Waste printed circuit boards (WPCBs) encompass about 3% of nearly 50 Mt of electronic waste (e-waste) annual generation representing one of the fastest-growing categories of global waste. WPCBs consists of glass-reinforced epoxy resins and a number of metallic components, including base and precious metals (PM) with a concentration higher than those of primary resources, making them economically attractive for recycling. The most significant and critical issue for the processing of e-wastes and WPCBs is to deal successfully with the halogenated flame retardants (HFR) content and heavy metals (such as Pb, Hg, and Cd), which make e-waste a hazardous waste with significant environmental concerns. The main objective of this study was to develop, design, and demonstrate a mechanical/physical separation flowsheet for efficient, low-cost, and environmentally sustainable recovery of base and precious metals from WPCBS. WPCBs, which were dismantled, shredded to 6 cm top size, and processed using a thermolyzer process by CHZ Technology Inc. were used in this study. The thermolyzer process produced clean syngas and plastic-free solid char, while producing no environmental hazards. The solid char mainly contained metals, carbon, and fiber glass. The solid char was first fully characterized for the liberation and potential recovery of base and precious metals. The elemental content of the char-metal mixture results showed that the base metals in the sample were mainly Cu (19.5%) and Al (4.3%). Regarding the precious metals, the sample contained approximately 32 ppm of Au, 10 ppm of Ag, and 3 ppm of Pd. The analysis of size and density fractions showed that most (i.e., 60-80%) of the base metals, reported to the coarse fractions (+1.19mm). The concentration of Cu in the coarse fractions varied from approximately 20-30% and was found to be less than 20% in the finer fractions. Aluminum had higher concentrations, ranging from 4 to 6% in the fractions coarser than 0.149 mm, and its concentration decreased to less than 1% in the fraction finer than -0.149 mm. The majority (i.e., 69%) of the Au was present in the fine fractions (-1.19 mm), out of which approximately 34% by weight with Au concentration of about 50 ppm was reported in the finest size fraction (i.e., -0.149 mm). Ag and Pd were relatively equally distributed in all other fractions ranging from 5-12 ppm and 1-4 ppm, respectively. The sized density fractionation showed that the metals in the fraction coarser than 0.5 mm were interlocked, while the size fractions of 0.5 mm x 0.149 mm, and finer than 0.149 mm were relatively and well liberated. Therefore, only the former fraction was required to be comminuted to increase liberation, and the latter fractions were screened and directly subjected to appropriate physical separation. As a result, the feed to the comminution circuitry was reduced by 12%. Integrated with the removal of plastic components by the thermolyzer process, the reduction of the feed load to the comminution circuitry was 52%. The content of non-metals., base metals, and precious metals in their corresponding sized density fractionations revealed that base and precious metals can be potentially concentrated by gravity separation. Upon characterization, the differences in the malleability of metals present in WPCBs was utilized for the selective liberation of metals in PCBs in various size fractions. The WPCBs were mechanically processed through comminution by rod mill followed by screening to liberate metals in various size fractions. The milling retention time was optimized to maximize the degree of liberation and minimize overgrinding, reducing energy consumption and preventing excessive generation of fine particles. The optimum milling time was found to be 15 min, equivalent to 2 kg/h feed rate in the laboratory rod mill, for metal liberation, at which more than 80% degree of liberation of metal was obtained without overgrinding the materials. Upon optimization, materials coarser than 0.5 mm were comminuted using rod mills for metal liberation, followed by screening into coarse, medium, and fine (+0.5 mm, 0.5 mm x 0.149 mm, and -0.149 mm, correspondingly) fractions for downstream physical separation. To investigate the potential of physical separation techniques to concentrate Cu, Al, Au, Ag, and Pd, gravity and magnetic separations were studied. A wet jigging, shaking table, and multi-gravity separator (MGS) were utilized for the coarse, medium, and fine size fractions. The Cu and Al recovery using the jig was found to be 92% and 80% with a grade of 72% and 14%, respectively. The shaking table concentrated Cu with 69% and 87% grade and 60% and 87% recovery, Au with 416 ppm and 36 ppm grade and 86% and 91% recovery, Ag with 272 ppm and 107 ppm grade and 38% and 90% recovery, Pd with 6.8 ppm and 7 ppm grade and 19% and 82% recovery for both non-ground and ground samples, respectively. Al with grade more than 11% and recovery more than 70% was obtained in the shaking table middling and tailing. MGS recovered 98% and 99% of Cu with 9.6% and 16% grade, 99% and 97% of Al with 8% and 8% grade, 68% and 67% of Au with 143 ppm and 87 ppm grade, 90% of Ag with 26 ppm grade, and 94% and 89% of Pd with 7 ppm and 6 ppm grade for both non-ground and ground samples, respectively. Based on obtained results, a process flowsheet was proposed. The flowsheet can produce a concentrate of significantly high grade and recovery of target elements using the combination of low-cost and environmentally friendly physical separation processes. The results showed that Cu, Al, Au, Ag, and Pd with 45%, 10%, 134 ppm, 89 ppm, and 6 ppm grade and 93%, 61%, 70%, 72%, and 80% recovery, respectively, were successfully produced. The recovery and grade values can be further improved through the addition of cleaner and scavenger units as well as recirculating loads. The flowsheet provides a successful pathway for recycling WPCBs.

This book is open access under a CC BY 4.0 license.This book presents results relevant in the manufacturing research field, that are mainly aimed at closing the gap between the academic investigation and the industrial application, in collaboration with manufacturing companies. Several hardware and software prototypes represent the key outcome of the scientific contributions that can be grouped into five main areas, representing different perspectives of the factory domain:1) Evolutionary and reconfigurable factories to cope with dynamic production contexts characterized by evolving demand and technologies, products and processes.2) Factories for sustainable production, asking for energy efficiency, low environmental impact products and processes, new de-production logics, sustainable logistics.3) Factories for the People who need new kinds of interactions between production processes, machines, and human beings to offer a more comfortable and stimulating working environment.4) Factories for customized products that will be more and more tailored to the final user’s needs and sold at cost-effective prices.5) High performance factories to yield the due production while minimizing the inefficiencies caused by failures, management problems, maintenance.This books is primarily targeted to academic researchers and industrial practitioners in the manufacturing domain.

WEEE Recycling: Research, Development, and Policies covers policies, research, development, and challenges in recycling of waste electrical and electronic equipment (WEEE). The book introduces WEEE management and then covers the environmental, economic, and societal applications of e-waste recycling, focusing on the technical challenges to designing efficient and sustainable recycling processes—including physical separation, pyrometallurgical, and hydrometallurgical processes. The development of processes for recovering strategic and critical metals from urban mining is a priority for many countries, especially those having few available ores mining. - Describes the two metallurgical processes—hydro- and pyro-metallurgy—and their application in recycling of metals - Provides a life cycle analysis in the WEEE recycling of metals - Outlines how to determine economic parameters in the recycling of waste metals - Discusses the socio economic and environmental implication of metal recycling

This collection focuses on energy efficient technologies including innovative ore beneficiation, smelting technologies, recycling and waste heat recovery. The volume also covers various technological aspects of sustainable energy ecosystems, processes that improve energy efficiency, reduce thermal emissions, and reduce carbon dioxide and other greenhouse emissions. Papers addressing renewable energy resources for metals and materials production, waste heat recovery and other industrial energy efficient technologies, new concepts or devices for energy generation and conversion, energy efficiency improvement in process engineering, sustainability and life cycle assessment of energy systems, as well as the thermodynamics and modeling for sustainable metallurgical processes are included. This volume also offers topics on CO2 sequestration and reduction in greenhouse gas emissions from process engineering, sustainable technologies in extractive metallurgy, as well as the materials processing and manufacturing industries with reduced energy consumption and CO2 emission. Contributions from all areas of non-nuclear and non-traditional energy sources, such as solar, wind, and biomass are also included in this volume.Papers from the following symposia are presented in the book:Energy TechnologiesAdvances in Environmental Technologies: Recycling and Sustainability Joint SessionDeriving Value from Challenging Waste Materials: Recycling and Sustainability Joint SessionSolar Cell Silicon

New discoveries of the properties of gold at a nanoscale, and its effective use in modern technologies, have been driving a virtual 'gold rush'. Depleting natural resources has meant that the recovery of gold continues to grow in importance and relevance.The Recovery of Gold from Secondary Sources analyses the most advanced technology in gold recovery and recycling from spent sources of mobile phones, unwanted electronic equipment and waste materials. State-of-the-art techniques of hydrometallurgical and bio-metallurgical processing, leaching, cementing, adsorbing and separation through bio-sorbents are all described in detail, providing a guide for students and researchers. Discussion of environmentally friendly methods of recovery are presented, in order to provide modern-day alternatives to previous techniques. For those interested in the study of gold recovery this book gives a comprehensive overview of current recovery, making it the ultimate source of information for students, researchers, chemists, metallurgists, environmental scientists and electronic waste recovery experts.

E-waste management is a serious challenge across developed, transition, and developing countries because of the consumer society and the globalization process. E-waste is a fast-growing waste stream which needs more attention of international organizations, governments, and local authorities in order to improve the current waste management practices. The book reveals the pollution side of this waste stream with critical implications on the environment and public health, and also it points out the resource side which must be further developed under the circular economy framework with respect to safety regulations. In this context, complicated patterns at the global scale emerge under legal and illegal e-waste trades. The linkages between developed and developing countries and key issues of e-waste management sector are further examined in the book.