Grundlagen eines semidirekten Recyclingprozesses für Hartmetalle

Translated title of the contribution: Basis of a semidirect recycling process for hard metals

Gregor Kücher

Research output: ThesisDoctoral Thesis

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Abstract

The aim of the present work comprises a demonstration about the potential of a semi-direct recycling approach for hard metals. In contrast to the two main routes, the possibility to reduce expenses or to achieve a higher quality of the recyclate displays an interesting chance. However, at the moment a lack of understanding of the chemical-kinetic basis exists for such a process. Furthermore, there remains a discussion in literature whether a selective leaching of the binder metal is realizable without oxidizing the hard phase. In addition to a literature and patent research, which illustrates the state of the art, the introduction of a modified experimental method enables the secure determination of the reaction mechanism without the common implication of a shrinking reaction surface. Also, a pretreatment of the liquid probe allows a secure quantification of W in acidic media. This way, the calculation of the leaching selectivity is carried out. The resulting empirical model equation shows in dependence of the studied factors how the reaction can be controlled to achieve a selective leaching of the binder without oxidation of the hard phase. Besides, additional screening tests clarify the chance to simultaneously remove surface coatings from the substrates as well as an alternative application, namely the selective leaching of cermets.
Translated title of the contributionBasis of a semidirect recycling process for hard metals
Original languageGerman
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Luidold, Stefan, Assessor A (internal)
  • Friedrich, Bernd, Assessor B (external), External person
Publication statusPublished - 2019

Bibliographical note

embargoed until 18-12-2023

Keywords

  • semidirect recycling
  • hard metal
  • leaching
  • carbide skeleton
  • kinetic
  • hydrometallurgy
  • tungsten analysis
  • cobalt lixiviation
  • kinetic model equation
  • reaction mechanism
  • leaching selectivity
  • acid
  • hydrogen peroxide
  • binder
  • reaction control

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