Metal Recovery from Printed Circuit Boards

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Environmental Mineralogy and Biogeochemistry".

Deadline for manuscript submissions: closed (20 May 2023) | Viewed by 9697

Special Issue Editors


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Guest Editor
Department of Chemical Engineering and Metallurgy, University of Sonora, Hermosillo 83000, Mexico
Interests: hydrometallurgy; precious metals recovery; solvent extraction; metals recycling from PCB
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Guest Editor
Facultad de Metalurgia, Universidad Autónoma de Coahuila, Monclova 25710, Mexico
Interests: hydrometallurgy; wastewater and wastes treatment; thermodynamic and kinetics analysis
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue aims to publish high-quality original research papers and critical reviews featuring the fundamental aspects and industrial applications in the field of processing and extractive metallurgy of secondary resources.

Every year, natural mineral resources are further depleted, or their extraction becomes more difficult. In addition to the decrease in metal grades and contents, most of the minerals in the Earth's crust are becoming more difficult to extract and require more complex processing, so their exploitation is unaffordable. That is why it is necessary to look for alternatives in electrical and electronic waste equipment trying to make the most of the extraction and recovery of metals. Recently, the production of waste of electrical and electronic materials globally has been considered a potential source of base metals and precious and platinum group metals, and strategic metals, such as lithium and rare earth metals. It is important to investigate the extraction of metals using physical and chemical separation methods and advanced analytical techniques, applied mineralogy, process design, and modeling. The environmental aspects of mineral processing are also covered.

Physical separations: comminution; classification; sorting; gravity, magnetic and electric concentration; froth flotation, coagulation, and flocculation.

Chemical (hydro /pyro) processes: Oxidation of metal components, extraction of metals, leaching and bacterial leaching, concentration and purification of metals in solutions, precipitation, and the electrowinning of metals. Drying, calcination, sulfide roasting, smelting, oxide reduction, conversion, and refining metals at high temperatures.

Thermodynamic and kinetic analysis of the leaching and precipitation of metals; equilibrium studies in extraction by solvents and ion exchange resins; equilibrium studies at high temperatures; electrochemical studies; modeling of solid–liquid systems; Multiparticle systems.

Papers presenting fundamental studies and discussing the above-mentioned aspects of metal recovery from printed circuit boards are invited for this Special Issue.

Prof. Dr. Jesús Leobardo Valenzuela-García
Prof. Dr. Francisco Raul Carrillo Pedroza
Guest Editors

Manuscript Submission Information

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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 2400 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

  • hydrometallurgy
  • biometallurgy
  • pyrometallurgy
  • modeling, simulation
  • environment, recycling
  • flotation chemistry

Published Papers (3 papers)

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Research

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15 pages, 3480 KiB  
Article
Deportment of Metals from E-Waste PCBs towards Alloy and Slag Phases during Smelting Using CaO-Al2O3-SiO2-B2O3 Slags
by Md Khairul Islam, Michael Somerville, Mark I. Pownceby, James Tardio, Nawshad Haque and Suresh Bhargava
Minerals 2023, 13(6), 727; https://doi.org/10.3390/min13060727 - 26 May 2023
Viewed by 1181
Abstract
Printed circuit boards (PCBs) from antiquated electronic goods were processed by a pyrometallurgical route to produce and separate alloy and slag phases. The process involved initial size reduction of PCBs, followed by pyrolysis at 500 °C for 6 h and finally smelting of [...] Read more.
Printed circuit boards (PCBs) from antiquated electronic goods were processed by a pyrometallurgical route to produce and separate alloy and slag phases. The process involved initial size reduction of PCBs, followed by pyrolysis at 500 °C for 6 h and finally smelting of the solid materials in an electric furnace. A preliminary smelting test was performed at 1600 °C to estimate the composition of the slag generated. In later kilogram-scale smelting experiments, B2O3 flux was added along with CaO and SiO2 to decrease the liquidus temperature required to smelt the PCBs. The level of fluxing was adapted from earlier phase equilibria studies of the CaO-Al2O3-SiO2-B2O3 slag system. Results showed that the flux decreased the melting temperature and assisted the recovery of most valuable metals within the alloy phase at 1350 °C smelting temperature. The alloy phase recovered 99.8% of Cu, 99% of Sn, and 100% of precious metals (Au, Ag, Pt). A fluxing strategy for smelting high Al2O3 containing e-waste PCBs was proposed based on the experimental findings of this research. Full article
(This article belongs to the Special Issue Metal Recovery from Printed Circuit Boards)
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12 pages, 4644 KiB  
Article
Base Metals Extraction from Printed Circuit Boards by Pressure Acid Leaching
by Guadalupe Martinez-Ballesteros, Jesus Leobardo Valenzuela-Garcia, Agustin Gomez-Alvarez, Martin Antonio Encinas-Romero, Flerida Adriana Mejia-Zamudio and Aaron de Jesus Rosas-Durazo
Minerals 2023, 13(1), 98; https://doi.org/10.3390/min13010098 - 08 Jan 2023
Cited by 2 | Viewed by 1611
Abstract
Printed circuit boards (PCBs) are a valuable source of raw materials for metal recycling considering that base metal concentration analyses have confirmed that PCB powders are multimetallic in nature and contain high concentrations of Cu, Zn, Ni, and Fe. Given that minerals are [...] Read more.
Printed circuit boards (PCBs) are a valuable source of raw materials for metal recycling considering that base metal concentration analyses have confirmed that PCB powders are multimetallic in nature and contain high concentrations of Cu, Zn, Ni, and Fe. Given that minerals are not renewable resources, these metals can be recycled through hydrometallurgical processes. In this study, we determined that 2 M sulfuric acid, 0.55 MPa oxygen pressure, and a temperature of 90 °C represent the optimal conditions for leaching of Cu, Zn, and Ni of PCBs, obtaining the highest observed values of recovery of greater than 90% for Zn and 98% for Cu and Ni. The characterization of PCBs by SEM–EDS analyses showed that plates mainly consist of Cu, Ni, and Zn. PCBs can be seen as a potential secondary resource for the recovery of copper, nickel, and zinc. The best potential and pH conditions for the extraction of Cu, Zn, and Ni were also determined on the basis of thermodynamic diagrams. Full article
(This article belongs to the Special Issue Metal Recovery from Printed Circuit Boards)
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Review

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25 pages, 2212 KiB  
Review
Bioleaching of Metals from E-Waste Using Microorganisms: A Review
by Adegoke Isiaka Adetunji, Paul Johan Oberholster and Mariana Erasmus
Minerals 2023, 13(6), 828; https://doi.org/10.3390/min13060828 - 18 Jun 2023
Cited by 10 | Viewed by 6135
Abstract
The rapid and improper disposal of electronic waste (e-waste) has become an issue of great concern, resulting in serious threats to the environment and public health. In addition, e-waste is heterogenous in nature, consisting of a variety of valuable metals in large quantities, [...] Read more.
The rapid and improper disposal of electronic waste (e-waste) has become an issue of great concern, resulting in serious threats to the environment and public health. In addition, e-waste is heterogenous in nature, consisting of a variety of valuable metals in large quantities, hence the need for the development of a promising technology to ameliorate environmental hazards associated with the indiscriminate dumping of e-waste, and for the recovery of metal components present in waste materials, thus promoting e-waste management and reuse. Various physico-chemical techniques including hydrometallurgy and pyrometallurgy have been employed in the past for the mobilization of metals from e-waste. However, these approaches have proven to be inept due to high operational costs linked to the consumption of huge amounts of chemicals and energy, together with high metal loss and the release of secondary byproducts. An alternative method to avert the above-mentioned limitations is the adoption of microorganisms (bioleaching) as an efficient, cost-effective, eco-friendly, and sustainable technology for the solubilization of metals from e-waste. Metal recovery from e-waste is influenced by microbiological, physico-chemical, and mineralogical parameters. This review, therefore, provides insights into strategies or pathways used by microorganisms for the recovery of metals from e-waste. Full article
(This article belongs to the Special Issue Metal Recovery from Printed Circuit Boards)
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