Implementation of Alternative Reducing Agents in Metallurgical Operations

Gernot Rösler

Research output: ThesisDoctoral Thesis

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Abstract

Since the anthropogenic greenhouse gas emissions are increasing more and more, the European Commission introduced the so-called emission trading system. With this, the CO2 emissions evolved by the manufacturing industry based in Europe have to be reported and balanced by acquired emission allowances. The main focus now is to lower the emissions by process optimization. It is well-known that the metallurgical industry is a big polluter, and now searching for alternatives. Since this industry is mostly based on the utilization of fossil carbon carrier, CO2 emissions have to be accounted and paid. The present thesis focuses on the implementation of alternative reducing agents in metallurgical recycling processes to induce a minimization of the accountable emissions. The main goal is the conversion and subsequent characterization of waste biomass into a renewable charcoal and pyrolysis gas. The produced alternative reducing agent is forwarded to the desired metallurgical process with a subsequent evaluation. Especially the developed “2sDR” (Two step dust recycling)-process is adapted to run by charcoal to minimize the CO2 emission at the simultaneous recovery of heavy metals from EAFD´s. This new recycling process was developed to treat EAF-dusts during melting of steel scrap without any limitation regarding material properties. A main goal of this recycling process was to generate no new wastes, according to the Zero Waste principles. The second utilization possibility of charcoal and pyrolysis gas considered in this thesis is the product upgrade of Waelz oxide as well as Waelz slag. Waelz oxide has to be treated in advance to the recycling in the primary zinc industry since it contains several impurities. The treatment of Waelz slag has become mandatory because of the change in the legal requirements, since Waelz slag is classified as hazardous waste. Both species were treated using pyrolysis gas respectively charcoal achieving very promising results. Beside the already mentioned benefits due to the utilization of renewable resource in metallurgical processes, a further advantage could be seen in the low quantity of sulphur. The applied processes using renewable resources generates in products which do not require intermediate treatment and can therefore directly be forwarded to their final application.
Translated title of the contributionImplementierung von alternativen Reduktionsmitteln in metallurgischen Betrieben
Original languageEnglish
QualificationDr.mont.
Supervisors/Advisors
  • Antrekowitsch, Jürgen, Assessor A (internal)
  • Török, Tamás, Assessor B (external), External person
Publication statusPublished - 2015

Bibliographical note

embargoed until 12-03-2020

Keywords

  • Recycling
  • Charcoal
  • Pyrolysis Gas
  • Electric Arc Furnace Dust
  • 2sDR

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