Urban mining by flash Joule heating

AbstractPrecious metal recovery from electronic waste, termed urban mining, is important for a circular economy. Present methods for urban mining, mainly smelting and leaching, suffer from lengthy purification processes and negative environmental impacts. Here, a solvent-free and sustainable process by flash Joule heating is disclosed to recover precious metals and remove hazardous heavy metals in electronic waste within one second. The sample temperature ramps to ~3400 K in milliseconds by the ultrafast electrical thermal process. Such a high temperature enables the evaporative separation of precious metals from the supporting matrices, with the recovery yields >80% for Rh, Pd, Ag, and >60% for Au. The heavy metals in electronic waste, some of which are highly toxic including Cr, As, Cd, Hg, and Pb, are also removed, leaving a final waste with minimal metal content, acceptable even for agriculture soil levels. Urban mining by flash Joule heating would be 80× to 500× less energy consumptive than using traditional smelting furnaces for metal-component recovery and more environmentally friendly.

Download Full-text

From Waste to Green Applications: The Use of Recovered Gold and Palladium in Catalysis

Molecules ◽

10.3390/molecules26175217 ◽

2021 ◽

Vol 26 (17) ◽

pp. 5217

Author(s):

Sean McCarthy ◽

Alvin Lee Wei Jie ◽

D. Christopher Braddock ◽

Angela Serpe ◽

James D. E. T. Wilton-Ely

Keyword(s):

Circular Economy ◽

Precious Metal ◽

Critical Appraisal ◽

Catalytic Properties ◽

Raw Materials ◽

Precious Metals ◽

Environmentally Benign ◽

Innovative Approach ◽

Industrial Processes ◽

Direct Use

The direct use in catalysis of precious metal recovery products from industrial and consumer waste is a very promising recent area of investigation. It represents a more sustainable, environmentally benign, and profitable way of managing the low abundance of precious metals, as well as encouraging new ways of exploiting their catalytic properties. This review demonstrates the feasibility and sustainability of this innovative approach, inspired by circular economy models, and aims to stimulate further research and industrial processes based on the valorisation of secondary resources of these raw materials. The overview of the use of recovered gold and palladium in catalytic processes will be complemented by critical appraisal of the recovery and reuse approaches that have been proposed.

Download Full-text

Precious Metal Distributions Between Copper Matte and Slag at High $$ P_{{{\text{SO}}_{ 2} }} $$ in WEEE Reprocessing

Metallurgical and Materials Transactions B ◽

10.1007/s11663-021-02059-z ◽

2021 ◽

Vol 52 (2) ◽

pp. 871-882

Author(s):

Min Chen ◽

Katri Avarmaa ◽

Lassi Klemettinen ◽

Hugh O’Brien ◽

Junjie Shi ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Precious Metal ◽

Electronic Waste ◽

Precious Metals ◽

Matte Grade ◽

Distribution Coefficients ◽

Copper Matte ◽

Copper Smelting ◽

Gold Silver ◽

Ar Gas

AbstractThe distributions of precious metals (gold, silver, platinum, and palladium) between copper matte and silica-saturated FeOx-SiO2/FeOx-SiO2-Al2O3/FeOx-SiO2-Al2O3-CaO slags were investigated at 1300 °C and $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 = 0.5 atm. The experiments were carried out in silica crucibles under flowing CO-CO2-SO2-Ar gas atmosphere. The concentrations of precious metals in matte and slag were analyzed by Electron Probe X-ray Microanalysis and Laser Ablation-High-Resolution Inductively Coupled Plasma-Mass Spectrometry, respectively. The precious metal concentrations in matte and slag, as well as the distribution coefficients of precious metals between matte and slag, were displayed as a function of matte grade. The present results obtained at $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 of 0.5 atm were compared with previous results at $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 of 0.1 atm for revealing the effects of $$ P_{{{\text{SO}}_{ 2} }} $$ P SO 2 and selected slag modifiers (CaO and Al2O3) on precious metal distributions at copper matte smelting conditions. The present results also contribute experimental thermodynamic data of precious metal distributions in pyrometallurgical reprocessing of electronic waste via copper smelting processes.

Download Full-text

Precious metal recovery from electronic waste by a porous porphyrin polymer

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2000606117 ◽

2020 ◽

pp. 202000606 ◽

Cited By ~ 4

Author(s):

Yeongran Hong ◽

Damien Thirion ◽

Saravanan Subramanian ◽

Mi Yoo ◽

Hyuk Choi ◽

...

Keyword(s):

Precious Metal ◽

Density Functional ◽

Printed Circuit Boards ◽

Electronic Waste ◽

Precious Metals ◽

Metal Recovery ◽

Porous Polymer ◽

Circuit Boards ◽

Functional Theory ◽

Printed Circuit

Urban mining of precious metals from electronic waste, such as printed circuit boards (PCB), is not yet feasible because of the lengthy isolation process, health risks, and environmental impact. Although porous polymers are particularly effective toward the capture of metal contaminants, those with porphyrin linkers have not yet been considered for precious metal recovery, despite their potential. Here, we report a porous porphyrin polymer that captures precious metals quantitatively from PCB leachate even in the presence of 63 elements from the Periodic Table. The nanoporous polymer is synthesized in two steps from widely available monomers without the need for costly catalysts and can be scaled up without loss of activity. Through a reductive capture mechanism, gold is recovered with 10 times the theoretical limit, reaching a record 1.62 g/g. With 99% uptake taking place in the first 30 min, the metal adsorbed to the porous polymer can be desorbed rapidly and reused for repetitive batches. Density functional theory (DFT) calculations indicate that energetically favorable multinuclear-Au binding enhances adsorption as clusters, leading to rapid capture, while Pt capture remains predominantly at single porphyrin sites.

Download Full-text

Issues and solutions of electronic waste urban mining for circular economy transition: An Indian context

Journal of Environmental Management ◽

10.1016/j.jenvman.2021.112373 ◽

2021 ◽

Vol 290 ◽

pp. 112373

Author(s):

Manu Sharma ◽

Sudhanshu Joshi ◽

Kannan Govindan

Keyword(s):

Circular Economy ◽

Electronic Waste ◽

Urban Mining ◽

Indian Context

Download Full-text

Towards a Smart E-Waste System Utilizing Supply Chain Participants and Interactive Online Maps

Recycling ◽

10.3390/recycling6010008 ◽

2021 ◽

Vol 6 (1) ◽

pp. 8

Author(s):

Tetiana Shevchenko ◽

Michael Saidani ◽

Yuriy Danko ◽

Ievgeniia Golysheva ◽

Jana Chovancová ◽

...

Keyword(s):

Waste Management ◽

Business Model ◽

Electronic Waste ◽

Precious Metals ◽

Local Delivery ◽

Waste Collection ◽

Business Model Canvas ◽

Online Maps ◽

Delivery Services ◽

Reduction Of Co2

Efficient electronic waste (e-waste) management is one of the vital strategies to save materials, including critical minerals and precious metals with limited global reserves. The e-waste collection issue has gained increasing attention in recent years, especially in developing countries, due to low collection rates. This study aims to search for progressive solutions in the e-waste collection sphere with close-to-zero transport and infrastructure costs and the minimization of consumers’ efforts towards an enhanced e-waste management efficiency and collection rate. Along these lines, the present paper develops a smart reverse system of e-waste from end-of-life electronics holders to local recycling infrastructures based on intelligent information technology (IT) tools involving local delivery services to collect e-waste and connecting with interactive online maps of users’ requests. This system considers the vehicles of local delivery services as potential mobile collection points that collect and deliver e-waste to a local recycling enterprise with a minimum deviation from the planned routes. Besides e-waste transport and infrastructure costs minimization, the proposed smart e-waste reverse system supports the reduction of CO2 through the optimal deployment of e-waste collection vehicles. The present study also advances a solid rationale for involving local e-waste operators as key stakeholders of the smart e-waste reverse system. Deploying the business model canvas (BMC) toolkit, a business model of the developed system has been built for the case of Sumy city, Ukraine, and discussed in light of recent studies.

Download Full-text

Genesis of Precious Metal Mineralization in Intrusions of Ultramafic, Alkaline Rocks and Carbonatites in the North of the Siberian Platform

Minerals ◽

10.3390/min11040354 ◽

2021 ◽

Vol 11 (4) ◽

pp. 354

Author(s):

Anatoly M. Sazonov ◽

Aleksei E. Romanovsky ◽

Igor F. Gertner ◽

Elena A. Zvyagina ◽

Tatyana S. Krasnova ◽

...

Keyword(s):

High Temperature ◽

Siberian Platform ◽

Precious Metal ◽

Native Gold ◽

Precious Metals ◽

Ore Formation ◽

Central Type ◽

Alkaline Rocks ◽

The North ◽

Pge Mineralization

The gold and platinum-group elements (PGE) mineralization of the Guli and Kresty intrusions was formed in the process of polyphase magmatism of the central type during the Permian and Triassic age. It is suggested that native osmium and iridium crystal nuclei were formed in the mantle at earlier high-temperature events of magma generation of the mantle substratum in the interval of 765–545 Ma and were brought by meimechite melts to the area of development of magmatic bodies. The pulsating magmatism of the later phases assisted in particle enlargement. Native gold was crystallized at a temperature of 415–200 °C at the hydrothermal-metasomatic stages of the meimechite, melilite, foidolite and carbonatite magmatism. The association of minerals of precious metals with oily, resinous and asphaltene bitumen testifies to the genetic relation of the mineralization to carbonaceous metasomatism. Identifying the carbonaceous gold and platinoid ore formation associated genetically with the parental formation of ultramafic, alkaline rocks and carbonatites is suggested.

Download Full-text

3D MXene hybrid architectures for the cold-resistant, rapid and selective capture of precious metals from electronic waste and mineral

Chemical Engineering Journal ◽

10.1016/j.cej.2021.132493 ◽

2022 ◽

Vol 428 ◽

pp. 132493

Author(s):

Zhen Qin ◽

Hongxia Deng ◽

Ruihua Huang ◽

Shanshan Tong

Keyword(s):

Electronic Waste ◽

Precious Metals ◽

Hybrid Architectures

Download Full-text

Emulsion Liquid Membrane Extraction of Silver from Photographic Waste using Tetramethylthiuram Disulfide (TMTDS) as a Mobile Carrier

Journal of Applied Membrane Science & Technology ◽

10.11113/amst.v3i1.35 ◽

2017 ◽

Vol 3 (1) ◽

Author(s):

Norasikin Othman ◽

Chan Kit Hie ◽

Chiong Tung ◽

Hanapi Mat ◽

Masahiro Goto

Keyword(s):

Heavy Metals ◽

Liquid Membrane ◽

Raw Materials ◽

Precious Metals ◽

Membrane Extraction ◽

Industrial Wastes ◽

Emulsion Liquid Membrane ◽

Tetramethylthiuram Disulfide ◽

Mobile Carrier ◽

Liquid Membrane Extraction

The recovery of precious metals such as silver from photographic wastes is required in order to save raw materials and to protect the environment from dispersed compound, especially heavy metals. For that matter, several technologies have been used such as precipitation, electrolytic, and ion exchange processes which offer some advantages as well as drawbacks over others. Recently, emulsion liquid membrane extraction has been recognized to be a potential process for industrial wastes treatment and recovery of heavy metals. This process has the ability to selectively separate and rapidly concentrate metals through its very thin layer liquid membrane which has a large interfacial area. An attempt was made to recover silver from liquid photographic wastes using tetramethylthiuram disulfide as a mobile carrier. The important variables affecting the emulsion liquid membrane (ELM) process including residence time, surfactant concentration, carrier concentration, level of agitation and phase ratio between emulsion and feed phase were investigated. The results showed that tetramethylthiuram disulfide is selective towards silver (>80%) compared to other metals in the photographic waste. The highest silver extraction is obtained using 0.05 M tetramethylthiuram disulfide, 3% (w/v) Span 80, 300 rpm stirring speed, 1.0 M thiourea in 0.1 M HCl stripping agent, 1:3 of treat ratio, and toluene as the diluent.

Download Full-text