Classification of metals and plastics from printed circuit boards (PCB) using air classifier

Eswaraiah, C.; Kavitha, T.; Vidyasagar, S.; Narayanan, S.

doi:10.1016/j.cep.2006.11.010

Cited by 138 publications

(61 citation statements)

References 8 publications

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“…Zhang and Forssberg 147 used a shape separator for separating mixed waste generated from personal computers and PWBs. Eswaraiah et al 148 compared the efficiency of separating metals from nonmetals for ground PWBs using a float-sink method (specific gravity ϭ 1.85 zinc chloride solution) and vertical column air classification. Duan et al 149 examined metal recovery from PWBs using a combined process of wet impact crushing followed by centrifugal density separation.…”

Section: Separation Technologiesmentioning

confidence: 99%

Environmental Issues and Management Strategies for Waste Electronic and Electrical Equipment

Townsend

2011

Journal of the Air & Waste Management Association

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Issues surrounding the impact and management of discarded or waste electronic and electrical equipment (WEEE) have received increasing attention in recent years. This attention stems from the growing quantity and diversity of electronic and electrical equipment (EEE) used by modern society, the increasingly rapid turnover of EEE with the accompanying burden on the waste stream, and the occurrence of toxic chemicals in many EEE components that can pose a risk to human and environmental health if improperly managed. In addition, public awareness of the WEEE or "e-waste" dilemma has grown in light of popular press features on events such as the transition to digital television and the exportation of WEEE from the United States and other developed countries to Africa, China, and India, where WEEE has often not been managed in a safe manner (e.g., processed with proper safety precautions, disposed of in a sanitary landfill, combusted with proper air quality procedures). This paper critically reviews current published information on the subject of WEEE. The definition, magnitude, and characteristics of this waste stream are summarized, including a detailed review of the chemicals of concern associated with different components and how this has changed and continues to evolve over time. Current and evolving management practices are described (e.g., reuse, recycling, incineration, landfilling). This review discusses the role of regulation and policies developed by governments, institutions, and product manufacturers and how these initiatives are shaping current and future management practices.

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Section: Separation Technologiesmentioning

confidence: 99%

Environmental Issues and Management Strategies for Waste Electronic and Electrical Equipment

Townsend

2011

Journal of the Air & Waste Management Association

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“…There are many papers reporting on the recovery of high content metals (Cu, Al, Sn) or precious metals (Au, Ag) from WPCBs using physical, chemical, or biological methods, or a combination of these approaches [1][2][3][4][5][6][7][8][9][10][11][12]. However, these processes are very difficult to perform and are expensive not only for the concentration of minor metals but also for their individual recovery.…”

Section: Introductionmentioning

confidence: 99%

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Kim

Lee

2016

Metals

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Abstract:The leaching kinetics of zinc from zinc oxide-based metal oxide varistors (MOVs) was investigated in H 2 SO 4 at atmospheric pressure. Kinetics experiments were carried out at various agitation speeds, particle sizes, initial H 2 SO 4 concentrations, and reaction temperatures. It was determined that the leaching rate of zinc was independent of agitation speed above 300 rpm and also independent of particle size below 105 µm, whereas it dramatically increased with an increasing H 2 SO 4 concentration. Except for when the H 2 SO 4 concentration was varied, the m-values were almost constant at varying agitation speeds (m-values: 0.554-0.579), particle sizes (m-values: 0.507-0.560) and reaction temperature (m-values: 0.530-0.560) conditions. All of the m-values in these experiments were found to be below 0.580. Therefore, it is proposed that the extraction of zinc is a diffusion-controlled reaction. The leaching kinetics followed the D3 kinetic equation with a rate-controlling diffusion step through the ash layers, and the corresponding apparent activation energy was calculated as 20.7 kJ/mol in the temperature range of 313 K to 353 K.

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“…For example, the leaching of nickel and copper is carried out selectively and gold can be recovered in high purity. However, the solutions are highly corrosive and hazardous, as concentrated nitric acid, hydrochloric acid and/or cyanide solutions are used for leaching over long dissolution times [13][14][15]. Destruction of the resin by dissolution in acid/alkali also represents a waste of non-renewable organic resources.…”

Section: Introductionmentioning

confidence: 99%

Chemical Recycling of Printed Circuit Board Waste by Depolymerization in Sub- and Supercritical Solvents

Yıldırır

Onwudili

Williams

2015

Waste Biomass Valor

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Disposal of waste printed circuit boards is regarded as a potential major environmental problem due to their heavy metal content. Therefore, recycling waste printed circuit boards represents an opportunity to recover the high value resin chemicals and the high value metals that are present. In this study, the solvo-thermal depolymerisation of waste printed circuit boards obtained from desktop computer monitors was carried out using water, ethanol and acetone between 300 -400 °C. Alkalis (NaOH, KOH) were used as additives to promote the removal of the resin fraction of the printed circuit boards. At 400 °C, 94% resin removal was achieved when water was used as the solvent, in the presence of NaOH. The liquid produced in the process was analysed by GC/MS and the results showed that it was mainly composed of phenol, and some phenolic compounds, with up to 62.5 wt% present as phenol in the liquid phase.

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Classification of metals and plastics from printed circuit boards (PCB) using air classifier

Cited by 138 publications

References 8 publications

Environmental Issues and Management Strategies for Waste Electronic and Electrical Equipment

Environmental Issues and Management Strategies for Waste Electronic and Electrical Equipment

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Chemical Recycling of Printed Circuit Board Waste by Depolymerization in Sub- and Supercritical Solvents

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