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6 pages, 1088 KiB

Open AccessEditorial

Editorial for Special Issue “Modeling, Design and Optimization of Multiphase Systems in Minerals Processing”

by Luis A. Cisternas

Minerals 2020, 10(2), 134; https://doi.org/10.3390/min10020134 - 3 Feb 2020

Cited by 11 | Viewed by 1859

Abstract

The exploitation of mining resources has been fundamental for the development of humanity since before industrialization [...] Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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14 pages, 6452 KiB

Open AccessArticle

Turbulence Models for Single Phase Flow Simulation of Cyclonic Flotation Columns

by Shiqi Meng, Xiaoheng Li, Xiaokang Yan, Lijun Wang, Haijun Zhang and Yijun Cao

Minerals 2019, 9(8), 464; https://doi.org/10.3390/min9080464 - 30 Jul 2019

Cited by 11 | Viewed by 4040

Abstract

Cyclonic fields are important for cyclonic static microbubble flotation columns (FCSMCs), one of the most important developments in column flotation technology, particularly for separation of fine particles, where the internal flow field has enormous influence on flotation performance. PIV (particle image velocimetry) and [...] Read more.

Cyclonic fields are important for cyclonic static microbubble flotation columns (FCSMCs), one of the most important developments in column flotation technology, particularly for separation of fine particles, where the internal flow field has enormous influence on flotation performance. PIV (particle image velocimetry) and CFD (computational fluid dynamics) are the most effective methods to study flow fields. However, data is insufficient for FCSMC flow fields and similar cyclonic equipment, with turbulence model simulations producing different views to measured data. This paper employs an endoscope and PIV to measure axial and cross sections for single-phase swirling flow fields in FCSMCs. We then compare various turbulence model simulations (Reynolds stress model (RSM), standard k-ε, realizable k-ε, and RNG (renormalization group) k-ε) to the measured data. The RSM (Reynolds stress model) predicts cyclonic flow field best in flotation columns with 16.22% average relative velocity deviation. Although the realizable k-ε model has less than 30% relative deviation in radial and tangential directions, axial deviations reach 78.11%. Standard k-ε and RNG k-ε models exhibited approximately 40% and 30% radial and tangential deviation, respectively, and cannot be used even for trend predictions for axial velocity. k-ε models are based on isotropic assumptions with semi-empirical formulas summarized from experiments, whereas RSM fundamentally considers laminar flow and Reynolds stress, and hence is more suitable for anisotropic performance. This study will contribute to flotation column and other cyclonic flow field equipment research. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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18 pages, 16648 KiB

Open AccessArticle

Novel Insights into the Hydroxylation Behaviors of α-Quartz (101) Surface and its Effects on the Adsorption of Sodium Oleate

by Chenyang Zhang, Zhijie Xu, Yuehua Hu, Jianyong He, Mengjie Tian, Jiahui Zhou, Qiqi Zhou, Shengda Chen, Daixiong Chen, Pan Chen and Wei Sun

Minerals 2019, 9(7), 450; https://doi.org/10.3390/min9070450 - 19 Jul 2019

Cited by 51 | Viewed by 4875

Abstract

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca²⁺-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules [...] Read more.

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca²⁺-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca²⁺ in the form of Ca(H₂O)₃(OH)⁺ can greatly promote the adsorption of OL⁻ on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL⁻ ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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13 pages, 3316 KiB

Open AccessArticle

Optimization of the Heap Leaching Process through Changes in Modes of Operation and Discrete Event Simulation

by Manuel Saldaña, Norman Toro, Jonathan Castillo, Pía Hernández and Alessandro Navarra

Minerals 2019, 9(7), 421; https://doi.org/10.3390/min9070421 - 10 Jul 2019

Cited by 25 | Viewed by 4857

Abstract

The importance of mine planning is often underestimated. Nonetheless, it is essential in achieving high performance by identifying the potential value of mineral resources and providing an optimal, practical, and realistic strategy for extraction, which considers the greatest quantity of options, materials, and [...] Read more.

The importance of mine planning is often underestimated. Nonetheless, it is essential in achieving high performance by identifying the potential value of mineral resources and providing an optimal, practical, and realistic strategy for extraction, which considers the greatest quantity of options, materials, and scenarios. Conventional mine planning is based on a mostly deterministic approach, ignoring part of the uncertainty presented in the input data, such as the mineralogical composition of the feed. This work develops a methodology to optimize the mineral recovery of the heap leaching phase by addressing the mineralogical variation of the feed, by alternating the mode of operation depending on the type of ore in the feed. The operational changes considered in the analysis include the leaching of oxide ores by adding only sulfuric acid (H₂SO₄) as reagent and adding chloride in the case of sulfide ores (secondary sulfides). The incorporation of uncertainty allows the creation of models that maximize the productivity, while confronting the geological uncertainty, as the extraction program progresses. The model seeks to increase the expected recovery from leaching, considering a set of equiprobable geological scenarios. The modeling and simulation of this productive phase is developed through a discrete event simulation (DES) framework. The results of the simulation indicate the potential to address the dynamics of feed variation through the implementation of alternating modes of operation. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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12 pages, 4353 KiB

Open AccessArticle

Molecular Modeling of Interactions between N-(Carboxymethyl)-N-tetradecylglycine and Fluorapatite

by Nan Nan, Yimin Zhu, Yuexin Han and Jie Liu

Minerals 2019, 9(5), 278; https://doi.org/10.3390/min9050278 - 6 May 2019

Cited by 9 | Viewed by 2923

Abstract

In this study, a flotation collector N-(carboxymethyl)-N-tetradecylglycine (NCNT) was introduced for the purpose of energy-saving, and its adsorption ability on a fluorapatite (001) surface was investigated by density functional theory calculation. The results of frontier molecular orbital analysis of NCNT and adsorption energy [...] Read more.

In this study, a flotation collector N-(carboxymethyl)-N-tetradecylglycine (NCNT) was introduced for the purpose of energy-saving, and its adsorption ability on a fluorapatite (001) surface was investigated by density functional theory calculation. The results of frontier molecular orbital analysis of NCNT and adsorption energy between NCNT and fluorapatite (FAp) showed that NCNT possessed better activity and stronger interactions in the reagent–FAp system than oleic acid (OA). A simulation model revealed that the adsorption positions of NCNT on the fluorapatite surface are calcium atoms, at which NCNT chemisorbed on (001) fluorapatite surface via a bidentate geometry involving the formation of two Ca–O bonds. Flotation experiments verified that NCNT had a good recovery of 92.27% on FAp at pH 3.5, which was slightly lower than OA. Moreover, NCNT was used at 16 °C, which was much lower than the OA’s service condition (25 °C). Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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19 pages, 1167 KiB

Open AccessArticle

Heat-Assisted Batch Settling of Mineral Suspensions in Inclined Containers

by Cristian Reyes, Christian F. Ihle, Fernando Apaz and Luis A. Cisternas

Minerals 2019, 9(4), 228; https://doi.org/10.3390/min9040228 - 12 Apr 2019

Cited by 7 | Viewed by 3942

Abstract

In mineral processing, the common requirement for progressively finer milling due to the decreasing of ore grades implies the need for more challenging water recovery conditions in thickeners. Several mining operations exist in arid areas, where water recovery becomes critical. The present paper [...] Read more.

In mineral processing, the common requirement for progressively finer milling due to the decreasing of ore grades implies the need for more challenging water recovery conditions in thickeners. Several mining operations exist in arid areas, where water recovery becomes critical. The present paper explores the process of particle separation in batch inclined settlers where the downward facing wall is subject to heating. To this purpose, two-dimensional numerical simulations using a mixture model have been run for a number of combinations of temperature jumps at the downward facing fall, particle diameters, and concentrations. Results show that, for particle sizes on the order of 10 µm, heating has a significant effect on the particle settling velocity at the bottom, but it also promotes particle resuspension, affecting the particle concentration at the supernatant layer. The initial concentration also affects settling: for the concentration range tested (8%–15% by volume), when re-normalized by the average concentration, particle accumulation rates at the bottom were found to be lower for higher average concentrations, thus suggesting that the separation process is more efficient at lower concentrations. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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22 pages, 1162 KiB

Open AccessFeature PaperArticle

Design of Flotation Circuits Using Tabu-Search Algorithms: Multispecies, Equipment Design, and Profitability Parameters

by Freddy A. Lucay, Edelmira D. Gálvez and Luis A. Cisternas

Minerals 2019, 9(3), 181; https://doi.org/10.3390/min9030181 - 15 Mar 2019

Cited by 14 | Viewed by 4181

Abstract

The design of a flotation circuit based on optimization techniques requires a superstructure for representing a set of alternatives, a mathematical model for modeling the alternatives, and an optimization technique for solving the problem. The optimization techniques are classified into exact and approximate [...] Read more.

The design of a flotation circuit based on optimization techniques requires a superstructure for representing a set of alternatives, a mathematical model for modeling the alternatives, and an optimization technique for solving the problem. The optimization techniques are classified into exact and approximate methods. The first has been widely used. However, the probability of finding an optimal solution decreases when the problem size increases. Genetic algorithms have been the approximate method used for designing flotation circuits when the studied problems were small. The Tabu-search algorithm (TSA) is an approximate method used for solving combinatorial optimization problems. This algorithm is an adaptive procedure that has the ability to employ many other methods. The TSA uses short-term memory to prevent the algorithm from being trapped in cycles. The TSA has many practical advantages but has not been used for designing flotation circuits. We propose using the TSA for solving the flotation circuit design problem. The TSA implemented in this work applies diversification and intensification strategies: diversification is used for exploring new regions, and intensification for exploring regions close to a good solution. Four cases were analyzed to demonstrate the applicability of the algorithm: different objective function, different mathematical models, and a benchmarking between TSA and Baron solver. The results indicate that the developed algorithm presents the ability to converge to a solution optimal or near optimal for a complex combination of requirements and constraints, whereas other methods do not. TSA and the Baron solver provide similar designs, but TSA is faster. We conclude that the developed TSA could be useful in the design of full-scale concentration circuits. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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17 pages, 5862 KiB

Open AccessArticle

Study of K-Feldspar and Lime Hydrothermal Reaction: Phase and Mechanism with Reaction Temperature and Increasing Ca/Si Ratio

by Shanke Liu, Cheng Han and Jianming Liu

Minerals 2019, 9(1), 46; https://doi.org/10.3390/min9010046 - 14 Jan 2019

Cited by 20 | Viewed by 7313

Abstract

To elucidate the physicochemical properties of the artificial silicate composite material, K-feldspar and lime were reacted in mild hydrothermal conditions (different reaction temperatures and various K-feldspar/lime ratios). Formed phases were investigated using various techniques, such as X-ray powder diffraction, the Rietveld method, scanning [...] Read more.

To elucidate the physicochemical properties of the artificial silicate composite material, K-feldspar and lime were reacted in mild hydrothermal conditions (different reaction temperatures and various K-feldspar/lime ratios). Formed phases were investigated using various techniques, such as X-ray powder diffraction, the Rietveld method, scanning electron microscopy (SEM), and inductively coupled plasma-optical emission spectrometry. The analysis revealed that tobermorite, grossular (hydrogarnet), alpha-dicalcium silicate hydrate (α-C₂SH), amorphous calcium silicate hydrate, potassium carbonate, bütschliite, calcite, and calcium hydroxide formed with various conditions. Both the temperature and the Ca/Si molar ratio in the starting material greatly affected the formation of phases, especially the generation of tobermorite and α-C₂SH. The substitution of H₄O₄ ↔ SiO₄ proceeded with the increase of the Ca/Si molar ratio rather than the reaction temperature and the reaction time. More hydrogen was incorporated in hydrogarnet through the substitution of H₄O₄ ↔ SiO₄ with the increase of the Ca/Si molar ratio in the starting material. Due to the properties of tobermorite as a cation exchanger and its potential applications in hazardous waste disposal, experimental parameters should be optimized to obtain better performance of the artificial silicate composite material from K-feldspar and lime hydrothermal reaction. The dissolution mechanism of K-feldspar was also discussed. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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14 pages, 3461 KiB

Open AccessArticle

Optimizing Flotation Circuit Recovery by Effective Stage Arrangements: A Case Study

by Vahid Radmehr, Sied Ziaedin Shafaei, Mohammad Noaparast and Hadi Abdollahi

Minerals 2018, 8(10), 417; https://doi.org/10.3390/min8100417 - 20 Sep 2018

Cited by 9 | Viewed by 5762

Abstract

Recovery is one of the most important metallurgical parameters in designing and evaluating flotation circuits. The present study used the recovery arrangement for two and three stage circuits to evaluate the effect of stage recovery on the overall circuit recovery and flotation circuit [...] Read more.

Recovery is one of the most important metallurgical parameters in designing and evaluating flotation circuits. The present study used the recovery arrangement for two and three stage circuits to evaluate the effect of stage recovery on the overall circuit recovery and flotation circuit configuration. The results showed that mainly the highest recovery value should be assigned to the rougher stage in order to achieve the maximum overall circuit recovery. Countercurrent rougher-cleaner and rougher-scavenger circuits, in which recycling streams step back one stage at a time, follow a general rule for the assignment of recovery. Finally, a flotation plant containing six flotation banks was examined as a case study. A program for calculating total circuit recovery, for all possible combinations of recovery was developed in MATLAB software. 720 recovery combinations were evaluated. The results showed that optimal recovery allocation in stages could be effective in achieving overall circuit recovery. It was shown that the use of a large number of stages in some of the flotation circuits leads to the loss of equipment and additional costs. The proposed approach can be employed as an effective tool for designing and optimizing various flotation circuits and their operational parameters. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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21 pages, 7366 KiB

Open AccessArticle

Evaluation of Magnetic Separation Efficiency on a Cassiterite-Bearing Skarn Ore by Means of Integrative SEM-Based Image and XRF–XRD Data Analysis

by Markus Buchmann, Edgar Schach, Raimon Tolosana-Delgado, Thomas Leißner, Jennifer Astoveza, Marius Kern, Robert Möckel, Doreen Ebert, Martin Rudolph, Karl Gerald Van den Boogaart and Urs A. Peuker

Minerals 2018, 8(9), 390; https://doi.org/10.3390/min8090390 - 6 Sep 2018

Cited by 29 | Viewed by 9730

Abstract

Image analysis data obtained from scanning electron microscopy provided data for a detailed evaluation of the separation efficiency for various processes involving the beneficiation of particulate materials. A dry magnetic separation by a drum type magnetic separator served as a case study to [...] Read more.

Image analysis data obtained from scanning electron microscopy provided data for a detailed evaluation of the separation efficiency for various processes involving the beneficiation of particulate materials. A dry magnetic separation by a drum type magnetic separator served as a case study to visualize effects of processing of a skarn ore with a high content of cassiterite as ore mineral (~4 wt%). For this material, iron oxides and silicates are the main gangue mineral groups. Based on the obtained data, partition curves were generated with the help of local regression. From the partition curves, the separation efficiency was evaluated and the relevant particle properties deduced. A detailed analysis of the bias of the quantitative mineralogical data is presented. This bias was monitored and further analyzed in detail. Thorough analysis of feed and products of magnetic separation enabled identification of the most important factors that control losses of cassiterite to the magnetic product, namely the association with iron oxides and particle sizes below ~40 µm. The introduced methodology is a general approach applicable for the optimization of different separation processes and is not limited to the presented case study. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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16 pages, 3365 KiB

Open AccessArticle

New Insights into the Configurations of Lead(II)-Benzohydroxamic Acid Coordination Compounds in Aqueous Solution: A Combined Experimental and Computational Study

by Jianyong He, Haisheng Han, Chenyang Zhang, Yuehua Hu, Dandan Yuan, Mengjie Tian, Daixiong Chen and Wei Sun

Minerals 2018, 8(9), 368; https://doi.org/10.3390/min8090368 - 25 Aug 2018

Cited by 26 | Viewed by 3900

Abstract

Novel collector lead(II)-benzohydroxamic acid (Pb(II)–BHA) complexes in aqueous solution were characterized by using experimental approaches, including Ultraviolet-visible (UV-Vis) spectroscopy and electrospray ionization-mass spectrometry (ESI-MS), as well as first-principle density functional theory (DFT) calculations with consideration for solvation effects. The Job plot delineated that [...] Read more.

Novel collector lead(II)-benzohydroxamic acid (Pb(II)–BHA) complexes in aqueous solution were characterized by using experimental approaches, including Ultraviolet-visible (UV-Vis) spectroscopy and electrospray ionization-mass spectrometry (ESI-MS), as well as first-principle density functional theory (DFT) calculations with consideration for solvation effects. The Job plot delineated that a single coordinated Pb(BHA)⁺ should be formed first, and that the higher coordination number complexes can be formed subsequently. Moreover, the Pb(II)–BHA species can aggregate with each other to form complicated structures, such as Pb(BHA)₂ or highly complicated complexes. ESI-MS results validated the existence of Pb-(BHA)_n=1,2 under different solution pH values. Further, the first-principles calculations suggested that Pb(BHA)⁺ should be the most stable structure, and the Pb atom in Pb(BHA)⁺ will act as an active site to attack nucleophiles. These findings are meaningful to further illustrate the adsorption mechanism of Pb(II)–BHA complexes, and are helpful for developing new reagents in mineral processing. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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16 pages, 5199 KiB

Open AccessArticle

Determination of Dissolution Rates of Ag Contained in Metallurgical and Mining Residues in the S₂O₃²⁻-O₂-Cu²⁺ System: Kinetic Analysis

by Julio C. Juárez Tapia, Francisco Patiño Cardona, Antonio Roca Vallmajor, Aislinn M. Teja Ruiz, Iván A. Reyes Domínguez, Martín Reyes Pérez, Miguel Pérez Labra and Mizraim U. Flores Guerrero

Minerals 2018, 8(7), 309; https://doi.org/10.3390/min8070309 - 23 Jul 2018

Cited by 8 | Viewed by 3654

Abstract

The materials used to conduct kinetic study on the leaching of silver in the S₂O₃²⁻-O₂-Cu²⁺ system were mining residues (tailings) from the Dos Carlos site in the State of Hidalgo, Mexico, which have an estimated [...] Read more.

The materials used to conduct kinetic study on the leaching of silver in the S₂O₃²⁻-O₂-Cu²⁺ system were mining residues (tailings) from the Dos Carlos site in the State of Hidalgo, Mexico, which have an estimated concentration of Ag = 71 g∙ton⁻¹. The kinetic study presented in this paper assessed the effects of the following variables on Ag dissolution rate: particle diameter (d₀), temperature (T), copper concentration [Cu²⁺], thiosulfate concentration [S₂O₃²⁻], pH, [OH⁻], stirring rate (RPM), and partial pressure of oxygen (PO₂). Temperature has a favorable effect on the leaching rate of Ag, obtaining an activation energy (Ea) = 43.5 kJ∙mol⁻¹ in a range between 288 K (15 °C) and 328 K (55 °C), which indicates that the dissolution reaction is controlled by the chemical reaction. With a reaction order of n = 0.4, the addition of [Cu²⁺] had a catalytic effect on the leaching rate of silver, as opposed to not adding it. The dissolution rate is dependent on [S₂O₃²⁻] in a range between 0.02 mol·L⁻¹ and 0.06 mol·L⁻¹. Under the studied conditions, variables d₀, [OH⁻] and RPM did not have an effect on the overall rate of silver leaching. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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Review

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28 pages, 5890 KiB

Open AccessFeature PaperReview

Trends in Modeling, Design, and Optimization of Multiphase Systems in Minerals Processing

by Luis A. Cisternas, Freddy A. Lucay and Yesica L. Botero

Minerals 2020, 10(1), 22; https://doi.org/10.3390/min10010022 - 25 Dec 2019

Cited by 34 | Viewed by 7081

Abstract

Multiphase systems are important in minerals processing, and usually include solid–solid and solid–fluid systems, such as in wet grinding, flotation, dewatering, and magnetic separation, among several other unit operations. In this paper, the current trends in the process system engineering tasks of modeling, [...] Read more.

Multiphase systems are important in minerals processing, and usually include solid–solid and solid–fluid systems, such as in wet grinding, flotation, dewatering, and magnetic separation, among several other unit operations. In this paper, the current trends in the process system engineering tasks of modeling, design, and optimization in multiphase systems, are analyzed. Different scales of size and time are included, and therefore, the analysis includes modeling at the molecular level (molecular dynamic modeling) and unit operation level (e.g., computational fluid dynamic, CFD), and the application of optimization for the design of a plant. New strategies for the modeling, design, and optimization of multiphase systems are also included, with a strong focus on the application of artificial intelligence (AI) and the combination of experimentation and modeling with response surface methodology (RSM). The integration of different modeling techniques such as CFD with discrete element simulation (DEM) and response surface methodology (RSM) with artificial neural networks (ANN) is included. The paper finishes with tools to study the uncertainty, both epistemic and stochastic, based on uncertainty and global sensitivity analyses, which is present in all mineral processing operations. It is shown that all of these areas are very active and can help in the understanding, operation, design, and optimization of mineral processing that involves multiphase systems. Future needs, such as meso-scale modeling, are highlighted. Full article

(This article belongs to the Special Issue Modeling, Design and Optimization of Multiphase Systems in Minerals Processing)

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