Valuable Metal Recycling

Cho, Bong-Gyoo; Lee, Jae-chun; Yoo, Kyoungkeun

doi:10.3390/met8050345

Cited by 4 publications

(5 citation statements)

References 16 publications

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“…The presence of several metals of different chemical nature in increasingly miniaturized products, and incorporated in complex matrixes encompassing ceramics, resins, plastics, and especially halogenated substances (based on chlorine and bromine) makes their recycling process quite complex. A spectrum of contributions focused on current state-of-the-art research on metal recycling from wastes was introduced in a special issue (Valuable Metal Recycling) of Metals [8]. An extensive overview for the recovery of high value metals from electronic waste and spent catalysts using improved pyrometallurgical and hydrometallurgical technologies was given by Ding et al [9].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

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Development of our modern society requests a number of critical and strategic elements (platinum group metals, In, Ga, Ge…) and high value added elements (Au, Ag, Se, Te, Ni…) which are often concentrated in by-products during the extraction of base metals (Cu, Pb, Zn…). Further, recycling of end-of-life materials employed in high technology, renewable energy and transport by conventional extractive processes also leads to the concentration of such chemical elements and their compounds in metallurgical by-products and/or co-products. One of these materials, copper anode slime (CAS), derived from a copper electrolytic refining factory, was used for this study. The sample was subjected to isothermal treatment from 225 to 770 °C under air atmosphere and the reaction products were systematically analyzed by scanning electron microscopy through energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) to investigate the thermal behavior of the treated sample. The main components of the anode slime (CuAgSe, Cu2-xSeyS1-y, Ag3AuSe2) react with oxygen, producing mostly copper and selenium oxides as well as Ag-Au alloys as final products at temperatures higher than 500 °C. Selenium dioxide (SeO2) is volatilized and recovered in pure state by cooling the gaseous phase, whilst copper(II) oxide, silver, gold and tellurium remain in the treatment residue.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2019

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“…The results described in Part I [ 1 ] of this investigation combined with research works cited therein [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ] gave a general view of needs and secondary sources for a large range of materials, identified frequently as critical and strategic materials, and they are indispensable for present and forthcoming innovations in renewable energies, transportation and cutting-edge technologies.…”

Section: Introductionmentioning

confidence: 80%

“…As shown in Figure 18, gold, which is used in PCBs to assure circuit board contacts, seems to be inert to the treatment at this temperature. A thermodynamic calculation [39] showed that the values of the ∆ r G • for the reaction (6), (7), (8) and (9) at 500 • C are −119.80, −124.11, −143.22 and -119.97 kJ/mol HBr, respectively. Such negative values suggest that the envisaged reactions are favorable from the thermodynamic point of view.…”

Section: Preliminary Results For Treatment Of E-waste In Airmentioning

confidence: 99%

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High-Value Elements from By-Products and End-of-Life Materials, Part II: Processing in Presence of Halogenated Atmosphere

et al. 2020

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During the treatment of copper anode slime (CAS) under an air atmosphere, several aspects of the interactions of its main components (CuAgSe, Cu2−xSeyS1−y, Ag3AuSe2) with oxygen were described in Part I. As a comparative and complementary study, this work deals with the thermal behavior of CAS under air in the presence of polyvinyl chloride (PVC) between 195 and 770 °C. The preliminary thermal treatment of an e-waste sample containing brominated substances was also performed. The reaction products were systematically analyzed by scanning electron microscopy through energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) to investigate the thermal behaviors of the studied samples in a halogenated medium. At low temperatures, the copper, silver and selenium compounds of the CAS reacted with the HCl, issued from PVC degradation, leading to the formation of their respective chlorides. Bromides of valuable metals (Cu, Pb, Sn…) were synthesized during the e-waste treatment at 500 °C and they were distributed between the solid residue and gaseous phase. The data obtained give an insight into the reactivity of several metals towards halogenated substances, which may be valuable information for conducting the extraction and recycling of targeted elements from industrial by-products and end-of-life materials by a thermochemical route.

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“…According to the above, there is a great potential in transforming industrial and electronic wastes in materials resources. However, recycling remains at a low level, so there is a needing to work in searching for improvements to the actual technologies applied to recover precious metals from wastes [ 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Use of the O2-Thiosemicarbazide System, for the Leaching of: Gold and Copper from WEEE & Silver Contained in Mining Wastes

et al. 2021

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Environmental pollution today is a latent risk for humanity, here the need to recycle waste of all kinds. This work is related to the kinetic study of the leaching of gold and copper contained in waste electrical and electronic equipment (WEEE) and silver contained in mining wastes (MW), using the O2-thiosemicarbazide system. The results obtained show that this non-toxic leaching system is adequate for the leaching of said metals. Reaction orders were found ranging from 0 (Cu), 0.93 (Ag), and 2.01 (Au) for the effect of the reagent concentration and maximum recoveries of 77.7% (Cu), 95.8% (Au), and 60% (Ag) were obtained. Likewise, the activation energies found show that the leaching of WEEE is controlled by diffusion (Cu Ea = 9.06 and Au Ea = 18.25 kJ/Kmol), while the leaching of MW (Ea = 45.55 kJ/Kmol) is controlled by the chemical reaction. For the case of stirring rate, it was found a low effect and only particles from WEEE and MW must be suspended in solution to proceed with the leaching. The pH has effect only at values above 8, and finally, for the case of MW, the O2 partial pressure has a market effect, going the Ag leaching from 33% at 0.2 atm up to 60% at a 1 atm.

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Valuable Metal Recycling

Abstract: As the global economy grows, demand for metal continues to increase. Unfortunately, metal resources are in limited supply [...]

Cited by 4 publications

References 16 publications

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

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

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High-Value Elements from By-Products and End-of-Life Materials, Part II: Processing in Presence of Halogenated Atmosphere

Use of the O2-Thiosemicarbazide System, for the Leaching of: Gold and Copper from WEEE & Silver Contained in Mining Wastes

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