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Special Issue "Minerals Study, Applications and Processing: Building the Foundations of a Green Future"

A special issue of Minerals (ISSN 2075-163X).

Deadline for manuscript submissions: closed (30 April 2022) | Viewed by 7240

Special Issue Editors

Prof. Dr. Anthimos Xenidis
E-Mail Website
Guest Editor
School of Mining and Metallurgical Engineering, National Technical University of Athens, Athens, Greece
Interests: processing; metallurgy; geochemistry; environmental technologies for waste treatment; contaminated soils and groundwater; risk assessment
Prof. Dr. Anastasios Zouboulis
E-Mail Website
Guest Editor
Laboratory of Chemical & Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
Interests: separation sciences and related technologies; wastewater/water treatment; membrane fouling; aerobic/anaerobic digestion; recovery/removal of metals from liquid waste streams; physicochemical methods for the treatment of contaminated water sources or of wastewaters, biological/aerobic or anaerobic treatment methods; combinations of biological and physicochemical methods; treatment/recycling issues of toxic industrial solid wastes; hydrometallurgical; physico-chemical (solidification/stabilization); thermal (vitrification), or appropriate combinations of treatment processes; carbon capture utilization and storage (CCUS)
Special Issues, Collections and Topics in MDPI journals
Dr. Evangelos Tzamos
E-Mail Website
Guest Editor
Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
Interests: field geology; mining; mineral processing; ore mineralogy; mining wastes; critical raw materials; environmental assessment

Special Issue Information

Dear Colleagues,

The need to adopt a circular economy model, incorporating all processing practices, and to formulate a development strategy that emphasizes critical raw material exploration and environmental integrity emerges as a major challenge for the mining industry. The engagement of mining and metallurgical companies with the research community, the policymakers and modern society appears as the only opportunity to accelerate the transformation of such a primary sector of the economy and promote innovative ideas, tools and methodologies.

On this concept, the main concern of the International Conference on Raw Materials and Circular Economy is to bring together academics, engineers, early-stage scientists, industry executives, agents of public bodies, stakeholders and other professionals from the field of raw materials for a comprehensive, cross-discipline exchange of knowledge. The main topics of the conference include:

  • New trends in mineral exploration and characterization;
  • Advances in mineral processing;
  • Sustainable metallurgy;
  • Novel industrial minerals;
  • Environment and energy issues;
  • Waste valorization;
  • Education on minerals;
  • Circular economy strategies;
  • Hygiene and safety aspects.

We invite all people from research institutes, government bodies and industry professionals to participate in the conference and share their latest developments in one of the trending topics. To all that are joining us at the conference, please do not miss out on this the opportunity to submit your full paper to the Special Issue.

Interesting contributions from RawMat 2021 and other researchers who work in this field are both welcome!

Prof. Dr. Anthimos Xenidis
Prof. Dr. Anastasios Zouboulis
Dr. Evangelos Tzamos
Guest Editors

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 submissions that pass pre-check are 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 2000 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

  • Critical raw materials
  • Circular economy strategies
  • Mining
  • Processing
  • Sustainability
  • Metallurgy
  • Industrial minerals
  • Environmental monitoring

Published Papers (5 papers)

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Research

Article
Structural and Surface Modification of Oxalic-Acid-Activated Bentonites in Various Acid Concentrations for Bleaching Earth Synthesis—A Comparative Study
Minerals 2022, 12(6), 764; https://doi.org/10.3390/min12060764 - 16 Jun 2022
Cited by 1 | Viewed by 654
Abstract
The aim of this study is to investigate the oxalic acid activation of bentonites containing different types of smectites, analyse their surface modification as a function of acid concentration and create good quality bleaching earths. In particular, two different bentonite samples (one containing [...] Read more.
The aim of this study is to investigate the oxalic acid activation of bentonites containing different types of smectites, analyse their surface modification as a function of acid concentration and create good quality bleaching earths. In particular, two different bentonite samples (one containing aluminum and one containing ferruginous smectite), after being characterized through XRD, XRF and FT-IR analysis, are treated with oxalic acid at a concentration of 0.5, 0.7 and 1 M. Their structural modifications after treatment are observed through FT-IR spectra and surface area and porosity measurement (using the BET equation and the BJH method, respectively) combined with the determination of the main structural metals’ extraction from them (using an atomic adsorption spectrometer). The results showed that the ferruginous smectite is more susceptible to oxalic acid activation compared to the aluminum smectite, and all the final products have developed extra porosity in their structure while retaining the structure of smectite (even at 0.5 M acid concentration). The activated samples were used as bleaching earths in soybean oil, and the results proved that Lovibond yellow and red colours as well as the chlorophyll of oil (measured spectrophotometrically) were reduced to the values set by the specifications. Full article
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Article
A Methodology Combining IDEF0 and Weighted Risk Factor Analysis for the Strategic Planning of Mine Reclamation
Minerals 2022, 12(6), 713; https://doi.org/10.3390/min12060713 - 03 Jun 2022
Cited by 1 | Viewed by 803
Abstract
The reclamation of lignite surface mines is a long-term commitment of high complexity. These reclamation projects consist of land use repurposing, reinstatement of landforms and landscape, remediation of polluted soils and water bodies, restoration of ecosystems, and other related activities, which are usually [...] Read more.
The reclamation of lignite surface mines is a long-term commitment of high complexity. These reclamation projects consist of land use repurposing, reinstatement of landforms and landscape, remediation of polluted soils and water bodies, restoration of ecosystems, and other related activities, which are usually developed when mines enter the ultimate phase of their operational life. Nowadays, reclamation is supported by regulatory settings and legislative provisions, which motivate the affected communities to move towards a circular economy and sustainable development. This paper investigates the geoenvironmental and socioeconomic problems of reclamation and draws research questions on how the strategic planning of a reclamation project can be performed and how the relevant project risks can be investigated and managed. In turn, a prototype methodology based on experts’ judgment is suggested with a case study combining: (a) the IDEF0 (Integrated DEFinition Function) modelling technique, as a low cost and easy-to-develop tool enabling strategic planning of reclamation projects, and (b) the Weighted Risk Factor analysis (WRF) as a suitable method for effective risk analysis and response planning in post-mining frameworks. Finally, a discussion on the methodology and proposals for further research are provided. Full article
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Article
The Effects of Surface Lignite Mines Closure on the Particulates Concentrations in the Vicinity of Large-Scale Extraction Activities
Minerals 2022, 12(3), 347; https://doi.org/10.3390/min12030347 - 14 Mar 2022
Cited by 1 | Viewed by 1031
Abstract
The European green deal and energy transition policies and the competition primarily shaped by the high price of carbon dioxide emission allowances and the consistently reduced cost of renewable energy technologies directly affect the coal and lignite extraction industry. Lignite production in Western [...] Read more.
The European green deal and energy transition policies and the competition primarily shaped by the high price of carbon dioxide emission allowances and the consistently reduced cost of renewable energy technologies directly affect the coal and lignite extraction industry. Lignite production in Western Macedonia Lignite Centre reduced from 43.2 million tons in 2010 to 10.3 million tons in 2020. This development affects the ambient air quality of the large lignite mine area, as evidenced by the records of 10 monitoring stations incorporating the laser light scattering method. All stations measure reduced particulate matter (PM10 and PM2.5) concentrations compared to the period before 2010, while the number of annual exceedances of the limit value for the daily average PM10 concentrations has been decreased. Moreover, differences in air quality measurements of monitoring stations related to their distance from mining activities now tend to be minimized. Based on these facts, it can be predicted that, after the closure of lignite extraction and the electricity generation activities, the concentration of particulates in the atmosphere will reach the typical levels for rural areas of Southern Europe, no matter what the mines’ land reforestation and repurposing program will include. Full article
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Article
Mining Waste as a Potential Additional Source of HREE and U for the European Green Deal: A Case Study of Bangka Island (Indonesia)
Minerals 2022, 12(1), 44; https://doi.org/10.3390/min12010044 - 28 Dec 2021
Cited by 5 | Viewed by 1393
Abstract
The European Commission has adopted the European Green Deal strategy, which aims to achieve climate neutrality in the EU by 2050. To achieve this goal, it is necessary to shift the economy toward the use of green and renewable energy. Critical raw materials [...] Read more.
The European Commission has adopted the European Green Deal strategy, which aims to achieve climate neutrality in the EU by 2050. To achieve this goal, it is necessary to shift the economy toward the use of green and renewable energy. Critical raw materials (CRMs), Li, Co, REE, Te, Sc and others, are used in renewable energy sources (RES) production. The EU lacks its own CRM deposits, and additionally, the access to already identified deposits is limited, which is making the EU countries search for alternative CRM sources. One such source of CRMs may be mining waste generated on the Indonesian island of Bangka as a result of processing cassiterite-bearing sands. Studies of the mineral composition of the waste using the XRD method reveal rich contents of xenotime (0.79–17.55 wt%), monazite (1.55–21.23 wt%), zircon (1.87–64.35 wt%) and other minerals, carriers of valuable metals, such as Sn, Ti, Nb, Ta. The point mineral chemistry analyses were performed using EPMA. Xenotime is the main carrier of heavy rare earth elements (HREE), especially the “most critical” HREEs: Gd2O3 (1.42–7.16 wt%), Dy2O3 (2.28–11.21 wt%), Er2O3 (2.44–7.85 wt%), and Yb2O3 (1.71–7.10 wt%). Xenotime is characterized by a complex internal structure resulting from metasomatic processes occurring during their formation. In SEM-BSE imaging, they show zonation of internal structure, which is the effect of an HREE, Y, Si and U substitution in the crystal structure. On the other hand, thorite ThSiO4 and uranothorite (Th,U)SiO4 inclusions are present in xenotimes. The ICP-MS/ES studies of tailings reveal very high contents of HREE + Y (up to 7.58 wt%), U (up to 0.11), Th (up to 0.75 wt%) and Sc (132 ppm). A CRM source diversification is part of the strategy to ensure the security of raw materials for countries of the European Union and the green transformation of the continent. Bilateral EU–Indonesia cooperation in the geological exploration and development of primary and secondary sources may contribute to an increase in the supply of HREEs to the global market. Full article
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Article
Analyzing Stability Conditions and Ore Dilution in Open Stope Mining
Minerals 2021, 11(12), 1404; https://doi.org/10.3390/min11121404 - 11 Dec 2021
Cited by 1 | Viewed by 2328
Abstract
Ore dilution is a fundamental problem for the production process in underground mining operations. Especially in open stoping methods of underground mining, the continuous estimation, monitoring and treatment of instability issues is considered necessary in order to maintain the consistency of the production [...] Read more.
Ore dilution is a fundamental problem for the production process in underground mining operations. Especially in open stoping methods of underground mining, the continuous estimation, monitoring and treatment of instability issues is considered necessary in order to maintain the consistency of the production process. This paper aims to combine empirical nomograms of stability estimation and numerical approaches and thus link the extensive experiences of the empirical design and the quantitative data derived by numerical analyses. To facilitate this, a large number of different geomechanical conditions were modeled and analyzed in the pursuit of obtaining valid and applicable relationships between the empirical stability graphs’ approaches and the numerical simulation models. The parametric analysis was made to express the stability conditions and the dilution with specific design characteristics, using prevalent stability-graph approaches while the numerical models were tested using the RS2 software package. The obtained results include direct and easy-to-use mathematical expressions that can be applied during the initial design of the stoping process, especially for the case of sidewalls (hanging walls and foot walls). Furthermore, through the research, an initial proposal is made for a dilution-based stability graph that could be utilized for the early identification of dilution. Full article
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