Recycling value materials from waste PCBs focus on electronic components: Technologies, obstruction and prospects. Issue 5 (October 2022)

• Record Type: Journal Article
• Authors: Wu, Changfa; Awasthi, Abhishek Kumar; Qin, Wenqing; Liu, Wei; Yang, Congren
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 5(2022)
• Publication Date: 2022-10
• Subjects: e-waste electronic waste -- WPCBs waste printed circuit boards -- ECs electronic components -- WECs waste electronic components -- CPUs central processing units -- RAM random access memory -- VOCs volatile organic compounds -- PCBs polychlorinated biphenyls -- PBDEs polybrominated diphenyl ethers -- PAHs polycyclic aromatic hydrocarbons -- BFRs brominated flame retardants -- PCDD/Fs polychlorinated dibenzo-p-dioxins/furans -- SMT Surface Mounting Technology -- THT Through Hole Installation Technology -- ICs integrated circuits -- TCs tantalum capacitors -- AECs aluminum electrolytic capacitors -- MLCCs multilayer ceramic capacitors -- YOLO You Only Look Once -- AWJ abrasive waterjet -- SCF Supercritical fluid -- SCWO supercritical water oxidation -- SCWD supercritical water depolymerization -- scCO2 Supercritical CO2 -- NCAA near-critical aqueous ammonia; E-waste -- Electronic components -- Metal recycling; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.108516
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: The progress of science and technology speeds up the upgrading of electrical and electronic equipment, resulting in the generation of electronic waste (e-waste). Electronic components (ECs) mount on printed circuit board (PCBs) containing high percent of precious metals, are an indispensable part of e-waste. In this article, integrated and systematic processes adopted for metallic recovering from waste ECs (WECs) were critically reviewed. Disassembly is the first step in recycling of WECs. Various automatic disassembly technologies and subsequent intelligent classification processes were introduced firstly. As a pretreatment step, metals enrichment plays a significant role in upgradation and efficient metal recovery, via physical, pyrolysis, supercritical fluid, and combined technologies. With the confirmed superiority of economic and effective, pyrometallurgical process (smelting-refining) has been conducted at a commercial scale. Hydrometallurgical process with chemical leaching and bioleaching are introduced. Various approaches and techniques for metal elements selective recovery from the leachates including ionic liquids, solvent extraction, electrowinning, adsorption, and precipitation are illustrated. Finally, a complete framework for recycling WECs is established. This study provides guidance for the development of clean and efficient recycling technology of WECs and mitigate various scientific and technological challenges for the e-waste recycling in the circular economy. Graphical Abstract: ga1 Highlights: Various WECs and the disassembly techniques have been introduced. Physical, pyrolysis and supercritical fluid methods are discussed. Pyrometallurgical and hydrometallurgical processes for WECs recovery are summarized. Advantages, obstruction and prospects of various technologies are also analyzed.