Desafíos y estrategias de mejora en el manejo y procesamiento de e-waste

The rise of the use of electric and electronic equipment (eee), has resulted in the increase of the quantities of electronic waste (e-waste) generated worldwide. These solid residues are the fastest waste stream worldwide, increasing 3 to 4% annually. It has been estimated that in 2018, 49.8 Mt will be produced globally, however, only 20% would be formally processed. There are several factors that directly influence on the e-waste generation, such as the programmed obsolescence, technology advances, and the need of newer, faster and updated equipment. This article reports problems related to the e-waste generation worldwide, and improvement alternatives to minimize the environmental impact associated to the e-waste disposal. Among the problems, amounts of e-waste generated globally and regionally are presented, and the inherent complexity related to the eee composition, and consequent limitations in the e-waste management. The alternatives to address these issues are based on the concept of circular economy, that considers not only the final product, but also the design, process and impacts related to the manufacture. Those alternatives include the green product design and changes on the manufacture of eee, and sustainable recycling processes once the eee reach their end-of-life, including the materials substitution during the manufacturing process by using environmentally friendly substances.El incremento del uso de aparatos eléctricos y electrónicos (aee), ha provocado la generación de grandes volúmenes de e-waste a escala global. Dichos residuos son los que más rápidamente aumentan en el mundo, se incrementan de 3 a 4% por año. Se estima que la generación global de e-waste durante el 2018 será de 49,8 millones de toneladas (Mt), de los cuales solamente un 20% sería formalmente procesado. Existen ciertos factores que influyen directamente en la generación de e-waste, tales como la obsolescencia programada, avances tecnológicos, y necesidad de recambio por equipos más nuevos, rápidos, y con características mejoradas. Este artículo reporta la problemática de la generación de e-waste a nivel mundial, y alternativas de mejora para minimizar el impacto medioambiental asociado a su disposición. Dentro de la problemática, se indican volúmenes, complejidad inherente de la composición de los aee, y consecuentes limitaciones en el manejo de los e-waste. Las alternativas para abordar dicha problemática se encuentran dentro del concepto de economía circular, que considera no solamente el producto final, sino que también el diseño, proceso e impactos relacionados a la manufactura. Dichas alternativas van desde el ecodiseño y cambios en la fabricación de aee, hasta procesos sustentables de reciclaje una vez que estos alcancen su vida útil, incluyendo la sustitución de materiales en el proceso de manufactura por sustancias medioambientalmente más amigables

Recent Developments in the Field of Carbon Fibers

Carbon fibres are lightweight, chemically stable materials with high mechanical strength, and have state-of-the-art applications in aerospace, marine, construction and automotive sectors. The demand for carbon fibre?based components is expected to grow dramatically with expanding opportunities for lightweight metals and composites. Although this field has achieved a high level of maturity, nanoscale developments in carbon fibres have seen dramatic improvements in the functions of conventional biomaterials and composites. This book reveals several new developments in the field to enhance characteristics of carbon fibres and their composites, novel applications for tissue engineering, biological scaffoldings and implants, recycling and reuse of end-of-life CFRP and manufacturing waste and other issues of concern in the field of carbon fibres

Desafíos y estrategias de mejora en el manejo y procesamiento de e-waste

The rise of the use of electric and electronic equipment (eee), has resulted in the increase of the quantities of electronic waste (e-waste) generated worldwide. These solid residues are the fastest waste stream worldwide, increasing 3 to 4% annually. It has been estimated that in 2018, 49.8 Mt will be produced globally, however, only 20% would be formally processed. There are several factors that directly influence on the e-waste generation, such as the programmed obsolescence, technology advances, and the need of newer, faster and updated equipment. This article reports problems related to the e-waste generation worldwide, and improvement alternatives to minimize the environmental impact associated to the e-waste disposal. Among the problems, amounts of e-waste generated globally and regionally are presented, and the inherent complexity related to the eee composition, and consequent limitations in the e-waste management. The alternatives to address these issues are based on the concept of circular economy, that considers not only the final product, but also the design, process and impacts related to the manufacture. Those alternatives include the green product design and changes on the manufacture of eee, and sustainable recycling processes once the eee reach their end-of-life, including the materials substitution during the manufacturing process by using environmentally friendly substances.El incremento del uso de aparatos eléctricos y electrónicos (aee), ha provocado la generación de grandes volúmenes de e-waste a escala global. Dichos residuos son los que más rápidamente aumentan en el mundo, se incrementan de 3 a 4% por año. Se estima que la generación global de e-waste durante el 2018 será de 49,8 millones de toneladas (Mt), de los cuales solamente un 20% sería formalmente procesado. Existen ciertos factores que influyen directamente en la generación de e-waste, tales como la obsolescencia programada, avances tecnológicos, y necesidad de recambio por equipos más nuevos, rápidos, y con características mejoradas. Este artículo reporta la problemática de la generación de e-waste a nivel mundial, y alternativas de mejora para minimizar el impacto medioambiental asociado a su disposición. Dentro de la problemática, se indican volúmenes, complejidad inherente de la composición de los aee, y consecuentes limitaciones en el manejo de los e-waste. Las alternativas para abordar dicha problemática se encuentran dentro del concepto de economía circular, que considera no solamente el producto final, sino que también el diseño, proceso e impactos relacionados a la manufactura. Dichas alternativas van desde el ecodiseño y cambios en la fabricación de aee, hasta procesos sustentables de reciclaje una vez que estos alcancen su vida útil, incluyendo la sustitución de materiales en el proceso de manufactura por sustancias medioambientalmente más amigables

Recycling of electronic waste for the recovery of value-added materials

Electronic waste (e-waste) is one of the fastest increasing waste streams worldwide due to unprecedented growth of the electronics industry, rapid obsolescence and subsequent disposal of electronic devices. Printed circuit boards (PCBs), the central component of electronic devices, are highly complex. PCBs are an important resource of metals, and contain substantial amounts of copper, tin, lead and precious metals in concentrations considerably higher than in their ores. The high value and limited reserves of minerals containing these metals makes their urban mining from waste PCBs very attractive. However, these also contained significant quantities of hazardous and toxic materials, which can result in high levels of pollution when such waste is landfilled or processed inappropriately. Research presented in this thesis is focused on developing a novel approach to recover metals and other valuable resources from waste PCBs. High temperature pyrolysis was carried out on waste PCBs in a horizontal tube furnace in the temperature range 750°C–1350°C under Argon atmosphere. Samples were placed in the cold zone of the furnace for 10 minutes to avoid thermal shock, then exposed to high temperatures for up to 20 minutes, and were quenched. This process resulted in the phase separation of solid products into a carbonaceous fraction (NMF) and a metallic phase, composed of copper rich sheets/droplets and tin-lead rich droplets and some wires. Significant proportions of Ag, Au, Pd and Pt were found to be concentrated within the metallic phases; very limited quantities of precious metals were observed in carbons and oxides in NMFs. Inert atmosphere prevented the re-oxidation of metals and loss of carbon in the gaseous fraction. High temperature pyrolysis was successful in recovering copper based alloys and carbon resources, and concentrated precious metals from e-waste. This approach also reduced the volume of material for further processing and management; minimal amounts of secondary wastes were produced. Recycling e-waste is expected to lead to enhance metal recovery, conserve natural resources and provide an environmentally sustainable solution to waste management

Novel Approach for Processing Hazardous Electronic Waste

AbstractRapid urbanization, a general improvement in living standards and increased consumption has resulted in the generation of unprecedented amounts of waste in recent years. Among different wastes, electronic wastes (e-waste) volumes are growing three times faster than any other forms of urban waste. It is estimated that 20 to 50 million tonnes of e-waste are generated worldwide every year. E-waste contains over 1000 different substances; some are toxic and hazardous, which cause serious problems to environment and on human health. Generation of waste residues during recovery of precious metals from e-waste, the presence of hazardous lead, waste plastics, secondary pollution caused by landfilling non-metallic residues are some of the problems associated with recycling e-waste.We report a novel approach to recover valuable materials from waste printed circuit boards; controlled pyrolysis of e-waste was carried out at high temperatures (750-1550°C) in an argon atmosphere. Segregation of lead and other metals was investigated as a function of temperature and reaction products were analyzed using Inductively Coupled Plasma spectroscopy and Scanning Electron Microscopy. Temperatures above 1350°C were required to completely remove lead and other metals from e-waste; waste residue that was left behind was predominantly composed of carbon. Further research was carried out on the utilization of lead free non-metallic residue as a carbon source in ironmaking application. Non-metallic residual waste from recycling PCB was found to be a promising reductant in ironmaking applications. This research has laid the foundations of a ‘Zero Waste’ approach for managing and recycling electronic waste

An Overview on Solid Waste Generation and Management: Current Status in Chile

The widespread generation of, ever increasing volumes of and the sustainable management of solid wastes are global issues of great concern. Due to wide variations in composition and associated complexities, significant efforts are required for their collection, processing and environmentally safe disposal in a cost effective manner. An overview of solid wastes is presented in this article with a specific focus on municipal solid wastes and industrial waste from the iron/steelmaking and aluminium industries. Key waste issues such as its sources, compositions, volumes, the factors affecting waste generation and waste processing are first discussed, followed by a further discussion regarding recycling, resource recovery, disposal and the associated environmental impacts. In a special case study, waste generation and management in Chile is presented in greater detail. Detailed information is provided on government initiatives and legislation for integrated solid waste management and its movement towards a circular economy. Measures include regulations on waste management framework which concerns the transboundary movements of hazardous wastes, persistent organic pollutants, the closure of mining activities and installations and restrictions on plastics disposal. With Chile being world’s largest producer of copper, significant efforts for mining waste management, its infrastructure and procedures are being put in place to reduce the environmental impact of the mining sector and its associated waste generation

Formation of carbyne-like materials during low temperature pyrolysis of lignocellulosic biomass: A natural resource of linear sp carbons

Abstract The exploration, understanding and potential applications of ‘Carbyne’, the one-dimensional sp allotrope of carbon, have been severely limited due to its extreme reactivity and a tendency for highly exothermic cross-linking. Due to ill-defined materials, limited characterization and a lack of compelling definitive evidence, even the existence of linear carbons has been questioned. We report a first-ever investigation on the formation of carbyne-like materials during low temperature pyrolysis of biobased lignin, a natural bioresource. The presence of carbyne was confirmed by detecting acetylenic –C≡C– bonds in lignin chars using NMR, Raman and FTIR spectroscopies. The crystallographic structure of this phase was determined as hexagonal: a = 6.052 Å, c = 6.96 Å from x-ray diffraction results. HRSEM images on lignin chars showed that the carbyne phase was present as nanoscale flakes/fibers (~10 nm thick) dispersed in an organic matrix and showed no sign of overlapping or physical contact. These nanostructures did not show any tendency towards cross-linking, but preferred to branch out instead. Overcoming key issues/challenges associated with their formation and stability, this study presents a novel approach for producing a stable condensed phase of sp-bonded linear carbons from a low-cost, naturally abundant, and renewable bioresource