Abstract
Waste from information technology (IT) and telecommunication equipment (WITTE) constitutes a significant fraction of waste from electrical and electronic equipment (WEEE). The presence of rare metals and hazardous materials (e.g., heavy metals or flame retardants) makes the necessary recycling procedures difficult and expensive. Important efforts are being made for Waste Printed Circuit Board (WPCB) recycling because, even if they only amount to 5–10% of the WITTE weight, they constitute up to 80% of the recovered value. This paper summarizes the recycling techniques applicable to WPCBs. In the first part, dismantling and mechanical recycling techniques are presented. Within the frame of electro-mechanical separation technology, the chain process of shredding, washing, and sieving, followed by one or a combination of magnetic, eddy current, corona electrostatic, triboelectrostatic, or gravity separation techniques, is presented. The chemical and electrochemical processes are of utmost importance for the fine separation of metals coming from complex equipment such as WPCBs. Thermal recycling techniques such as pyrolysis and thermal treatment are presented as complementary solutions for achieving both an extra separation stage and thermal energy. As the recycling processes of WPCBs require adequate, efficient, and ecological recycling techniques, the aim of this survey is to identify and highlight the most important ones. Due to the high economic value of the resulting raw materials relative to the WPCBs’ weight and composition, their recycling represents both a necessary environmental protection action, as well as an economic opportunity.
Highlights
Waste management is associated with the manufacturing process of all products
Mechanical separation and electrical-conductivity separation, electrostatic separation, corona electrostatic separation, and tribo-electrical separation have been developed as effective techniques for isolating other components from the waste from electrical and electronic equipment (WEEE) [75]
The metals and non-metals could be separated by electrostatic corona separation with good performance under the particle size condition of Waste Printed Circuit Board (WPCB), if they are between 0.6 and 1.2 mm. [97]
Summary
Waste management is associated with the manufacturing process of all products. The most recommended waste management approaches include the reduction of the quantity of generated waste, the expansion of environmentally friendly recycling technologies, and the maximization of re-use while at the same time fulfilling governmental measures related to waste management. Disassembled PCBs (except power boards) usually contain metal films, Au or Au-plated connectors, pins, slots, integrated circuits (IC), chips of different sizes, resistors, condensers, etc. Integrated circuit chips, central processing units (CPUs), Au pins, connectors, and small capacitors contain minor amounts of precious metals, of high scrap value [48]. The potential value of each scrap PCB varies mainly according to its size and number of Au-plated connectors, Au pins, small capacitors, integrated circuit chips, and the surface of Au plates. Once the electronic components are separated from the PCBs and sorted, each category should be further processed and refined. AAnn eemmpphhaassiiss oonn WWPPCCBB rreeccyycclliinngg tteecchhnniiqquueess iiss pprreesseenntteedd iinn tthhiiss aarrttiiccllee,, aass tthheeyy hhaavvee tthhee hhiigghheesstt eeccoonnoommiicc vvaalluuee iinn tteerrmmss ooff tthheeiirr vvoolluummee ((wweeiigghhtt)) aanndd ccoommppoossiittiioonn. The PCB recycling process can be divided into three main phases—disassembly, treatment, and rTefihneePmCeBnrte—cyrecsliunlgtinpgroicneasssceat nofb(ealdmivoisdtepduirnet)ortahwreme amtearinialpsh[a5s4e].s—disassembly, treatment, and refin1e.mDenista—ssreemsubltliyng[5i5n]:aDsaent goef r(oaulms opsrtopduurcets) (rea.wg.,mAaltreardiailasto[5r4s,].capacitors, batteries, etc.), valuable produ1.cDtsi(sea.sgs.e, mmbiclyro[p5r5o]:cDesasnogrseraonuds pmroedmuocrtises(e),.ga.,nAdl mraedtiaaltloicrsa, ncadppaclaitsotircs,fibxattuterreisesa,reetcc.)o,mvapllueatebllye rpermodouvecdtsfr(oe.mg.,thme imcraoipnrbooceasrdso, rins oarnddermtoemavooriidesf)u, rathnedr mcoenttaalmlicinaantidonpdlausrtiincgfitxhteurreecsycalriengcopmropcleestseelsy; remo2v.eTdrefartommentth: ePCmBasinarebodaisridn,teignraoterddeirnttoomaivcrooidpafrutrst,huesrincgosnetvaemrainl adteiovnicedsu(eri.gn.g, sthhreedrdeecryscalinndg gnprorionncmde2ese.rstTsae)rslse;toabtybmemecnoamtn:iPepCualBuastnianifrgoertdmhiesipirnotdweigffdreearrte.endStuipnbhtsoyesqmiuciaeclnroctloypn,actrhetpse,stsues(peino.ggw.,sdtehevriecsrkaanrleedssese,vpmicaearsgant(eeed.tgi.si,nmstho, romerdewdtaeelirsgshaatnn)d.d grind3e. rRs)efitonbemeceonmt:eMa eutnalifpoorwmdpeorswadreerp.rSoucebssseeqduuesnitnlyg,ththeetseechpnoowlodgeiress aavreaisleapblaer(aet.egd., ipnytroommeettaalllsuarngyd, hnyodnrmometaeltsalbluyrmgya,noirpaulcaotminbginthaetiior ndiofffetrheenmt p) htoyosibctaalincoanlcmeopstst p(eu.gre., stehcicoknndeasrsy, mresaogunrecteissm[5,6o]r. weight)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
