Novel technologies and conventional processes for recovery of metals from waste electrical and electronic equipment: Challenges &amp; opportunities – A review

Chauhan, Garima; Jadhao, Prashant Ram; Pant, Kamal Kishore; Nigam, K.D.P.

doi:10.1016/j.jece.2018.01.032

Cited by 140 publications

(51 citation statements)

References 155 publications

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“…In the 21st century, the usage as well as the utilization and production of electronic materials both for business and household purposes have expanded exponentially step by step and have compounded the problem of piling electronic waste (e-waste). Low prices, new technologies innovation and addition of new features are also causing the replacement of electronic products at a quicker rate [1]. In both developed and developing countries, it creates a huge quantity of wastes in the form of obsolete electrical and electronic products [2].…”

Section: Introductionmentioning

confidence: 99%

“…Thus, total disposal of the e-waste is not possible through mechanical routes [10][11][12][13]. Environmental pollution is caused by the treatment or handling of poor and improper recycling processes by release of toxic materials in e-waste from landfilling or treatment or from the end-products and compounds after these procedures [1,4,14]. Due to the presence of halogenated flame retardants (HFR) in the feed of e-waste, it causes formation of dioxins, which are very harmful.…”

Section: Introductionmentioning

confidence: 99%

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Recovery of basic valuable metals and alloys from E-waste using microwave heating followed by leaching and cementation process

et al. 2019

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The whole world understands about the crisis of harmful electronic waste as it is increasing the usage and its disposal. The Government of India asked researchers to come out with innovative alternative solutions, apart from existing conventional methods for safe reuse, recycling and proper disposal particularly for electronic solid waste system. The solution is found which consists of microwave heat treatment followed by acid leaching. The e-waste was first crushed and then the sample was melted in microwave heat treatment to recover the valuable metal in the form of metallic mixture. This mixture was further subjected to acid leaching process in the presence of hydrogen peroxide to form leached liquor. The analysis with X-ray diffraction, image mapping and energy-dispersive X-ray spectroscopy shows that the leached liquor sample mainly contain iron, aluminum and copper, mostly in the form of alloys. The results with field-emission scanning electron microscope analysis, also shows that approximately ninety percent leaching efficiency is observed for nickel, cobalt and copper with hydrochloric acid as solvent, whereas iron and aluminum produced less than forty percent. Further, these results are also compared with the existing methods based on the response surface method through thermal plasma process.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Recovery of basic valuable metals and alloys from E-waste using microwave heating followed by leaching and cementation process

et al. 2019

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“…It involves the use of chemical reactions in aqueous or organic solutions [15]. It is the most highly developed technology due to: (1) safe disposal of precipitates and eluates; (2) significant and easy recovery of metals; (3) relatively low energy requirement; 4) easy implementation at laboratory scale for testing new processes and materials; (5) relatively low capital investment and operating costs [16,17]. Several studies have investigated hydrometallurgy processes by using strong mineral acids (HCl, HNO 3 , and H 2 SO 4 ) for leaching of heavy metals from various solids such as soil, sludge, electronic waste, fly ash, etc.…”

Section: Introductionmentioning

confidence: 99%

Column Leaching Tests to Valorize a Solid Waste from the Decommissioning of Coal-Fired Power Plants

et al. 2019

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Solid waste from the decommissioning of coal-fired power plants collected from a power plant in Spain (Puertollano, Ciudad Real) was subjected to acid leaching tests in columns to evaluate the leachability of several valuable and toxic metals (Al, Ca, Fe, K, Mg, Na, Ti, V, Cr, Mn, Ni, and Zn). First, the contaminated waste, delivered by a national company, was chemically characterized. Second, column-leaching tests were conducted using two different acid solutions (nitric and sulfuric acid). The effect of the leaching agent concentration and time of leaching were examined. The results of column leaching tests showed that different concentrations of the acid solutions leached different proportions of Al, Fe, Mg, Mn, Ni, V, and Zn, which were leached by acid solutions from the solid waste sample. In general, use of sulfuric acid at pH 0.5 resulted in better leaching. Next, a comparison between three different configurations (one single stage without recirculation, one single stage with total recirculation of leachate and leaching in two consecutive stages: one with total recirculation of leachate and another one with acid set to a pH value of 0.5 and without recirculation) was performed. At the end of the experiments, all leaching methods resulted in comparable yields for Al (0.36–0.48%), Fe (5.99–6.40%), Mg (4.43–5.11%), Mn (2.71–2.83%), Ni (12.08–12.75%), V (0.08–0.34%), and Zn (23.62–25.28%). However, better results were obtained when two consecutive stages were carried out. Additionally, the effect of forced aeration on leachability was studied. Finally, this investigation showed that hydrometallurgical treatment of contaminated solid by means of acid leaching followed by basic leaching and a water wash between these stages was a potentially feasible method for reducing hazardous levels of the residue.

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“…In recent years, several separation technologies developed in mineral processing engineering, based on the differences in physical and chemical properties, have been applied to separate metals and non-metals from electric and electronic waste. Several studies have reviewed the progress and the potential of the available techniques, for the recovery of metals and non-metals from electric and electronic waste [2][3][4][5][6][7][8]. These technologies include the application of physical separation, such as gravity methods [9][10][11][12]; magnetic separation [13][14][15]; electrostatic separation by the corona method [13,16,17]; electrical conductivity (Eddy currents) methods [18][19][20] and froth flotation [11,[21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Separation of Copper from Electric Cable Waste Based on Mineral Processing Methods: A Case Study

Pita

Castilho

2018

Minerals

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Recycling of electrical cable waste requires a separation between the metal and the insulating material. The objective of this work was to separate the copper from the plastic in electrical cable waste previously ground below 2 mm, using jigging, shaking table and froth flotation techniques. The effect of particle size was also analysed. Jigging and shaking table proved to be effective in the separation of copper from plastics. The result was a copper concentrate with a copper grade of about 97% by both methods and a copper recovery of about 97%. Jigging separation had similar separation efficiencies in the seven-sized fractions, but in shaking table, the separation efficiency improved with an increase in particles size. The separation achieved by froth flotation had lower efficiencies (85%), because plastics are naturally hydrophobic and copper presents some hydrophobic behaviour. In this technique, the addition of depressant agents was mandatory for the depression of copper, even at low concentrations. The best results were obtained with concentrations of 10 −1 mg/L of sodium sulfide (407410 Sigma-Aldrich, Sigma-Aldrich Corporation, St. Louis, MO, USA) and meso-2,3-Dimercaptosuccinic acid (D7881 Sigma-Aldrich).

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Novel technologies and conventional processes for recovery of metals from waste electrical and electronic equipment: Challenges & opportunities – A review

Cited by 140 publications

References 155 publications

Recovery of basic valuable metals and alloys from E-waste using microwave heating followed by leaching and cementation process

Recovery of basic valuable metals and alloys from E-waste using microwave heating followed by leaching and cementation process

Column Leaching Tests to Valorize a Solid Waste from the Decommissioning of Coal-Fired Power Plants

Separation of Copper from Electric Cable Waste Based on Mineral Processing Methods: A Case Study

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