Master Thesis

Recovery of non-ferrous metals from dry magnetic incinerator bottom ash

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Scope and objective

According to the current state of the art, no NFe metal is recovered from the magnetic IBA. Mainly because the NFe metals do not occur freely in the magnetic IBA but are merged with magnetic material. This complicates the recovery and additional the NFe potential in the magnetic IBA is supposedly small according to the BAFU measuring method [7]. That the potential is larger than expected has already been shown by the ZAV Recycling AG and will be further proved in this master thesis.

Although the magnetic IBA arises from 0.2 to 15mm only the magnetic IBA larger than 1mm is taken into account in this master thesis. This was done because experience showed that the magnetic IBA smaller than 1mm is more difficult to handle and the expected NFe metal potential is lower. In the beginning the challenge of the NFe metal liberation is investigated by testing different physical crushing methods with magnetic IBA from the ZAV Recycling AG (ZAV Re) in cooperation with the ZAR in Hinwil. Further, it was examined whether the liberated NFe metals can then be recovered with the usual NFe metal recovery via an eddy current separator or a density separation. Since magnetism is a major factor in magnetic IBA, a dependence of magnetic strength and NFe metal content is investigated in a another experiment. 

The aim of this master thesis is to develop a process, based on the gained knowledge, which is able to recover NFe metal from the magnetic IBA. With this developed process a main experiment is conducted to evaluate the potential and to present an ecological assessment.

Student: Björn Zenger
Supervision: Fabian Di Lorenzo (Stiftung ZAR)
Head: Dr. Stephan Pfister (ETHZ)

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