Analitika plemenitih kovin v elektronskih odpadkih z metodo ICP-OES in primerjava dveh metod razklopa

Šmic, Nejc (author), Kolar, Mitja (mentor)

V vsaki elektronski napravi, ki kasneje postane odpadek (elektronski odpadek / e-odpadek), se nahajajo različne kovine, med katerimi so tudi plemenite kovine. Med njimi se najde tako zlato, srebro kot tudi platina, paladij, rutenij ter rodij. Ker se iz leta v leto povečuje količina elektronskih odpadkov, so ti postali posebej zanimivi, saj vsebujejo višjo količino plemenitih kovin kakor pri klasičnem rudarjenju. Z namenom pridobivanja plemenitih kovin so se razvili različni načini recikliranja tovrstnih odpadkov. Poznamo pirometalurški, hidrometalurški in biometalurški postopek pridobivanja plemenitih kovin. Vsi tovrstni procesi imajo tako prednosti kot slabosti. V diplomskem delu je prikazano določevanje plemenitih kovin v različnih vzorcih elekronskih odpadkov. Za določevanje tovrstnih kovin smo uporabili induktivno sklopljeno plazmo z optično emisijsko spektroskopijo (ICP-OES). Poleg določevanja plemenitih kovin v vzorcih pa smo tudi med seboj primerjali dve metodi razklopa, in sicer klasični razklop z zlatotopko in kislinski razklop z mikrovalovno pečico ter tako primerjali, ali razklop tudi vpliva na določevanje vsebnosti plemenitih kovin v vzorcih. Pri diplomskem delu smo ugotavljali, kateri elektronski odpadki vsebujejo največ plemenitih kovin ter katerih, in ali način razklopa vzorca vpliva na končne rezultate. Ugotovili smo, da pri vseh vzorcih ne glede na razklop ne zaznamo platine ter pri posameznih vzorcih prav tako ne zaznamo rutenija. Največjo vsebnost zlata smo zaznali v mobilnih telefonih ne glede na razklop. V posameznih vzorcih mobilnih telefonov smo zaznali, da ti vsebujejo približno od 2,5 % do 4,6 % zlata na posamezna tiskana vezja s klasičnim razklopom, z MW razklopom pa posamezna tiskana vezja vsebujejo približno 1 % do 3,8 % zlata. Ugotovili smo tudi, da sam razklop vzorca vpliva na končne rezultate. To je najbolj opazno pri vsebnosti srebra v vzorcih, npr. pri klasičnem razklopu je prisotnega povprečno 3,5 % srebra med tem, ko se pri razklopu z MW nahaja povprečno 0,04 % srebra v vzorcu analiziranega z aparaturo ICP-OES.

• Language: Slovenian
• Keywords: elektronski odpadki, plemenite kovine, zlatotopka, kislinski razklop z mikrovalovno pečico, ICP-OES
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2022
• PID: 20.500.12556/RUL-141916
• COBISS.SI-ID: 128580355
• Publication date in RUL: 11.10.2022

Secondary language

• Language: English
• Title: Analytics of precious metal in electronic waste using the ICP-OES method and comparison of two digestion methods

Abstract

In every electronic device, which later becomes waste (electronic waste / e–waste), there are various metals, including precious metals. Among them are gold, silver as well as platinum, palladium, ruthenium and rhodium. Since the amounts of e-waste are increasing year by year, they have become particularly interesting, as they contain a higher amount of precious metals than in classic mining. In order to obtain precious metals, various methods of recycling electronic waste have been developed. We know the pyrometallurgical, hydrometallurgical and biometallurgical process of obtaining precious metals. In all these processes, there are advantages and disadvantages of this type of process. The diploma thesis presents the determination of precious metals in various samples of electronic waste. Inductively coupled plasma by optical emission spectroscopy (ICP-OES), was used to determine such metals. In addition to the determination of precious metals in the samples, we had also compared the two methods of digestion. Namely, the classic digestion with aqua regia and the acid digestion with a microwave oven and comparing whether the digestion also affects the determination of the precious metal content in the samples. In the diploma work, we determined which electronic waste contains the most precious metals and which and whether the digestion methods of the sample also affect the final results. We found that platinum was not detected in all samples, regardless of the digestion, and ruthenium was not detected in any individual sample. The highest gold content was detected in mobile phones regardless of the digestion. In individual samples of mobile phones we detected approximately 2,5 % to 4,6 % gold per individual printed circuit board with classic breakdown, and with MW breakdown each individual printed circuit board contained approximately 1 % to 3,8 % of gold. We also found that the type of digestion also affect the final results. This is most noticeable in the final results of silver in the samples, e.g. with classic digestion, an average 3,5 % of silver, while with acid digestion with MW, an average of 0,04 % silver is present in the sample analysed by ICP-OES.

• Keywords: electronic waste, precious metals, aqua regia, acid digestion with microwave, ICP-OES