An overview of recycling and treatment of scrap computers

Lee, Ching-Hwa; Chang, Chang-Tang; Fan, Kuo-Shuh; Chang, Ting‐Yung

doi:10.1016/j.jhazmat.2004.07.013

Cited by 134 publications

(62 citation statements)

References 2 publications

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“…This process is closely related to the quantity of products removed from the market [1][2][3][4][5]. The electronic and electro-technical fields go through changes every day since the beginning of rapid technological achievements [6]. Good examples are computer monitors and TV sets that are composed of cathode ray tube (CRT) glass.…”

Section: Introductionmentioning

confidence: 99%

“…In the last 10 years this area has been intensely discussed by researchers due to high costs required for disposal but especially as a consequence of the new environmental regulations [8][9][10][11]. Electrical and electronic waste equipment involves serious environmental problems both due to their growing volume as well as to their toxicity caused by their content in Pb, Mn, Zn, Sn, Co etc., respectively.…”

Section: Introductionmentioning

confidence: 99%

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Study of (Pb, Ba) - CRT glass waste behavior as a partial aggregate replacement in cement mortars

Hornea¹,

Gorea²,

Har³

2017

Studia UBB Chemia

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This study investigates the usability of the cathode ray tube (CRT) glass waste in a binder system. The raw materials -glass waste, river sand and cement were characterised. CRT waste was added in the amount of 30, 40 to 50 weight percent, as replacement for river sand. Glass chemical composition shows a high content in lead and alkaline oxides. Mortar prisms were prepared and kept under humid conditions. The mechanical properties were studied after 7, 28 and 90 days respectively. SEM with additional EDS was used in order to investigate the microstructure of the samples. All the samples containing glass waste achieved higher compressive strength than the control mortar. After 14, 28 and 42 days of maintaining the mortar in water no evidence of Pb was detected in the solutions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of (Pb, Ba) - CRT glass waste behavior as a partial aggregate replacement in cement mortars

Hornea¹,

Gorea²,

Har³

2017

Studia UBB Chemia

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“…At the same time, frequent improvements in equipment features and functions have decreased the average life span of consumer electronic devices, thereby increasing the volume of e-waste generated from the obsolete devices (Lee et al, 2004;Williams et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Lead recovery from cathode ray tube funnel glass with mechanical activation

Yuan

Zhang

et al. 2012

Journal of the Air & Waste Management Association

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In the disposal of electronic waste, cathode ray tube (CRT) funnel glass remains an urgent environmental problem because of its high lead content. This research developed mechanical activation as a pretreatment process, and it proved to be an effective method for extracting lead from CRT funnel glass. The effects of mechanical activation on the structural changes of CRT funnel glass were investigated using X-ray diffraction (XRD), particle size analysis, specific surface area (SSA), and a scanning electron microscope (SEM). Nitric acid leaching behaviors of the activated CRT funnel glass were studied by varying several parameters: leaching time, liquid-to-solid ratio, acid concentration, and heating temperature, as well as various conditions of activation. The lead recovery rate was observed to increase rapidly, particularly with increases in activation time and leaching temperature, but to vary relatively less under other experimental parameters. Under the optimal leaching conditions, the lead recovery rate for funnel glass activated for 2 hr at the rotational speed of 500 rpm (by ball mill) reached 92.5%, compared with 1.2% from the unactivated sample.Implications: CRT funnel glass containing lead has become a serious environmental problem facing the whole world. In order to dispose of CRT funnel glass, some technologies have been developed. However, these technologies are associated with higher operation and maintenance costs. In this study, mechanical activation was introduced to change the physicochemical properties of CRT funnel glass, which can transform the glass into an easily dissolved one. Under atmospheric pressure leaching conditions, good recovery rate for lead can be achieved and the residue has wide uses. The process can be applied to treat other leaded glass or leadcontaining wastes.

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“…Debido a las rápidas mejoras en las tecnologías de manufactura electrónica, los computadores se han convertido en productos electrónicos de corta vida, lo que termina en una gran cantidad de computadores desechados que pueden contaminar seriamente el medio ambiente [1]. Para aportar una solución, muchos investigadores han desarrollado trabajos en los que diferentes partes de computador se reutilizan y adaptan para dar soluciones innovadoras a problemas en diversos ámbitos.…”

Section: Introductionunclassified

Control PID tipo fraccional para la posición del cabezal de una unidad de CD para aplicaciones en microscopia óptica

Valencia¹,

Cardona²

2012

Iteckne

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Resumen-En este artículo se diseña un control PID tipo fraccional para la posición del cabezal de una unidad de CD que se piensa emplear en el desarrollo de un microscopio óptico motorizado. En dicha aplicación se reemplazará el disco o CD por una placa con la muestra que va a ser estudiada, y se usará el cabezal de la unidad para iluminar la muestra. Con el controlador diseñado se busca que no haya dependencia del subcó-digo escrito en un CD para determinar la posición del cabezal, para lo cual se usará un ratón de computador como sensor de posición. También se busca un control que mejore el desempeño del sistema y que sea robusto frente a las incertidumbres en el modelo de la planta, razón por la cual se empleará un control tipo fraccional (PI^λD^μ) y se ajustarán los parámetros K_p, K_i, K_d, λ, μ con cinco especificaciones de robustez. Para la sintonización del control se utiliza la toolbox de optimización de Matlab con la función fmincon. Al final del artículo se presentan los resultados en simulación, se concluye sobre la resolución obtenida, la robustez del controlador y la viabilidad del sistema de control para ser empleado en un microscopio.Palabras clave-Control de posición, Control Fraccional, Control Robusto, Microscopía óptica, ratón óptico, unidad de CD.Abstract-On this work a fractional PID controller is designed for a CD pickup head position control that is intended to use in the development of a motorized optical microscope. In such an application the disk or CD would be replaced by a plate with the sample to be studied, and the pickup head would be used to illuminate the sample. The controller is designed in such a way that there is no dependence on a CD written subcode to determine the position of the head, and for this, a computer mouse is used as a position sensor. We also look for the controller to improve the system performance and to be robust against model uncertainties of the plant, that is why we use a fractional controller PI^λ D^μ and adjust the parameters K_p, K_i, K_dλ and μ according to five robustness rules. For tuning the control we use the Matlab optimization toolbox together with fmincon function. At the end of the paper we present the simulation results, concluding about the resolution obtained, the robustness of the controller and the viability of the control system to be used in a microscope.

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An overview of recycling and treatment of scrap computers

Cited by 134 publications

References 2 publications

Study of (Pb, Ba) - CRT glass waste behavior as a partial aggregate replacement in cement mortars

Study of (Pb, Ba) - CRT glass waste behavior as a partial aggregate replacement in cement mortars

Lead recovery from cathode ray tube funnel glass with mechanical activation

Control PID tipo fraccional para la posición del cabezal de una unidad de CD para aplicaciones en microscopia óptica

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