Mineral processing technologies on biomass preparation for byproduct benefit in metallurgy

Diego Herrera

Research output: ThesisDoctoral Thesis

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Abstract

The current thesis reviews wood biomass technology emphasizing its preparation with mineral and thermal processing techniques; records experimental work with three biomass types; and covers a thermodynamic model of zinc oxide reduction with biocoal. The document is divided into Theory, Experiments, and Carbothermic Model of Zinc Oxide Reduction. Theory covers legislation on biomass usage in Austria, biomass as technical material, and biocoal production. It presents the Austrian legal framework for forestry and its implications on harvesting and material supply. It also describes biomass from a physicochemical viewpoint, mainly its carbonization. Additionally, several topics on biomass economy are discussed: biomass trade, resources, prices, and logistics. Finally, pelleting, or biomass densification, is presented. Experiments, on the other hand, covers studies on raw and processed biomass, and pellet production with thermally processed biomass and electric arc furnace dust (EAFD). Bark, saw dust, and wood chips from were studied as potential materials to be used in engineering. The analyses emphasized the material physicothermal properties: particle size distribution, bulk density, proximate, elementary, and thermal analyses. From the studied biomass types, wood chips were selected for further study. The material was carbonized under inert atmosphere to release moisture and volatile matter, leaving behind its (fixed) carbon content alone; \ie, turning raw biomass into biocoal. The biocoal thereof produced was pelleted with EAFD containing zinc oxide. Unfortunately, resource and equipment constraints rendered impossible to measure experimentally the actual reduction. Nevertheless, it is expected that the theoretical amount of carbon in biocoal be sufficient to reduce the zinc oxide contained in EAFD into zinc, which could then be recovered. Finally, the carbothermic reduction of zinc oxide was analyzed by thermodynamic principles and methods. Hence, first principles such as the laws of thermodynamics served for the deduction of relations between temperature, pressure, further process parameters, and material properties. The results thus obtained coincide with experimental findings, as well as current operating conditions of industrial processes.
Translated title of the contributionAufbereitung von Biomasse für den Einsatz in der Aufarbeitung von Nebenprodukten der Metallurgie
Original languageEnglish
QualificationDr.mont.
Supervisors/Advisors
  • Flachberger, Helmut, Assessor A (internal)
  • Luidold, Stefan, Assessor B (internal)
Publication statusPublished - 2016

Bibliographical note

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Keywords

  • biomass
  • Austrian biomass legislation
  • biomass economics
  • biomass thermal conversion
  • carbonisation
  • biocoal
  • pelleting
  • zinc oxide reduction

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