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Processing of End-of-Life Materials and Industrial Wastes–Volume 2
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Processing of End-of-Life Materials and Industrial Wastes–Volume 2

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Manufacturing Processes and Systems".

Deadline for manuscript submissions: closed (20 December 2024) | Viewed by 29174

Special Issue Editor

Dr. Ndue Kanari

E-Mail Website
Guest Editor
GeoRessources Laboratory, UMR 7359 CNRS, University of Lorraine, Nancy, France
Interests: materials processing; waste treatment; recycling; critical and strategic elements; thermochemical process
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Nowadays, along with the most common metals (Fe, Al, Cu, Zn, Ni…), a wide range of chemical elements (rare earth elements-REEs, Nb, Ta, W, In, Ga, Ge, platinum-group metals-PGMs, Li, Be, Sb, Mg, Co, V, Hf, Ti…) are in increasing demand and crucial for the development of renewable energies, the manufacturing of electrical and electronic equipment, new transportation modes, and for diverse advanced industries, which constitute the foundation of innovative high technologies [1]. These elements (mostly metals) are commonly considered to be critical and strategic materials. According to criticality assessments, the number of critical materials (CRMs) for the European Union has grown from 14 CRMs in 2011 to reach 30 CRMs in 2020. With the shortage of natural deposits rich in metals, other sourcing approaches should be envisaged to secure the societal needs of CRMs in the future.

In this context, this issue aims to bring together the latest scientific developments and technological progress in the processing of the following materials (but not limited to):

  • Low-grade raw materials (ores and concentrates of above-mentioned metals)
  • End-of-life materials (e-scraps, end-of-life vehicles, spent batteries and catalysts, etc.)
  • Industrial wastes and by-products (slags, ashes, dusts, sludges, etc.)

This issue emphasizes innovative approaches and advanced understanding and modeling related to thermal and combined methods (e.g., pyro-hydrometallurgy) for the processing of complex raw materials and residues. Unit processes (such as dry halogenation) and alternative approaches for the selective extraction of targeted metals are also appreciated.

Research contributions addressing recent progress in industrial wastes transformation into valuable materials and involving greener and/or more sustainable chemistry and process [2] are also greatly encouraged.

After our successful first volume [3], this Special Issue (second volume) welcomes regular articles, review articles, and short communications/notes about the above-mentioned fields and topics.

Reference

[1]   Kanari, N.; Allain, E.; Shallari, S.; Diot, F.; Diliberto, S.; Patisson, F.; Yvon, J. Thermochemical Route for Extraction and Recycling of Critical, Strategic and High Value Elements from By-Products and End-of-Life Materials, Part I: Treatment of a Copper By-Product in Air Atmosphere. Materials 2019, 12, 1625, https://doi.org/10.3390/ma12101625.

[2]   Kanari, N.; Ostrosi, E.; Diliberto, C.; Filippova, I.; Shallari, S.; Allain, E.; Diot, F.; Patisson, F.; Yvon, J. Green Process for Industrial Waste Transformation into Super-Oxidizing Materials Named Alkali Metal Ferrates (VI). Materials 2019, 12, 1977, https://doi.org/10.3390/ma12121977.

[3]   Kanari, N.; Shallari, S.; Allain, E. Processing of End-of-Life Materials and Industrial Wastes. Materials 2022, 15, 7662. https://doi.org/10.3390/ma15217662.

You are cordially invited to submit manuscripts for this Special Issue.

Dr. Ndue Kanari
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 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. Materials is an international peer-reviewed open access semimonthly 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 2600 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

  • low-grade raw materials
  • end-of-life materials
  • industrial wastes and by-products
  • rare-earth elements (REE) ores and concentrates
  • Li, Ta-Nb-Sn raw materials
  • thermochemical and combined methods for processing
  • extractive metallurgy
  • dry halogenation (chlorination)
  • thermodynamics and kinetics
  • valuable, critical and strategic elements (CRMs)
  • extraction and recovery
  • green chemistry/process

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Published Papers (16 papers)

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17 pages, 9317 KiB  
Article
Development of Technologies for Processing Polypropylene Foil Waste and Their Use in the Production of Finished Products
by Damian Dziadowiec, Karina Walburg, Danuta Matykiewicz, Jacek Andrzejewski and Marek Szostak
Materials 2024, 17(21), 5192; https://doi.org/10.3390/ma17215192 - 24 Oct 2024
Viewed by 1012
Abstract
This work aims to assess the possibility of using packaging industry waste to modify polypropylene products (PPs). The products were made in the form of extruded foil and injected samples. The products were produced using regranulate made of polypropylene cast foil. Maleic anhydride-modified [...] Read more.
This work aims to assess the possibility of using packaging industry waste to modify polypropylene products (PPs). The products were made in the form of extruded foil and injected samples. The products were produced using regranulate made of polypropylene cast foil. Maleic anhydride-modified polypropylene (MAPP) and polyolefin elastomer (POE) with a glycidyl ester functional group were used to modify the polypropylene. The samples were produced based on 50% foil waste reground and 50% pure PP. The rheological properties of the blends were assessed using the melt mass flow rate (MFR) technique; thermal properties using the differential scanning calorimetry method (DSC). The products manufactured using the injection molding method were subjected to an analysis of mechanical properties, such as tensile strength and impact strength. Also, in the case of film samples, tensile strength was assessed. Color-change assessments with CIE L*a*b* were carried out for all materials. Injection-molded products based on recycled metallized cast foil showed favorable mechanical properties such as tensile strength (1 MAPP = 26.7 MPa; 2 MAPP = 27.1 MPa), which was higher than the original material (cPP = 20.7 MPa). Also, for the films produced from regrind, the tensile strength was at a level similar (1 MAPP = 24.6 MPa; 2 MAPP/POE = 25.1 MPa) to the films extruded from virgin materials (cPP = 24.9 MPa). The introduction of a POE additive to the blends resulted in increased impact strength (1 MAPP/POE = 31 kJ/mol; 2MAPP/POE = 18 kJ/mol; 3 MAPP/POE = 11 kJ/mol) in relation to unmodified samples (cPP = 7 kJ/mol). The introduction of a POE additive to the tested mixtures improved the impact strength of the injected products by almost 4 times for sample 1 MAPP/POE and 2.5 times for sample 2 MAPP/POE in comparison to virgin cPP. These studies confirmed that foil waste can be successfully used to modify polypropylene products shaped both in the injection and extrusion processes. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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18 pages, 3971 KiB  
Article
Selective Extraction of Valuable and Critical Metals in Cassiterite Concentrate by Dry Chlorination, Part I: Thermodynamic and Modelling Perspective
by Allen Yushark Fosu, Bastien Demeusy, Frédéric Diot, Tiina Lavonen, Veronika Meriläinen, Danièle Bartier, Yann Foucaud and Ndue Kanari
Materials 2024, 17(17), 4186; https://doi.org/10.3390/ma17174186 - 23 Aug 2024
Cited by 1 | Viewed by 1413
Abstract
The chlorination of oxides of major concern in cassiterite concentrate with various chlorinating agents is investigated in light of their thermodynamic feasibilities to extract and recover their valuable metal components. Mechanisms responsible for the processes and their Gibbs free energy changes as a [...] Read more.
The chlorination of oxides of major concern in cassiterite concentrate with various chlorinating agents is investigated in light of their thermodynamic feasibilities to extract and recover their valuable metal components. Mechanisms responsible for the processes and their Gibbs free energy changes as a function of temperature to selectively separate and/or recover the metal(s) of interest and unwanted ones as their metallic chlorides are identified. Attention is given to gaseous (Cl2 and Cl2 + CO mixture) and solid (CaCl2 and MgCl2) chlorine sources, from which Cl2 + CO shows no reaction selectivity for any of the oxides but a feasible metal chloride formation for all. Chlorine gas (Cl2), on the other hand, could selectively form chlorides with metals of +2 oxidation state in their oxides, leaving those of high oxidation state unreacted. MgCl2, unlike CaCl2, is found capable of producing calcium, ferrous, and stannic chloride from their metallic oxides with enhanced reaction tendencies in the presence of silicon dioxide (SiO2). An overall study of the thermodynamic feasibility of all chlorine sources looked at alongside operational and environmental viabilities suitably suggests MgCl2 for a selective extraction of the valuable metal components in a cassiterite concentrate, in which case, moderate temperatures seem promising. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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16 pages, 1371 KiB  
Article
Geopolymer Materials from Fly Ash—A Sustainable Approach to Hazardous Waste Management
by Katarzyna Zarębska, Jakub Szczurowski, Joanna Muszyńska and Paweł Baran
Materials 2024, 17(14), 3515; https://doi.org/10.3390/ma17143515 - 16 Jul 2024
Cited by 2 | Viewed by 1344
Abstract
This study explores the utilisation challenges of fly ash from municipal waste incineration, specifically focusing on ash from a dry desulphurisation plant (DDS), which is categorised as hazardous due to its high heavy metal content. The ash’s low silicon and calcium contents restrict [...] Read more.
This study explores the utilisation challenges of fly ash from municipal waste incineration, specifically focusing on ash from a dry desulphurisation plant (DDS), which is categorised as hazardous due to its high heavy metal content. The ash’s low silicon and calcium contents restrict its standalone utility. Laboratory investigations initially revealed that geopolymers derived solely from fly ash after flue gas treatment (FGT), in combination with coal combustion fly ash, exhibited low compressive strength (below 0.6 MPa). However, the study demonstrated significant improvements by modifying the FGT ash through water leaching. This process enhanced its performance when mixed with high-silica and -aluminium fly ash, resulting in geopolymers achieving compressive strengths of up to 18 MPa. Comparable strength outcomes were observed when the modified ash was blended with commercial cement. Leachability tests conducted for heavy metals (HMs) such as copper, zinc, lead, cadmium, and nickel indicated that their concentrations fell below the regulatory limits for landfill disposal: 2, 4, 0.5, 0.04, and 0.4 mg/kg, respectively. These results underscore the effectiveness of water-washing FGT ash in conjunction with other materials for producing geopolymers, contributing to sustainable waste management practices. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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23 pages, 4892 KiB  
Article
The Impact of Abiotic and Biotic Conditions for Degradation Behaviors of Common Biodegradable Products in Stabilized Composts
by Sylwia Stegenta-Dąbrowska, Marek Korendał, Maks Kochanowicz, Marcin Bondos, Paweł Wiercik, Agnieszka Medyńska-Juraszek and Christian Zafiu
Materials 2024, 17(12), 2948; https://doi.org/10.3390/ma17122948 - 16 Jun 2024
Cited by 1 | Viewed by 1987
Abstract
This work examines the influence of the degradation behaviors of biotic and abiotic conditions on three types of biodegradable products: cups from PLA and from cellulose, and plates from sugarcane. The main objective of this study was to evaluate if biodegradable products can [...] Read more.
This work examines the influence of the degradation behaviors of biotic and abiotic conditions on three types of biodegradable products: cups from PLA and from cellulose, and plates from sugarcane. The main objective of this study was to evaluate if biodegradable products can be degraded in composts that were stabilized by backyard composting. Furthermore, the impact of crucial abiotic parameters (temperature and pH) for the degradation behaviors process was investigated. The changes in the biopolymers were analyzed by FTIR spectroscopy. This work confirmed that abiotic and biotic conditions are important for an effective disintegration of the investigated biodegradable products. Under abiotic conditions, the degradation behaviors of PLA were observable under both tested temperature (38 and 59 °C) conditions, but only at the higher temperature was complete disintegration observed after 6 weeks of incubation in mature compost. Moreover, our research shows that some biodegradable products made from cellulose also need additional attention, especially with respect to incorporated additives, as composting could be altered and optimal conditions in composting may not be achieved. This study shows that the disintegration of biodegradable products is a comprehensive process and requires detailed evaluation during composting. The results also showed that biodegradable products can also be degraded post composting and that microplastic pollution from biodegradable polymers in soil may be removed by simple physical treatments. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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20 pages, 63501 KiB  
Article
The Different Properties of Geopolymer Composites Reinforced with Flax Fibers and Carbon Fibers
by Francesca Brugaletta, Anton Frederik Becher, Danilo Laurent Rostagno, JeongHye Kim, José Ignacio Fresneda Medina, Celina Ziejewska, Joanna Marczyk and Kinga Korniejenko
Materials 2024, 17(11), 2633; https://doi.org/10.3390/ma17112633 - 29 May 2024
Cited by 3 | Viewed by 1482
Abstract
The main motivation for this research was to improve the properties of geopolymers by reinforcement using synthetic and natural fibers, and to gain new knowledge regarding how the nature and/or the quantity of reinforcement fibers influences the properties of the final geopolymers. The [...] Read more.
The main motivation for this research was to improve the properties of geopolymers by reinforcement using synthetic and natural fibers, and to gain new knowledge regarding how the nature and/or the quantity of reinforcement fibers influences the properties of the final geopolymers. The main objective was to investigate the effects of different types of reinforcement fibers on the properties of the geopolymers. These reinforcement fibers were mainly environmentally friendly materials that can be used as alternatives to ordinary Portland cement. The authors used fly ash and river sand as the raw materials for the matrix, and added carbon fibers (CF), flax fibers (FF), or a hybrid of both (CFM) as reinforcements. The samples were prepared by mixing, casting, and curing, and then subjected to various tests. The main research methods used were compressive strength (CS), flexural strength (FS), water absorption (WA), abrasion resistance (Böhme’s disk method), microstructure analysis (SEM), chemical composition (XRF), and crystal structure analysis (XRD). The results showed that the addition of fibers partially improved the mechanical properties of the geopolymers, as well as reducing microcracks. The CF-reinforced geopolymers exhibited the highest compressive strength, while the FF-reinforced geopolymers showed the lowest water absorption. The authors, based on previous research, also discussed the factors that influence fiber-matrix adhesion, and the optimal fiber content for geopolymers. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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18 pages, 5631 KiB  
Article
Use of Alkaline-Activated Energy Waste Raw Materials in Geopolymer Concrete
by Marta Nalewajko and Michał Bołtryk
Materials 2024, 17(10), 2253; https://doi.org/10.3390/ma17102253 - 10 May 2024
Viewed by 1049
Abstract
Silica fly ash, Certyd aggregate, and an alkaline solution were used to produce lightweight geopolymer concretes. The compressive strength, water absorption, and bulk density results, along with SEM photos showing the structure of the obtained composite, were obtained. Tests conducted on the specifications [...] Read more.
Silica fly ash, Certyd aggregate, and an alkaline solution were used to produce lightweight geopolymer concretes. The compressive strength, water absorption, and bulk density results, along with SEM photos showing the structure of the obtained composite, were obtained. Tests conducted on the specifications of lightweight geopolymer concretes have revealed significant chemical interactions between the ash aggregate and the geopolymer mortar, particularly when the coarse aggregate surface has been pre-treated with an alkaline solution. A statistical analysis of the experimental data, which investigated the influence of three key variables on the compressive strength, water absorption, and bulk density of lightweight geopolymer concrete (LBG), identified the following factors as having the most substantial impact: the quantity of alkali used, the curing temperature, and the concentration of alkali in the mixture. The optimal test series exhibited a commendable compressive strength of 20.14 megapascals (MPa), accompanied by a water absorption rate of 14.72%, and a bulk density of 1486.6 kg per cubic meter (kg/m³). These findings underscore the importance of alkali content, curing temperature, and alkali concentration in tailoring the properties of lightweight geopolymer concrete to meet specific performance requirements. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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22 pages, 24259 KiB  
Article
The Waelz Slag from Electric Arc Furnace Dust Processing: Characterization and Magnetic Separation Studies
by Pavel Grudinsky, Anfisa Yurtaeva, Denis Pankratov, Liliya Pasechnik, Roman Musaelyan and Valery Dyubanov
Materials 2024, 17(10), 2224; https://doi.org/10.3390/ma17102224 - 8 May 2024
Cited by 2 | Viewed by 2023
Abstract
The Waelz slag generated during electric arc furnace dust processing is an iron-rich product with significant amounts of iron, zinc and copper. About 600–800 kg of the Waelz slag is generated per ton of the dust processed. The Waelz slag samples from two [...] Read more.
The Waelz slag generated during electric arc furnace dust processing is an iron-rich product with significant amounts of iron, zinc and copper. About 600–800 kg of the Waelz slag is generated per ton of the dust processed. The Waelz slag samples from two different plants were thoroughly characterized using inductively coupled plasma optical emission spectroscopy (ICP-AES), X-ray diffraction analysis (XRD), chemical phase analysis, Mössbauer spectroscopy and other supporting methods. The phase distribution of iron, zinc and copper was determined in the Waelz slag samples. Low-intensity wet magnetic separation was tested for the iron recovery from the Waelz slag samples. It was found that the Waelz slag samples have complex chemical and mineralogical compositions, which can impede the selective recovery of valuable elements. The obtained results indicate that the chemical and mineralogical composition of the Waelz slag samples has a considerable effect on the magnetic separation indexes. The experiments showed that the iron concentrates with Fe contents of 73% and 46.8% with the metallization degrees of 87.2% and 57.5% and the iron recovery degree of 54.8% and 52.9% were obtained at optimal conditions for two different samples, respectively, without selective segregation of Cu and Zn in the magnetic or non-magnetic fraction. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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25 pages, 11428 KiB  
Article
Use of Limestone Sludge in the Preparation of ɩ-Carrageenan/Alginate-Based Films
by Pedro Adão, Maria da Luz Calado, Wilson Fernandes, Luís G. Alves, Leonor Côrte-Real, Mafalda Guedes, Ricardo Baptista, Raul Bernardino, Maria M. Gil, Maria Jorge Campos and Susana Bernardino
Materials 2024, 17(7), 1668; https://doi.org/10.3390/ma17071668 - 5 Apr 2024
Cited by 2 | Viewed by 1835
Abstract
The use of processed limestone sludge as a crosslinking agent for films based on Na–alginate and ɩ-carrageenan/Na-alginate blends was studied. Sorbitol was tested as a plasticizer. The produced gel formulations included alginate/sorbitol and carrageenan/alginate/sorbitol mixtures, with tested sorbitol concentrations of 0.0, 0.5 and [...] Read more.
The use of processed limestone sludge as a crosslinking agent for films based on Na–alginate and ɩ-carrageenan/Na-alginate blends was studied. Sorbitol was tested as a plasticizer. The produced gel formulations included alginate/sorbitol and carrageenan/alginate/sorbitol mixtures, with tested sorbitol concentrations of 0.0, 0.5 and 1.0 wt%. The limestone sludge waste obtained from the processing of quarried limestone was converted into an aqueous solution of Ca2+ by dissolution with mineral acid. This solution was then diluted in water and used to induce gel crosslinking. The necessity of using sorbitol as a component of the crosslinking solution was also assessed. The resulting films were characterized regarding their dimensional stability, microstructure, chemical structure, mechanical performance and antifungal properties. Alginate/sorbitol films displayed poor dimensional stability and were deemed not viable. Carrageenan/alginate/sorbitol films exhibited higher dimensional stability and smooth and flat surfaces, especially in compositions with 0.5 wt% sorbitol. However, an increasing amount of plasticizer appears to result in severe surface cracking, the development of a segregation phenomenon affecting carrageenan and an overall decrease in films’ mechanical resistance. Although further studies regarding film composition—including plasticizer fraction, film optimal thickness and film/mold material interaction—are mandatory, the attained results show the potential of the reported ɩ-carrageenan/alginate/sorbitol films to be used towards the development of viable films derived from algal polysaccharides. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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16 pages, 5040 KiB  
Article
Synthesis of Electrolytic Manganese Slag–Solid Waste-Based Geopolymers: Compressive Strength and Mn Immobilization
by Bao Mi, Hui Zhao, Meng Lu, Yi Zhou and Yongjie Xue
Materials 2024, 17(6), 1431; https://doi.org/10.3390/ma17061431 - 21 Mar 2024
Cited by 4 | Viewed by 1541
Abstract
The massive stockpiling of electrolytic manganese residue (EMR) has caused serious environmental pollution. In this study, EMR, coal gangue (CG), and fly ash (FA) were used as raw materials to obtain the optimal mix ratio based on Design-Expert mixture design. The effects of [...] Read more.
The massive stockpiling of electrolytic manganese residue (EMR) has caused serious environmental pollution. In this study, EMR, coal gangue (CG), and fly ash (FA) were used as raw materials to obtain the optimal mix ratio based on Design-Expert mixture design. The effects of activator modulus, liquid–solid (L/S) ratio, and curing temperature on the mechanical properties of geopolymers were investigated. The results showed that the compressive strength of the prepared geopolymer was 12.0 MPa, and the 28d leaching of Mn was 0.123 mg/L under the conditions of EMR:CG:FA = 0.43:0.34:0.23, L/S = 0.9, a curing temperature of 60 °C, and a curing time of 24 h. This indicates that the geopolymer is an environmentally friendly material with high compressive strength. The mineral composition of the geopolymer is mainly hydrated calcium silicate and geopolymer gel. In addition, a more stable new mineral phase, MnSiO3, was generated. The Fourier transform infrared (FTIR) spectrogram showed that the peak at 1100 m−1 was shifted to 1112 cm−1, which indicated that a geopolymerization reaction had occurred. Through scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis, it was identified that the geopolymerization produced a large amount of amorphous gelatinous substances with a relatively dense structure, the major elements being oxygen, silicon, aluminum, calcium, and sodium. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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12 pages, 5041 KiB  
Article
Improvement of the Hydrogen Storage Characteristics of MgH2 with Al Nano-Catalyst Produced by the Method of Electric Explosion of Wires
by Viktor N. Kudiiarov, Alan Kenzhiyev and Andrei V. Mostovshchikov
Materials 2024, 17(3), 639; https://doi.org/10.3390/ma17030639 - 28 Jan 2024
Cited by 3 | Viewed by 2035
Abstract
A new composite with a core–shell structure based on magnesium hydride and finely dispersed aluminum powder with an aluminum oxide shell was mechanically synthesized. We used magnesium chips to produce magnesium hydride and aluminum wire after exploitation to produce nano-sized aluminum powder. The [...] Read more.
A new composite with a core–shell structure based on magnesium hydride and finely dispersed aluminum powder with an aluminum oxide shell was mechanically synthesized. We used magnesium chips to produce magnesium hydride and aluminum wire after exploitation to produce nano-sized aluminum powder. The beginning of the hydrogen release from the composite occurred at the temperature of 117 °C. The maximum desorption temperature from the MgH2-EEWAl composite (10 wt.%) was 336 °C, compared to pure magnesium hydride—417 °C. The mass content of hydrogen in the composite was 5.5 wt.%. The positive effect of the aluminum powder produced by the electric explosion of wires method on reducing the activation energy of desorption was demonstrated. The composite’s desorption activation energy was found to be 109 ± 1 kJ/mol, while pure magnesium hydride had an activation energy of 161 ± 2 kJ/mol. The results obtained make it possible to expand the possibility of using magnesium and aluminum waste for hydrogen energy. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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21 pages, 7071 KiB  
Article
Mineral Weathering and Metal Leaching under Meteoric Conditions in F-(Ba-Pb-Zn) Mining Waste of Hammam Zriba (NE Tunisia)
by Oumar Barou Kaba, Fouad Souissi, Daouda Keita, Lev O. Filippov, Mohamed Samuel Moriah Conté and Ndue Kanari
Materials 2023, 16(23), 7443; https://doi.org/10.3390/ma16237443 - 30 Nov 2023
Cited by 4 | Viewed by 1701
Abstract
Mining waste is an obvious source of environmental pollution due to the presence of heavy metals, which can contaminate soils, water resources, sediments, air, and people living nearby. The F-(Ba-Pb-Zn) deposit of Hammam Zriba located in northeast Tunisia, 8 km southeast of Zaghouan [...] Read more.
Mining waste is an obvious source of environmental pollution due to the presence of heavy metals, which can contaminate soils, water resources, sediments, air, and people living nearby. The F-(Ba-Pb-Zn) deposit of Hammam Zriba located in northeast Tunisia, 8 km southeast of Zaghouan was intensively exploited from 1970 to 1992. More than 250,000 m3 of flotation tailings were produced and stored in the open air in three dumps without any measure of environmental protection. Thus, in this paper, mineralogical and chemical characterization, especially the sulfide and carbonate phases, were carried out to evaluate the potential for acid mining drainage (AMD) and metal leaching (ML). Conventional analytical methods (XRD, XRF, SEM) have revealed that this mining waste contains on average 34.8% barite–celestine series, 26.6% calcite, 23% quartz, 6.3% anglesite, 4.8% fluorite, 2.1% pyrite, and 0.4% sphalerite. The content of sulfides is less important. The tailing leaching tests (AFNOR NFX 31-210 standard) did not generate acidic leachate (pH: 8.3). The acidity produced by sulfide oxidation was neutralized by calcite present in abundance. Furthermore, the leaching tests yielded leachates with high concentrations of heavy metals, above the authorized thresholds. This high mobilization rate in potential toxic elements (PTE) represents a contamination risk for the environment. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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16 pages, 7552 KiB  
Article
Stress–Strain Behavior of Crushed Concrete as a Special Anthropogenic Soil
by Katarzyna Gabryś, Katarzyna Dołżyk-Szypcio, Zenon Szypcio and Wojciech Sas
Materials 2023, 16(23), 7381; https://doi.org/10.3390/ma16237381 - 27 Nov 2023
Cited by 2 | Viewed by 1197
Abstract
The stress–plastic dilatancy relationship was investigated for crushed concrete during drained and undrained triaxial compression tests in the light of the frictional state concept. The slope of the dilatant failure state line is greater than that of quartz sand for drained triaxial compression [...] Read more.
The stress–plastic dilatancy relationship was investigated for crushed concrete during drained and undrained triaxial compression tests in the light of the frictional state concept. The slope of the dilatant failure state line is greater than that of quartz sand for drained triaxial compression due to the crushing effect. The crushing effect parameters for drained and undrained conditions are very similar. Due to the very angular shape of crushed concrete grains, the crushing effect is observed at low stress levels. Some characteristic behaviors of geomaterials during shear are visible only in the stress ratio–plastic dilatancy plane and are very rarely presented in the literature. The stress ratio–plastic dilatancy relationship, which is basic in elastic–plastic modeling of geomaterials, can be described using the frictional state concept. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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20 pages, 6840 KiB  
Article
Fresh, Mechanical, and Thermal Properties of Cement Composites Containing Recycled Foam Concrete as Partial Replacement of Cement and Fine Aggregate
by Jan Pizoń
Materials 2023, 16(22), 7169; https://doi.org/10.3390/ma16227169 - 15 Nov 2023
Cited by 3 | Viewed by 1550
Abstract
The research presented in this article was conducted to evaluate the suitability of recycled foam concrete (RFC) as an ingredient in newly created cement mortars. The basis for an analysis was the assumption that the waste is collected selectively after separation from other [...] Read more.
The research presented in this article was conducted to evaluate the suitability of recycled foam concrete (RFC) as an ingredient in newly created cement mortars. The basis for an analysis was the assumption that the waste is collected selectively after separation from other waste generated during demolition. The motivation for the research and its main problem is a comparison of the performance of RFC used in various forms. RFC was used in two forms: (1) recycled foam concrete dust (RFCD) as a 25 and 50% replacement of cement, and (2) recycled foam concrete fine aggregate (RFCA) as a 10, 20, and 30% replacement of sand. The basic properties of fresh and hardened mortars were determined: consistency, density, initial setting time, absorbability, compressive strength, thermal conductivity coefficient, and heat capacity. Research is complemented with SEM observations. The properties of fresh mortars and mechanical parameters were decreased with the usage of any dosage of RFC in any form, but the thermal properties were improved. The required superplasticizer amount for proper consistency was raised four times for replacing cement with 50% of RFCD than for 25% of such replacement. The mix density dropped by about 8% and 9% for mortars with the replacement of 50% cement by RFCD and 30% sand by RFCA in comparison to reference mortar. A 30% decrease in initial setting time was observed for cement replacement. In the case of sand replacement, it was the opposite—an increase of 100%. The dry density decreased by about 14% and 11% for mortars with the replacement of 50% cement by RFCD and 30% sand by RFCA in comparison to reference mortar. Absorbability was raised by about two times after replacement with both RFCD and RFCA. Compressive strength after 28 days dropped significantly by 75% and 60%, and the thermal conductivity coefficient decreased by 20% and 50% with 50% RFCD added instead of cement and 30% RFCA replacing sand. It indicates greater efficiency in thermomechanical means from RFCA in comparison to RFCD. This material can be used especially in the production of plaster and masonry mortar. Linear correlations of dry density and thermal conductivity coefficient and the latter and compressive strength were proven as reliable for RFCD replacement of cement and RFCA replacement of sand in mortars with greater w/c ratio. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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27 pages, 8158 KiB  
Article
Investigation of the Bimodal Leaching Response of RAM Chip Gold Fingers in Ammonia Thiosulfate Solution
by Peijia Lin, Zulqarnain Ahmad Ali and Joshua Werner
Materials 2023, 16(14), 4940; https://doi.org/10.3390/ma16144940 - 11 Jul 2023
Cited by 4 | Viewed by 1891
Abstract
Oxidative thiosulfate leaching using Cu(II)-NH3 has been explored for both mining and recycling applications as a promising method for Au extraction. This study seeks to understand the dissolution behavior of Au from waste RAM chips using a Cu(II)-NH3-S2O [...] Read more.
Oxidative thiosulfate leaching using Cu(II)-NH3 has been explored for both mining and recycling applications as a promising method for Au extraction. This study seeks to understand the dissolution behavior of Au from waste RAM chips using a Cu(II)-NH3-S2O3 solution. In the course of this work, bimodal leaching and Au loss were observed in a manner that we have not identified in the literature. Identification of the existence of a specific Au-Ni-Cu lamellar structure in the gold fingers from RAM chips by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) revealed the possibility of interference between Au recovery and the existence of Cu and Ni. During leaching, the co-extraction of Ni was found to predict a negative impact on the Au recovery, as a result of chemical interactions from the Au-Ni-Cu interlayer. Decopperization as a pretreatment was found necessary to remove the pre-existing Cu and promote Au leaching. As part of the study parameters, such as Cu(II) concentration, aeration rates, thiosulfate and ammonia concentrations, particle sizes, and temperatures, were investigated. A satisfactory Au recovery of 98% was achieved using 50 mM Cu(II), 120 mL/min aeration rate, 0.5 M (NH3)2S2O3, and 0.75 M NH4OH (i.e., AT/AH ratio of 0.67) for 4 h residence time at room temperature (25 °C). However, there were several high recoveries prior to Au loss from the lixiviant. It was revealed that the main cause of lower Au recovery was due to a precipitation or cementation reaction that included a sulfur species formation. Because of the bimodal leaching, a composite response comprised of the time to Au loss and maximum recovery was developed, termed leaching proclivity, to facilitate statistical analysis. Furthermore, this study explores the interactions between Au-Ni-Cu and provides suggestions for improving Au thiosulfate leaching under the interference of co-existing metals from waste PCB materials. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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Review

Jump to: Research

17 pages, 2644 KiB  
Review
Insight into the Extractive Metallurgy of Tin from Cassiterite
by Allen Yushark Fosu, Danièle Bartier, Frédéric Diot and Ndue Kanari
Materials 2024, 17(13), 3312; https://doi.org/10.3390/ma17133312 - 4 Jul 2024
Cited by 2 | Viewed by 2388
Abstract
This review details both the conventional and emerging methods of extracting tin from cassiterite. The emerging methods reviewed include sulphuric acid leaching of SnO, cooling crystallization of SnO, sulphide leaching, alkaline leaching, and dry chlorination. From these methods, the conventional approach (direct reduction [...] Read more.
This review details both the conventional and emerging methods of extracting tin from cassiterite. The emerging methods reviewed include sulphuric acid leaching of SnO, cooling crystallization of SnO, sulphide leaching, alkaline leaching, and dry chlorination. From these methods, the conventional approach (direct reduction smelting) stands out as the sole method that is suitable for industrial application, with none of the emerging ones being promising enough to be a contender. The thermodynamics involved in the hydrometallurgical extraction of tin from the mineral are also discussed. ΔGo values calculated at 25 °C for the reduction–dissolution of SnO2 using reducing gases revealed feasibility only when carbon monoxide was used. An indication of the possible species produced during the hydrolysis of the oxide of the metal (SnO2 and SnO) as a function of pH (ranging from −2 to 14 and 0 to 14 for SnO2 and SnO, respectively) was noted and highlighted to link a Pourbaix diagram generated from literature data. This diagram suggests that the solubility of SnO2 in both strongly acidic and alkaline media is possible, but with a small dissolution window in each. The purification and recovery routes of the various processing techniques were then envisaged. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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19 pages, 4450 KiB  
Review
Zinc and Lead Metallurgical Slags as a Potential Source of Metal Recovery: A Review
by Katarzyna Nowińska and Zdzisław Adamczyk
Materials 2023, 16(23), 7295; https://doi.org/10.3390/ma16237295 - 23 Nov 2023
Cited by 8 | Viewed by 2718
Abstract
This article presents the mineralogical and chemical characteristics of zinc and lead smelting slags, with particular reference to the slags formed during the simultaneous production of Zn and Pb by the Imperial Smelting Process. These slags, because of the presence of many metals [...] Read more.
This article presents the mineralogical and chemical characteristics of zinc and lead smelting slags, with particular reference to the slags formed during the simultaneous production of Zn and Pb by the Imperial Smelting Process. These slags, because of the presence of many metals in their composition, mainly in the form of crystalline phases, are a valuable source for their extraction. Slags from Zn-Pb metallurgy are processed on an industrial scale using pyrometallurgical and hydrometallurgical methods, alongside which a number of experiments conducted to recover metals as efficiently as possible, including bioleaching experiments. Full article
(This article belongs to the Special Issue Processing of End-of-Life Materials and Industrial Wastes–Volume 2)
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