Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
5.7
3.1
Journals
Metals
Special Issues
Cutting-Edge Innovations in Metal Recovery from Electronic Waste: Challenges, Techniques...
share announcement

Cutting-Edge Innovations in Metal Recovery from Electronic Waste: Challenges, Techniques and Future Horizons

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (31 March 2026) | Viewed by 12553

Editor

Prof. Dr. Ernesto Chicardi

E-Mail Website
Guest Editor
Department of Engineering and Materials Science and Transportation, University of Seville, 41092 Sevilla, Spain
Interests: cermets; cemented carbides; powder metallurgy; ceramics; combustion reactions; high entropy alloys
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The escalating production of waste electrical and electronic equipment (WEEE) represents a critical challenge and opportunity for resource recovery and environmental protection. With global WEEE generation exceeding 62 million metric tons in 2022 and projected to reach 74 million metric tons by 2030, recycling rates remain alarmingly low—averaging just 17.4% globally. Despite this, WEEE contains significant amounts of valuable metals, such as gold, silver, and copper, with an estimated value of USD 91 billion in 2022 alone. Enhanced recovery and recycling could generate substantial economic and environmental benefits while mitigating the risks posed by hazardous materials, including heavy metals and toxic substances, in components such as printed circuit boards (PCBs).

This Special Issue explores cutting-edge advancements in metal recovery from WEEE, encompassing innovative mechanical, hydrometallurgical, pyrometallurgical, and biometallurgical methods. Emphasis is placed on environmentally friendly and economically viable technologies, such as the use of thiosulfates for gold leaching, froth flotation, and electrostatic separation. Contributions on size reduction techniques are also encouraged, as they play a pivotal role in metal liberation.

Topics of interest include the optimization of existing recycling technologies, the scalability of laboratory methods to industrial applications, and the integration of recycling processes into circular economy frameworks. Additionally, submissions addressing the economic implications of improved recycling rates, the potential for regulatory advancements, and the mitigation of environmental risks associated with WEEE mismanagement are welcome.

This Special Issue seeks to provide a comprehensive platform for interdisciplinary collaboration, fostering innovative solutions to transform WEEE from a growing global challenge into a valuable resource for sustainable development.

Prof. Dr. Ernesto Chicardi
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 250 words) can be sent to the Editorial Office for assessment.

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-anonymized peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals 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 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

  • e-waste recycling
  • metal recovery
  • circular economy
  • sustainable technologies
  • hydrometallurgy
  • pyrometallurgy
  • electrostatic separation
  • froth flotation
  • critical raw materials
  • WEEE management

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (4 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review

14 pages, 1611 KB  
Article
Towards Sustainable Hydrometallurgy: Water Reuse and Iron Recovery from Effluents of REE Extraction from NdFeB Magnets
by Misbah Ullah, Touseef Younas, Pietro Romano, Giuseppe Spagnoli, Francesco Vegliò and Nicolò Maria Ippolito
Metals 2026, 16(3), 317; https://doi.org/10.3390/met16030317 - 12 Mar 2026
Viewed by 814
Abstract
The NdFeB magnetic material is widely used in modern industry and electronics. Recycling spent magnets containing 30–40 wt.% Rare Earth Elements (REEs) and 60–70 wt.% iron is essential for resource recovery. This study focuses on treating wastewater from hydrometallurgical REE extraction to enable [...] Read more.
The NdFeB magnetic material is widely used in modern industry and electronics. Recycling spent magnets containing 30–40 wt.% Rare Earth Elements (REEs) and 60–70 wt.% iron is essential for resource recovery. This study focuses on treating wastewater from hydrometallurgical REE extraction to enable water reuse and iron recovery. Experiments investigated the influence of temperature (25–60 °C) and oxalic acid concentration (50–120% stoichiometric amount) on iron precipitation as the main focus. Optimal iron recovery of 85.3% and 86.8% was achieved at 25 °C using 80% and 100% stoichiometric oxalic acid, respectively. Simultaneously, praseodymium removal exceeded 94%. The Differential Scanning Calorimetry (DSC) analysis identified a peak between 168.8 °C and 245 °C, with the peak temperature recorded at 214.5 °C, indicating the optimal calcination temperature for iron oxalate. This was confirmed through oven testing and X-ray Diffraction (XRD) analysis. The treated effluent exhibited a Chemical Oxygen Demand (COD) of 418 mg/L, with residual Fe and Pr concentrations significantly reduced to 5.7 mg/L and 4.3 mg/L, respectively. This approach demonstrates an efficient method for wastewater treatment and resource valorization, promoting sustainability in the recycling sector. Full article
(This article belongs to the Special Issue Cutting-Edge Innovations in Metal Recovery from Electronic Waste: Challenges, Techniques and Future Horizons)
►▼ Show Figures

Graphical abstract

18 pages, 1471 KB  
Article
The Leaching of Valuable Metals (Li, Co, Ni, Mn, Cu) from Black Mass from Spent Lithium-Ion Batteries
by Rorie Gilligan, Glen P. O’Malley and Aleksandar N. Nikoloski
Metals 2025, 15(10), 1155; https://doi.org/10.3390/met15101155 - 19 Oct 2025
Cited by 6 | Viewed by 5418
Abstract
Near-complete (>99%) dissolution of lithium and cobalt was achieved by the leaching of black mass from spent (end-of-life) lithium-ion batteries (LiBs) using 4 M H2SO4 or HCl at 60 °C. Raising the temperature to 90 °C did not increase the [...] Read more.
Near-complete (>99%) dissolution of lithium and cobalt was achieved by the leaching of black mass from spent (end-of-life) lithium-ion batteries (LiBs) using 4 M H2SO4 or HCl at 60 °C. Raising the temperature to 90 °C did not increase the overall extraction of lithium or cobalt, but it increased the rate of extraction. At 60 °C, 2 M H2SO4 or 2 M HCl performed similarly to the 4 M H2SO4/HCl solution, although extractions were lower using 1 M H2SO4 or HCl (~95% and 98%, respectively). High extractions were also observed by leaching in low pulp density (15 g/L) at 60 °C with 2 M CH2ClCOOH. Leaching was much slower with hydrogen peroxide reductant concentrations below 0.5 mol/L, with cobalt extractions of 90–95% after 3 h. Pulp densities of up to 250 g/L were tested when leaching with 4 M H2SO4 or HCl, with the stoichiometric limit estimated for each test based on the metal content of the black mass. Extractions were consistently high, above 95% for Li/Ni/Mn/Cu with a pulp density of 150 g/L, dropping sharply above this point because of insufficient remaining acid in the solution in the later stages of leaching. The final component of the test work used leaching parameters identified in the previous experiments as producing the largest extractions, and just sulphuric acid. A seven-stage semi-continuous sulphuric acid leach at 60 °C of black mass from LiBs that had undergone an oxidising roast (2h in a tube furnace at 500 °C under flowing air) to remove binder material resulted in high (93%) extraction of cobalt and near total (98–100%) extractions of lithium, nickel, manganese, and copper. Higher cobalt extraction (>98%) was expected, but a refractory spinel-type cobalt oxide, Co3O4, was generated during the oxidising roast as a result of inefficient aeration, which reduced the extraction efficiency. Full article
(This article belongs to the Special Issue Cutting-Edge Innovations in Metal Recovery from Electronic Waste: Challenges, Techniques and Future Horizons)
►▼ Show Figures

Figure 1

15 pages, 734 KB  
Article
The Influence of Electrostatic Separation Parameters on the Recovery of Metals from Pre-Crushed PCBs
by Antonio Manuel Lopez-Paneque, Victoria Humildad Gallardo García-Orta, Jose Maria Gallardo, Ranier Enrique Sepúlveda-Ferrer and Ernesto Chicardi
Metals 2025, 15(8), 826; https://doi.org/10.3390/met15080826 - 23 Jul 2025
Cited by 4 | Viewed by 3186
Abstract
Electrostatic separation is a promising technology for the recovery of valuable metals from electronic waste, particularly from printed circuit boards (PCBs). This study explores the application of electrostatic separation for the selective recovery of metallic and non-metallic fractions from crushed PCBs (PCBs). The [...] Read more.
Electrostatic separation is a promising technology for the recovery of valuable metals from electronic waste, particularly from printed circuit boards (PCBs). This study explores the application of electrostatic separation for the selective recovery of metallic and non-metallic fractions from crushed PCBs (PCBs). The process exploits the differences in electrical properties between conductive metals and non-conductive polymers and ceramics, facilitating their separation through applied electric fields. The raw materials were pre-treated via mechanical comminution using shredders and hammer mills to achieve an optimal particle size distribution (<3 mm), which enhances separation efficiency. Ferrous materials were removed prior to electrostatic separation to improve process selectivity. Key operational parameters, including particle size, charge accumulation, environmental conditions, and separation efficiency, were systematically analysed. The results demonstrate that electrostatic separation effectively recovers high-value metals such as copper and gold while minimizing material losses. Additionally, the process contributes to the sustainability of e-waste recycling by enabling the recovery of non-metallic fractions for potential secondary applications. This work underscores the significance of electrostatic separation as a viable technique for e-waste management and highlights optimization strategies for enhancing its performance in large-scale recycling operations. Full article
(This article belongs to the Special Issue Cutting-Edge Innovations in Metal Recovery from Electronic Waste: Challenges, Techniques and Future Horizons)
►▼ Show Figures

Figure 1

Review

Jump to: Research

22 pages, 2091 KB  
Review
Separation Strategies for Indium Recovery: Exploring Solvent Extraction, Ion-Exchange, and Membrane Methods
by Ewa Rudnik
Metals 2026, 16(2), 156; https://doi.org/10.3390/met16020156 - 27 Jan 2026
Cited by 2 | Viewed by 2294
Abstract
Indium is a strategically important metal, essential for the production of transparent conductive oxides, flat panel displays, thin-film photovoltaics, and advanced optoelectronic devices. Due to its limited natural abundance and its occurrence in trace amounts alongside other metals in both primary and secondary [...] Read more.
Indium is a strategically important metal, essential for the production of transparent conductive oxides, flat panel displays, thin-film photovoltaics, and advanced optoelectronic devices. Due to its limited natural abundance and its occurrence in trace amounts alongside other metals in both primary and secondary sources, the recovery of indium through efficient separation techniques has gained increasing attention. This review discusses three major separation strategies for indium recovery: solvent extraction, ion-exchange, and membrane processes, applied to both synthetic solutions and real leachates. D2EHPA has demonstrated its applicability as an effective agent for indium separation, not only in solvent extraction but also as an impregnating agent in polymer resins and membranes. While solvent extraction achieves high recovery rates, ion-exchange resins and membrane-based methods offer significant advantages in terms of reusability, reduced chemical consumption, and minimal environmental impact. The selective separation of indium from impurities such as Fe3+ and Sn2+ remains a key consideration, which can be addressed by optimizing feed solution conditions or adjusting the selective stripping stages. A comparative overview of these methods is provided, focusing on separation efficiency, operational conditions, and potential integration into close-loop systems. The article highlights recent innovations and outlines the challenges involved in achieving sustainable indium recovery, in line with circular economy principles. Full article
(This article belongs to the Special Issue Cutting-Edge Innovations in Metal Recovery from Electronic Waste: Challenges, Techniques and Future Horizons)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-4
Back to TopTop