Special Issue "Mineral Liberation"

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Processing and Metallurgy".

Deadline for manuscript submissions: closed (30 June 2020).

Special Issue Editor

Dr. Pura Alfonso
Website
Guest Editor
Departament d'Enginyeria Minera, Industrial i TIC, Universitat Politècnica de Catalunya, 08242 Manresa, Spain
Interests: stable isotopes; geochemistry; quantitative mineralogy; geometallurgy; mineral deposits; environmental pollution
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Special Issue Information

Dear Colleagues,

Mineral liberation is essential for designing an optimal mineral processing. It depends on the mineralogical and textural characteristics of ores. The estimation of the liberation degree is fundamental to estimate the efficiency that can be achieved using a separation process. The use of automated mineralogy analysis provides valuable information about mineral liberation, such as its chemistry, mineral composition, and the shape and size of its particles. The extent of mineral liberation is a determining parameter to define the optimal comminution process in order to obtain the maximum grade during the separation process with the lowest energy consumption. In addition, knowing what minerals accompany the ore is necessary for applying separation techniques. This Special Issue aims to provide a compilation of the latest advances on mineral liberation. This issue covers a broad range of topics in which mineral liberation pays a fundamental role such as comminution, energy consumption, physical separation, and modelling.

Dr. Pura Alfonso Abella
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • mineral processing
  • ore
  • grade
  • particle size
  • textures
  • mineralogy
  • automated mineralogy
  • comminution
  • energy consumption
  • physical separation
  • modelling

Published Papers (7 papers)

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Research

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Open AccessArticle
Potential Benefits in Copper Sulphides Liberation through Application of HRC Device in Ore Comminution Circuits
Minerals 2020, 10(9), 817; https://doi.org/10.3390/min10090817 - 16 Sep 2020
Abstract
The article presents results of investigations on a high-pressure comminution process carried out in the roller press device, aiming at potential improvement of effectiveness of downstream beneficiation operations. The major point of interest of the paper concerned an assessment of the useful mineral [...] Read more.
The article presents results of investigations on a high-pressure comminution process carried out in the roller press device, aiming at potential improvement of effectiveness of downstream beneficiation operations. The major point of interest of the paper concerned an assessment of the useful mineral liberation in relation to the volume of operating pressing force in the press device. Obtained results of mineral liberation were compared to flotation effects and downstream grinding process in a ball mill. Environmental influence in terms of dust emission was also analysed. The feed material was crushed in the high-pressure roller crusher (HRC) device under four different values of pressing force (Fsp): 3.0, 3.5, 4.0 and 4.5 N/mm2. Each product then underwent the liberation analysis, together with determination the energy savings through calculation of Bond’s working index, flotation recoveries and grinding kinetics. Results of investigations showed that both the most favourable crushing results and mineral liberation level were achieved for the highest values of operational pressing force. Nevertheless, the observed effects were less than linear together with further increasing of Fsp in HRC device. However, the obtained results of investigation unambiguously showed that pressing force affects the obtained crushing results: comminution degrees and flotation recoveries were higher while the duration of downstream grinding operation and grinding energy consumption were lower. Full article
(This article belongs to the Special Issue Mineral Liberation)
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Open AccessArticle
Liberation Characteristics of Ta–Sn Ores from Penouta, NW Spain
Minerals 2020, 10(6), 509; https://doi.org/10.3390/min10060509 - 31 May 2020
Abstract
The strategic importance of tantalum and its scarcity in Europe makes its recovery from low grade deposits and tailings interesting. In Penouta, the contents of Ta and Sn in old tailings from an Sn mine are of economic interest. Due to the relatively [...] Read more.
The strategic importance of tantalum and its scarcity in Europe makes its recovery from low grade deposits and tailings interesting. In Penouta, the contents of Ta and Sn in old tailings from an Sn mine are of economic interest. Due to the relatively low grade of Ta of around 100 ppm, a detailed study of the mineralogy and liberation conditions is necessary. In this study, the mineralogy and the liberation characteristics of Sn and Ta ores of the Penouta tailings were investigated and compared with the current leucogranite outcropping ores. The characterization was conducted through X-ray diffraction, scanning electron microscopy, and electron microprobe. In addition, automated mineralogy techniques were used to determine the mineral associations and liberation characteristics of ore minerals. The grade of the leucogranite outcropping was found to be about 80 ppm for Ta and 400 ppm for Sn, and in the tailings used for the liberation study, the concentrations of Ta and Sn were about 100 ppm Ta and 500 ppm Sn, respectively. In both, the leucogranite outcropping and tailings, the major minerals found were quartz, albite, K-feldspar, and white mica. Ore minerals identified were columbite-group minerals (CGM), microlite, and cassiterite. The majority of CGM examined were associated with cassiterite, quartz, and muscovite particle compositions and cassiterite was mainly associated with CGM, quartz, and muscovite. The liberation size was 180 µm for CGM. Full article
(This article belongs to the Special Issue Mineral Liberation)
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Open AccessArticle
Understanding Mineral Liberation during Crushing Using Grade-by-Size Analysis—A Case Study of the Penuota Sn-Ta Mineralization, Spain
Minerals 2020, 10(2), 164; https://doi.org/10.3390/min10020164 - 13 Feb 2020
Cited by 1
Abstract
Coarse comminution test-work and modeling are powerful tools in the design and optimization of mineral processing plants and provide information on energy consumption. Additional information on mineral liberation characteristics can be used for assessing the potential of pre-concentration stages or screens in the [...] Read more.
Coarse comminution test-work and modeling are powerful tools in the design and optimization of mineral processing plants and provide information on energy consumption. Additional information on mineral liberation characteristics can be used for assessing the potential of pre-concentration stages or screens in the plant design. In ores of high-value metals (e.g., Ta, W), standard techniques—such as the mineralogical quantification of grain mounts by quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) or chemical analysis by X-ray fluorescence (XRF) can be challenging, due to the low relative abundance of such valuable minerals. The cost of QEMSCAN is also a limiting factor, especially considering the large number of samples required for the optimization of coarse comminution. In this study, we present an extended analytical protocol to a well-established mechanical test of interparticle breakage to improve the assessment of coarse mineral liberation characteristics. The liberation of ore minerals is a function of the rock texture and the difference in size and mechanical properties of the valuable minerals relative to gangue minerals and they may fraction in certain grain sizes if they behave differently during comminution. By analyzing the bulk-chemistry of the different grain size fractions produced after compressional testing, and by generating element by size diagrams, it is possible to understand the liberation characteristics of an ore. We show, based on a case study performed on a tantalum ore deposit, that element distribution can be used to study the influence of mechanical parameters on mineral liberation. This information can direct further mineralogical investigation and test work. Full article
(This article belongs to the Special Issue Mineral Liberation)
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Open AccessArticle
Modeling the Liberation of Comminuted Scheelite Using Mineralogical Properties
Minerals 2019, 9(9), 536; https://doi.org/10.3390/min9090536 - 03 Sep 2019
Abstract
In this paper, the modeling of the liberation of scheelite is presented. A pattern of concentration experiments was performed to investigate the scheelite liberation and distribution density calculation procedure. In this work, one sample from a Mittersill tungsten ore was studied. This work [...] Read more.
In this paper, the modeling of the liberation of scheelite is presented. A pattern of concentration experiments was performed to investigate the scheelite liberation and distribution density calculation procedure. In this work, one sample from a Mittersill tungsten ore was studied. This work describes a method for determining the downstream milling energy requirements for rod mill products based on a Bond mill test performance. The grade distribution of particles at a given size fraction was calculated using a predictive liberation model. The concentration behavior of these particles in size fractions was evaluated using batch concentrate tests. The recovery of particles in size/grade classes, image analysis using mineral liberation analysis (MLA), and function calculations were implemented for the modeling of the liberation. By describing the size, grade, and recovery data of particles in size/grade classes, a technique for the measurement of distribution functions was developed that relates beta distribution, a model for the function based on the incomplete beta function, and a solution to produce liberation modeling. It was shown that the predicted results agreed well with the observed results. With a procedure for measuring the liberation, it was possible to carry out the first experimental measurement of the beta distribution. This liberation/concentrate model has wide potential applications for metallurgy and plant design, where the liberation modeling is to be determined with the distribution density solution to the predictive mineral liberation function equation, which includes the liberation of ore samples and their liberation characteristics. Full article
(This article belongs to the Special Issue Mineral Liberation)
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Open AccessArticle
Effect of Comminution Methods on Low-Rank Coal Bubble–Particle Attachment/Detachment: Implications for Flotation
Minerals 2019, 9(7), 452; https://doi.org/10.3390/min9070452 - 21 Jul 2019
Cited by 2
Abstract
The floatability of fine low-rank coal particles can be greatly influenced by their morphological characteristics, such as shape and surface roughness. In this study, the attachment efficiency and detachment amplitude of fine low-rank coal particles produced by various comminution methods onto/from the bubble [...] Read more.
The floatability of fine low-rank coal particles can be greatly influenced by their morphological characteristics, such as shape and surface roughness. In this study, the attachment efficiency and detachment amplitude of fine low-rank coal particles produced by various comminution methods onto/from the bubble surface were investigated using homemade bubble–particle wrap angle and bubble–particle attachment/detachment testing systems. Results showed that the length–diameter ratio of rod-milled products was smaller than that of crushed products. The wrap angle of particles obtained by the crushed method was larger than that obtained by the rod-milled method, i.e., particles with greater length–diameter ratio showed higher attachment efficiency onto the bubble surface. Meanwhile, particles with greater length–diameter ratio exhibited a larger detachment amplitude, which suggests that it is more difficult to be detached from the bubble surface. However, rod-milled products showed lower attachment onto the bubble surface. The flotation test confirmed that the floatability ratio of crushed products was higher than that of rod-milled products, consistent with evidence from experimental analyses. This study provides a fundamental understanding of particle shapes for low-rank coal flotation by a novel research method combining the attachment efficiency and detachment amplitude of bubble–particle combinations. Full article
(This article belongs to the Special Issue Mineral Liberation)
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Open AccessArticle
Development of a Simulator for Random and Non-Random Breakage of Particles and Liberation of Grains Based on Voronoi Tessellation
Minerals 2019, 9(6), 341; https://doi.org/10.3390/min9060341 - 03 Jun 2019
Cited by 1
Abstract
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 [...] Read more.
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 comminuted particles were processed using the codes prepared in MATLAB®. Results showed that for the samples used in this study, the proportion of the intergranular breakage changes as the grade of the ore changes, with an agreement between simulations and experiments, independently from the energy level of comminution. Full article
(This article belongs to the Special Issue Mineral Liberation)
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Review

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Open AccessFeature PaperReview
X-ray Microcomputed Tomography (µCT) for Mineral Characterization: A Review of Data Analysis Methods
Minerals 2019, 9(3), 183; https://doi.org/10.3390/min9030183 - 15 Mar 2019
Cited by 7
Abstract
The main advantage of X-ray microcomputed tomography (µCT) as a non-destructive imaging tool lies in its ability to analyze the three-dimensional (3D) interior of a sample, therefore eliminating the stereological error exhibited in conventional two-dimensional (2D) image analysis. Coupled with the correct data [...] Read more.
The main advantage of X-ray microcomputed tomography (µCT) as a non-destructive imaging tool lies in its ability to analyze the three-dimensional (3D) interior of a sample, therefore eliminating the stereological error exhibited in conventional two-dimensional (2D) image analysis. Coupled with the correct data analysis methods, µCT allows extraction of textural and mineralogical information from ore samples. This study provides a comprehensive overview on the available and potentially useful data analysis methods for processing 3D datasets acquired with laboratory µCT systems. Our study indicates that there is a rapid development of new techniques and algorithms capable of processing µCT datasets, but application of such techniques is often sample-specific. Several methods that have been successfully implemented for other similar materials (soils, aggregates, rocks) were also found to have the potential to be applied in mineral characterization. The main challenge in establishing a µCT system as a mineral characterization tool lies in the computational expenses of processing the large 3D dataset. Additionally, since most of the µCT dataset is based on the attenuation of the minerals, the presence of minerals with similar attenuations limits the capability of µCT in mineral segmentation. Further development on the data processing workflow is needed to accelerate the breakthrough of µCT as an analytical tool in mineral characterization. Full article
(This article belongs to the Special Issue Mineral Liberation)
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