Entwicklung eines Verfahrenskonzepts zur Rückgewinnung von kritischen Metallen aus Elektronikschrott

Flerus, Benedikt; Friedrich, Bernd (Thesis advisor); Stauber, Rudolf (Thesis advisor); Goldmann, Daniel (Thesis advisor)

Aachen : RWTH Aachen University (2022, 2023)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2022

Abstract

The present thesis focusses on the development of a process concept which allows an extensive recovery of indium and gallium from electronic waste. Due to the high importance of indium and gallium for technological applications as well as the supply risk for both metals in Europe, the elaboration of alternative recycling strategies is on behalf of both policy and economy. However, the recycling concept presented in this study shall not substitute but rather supplement existing recycling routes for electronic waste in order to allow a holistic recycling. Regarding this research project, discarded smartphones were chosen as the raw material for the recovery of indium and gallium. In the first experimental part it is proven that pyrolysis is a suitable technology to completely separate indium from the rest of the input material by halogenation and vapor phase transport. Furthermore, the overall mass of the input material can be reduced up to 30 % due to the volatilisation of organics. Simultaneously, the embrittlement of the material facilitates subsequent mechanical treatment of the pyrolysis residue. In the second experimental part it is shown, that gallium, which remains in the pyrolysis residue, can be concentrated in a fine fraction together with other (critical) technology metals by grinding and sieving. Regarding the following selective extraction of gallium from the fines, oxidative alkaline leaching was identified to be an appropriate procedure. The results of this scientific work prove that the thermal treatment via pyrolysis is a key technology for the recovery of(critical) technology- and trace metals from smartphones.

Institutions

• Division of Materials Science and Engineering [520000]
• Chair of Process Metallurgy and Metal Recycling [522610]