Raziskava vsebnosti elementov redkih zemelj v prenosnih telefonih

magistrsko delo

Martin Smodiš (Author), Niko Samec (Mentor), Rebeka Rudolf (Co-mentor)

Abstract

V magistrski nalogi so obravnavani elementi redkih zemelj z vidika pridobivanja, uporabe in reciklaže. Prikazane so njihove edinstvene fizikalno-kemijske lastnosti. Zaradi teh se uporabljajo pri proizvodnji visokotehnoloških naprav, npr. v zaslonih prenosnih telefonov, televizij in računalnikov, trdih optičnih diskih, visokozmogljivih magnetih, svetilih in energijsko varčnih lučeh, senzorjih vozil, vetrnih turbinah, hibridnih vozilih, kot materiali za superprevodnike, laserje, gorivne celice, kot dodatki za kovinske zlitine idr. Na osnovi predstavljene tematike smo se v raziskovalnem delu magistrske naloge osredotočili na analiziranje odsluženih prenosnih telefonov s poudarkom na identifikaciji tistih sestavnih delov, v katerih najdemo elemente redkih zemelj. Ciljano smo izvedli raziskavo vsebnosti elementov redkih zemelj (v masnih %). Statistična analiza trga prenosnih telefonov kaže, da je bilo v letu 2015 na svetovni trg danih 1,917 milijarde prenosnih telefonov, od tega na evropski trg 210,3 milijona. Količina odsluženih prenosnih telefonov je iz leta v leto višja in bo v prihodnosti povzročala vse večje negativne okoljske posledice. Rešitev je zato v reciklaži odsluženih prenosnih telefonov s pridobivanjem sekundarnih surovin, kakor tudi elementov redkih zemelj iz njihovih sestavnih delov. Glavni namen magistrske naloge je bil znanstveno ovrednotiti, ali je reciklaža elementov redkih zemelj iz sestavnih delov odsluženih prenosnih telefonov upravičena glede na to, da se za njihovo proizvodnjo letno porabi tudi do 2.000 ton elementov redkih zemelj, pridobljenih z rudarjenjem iz zemeljske skorje. Za potrditev hipoteze smo naključno izbrali šest modelov prenosnih telefonov različnih proizvajalcev, izdelanih v letih 20042015. Za reprezentativne vzorce so bili izbrani magneti (vibrator in zvočnik), ki vsebujejo elemente redkih zemelj. Za potrditev prisotnosti in določitev vsebnosti elementov redkih zemelj v posameznih sestavnih delih prenosnih telefonov smo uporabili različne tehnike karakterizacije, kot sta svetlobna in vrstična elektronska mikroskopija v kombinaciji z mikrokemičnima analizama EDS in WDS. Preiskave so pokazale, da so magneti sestavljeni iz magnetnega jedra in protikorozijske zaščitne prevleke; slednja, debeline 2426 m, je sestavljena iz treh plasti (Ni-Cu-Ni). Magnetno jedro je sestavljeno iz Fe-Nd-Pr, v novejših prenosnih telefonih pa je obogateno tudi z Gd. Z obširnimi mikrokemičnimi analizami EDS in WDS na površini magnetnih jeder (vibrator in zvočnik) je bilo ugotovljeno, da je povprečna vsebnost elementov redkih zemelj (neodima, prazeodima in gadolinija) okoli 13,5 (mas. %) oziroma 0,082 g brez upoštevanja količin elementov redkih zemelj, ki se nahajajo v elektronskem vezju, mikrofonu, zaslonu in kameri. Na osnovi pregleda literature, študij, opravljenega raziskovalnega dela in rezultatov analiz v okviru te magistrske naloge lahko zaključimo, da je reciklaža odsluženih prenosnih telefonov ekonomsko upravičena. To bo veljalo pod pogojem, da se v obdobju 20152018 v skladu z evropsko direktivo zbere 45 %, predela 80 % in reciklira 70 % od 210,3 milijona odsluženih prenosnih telefonov, ki so bili dani na evropski trg v letu 2015. Naši izračuni kažejo, da bi lahko pri tej količini odsluženih prenosnih telefonov z ustreznimi reciklažnimi postopki ponovno pridobili približno 4.345 kg elementov redkih zemelj. Z okoljskotrajnostnega vidika je reciklaža prenosnih telefonov vsekakor upravičena in nujno potrebna, saj na ta način pomembno prispevamo k zmanjšanju nenadzorovanega kopičenja odpadne električne in elektronske opreme, k učinkoviti rabi virov, uravnoteženju trga elementov redkih zemelj, ponovnemu pridobivanju dragocenih sekundarnih surovin ter ne nazadnje k zmanjšanju negativnih vplivov na okolje.

Keywords

elementi redkih zemelj;kemijska sestava;statistična analiza;recikliranje;okoljska tveganja;prenosni telefoni;magistrske naloge;

Data

Language:	Slovenian
Year of publishing:	2016
Typology:	2.09 - Master's Thesis
Organization:	UM FS - Faculty of Mechanical Engineering
Publisher:	[M. Smodiš]
UDC:	502.174:546.65:621.395.721.5(043.2)
COBISS:	19801110
Views:	1091
Downloads:	151
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	Research of Rare Earth Elements´ Content in Mobile Phones
Secondary abstract:	This Master's thesis deals with the subject of rare earth elements regarding their extraction, use and recycling. Their unique physiochemical properties are shown, which make them indispensable in high-tech production. They are a vital part of phone displays, television and computer screens, optical disc drives, high-powered magnets, illuminants and energy-efficient lightbulbs, vehicle sensors, wind turbines, hybrid vehicles, act as materials in superconductors lasers, fuel cells, additives to alloys, etc. On this basis, the focus of the research part of this thesis was the analysis of old mobile devices with emphasis on components that contain rare earth elements. A research was conducted on rare earth elements` content in the mass fraction. A mobile phone global market analysis revealed that 9.917 billion mobile devices were sold on the global market in 2015, 210.3 million of which on the European market. The amount of scrapped mobile devices is increasing yearly and it is expected to have more and more negative effect on the environment in the future. Thus, the solution is recycling old mobile devices with the extraction of secondary elements as well as rare earth elements from their components. The main aim of this Master’s thesis was to assess, with scientific methods, whether recycling rare earth elements from mobile phones’ components is justifiable, seeing as 2,000 tons of rare earth elements extracted from the Earth’s crust are used yearly in their production. To confirm this hypothesis we randomly selected six types of mobile phones manufactured from 2004 to 2015 by different manufacturers. We obtained representative samples – magnets from the speaker and the vibrator containing rare earth elements. For determining the presence and content of rare earth elements in selected components, we opted for optical microscopy and SEM microscopy in combination with EDS-WDS microchemical analysis. The examinations showed that magnets comprise a magnetic core and an anti-corrosion coating layer. The latter, measuring 24-26m in thickness, consists of three layers (Ni-Cu-Ni), while the former’s structure is Fe-Nd-Pr, with the addition of gadolinium (Gd) in newer mobile phones. With further extensive WDS-EDS analysis on the magnetic cores' surfaces of the vibrator and the speaker we concluded that the approximate mass fraction of rare earth elements (neodymium, praseodymium, gadolinium) was 13.5 (%) or 0.082 g, not taking into account the quantity of rare earth elements found in the electrical circuit, microphone, display and camera. Based on the literature and studies´ overview, conducted research work and result analysis of this Master’s thesis we can conclude that the recycling of mobile phones is economically justifiable as long as it reaches the expected 45 % collecting rate, 80 % refining rate and 70 % recycling rate of the 210.3 million mobile phones put on the market in 2015 in the 2015-2018 period as planned in the EU’s Directive. Our calculations show that by using the appropriate recycling procedures on this quantity of disused mobile phones we could re-extract approximately 4,345 kg of rare earth elements. As for the environmental sustainability aspect, the recycling of mobile devices is most definitely justifiable and highly necessary as it contributes to diminishing the ever-growing accumulation of waste electronic and electrical equipment, efficient source usage, balancing rare earths elements market, re-extraction of secondary raw materials and, lastly, to reducing negative effects on the environment.
Secondary keywords:	rare earth elements;chemical composition;statistical analysis;recycling;environmental risks;portable phones;
URN:	URN:SI:UM:
Type (COBISS):	Master's thesis
Thesis comment:	Univ. v Mariboru, Fak. za strojništvo
Pages:	XI, 80 str.
ID:	9157059