Topic Editors

Dr. Sossio Fabio Graziano
Pharmacy Department, Federico II University, 49-80131 Naples, Italy
Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, 10129 Torino, Italy
Department of Earth Sciences, University of Torino, 10124 Torino, Italy
Department of Civil, Environmental and Architecture Engineering, Università degli Studi di Cagliari, 09124 Cagliari, Italy

Sustainable Recycling and Reuse of Industrial By-Products or Waste from Geo-Resource Exploitation

Abstract submission deadline
30 September 2025
Manuscript submission deadline
30 November 2025
Viewed by
11373

Topic Information

Dear Colleagues,

Recycling waste generated by the industrial exploitation of georesources could enhance the utilization of the useful minerals they contain, such as rare earth elements (REEs), critical raw materials (CRMs) and secondary raw materials. Consciously recovering quarry waste or reusing the waste produced by processing operations for georesources means considering them no longer as waste, but as secondary raw materials to be used in further production processes from the perspective of a circular economy; this thus enables vital objectives, such as the following, to be pursued:

  • The recovery of mineral raw materials resulting in the opening of new markets;
  • A reduction in landfills (up to their possible removal), resulting in soil dumping and a reduced impact on the landscape;
  • A reduction of business burdens related to the disposal and generation of added value related to the sale of mineral concentrates directly from quarries.

Herein, this Topic aims to collect original research articles and review papers.

The scope of this Topic includes, but is not limited to, the following areas of interest:

  • industrial waste management;
  • secondary raw materials;
  • exploitation of industrial by-products;
  • natural deposits and recovery of critical metals from waste materials and landfills;
  • innovative approaches for mineral exploitation;
  • sustainability in industrial processing;
  • sustainability in quarrying waste disposal.

Dr. Sossio Fabio Graziano
Dr. Rossana Bellopede
Dr. Giovanna Antonella Dino
Dr. Nicola Careddu
Topic Editors

Keywords

  • quarry waste
  • rare earth elements
  • critical raw materials
  • secondary raw materials
  • environmentally-friendly materials
  • landfill disposal alternative

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Materials
materials
3.1 5.8 2008 15.5 Days CHF 2600 Submit
Mining
mining
- 2.8 2021 19.6 Days CHF 1000 Submit
Recycling
recycling
4.6 6.8 2016 22.7 Days CHF 1800 Submit
Resources
resources
3.6 7.2 2012 33.4 Days CHF 1600 Submit
Sustainability
sustainability
3.3 6.8 2009 20 Days CHF 2400 Submit
Minerals
minerals
2.2 4.1 2011 18 Days CHF 2400 Submit

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Published Papers (9 papers)

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17 pages, 7074 KiB  
Article
Upcycling Mill Scale and Aluminum Dross for Sustainable Materials Processing: Synthesis of Hercynite via Fe2O3-Al2O3-C Combustion
by Nuntaporn Kongkajun, Benya Cherdhirunkorn and Somyote Kongkarat
Recycling 2024, 9(5), 80; https://doi.org/10.3390/recycling9050080 - 17 Sep 2024
Viewed by 480
Abstract
This study investigates the potential of utilizing industrial by-products—mill scale (MS) and aluminum dross (AD)—as sources of Fe2O3 and Al2O3, respectively, for hercynite (FeAl2O4) production. Through combustion of MS-AD-graphite systems at 1550 [...] Read more.
This study investigates the potential of utilizing industrial by-products—mill scale (MS) and aluminum dross (AD)—as sources of Fe2O3 and Al2O3, respectively, for hercynite (FeAl2O4) production. Through combustion of MS-AD-graphite systems at 1550 °C under air atmosphere, hercynite-based refractory materials were synthesized. Results confirm the viability of this upcycling approach for hercynite synthesis. During the formation of hercynite, the development of a dendritic structure can be observed, which subsequently fuses into a grain shape. XRD phase analysis using the Rietveld method revealed that the major components of the product with a C/O ratio of 1 were 85.11% FeAl2O4, 10.99% Al2O3, and 3.9% C. For the product with a C/O ratio of 2, the composition was 82.4% FeAl2O4, 13.0% Al2O3, and 4.6% C. The combustion of raw pellets with a C/O ratio of 1 at 1550 °C for 1 h in a normal air atmosphere is economically viable for producing hercynite, yielding 85.11 wt%. This approach presents a sustainable and eco-friendly alternative to using commercial raw materials, potentially eliminating the need for virgin alumina and iron ore. By repurposing waste materials from the steel and aluminum industries, this study contributes to the circular economy and aligns with the goal of zero waste. Full article
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18 pages, 1012 KiB  
Review
Research Trends on Valorisation of Agricultural Waste Discharged from Production of Distilled Beverages and Their Implications for a “Three-Level Valorisation System”
by Kelly Stewart, Nik Willoughby and Shiwen Zhuang
Sustainability 2024, 16(16), 6847; https://doi.org/10.3390/su16166847 - 9 Aug 2024
Viewed by 974
Abstract
The circular economy, driven by waste elimination, material circulation and nature regeneration, is crucial for business, people, and the environment. With the increasing demand for distilled beverages, managing agricultural waste like spent grains is paramount. While previous studies focused on individual beverages, investigating [...] Read more.
The circular economy, driven by waste elimination, material circulation and nature regeneration, is crucial for business, people, and the environment. With the increasing demand for distilled beverages, managing agricultural waste like spent grains is paramount. While previous studies focused on individual beverages, investigating technologies across different types of beverages has been overlooked. This paper provides a systematic review of agricultural waste valorisation over the past five years, focusing on four representative distilled beverages: whisk(e)y, tequila, baijiu and shochu. Research efforts have primarily focused on bioenergy production from whisk(e)y and tequila waste, whereas extracting functional substances is common for baijiu and shochu. Through integrating different technologies, a “Three-level Valorisation System” was proposed to enhance the translation of agricultural waste into value-added products like proteins. This system is directly relevant to the distilled beverage industry globally and applicable to associated industries such as biofuel and food production. Full article
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15 pages, 6308 KiB  
Article
Silicon Kerf Recovery via Acid Leaching Followed by Melting at Elevated Temperatures
by Tinotenda Mubaiwa, Askh Garshol, Alexander Azarov and Jafar Safarian
Recycling 2024, 9(4), 66; https://doi.org/10.3390/recycling9040066 - 8 Aug 2024
Viewed by 820
Abstract
The aim of this work was to study the purification of silicon kerf loss waste (KLW) by a combination of single-acid leaching followed by inductive melting at high temperatures with an addition of fluidized bed reactor (FBR) silicon granules. The KLW indicated an [...] Read more.
The aim of this work was to study the purification of silicon kerf loss waste (KLW) by a combination of single-acid leaching followed by inductive melting at high temperatures with an addition of fluidized bed reactor (FBR) silicon granules. The KLW indicated an average particle size (D50) of approximately 1.6 µm, and a BET surface area of 30.4 m2/g. Acid leaching by 1 M HCl indicated significant removal of impurities such as Ni (77%), Fe (91%) and P (75%). The combined two-stage treatment resulted in significant removal of the major impurities: Al (78%), Ni (79%), Ca (85%), P (92%) and Fe (99%). The general material loss during melting decreased with an increasing amount of FBR silicon granules which aided in the melting process and indicated better melting. It was observed that the melting behavior of the samples improved as the temperature increased, with complete melting being observed throughout the crucibles at the highest temperature (1800 °C) used, even without any additives. At lower temperatures (1600 °C–1700 °C) and lower FBR-Si (<30 wt.%) additions, the melting was incomplete, with patches of molten silicon and a lot of surface oxidation as confirmed by both visual observation and electron microscopy. In addition, it was indicated that more reactive and volatile elements (Ga, Mg and P) compared to silicon are partially removed in the melting process (51–87%), while the less reactive elements end up in the final silicon melt. It was concluded that if optimized, the combined treatment of single-acid leaching and inductive melting with the addition of granular FBR silicon has great potential for the recycling of KLW to solar cells and similar applications. Moreover, the application of higher melting temperatures is accompanied by a higher silicon yield of the process, and the involved mechanisms are presented. Full article
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20 pages, 4111 KiB  
Article
Valorization of Fine-Fraction CDW in Binary Pozzolanic CDW/Bamboo Leaf Ash Mixtures for the Elaboration of New Ternary Low-Carbon Cement
by Javier Villar-Hernández, Ernesto Villar-Cociña, Holmer Savastano, Jr. and Moisés Frías Rojas
Resources 2024, 13(7), 100; https://doi.org/10.3390/resources13070100 - 19 Jul 2024
Viewed by 797
Abstract
This paper presents the characterization of a binary mixture of construction and demolition waste (CDW) and bamboo leaf ash (BLAsh) calcined at 600 °C (novel mixture) and the study of its pozzolanic behavior. Different dosages in a pozzolan/Ca(OH)2 system were employed. The [...] Read more.
This paper presents the characterization of a binary mixture of construction and demolition waste (CDW) and bamboo leaf ash (BLAsh) calcined at 600 °C (novel mixture) and the study of its pozzolanic behavior. Different dosages in a pozzolan/Ca(OH)2 system were employed. The aim is the valorization of fine-fraction CDW that achieves a more reactive binary mixture and allows an adequate use of CDW as waste, as CDW is a material of limited use due to its low pozzolanic activity. The pozzolanic behavior of the mixture was analyzed using the conductometric method, which measures the electrical conductivity in the CDW + BLAsh/CH solution versus reaction time. With the application of a kinetic–diffusive mathematical model, the kinetic parameters of the pozzolanic reaction were quantified. This allowed a quantitative evaluation of the pozzolanic activity based on the values of these parameters. To validate these results, other experimental techniques were used: X-ray diffraction, thermogravimetry and scanning electron microscopy. Also, mechanical compressive strength assays were carried out. The results show an increase in the pozzolanic activity of binary mixes of CDW + BLAsh for all the dosages used in comparison to the pozzolanic activity of CDW alone. The quantitative assessment (kinetic parameters) shows that the binary mixture CDW50 + BLAsh50 is the most reactive (reaction rate constant of 7.88 × 10−1 h−1) and is superior to the mixtures CDW60 + BLAsh40 and CDW70 + BLAs30. Compressive strength tests show higher strength values for the ternary mixes (OPC + CDW + BLAsh) compared to the binary mixes (OPC + CDW). In view of the results, the binary blend of pozzolans CDW + BLAsh is suitable for the manufacture of future low-carbon ternary cements. Full article
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26 pages, 17996 KiB  
Article
Critical Raw Materials Supply: Challenges and Potentialities to Exploit Rare Earth Elements from Siliceous Stones and Extractive Waste
by Xinyuan Zhao, Faten Khelifi, Marco Casale, Alessandro Cavallo, Elio Padoan, Ke Yang and Giovanna Antonella Dino
Resources 2024, 13(7), 97; https://doi.org/10.3390/resources13070097 - 15 Jul 2024
Cited by 1 | Viewed by 1808
Abstract
Critical raw materials (CRMs) supply is a challenge that EU countries have to face, with many thinking about domestic procurement from natural ore deposits and anthropogenic deposits (landfills and extractive waste facilities). The present research focuses on the possibilities linked to the supply [...] Read more.
Critical raw materials (CRMs) supply is a challenge that EU countries have to face, with many thinking about domestic procurement from natural ore deposits and anthropogenic deposits (landfills and extractive waste facilities). The present research focuses on the possibilities linked to the supply of CRMs and the potential for exploiting rare earth elements (REEs), investigating a large variety of extractive waste and siliceous rocks in the Piedmont region (Northern Italy). Indeed, the recovery of REEs from the extractive waste (EW) of siliceous quarries and other siliceous ore deposits can be a valuable way to reduce supply chain risks. Starting with a review of the literature on mining activities in Piedmont and continuing with the sampling and geochemical, mineralogical, petrographic, and environmental characterization of EW facilities connected to siliceous dimension stones, of kaolinitic gneiss ore deposits, and of soils present near the investigated areas, this study shows that the degree of REEs enrichment differs depending on the sampling area (soil or EW) and lithology. The concentration of REEs in the EW at some sampling sites fulfils the indicators of industrial-grade and industrial recovery; the high cumulative production and potential market values of EW and the positive recovery effects through proven methodologies indicate a viable prospect of REE recovery from EW. However, REE recovery industrialization faces challenges such as the difficulty in achieving efficient large-scale recovery due to large regional differences in REE abundance, the mismatch between potential market value and waste annual production, etc. Nonetheless, in the future, EW from dimension stone quarries could be differentially studied and reused based on the enrichment and distribution characteristics of trace elements. The present paper shows investigation procedures undertaken to determine both CRMs potentialities and environmental issues (on the basis of literature data employed to select the more-promising areas and on sampling and characterization activities in the selected areas), together with procedures to determine the waste quantities and tentative economic values of REEs present in the investigated areas. This approach, tested on a large area (Piedmont region), is replicable and applicable to other similar case studies (at EU and non-EU levels) and offers decision makers the possibility to acquire a general overview of the potential available resources in order to decide whether and where to concentrate efforts (including economic ones) in a more detailed study to evaluate the exploitable anthropogenic deposits. Full article
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19 pages, 5324 KiB  
Article
Utilization of Natural Soils as a Remediation Method for Electric Arc Furnace and Ladle Slags
by Bilal Korkmaz and Asli Yalcin Dayioglu
Sustainability 2024, 16(12), 5244; https://doi.org/10.3390/su16125244 - 20 Jun 2024
Cited by 1 | Viewed by 828
Abstract
Steel slags are solid residual materials formed as by-products throughout the process of steel production within the steelmaking industry. These wastes have good physical properties such as high stiffness and friction angle for use as road fill materials or in geotechnical applications. However, [...] Read more.
Steel slags are solid residual materials formed as by-products throughout the process of steel production within the steelmaking industry. These wastes have good physical properties such as high stiffness and friction angle for use as road fill materials or in geotechnical applications. However, the presence of heavy metals and high alkalinity levels constitute significant environmental hazards and set limitations on using slags in engineering applications. While there have been investigations into the mechanical characteristics of steel slags, research on assessing potential harm when utilizing the materials in engineering applications is rare. This study examines the mitigation methods to address the environmental problems associated with steel slags. To do this, two different steel slags with different production techniques were treated with soils of different properties such as fine and coarse sand, bentonite, kaolin, and natural clay. The pH and electrical conductivity (EC) values of pure steel slags were determined using the water leach test (WLT). Variations in pH and EC values of steel slags subjected to treatment were evaluated through both WLT and sequential water leach (SWLT) tests. As a result, the high strength, stiffness, and drainage capability of EAF and LS steel slags make these materials suitable for road filling. This is further backed by their soaked and unsoaked CBR values. During the water leach tests, notable decreases in pH were observed with a 60% natural clay (NC) solution, resulting in a decrease of 1.2 and 0.7 in EAF and LS, respectively. The addition of sand had a negligible impact on pH due to its inert characteristics. Moreover, in sequential water leach tests, the most significant decrease in pH was observed with NC (with a reduction of 2.0 points for EAF and 0.9 points for LS) through enhanced ion exchange and extended periods of dilution and buffering. Also, the use of NC resulted in substantial decreases in EC for EAF and LS, with reductions of 77% and 81%, respectively. Moreover, heavy metal concentrations in leachate waters from pure steel slags have been detected, and the effect of treatment on aluminum and iron concentrations has been determined. The results indicate that the use of natural soil significantly drops the pH and lowers the trace metal concentrations within the leachate. Full article
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19 pages, 4295 KiB  
Article
Geopolymerization of Recycled Glass Waste: A Sustainable Solution for a Lightweight and Fire-Resistant Material
by Marios Valanides, Konstantinos Aivaliotis, Konstantina Oikonomopoulou, Alexandros Fikardos, Pericles Savva, Konstantinos Sakkas and Demetris Nicolaides
Recycling 2024, 9(1), 16; https://doi.org/10.3390/recycling9010016 - 7 Feb 2024
Cited by 1 | Viewed by 2460
Abstract
Glass is considered a sustainable material with achievable recovery rates within the EU. However, there are limited data available for construction glass waste management. Furthermore, glass is a heavy material, and considering the geographical limitations of Cyprus, the transportation trading cost within the [...] Read more.
Glass is considered a sustainable material with achievable recovery rates within the EU. However, there are limited data available for construction glass waste management. Furthermore, glass is a heavy material, and considering the geographical limitations of Cyprus, the transportation trading cost within the EU is extremely high. Therefore, another method for utilizing this by-product should be developed. The aim of this research is to investigate the production of a low-cost, lightweight and fireproof material able to retain its structural integrity, using the geopolymerization method with the incorporation of randomly collected construction glass waste. The glass waste was initially processed in a Los Angeles abrasion machine and then through a Micro-Deval apparatus in order to be converted to a fine powder. Mechanical (compressive and flexural strength), physical (setting time and water absorption) and thermal properties (thermal conductivity) were investigated. The fire-resistant materials presented densities averaging 450 kg/m3 with a range of compressive strengths of 0.5 to 3 MPa. Additionally, a techno-economic analysis was conducted to evaluate the viability of the adopted material. Based on the results, the final geopolymer product has the potential to be utilized as a fire resistance material, preventing yielding or spalling. Full article
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16 pages, 6752 KiB  
Article
Effect of Limestone Powder Mixing Methods on the Performance of Mass Concrete
by Lele Zhao, Tingshu He, Mengdie Niu, Xiulong Chang, Lei Wang and Yan Wang
Materials 2024, 17(3), 617; https://doi.org/10.3390/ma17030617 - 27 Jan 2024
Viewed by 878
Abstract
Using limestone powder (LP), the by-product of manufactured sand, to replace part of fly ash (FA) or manufactured sand could not only turn waste into treasure and decrease the price of concrete, but could also enhance the performance of concrete and reduce environmental [...] Read more.
Using limestone powder (LP), the by-product of manufactured sand, to replace part of fly ash (FA) or manufactured sand could not only turn waste into treasure and decrease the price of concrete, but could also enhance the performance of concrete and reduce environmental pollution. However, the impact of various LP incorporation methods on the performance of mass concrete was inconsistent. In this paper, the effects of LP on the workability, compressive strength, constrained expansion rate, hydration temperature and impermeability of mass concrete were studied by replacing FA or manufactured sand alone and replacing FA and manufactured sand simultaneously. The results showed that the impact of LP on the performance of mass concrete was equal when it replaced FA alone and FA and manufactured sand at the same time. When the replacement amount was 20%, the workability, expansibility and early strength of concrete were improved, but the later strength and impermeability were slightly reduced. The workability, compressive strength, expansibility and impermeability of mass concrete were improved when manufactured sand was replaced alone, and the optimal dosage was 10%. The LP, moreover, reduced the hydration temperature peak of concrete in three kinds of mixing methods, but the temperature peak appeared earlier. At lower dosages, LP optimized pore structure and promoted the early hydration of cement through filler effects and nucleation effects. When LP replaced manufactured sand, the microstructure of concrete was more dense, so the replacement of manufactured sand had a better effect on the improvement of concrete properties. A reference value for the use of LP in mass concrete is provided in this study. Full article
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21 pages, 9465 KiB  
Article
Removal of Fe3+ Ions from Aqueous Solutions by Adsorption on Natural Eco-Friendly Brazilian Palygorskites
by Antonieta Middea, Luciana dos Santos Spinelli, Fernando Gomes de Souza Junior, Thais de Lima Alves Pinheiro Fernandes, Luiz Carlos de Lima, Vitoria Maria Tupinamba Souza Barthem, Otávio da Fonseca Martins Gomes and Reiner Neumann
Mining 2024, 4(1), 37-57; https://doi.org/10.3390/mining4010004 - 19 Jan 2024
Viewed by 1113
Abstract
This work focuses on the characterization of five palygorskite clays from the Brazilian state of Piaui and their feasibility as eco-friendly adsorbents for the removal of Fe3+ ions from aqueous solutions. For characterization, we applied the techniques of X-ray diffraction (XRD), X-ray [...] Read more.
This work focuses on the characterization of five palygorskite clays from the Brazilian state of Piaui and their feasibility as eco-friendly adsorbents for the removal of Fe3+ ions from aqueous solutions. For characterization, we applied the techniques of X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), size distribution measurements, density measurement by He pycnometry, superconducting quantum interference device (SQUID) magnetometry, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTA), zeta potential measurement, hydrophobicity determination by contact angle, Brunauer–Emmett–Teller surface area analysis (BET technique) and atomic force microscopy (AFM). Batch experiments were performed in function of process parameters such as contact time and initial concentration of Fe3+. The natural palygorskites (Palys) had excellent performance for the removal of Fe3+ from aqueous solutions by adsorption (around 60 mg/g), and the Langmuir is supposedly the best model fitted the experimental data. Full article
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