Verhalten aluminiumhaltiger Reststoffe und minderwertiger Aluminiumschrotte beim Recycling unter Berücksichtigung von Sondermetallen

Translated title of the contribution: Behaviour of aluminium-containing residues and low-grade aluminium scrap during recycling including special metals

Research output: ThesisDoctoral Thesis

Abstract

In terms of production volume, aluminium is the leading metal in non-ferrous metallurgy. In particular, the recycling of aluminium-containing residues has strongly increased in the last few years and will continue to gain importance in the future. Due to the high affinity of aluminium to oxygen, oxidation of the molten bath is unavoidable, resulting in the formation of dross on the surface. Nevertheless, considering the metallic aluminium content, it represents a valuable residual material which must be processed further. In this thesis, the processing of the dross is evaluated and optimized with regard to the pressing for the recovery of metallic aluminium in the industrial process as well as the subsequent pyrometallurgical treatment in the salt drum furnace by means of a laboratory-scale experiment. In addition, investigations of the possible processing of aluminium-containing residues, which are produced during the remediation of a dross residue landfill, are carried out. In the aluminium industry, inferior scrap is defined as scrap that is strongly contaminated with other substances and whose melting yield is therefore low. Using such materials as feedstock, melting tests are carried out on a laboratory scale to illustrate the two-chamber furnace process and the processing of these scraps via liquid salt slag. Comprehensive analyses of the products and residues generated in these experiments as well as of the input materials are used to investigate the distribution of special metals in the aluminium recycling process. The element lithium and the rare earths are discussed here, as these will increasingly enter the secondary aluminium cycle in the future due to their applications. Analyses to determine the content of rare earths also take place during the remelting of the drosses. With the help of thermal pre-treatment, it is possible to optimize the melting yield and process control when using organically contaminated aluminium scrap. Within the scope of the present thesis, laboratory as well as industrial trials for the pyrolysis of compacted scraps in bare and painted form are carried out. This allows statements on the minimum duration of the thermal pre-treatment as well as on the optimal positioning of compacted scraps in the two-chamber furnace. Furthermore, the usefulness of the additional introduction of ambient air into the scrap chamber of the two-chamber furnace for direct post-combustion of the low-temperature carbonization gases produced there is investigated. The evaluation of the success of this targeted air introduction is done by measuring the pyrolysis gases and the dross quantities as well as by evaluating various furnace parameters.
Translated title of the contributionBehaviour of aluminium-containing residues and low-grade aluminium scrap during recycling including special metals
Original languageGerman
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Lehner, Markus, Assessor B (internal)
  • Antrekowitsch, Helmut, Assessor A (internal)
  • Schenk, Johannes, Co-Supervisor (internal)
  • Antrekowitsch, Jürgen, Supervisor (internal)
Publication statusPublished - 1800

Bibliographical note

embargoed until null

Keywords

  • aluminium
  • recycling
  • scrap
  • residues
  • special metals

Cite this