Studies on the Content of Selected Technology Critical Elements (Germanium, Tellurium and Thallium) in Electronic Waste

Joanna Willner,Magdalena Jablonska-Czapla,Agnieszka Fornalczyk,Marzena Rachwal,Katarzyna Grygoyc

doi:10.3390/ma14133722

Abstract

The article draws attention to the problem of the presence of metals: germanium (Ge), tellurium (Te), thallium (Tl), and others (Cd, Ba, Co, Mn, Cr, Cu, Ni, Pb, Sr, and Zn) in selected waste of electrical and electronic equipment (WEEE). As a result of the growing demand for new technologies, the global consumption of TECs has also been increasing. Thus, the amount of metals in circulation, of which the impacts on the environment have not yet been fully understood, is constantly increasing. Due to the low content of these metals in WEEE, they are usually ignored during e-waste analyses. The main aim of this study was to determine the distribution of Ge, Te, and Tl (and other elements) in ground sieve fractions (1.0, 0.5, 0.2, and 0.1 mm) of selected electronic components (solar lamps, solar cell, LED TV screens, LCD screens, photoresistors, photodiodes, phototransistors) and to determine the possible tendency of the concentrations of these metals in fractions. This problem is particularly important because WEEE recycling processes (crushing, grinding, and even collection and transport operations) can lead to dispersion and migration of TCE pollutants into the environment. The quantitative composition of e-waste was identified and confirmed by ICP-MS, ICP-OES and SEM-EDS, and XRD analyses. It was found that Ge, Te, and Tl are concentrated in the finest fractions of ground e-waste, together with Cd and Cr, which may favor the migration of these pollutants in the form of dust during storage and processing of e-waste.

Highlights

Germanium and tellurium are technology-critical elements (TCEs) in the EuropeanUnion (European COST Action TD1407: Network on Technology-Critical Elements) [1] and are crucialfor strategic sectors and new technologies, such as renewable energy, electric mobility, defense, aerospace, and digital technologies
The highest content of thallium was found in the TV screen material and solar cells in the form of solar panels: 0.81 mg·kg−1 and 0.38 mg·kg−1, respectively
The main carriers of germanium were photoresistors (2.59 mg·kg−1 ), while tellurium was the material for the liquid crystal display (LCD) screens of mobile phones (0.17 mg·kg−1 )

Summary

Introduction

Germanium and tellurium are technology-critical elements (TCEs) in the EuropeanUnion (European COST Action TD1407: Network on Technology-Critical Elements) [1] and are crucialfor strategic sectors and new technologies, such as renewable energy, electric mobility, defense, aerospace, and digital technologies. Despite its high toxicity, is used in the electronics industry as well. Nowadays, these three metals are widespread in the waste of electrical and electronic equipment (WEEE), and, at the same time, are neglected and little known. More attention should be paid to these metals present in electronic waste, due to possibility of their recovery, and as they can be source of environment pollution, releasedd from WEEE recycling sites. The first stage of the recycling chain, including collection and processing of e-waste, e.g., shredding, cutting, and grinding, especially in open air, can be a source of uncontrolled emissions of dust pollutants containing metals and other organic and inorganic compounds. Transported over some distance, dust can migrate to the immediate surroundings of e-waste collection plants (or longer distances depending on particle sizes), penetrating into water and soil environments

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