel laterite is classified as a limonite type and the nickel and cobalt content was 0.7 and 0.04%, respectively. Nickel is predominantly associated with hematite and goethite. Based on the mineralogical analysis of the ore, it is observed that remarkable part of nickel is located in hematite. Therefore, nickel cannot be released from hematite lattice. The nickel content in the laterite was 0.7% and the cobalt content 0.04%. The chemical composition of laterite equals with the occurrence of 38.9% iron oxides, 26.9% carbonates, 26.9% quartz, 4.8% chromite, 2.7% magnetite and 1.9% other minerals. EDS line profile analyses were completed on hematite/goethite ooids and there was a slight correlation in the quantities between iron and nickel in each individual ooid. However, iron and nickel do not always show a positive correlation. Nickel grade could be enriched from 0.7 wt.-percent to 0.91 wt.-percent; however nickel recovery was only 45%.
Mineral Processing
M. Maleki Moghaddam; E. Arghavani; A.R. Ghasemi; S. Banisi
Abstract
Liner design has become an increasingly more important tool for the AG/SAG mill performance optimization. The Sarcheshmeh copper complex concentration plant uses a SAG mill lined with 48 rows of Hi-Low type liners. Because of breakage of Low type liners and cold welding, the liner replacement task of ...
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Liner design has become an increasingly more important tool for the AG/SAG mill performance optimization. The Sarcheshmeh copper complex concentration plant uses a SAG mill lined with 48 rows of Hi-Low type liners. Because of breakage of Low type liners and cold welding, the liner replacement task of Low with new Hi type liners has become very difficult and time-consuming. With the objective of finding a new design for liners, numerical (3D DEM; discrete element method) simulation and physical modelling in a laboratory mill were used. It was found that changing the liner type from Hi-Low to Hi-Hi could provide an appropriate charge trajectory. The new Hi-Hi type shell liners were designed, manufactured, and installed. With the new liners, the number of broken liners over liner life reduced from 6 to 0 piece, the total changing time for one liner decreased from 21 to 16 minutes, and no cold welding of shell liners was observed. Comparison of the feed rate before and after installation of the new liners for a period of liner life showed an increase from 750 to 850 t/h, which was indicative of a higher flexibility of the mill in encountering ore hardness variations.
Mineral Processing
H. Shadi Naghadeh; M. Abdollahy; A. Khodadadi Darban; P. Pourghahramani
Abstract
The Esfordi phosphate concentrate mainly contains fluorapatite, monazite, and xenotime as rare earth element (REE) minerals, accounting for 1.5% of rare earth metals. The monazite and xenotime minerals are refractory and their decomposition is only possible at high temperatures. Thus mechanical activation ...
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The Esfordi phosphate concentrate mainly contains fluorapatite, monazite, and xenotime as rare earth element (REE) minerals, accounting for 1.5% of rare earth metals. The monazite and xenotime minerals are refractory and their decomposition is only possible at high temperatures. Thus mechanical activation was used in the present work for this purpose. After 90 minutes of mechanical activation, the X-ray amorphization phase and the maximum BET surface area were increased to 93.4% and 8.4 m2/g, respectively. The Williamson-Hall plot indicated that the crystallite size was decreased and the lattice strain was increased as a function of the milling intensity. A volume-weighted crystallite size of 64 nm and a lattice strain of 0.9% were achieved from the mechanically activated sample for 90 minutes. The leaching efficiency of REEs with 32% nitric acid at 85 °C was increased from 25% for the initial sample to about 95% for the activated samples. The first stage reaction rate constants for La, Nd, and Ce were increased from 8 × 10-7, 9 × 10-7,and 6 × 10-7 for the initial sample to 1.3 × 10-3, 9 × 10-4, and 7 × 10-4 for the mechanically activated samples at 60 °C, respectively. Also the apparent activation energy for La, Nd, and Ce for the initial sample was found to be about 210, 231, and 229 kJ/mol, which were decreased to 120, 91, and 80 kJ/mol, respectively, after 20 minutes of mechanical activation in an argon atmosphere. The results obtained suggested mechanical activation as an appropriate pre-treatment method for dissolution of REEs from phosphate concentrates containing refractory REE minerals at a lower cost and a higher recovery rate.
Mineral Processing
S. Khoshjavan; K. Moshashaei; B. Rezai
Abstract
In this research work, the effects of flotation parameters on coking coal flotation combustible material recovery (CMR) were studied by the artificial neural networks (ANNs) method. The input parameters of the network were the pulp solid weight content, pH, collector dosage, frother dosage, conditioning ...
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In this research work, the effects of flotation parameters on coking coal flotation combustible material recovery (CMR) were studied by the artificial neural networks (ANNs) method. The input parameters of the network were the pulp solid weight content, pH, collector dosage, frother dosage, conditioning time, flotation retention time, feed ash content, and rotor rotation speed. In order to select the most efficient model for this work, the outputs of different models were compared with each other. A five-layer ANN was found to be optimum with the architecture of 8, 15, 10, and 5 neurons in the input layer, and the first hidden, second hidden, and third hidden layers, respectively, as well one neurons in the output layer. In this work, the training, testing, validating, and data square correlation coefficients (R2) were achieved to be 0.995, 0.999, 0.999, and 0.998, respectively. The sensitivity analysis showed that the rotor speed and the solid weight content had the highest and lowest effects on CMR, respectively. It was verified that the predicted ANN values coincided very well with the experimental results.
