Current Status on Leaching Precious Metals from Waste Printed Circuit Boards

AbstractCurrent research on leaching precious metals from waste printed circuit boards (PCBs) in the world is introduced. In the paper, hydrometallurgical processing techniques including cyanide leaching, thiourea leaching, thiosulfate leaching, and halide leaching of precious metals are addressed in detail. In order to develop an environmentally friendly technique for recovery of precious metals from Waste PCBs, a critical comparison of main leaching methods is analyzed based on three-scale analytic hierarchy process (AHP). The results suggest that thiourea leaching and iodide leaching make more possible to replace cyanide leaching

Current Status and Future Perspective of Waste Printed Circuit Boards Recycling

AbstractFor waste electrical and electronic equipment (WEEE), large quantities of waste printed circuit boards (PCBs) are released into environment. In light of their characteristics including complex structures, high metals content and potential hazards, waste PCBs are regarded as the most difficult parts of WEEE to be recycled. Therefore in recent ten years, the issue has attracted much attention from researchers and enterprises. This article reviews the latest processes of waste PCBs developed from laboratories to pilot engineering applications, and presents the most suitable available technology for waste PCBs, typically categorized as manually dismantling and automatic approaches in developing and developed countries, respectively. Towards achieving the better sustainability and recyclability for waste PCBs, nonmetal powder and precious metals should be developed for a deep recovery following mechanical treatment. Additionally, a significant shift is emerging from dismantling for recycling of printed wiring boards, to disassembling for remanufacturing of electronic components, which will indicate that a new paradigm of reclaiming waste PCBs is shaping

Remanufacturing strategies : a solution for WEEE problem

The electrical and electronic equipment (EEE) industry has increased its mass production; however, the EEE life span has similarly diminished. Owing to the rapid expansion of manufacturing, innovation and consumer demand, there has been a vast improvement in various electronic equipment, so the amount of waste electrical and electronic equipment (WEEE, or e-waste) generated has also increased proportionally to production. The main objective of this article is to evaluate the remanufacturing concept which can be adopt by the electronic manufacturing industry. The article reveals differential steps debated by industry as well as academia in assets to reduce the amount of e-waste. The concept of e-waste remanufacturing is quite dissimilar from case studies among developing and developed countries and regions. The findings can assist the academic research and leads to industry regardless remanufacturing of used EEE or WEEE by exemplifying different methods and ideologies of remanufacturing implementation plus the main issues in this field

Accelerating circular economy solutions to achieve the 2030 agenda for sustainable development goals

Circular economy seems a vital enabler for sustainable use of natural resources which is also important for achieving the 2030 agenda for sustainable development goals. Therefore, a special session addressing issues of "sustainable solutions and remarkable practices in circular economy focusing materials downstream" was held at the 16th International Conference on Waste Management and Technology, where researchers and attendees worldwide were convened to share their experiences and visions. Presentations focusing on many key points such as new strategies, innovative technologies, management methods, and practical cases were discussed during the session. Accordingly, this article compiled all these distinctive presentations and gave insights into the pathway of circular economy towards the sustainable development goals. We summarized that the transition to circular economy can keep the value of resources and products at a high level and minimize waste production; the focus of governmental policies and plans with the involvement of public-private-partnership on 3Rs (reduce, reuse, and recycle) helps to improve the use of natural resources and take a step ahead to approach or achieve the sustainability

“Control-Alt-Delete”: Rebooting Solutions for the E-Waste Problem

A number of efforts have been launched to solve the global electronic waste (e-waste) problem. The efficiency of e-waste recycling is subject to variable national legislation, technical capacity, consumer participation, and even detoxification. E-waste management activities result in procedural irregularities and risk disparities across national boundaries. We review these variables to reveal opportunities for research and policy to reduce the risks from accumulating e-waste and ineffective recycling. Full regulation and consumer participation should be controlled and reinforced to improve local e-waste system. Aiming at standardizing best practice, we alter and identify modular recycling process and infrastructure in eco-industrial parks that will be expectantly effective in countries and regions to handle the similar e-waste stream. Toxicity can be deleted through material substitution and detoxification during the life cycle of electronics. Based on the idea of "Control-Alt-Delete", four patterns of the way forward for global e-waste recycling are proposed to meet a variety of local situations

A method to assess national metal criticality: the environment as a foremost measurement

Abstract Ever-increasing mineral demand inspires nations to inspect the metal criticality situation that would be an indispensable path to ensure supply security in a foreseeable future. A diverse range of methods has been used to analyze the criticality; however, except a few, their applicability is questionable due to varying results. This article presents and discusses an advanced method to measure the degree of national criticality of metals conjoining both previously noted and pioneer indicators while considering China as the sample at the necessary point. The formulated methodology consists of a three-dimensional framework: supply risk, environmental risk, and supply restriction risk. The risk score of each indicator under each dimension is calculated through a specifically designed methodology. The risk score range is interpreted to a general 0–100 scale. The final risk score of each dimension is determined by averaging the total indicator risk score of that dimension. The developed criticality method is applicable for countries, which take part in the mineral production. The environmental-risk assessment is performed for 56–62 countries in reference to copper and aluminum production. Further discussion in relation to the country-specific criticality is decentralized observing the risk severity of indicators under two succinct approaches: single-metal approach and multiple-metal approach. The obtained results associated with China demonstrate that substantial criticalities can be aggregated in supply restriction and environmental sides regarding copper and aluminum, respectively. However, the environmental-risk assessment conducted for various nations in the world shows a very low risk status except the China’s situation. Although, such indicator quantifications in the proposed method are transparent, robust, reliable, and flexible to encounter medium-term perspectives, the conducted assessment is relatively static since the evaluation is almost based on the year 2015 statistics and information. Nevertheless, the created methodology will be advantageous as a decision-making tool to implement productive national strategies and policies to achieve resource sustainability. Here, a national government can address certain issues related to the metal production by distinghushing indicator values. A government can also determine what optimizations would strategically profitable in short and medium terms such as recycling, substitutes, and imports

Examining the Temporal and Spatial Models of China’s Circular Economy Based upon Detailed Data of E-Plastic Recycling

Examining the circular economy model is crucial to enable the scaling up of industry and anthropogenic circularity practice. Electrical and electronic waste plastic (e-plastic) has become the focus of urban mining and circular economy due to its rapid growth, valuable resource and potential risks. This article focuses on the recycling companies’ experience in China from 2012 to 2017. The average recycling rate was 33.3% and the recycling amount in 2017 was 558 kt. A two-dimensional coupling model of economic development and renewable resources is firstly constructed. Eventually, four typical resource-based regional models are summarized, namely for demonstration regional model, commissioned regional model, traditional model and potential regional model. It also puts forward differentiated suggestions in terms of maintaining demonstration, strengthening policies, promoting transformation, and tapping potential. At the same time, it is recommended to explore the construction of large-region resource-based recycling centers and big data centers in resource-based demonstration areas

Mapping anthropogenic mineral generation in China and its implications for a circular economy

Anthropogenic mineral is absorbing wide concern in the context of circular economy, but its generation mechanism and quantity from product to waste remain unclear. Here we consider three product groups, 30 products, and use the revised Weibull lifespan model to map the generation of anthropogenic mineral and 23 types of the capsulated materials by targeting their evolution from 2010 to 2050. Total weight of anthropogenic mineral on average in China reached 39 Mt in 2010, but it will double in 2022 and quadruple in 2045. Stocks of precious metals and rare earths will increase faster than most base materials. The total economic potential in yearly-generated anthropogenic mineral is anticipated to grow markedly from 100 billion US$in 2020 to 400 billion US$ in 2050. Furthermore, anthropogenic mineral of around 20 materials will be capable to meet projected consumption of three product groups by 2050