Towards lower CO2 emissions in iron and steelmaking – Hydrogen-assisted reduction and cement-free briquettes
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
L5 lecture hall, Linnanmaa Campus, University of Oulu
Topic of the dissertation
Towards lower CO2 emissions in iron and steelmaking – Hydrogen-assisted reduction and cement-free briquettes
Doctoral candidate
a Master of Science (Technology) degree in Environmental Engineering Ahmed Abdelrahim
Faculty and unit
University of Oulu Graduate School, Faculty of Technology, Process Metallurgy Research Unit
Subject of study
Process Engineering
Opponent
Professor, Heat Engineering Prof. Henrik Saxén, Åbo Akademi University
Custos
Professor, D.Sc. (technology)/ Head of Process Metallurgy Research Unit Prof. Timo Fabritius, University of Oulu
Towards lower CO2 emissions in iron and steelmaking – Hydrogen-assisted reduction and cement-free briquettes
In this research, the influence of hydrogen and water vapor on the reduction of acid iron ore pellets was studied in conditions simulating an operating blast furnace. Pellets reduced in a hydrogen-containing gas were found to achieve a higher reduction rate and extent, resulting in higher surface area and porosity.
Additionally, several side streams from iron and steelmaking were used to produce cold bonded briquettes for use in a blast furnace utilizing an ettringite-based binder. The ettringite-based binder was produced primarily using ladle slag and used as an alternative to ordinary Portland cement as a binder in briquettes. Briquettes produced using ettringite-based binder were found to possess several technical, environmental, and economic advantages, including excellent compression and drop damage resistance compared to reference briquettes made using ordinary Portland cement, especially after 2 and 7 days of curing.
Moreover, laboratory tests were conducted to assess the suitability of self-reducing and slag-forming briquettes produced from side streams to be used in an electric arc furnace. Briquettes were made using organic and inorganic binders. Tests were carried out to assess the mechanical, chemical, and thermal properties through a series of tests, including a thermogravimetric analyzer (TGA) coupled with a mass spectrometer (MS), dilatometry, and melting trials. Based on the laboratory test results, two briquettes out of the seven tested briquettes were deemed suitable for an electric arc furnace, three of the briquettes were considered unsuitable, and two of the briquettes were considered of limited use.
Additionally, several side streams from iron and steelmaking were used to produce cold bonded briquettes for use in a blast furnace utilizing an ettringite-based binder. The ettringite-based binder was produced primarily using ladle slag and used as an alternative to ordinary Portland cement as a binder in briquettes. Briquettes produced using ettringite-based binder were found to possess several technical, environmental, and economic advantages, including excellent compression and drop damage resistance compared to reference briquettes made using ordinary Portland cement, especially after 2 and 7 days of curing.
Moreover, laboratory tests were conducted to assess the suitability of self-reducing and slag-forming briquettes produced from side streams to be used in an electric arc furnace. Briquettes were made using organic and inorganic binders. Tests were carried out to assess the mechanical, chemical, and thermal properties through a series of tests, including a thermogravimetric analyzer (TGA) coupled with a mass spectrometer (MS), dilatometry, and melting trials. Based on the laboratory test results, two briquettes out of the seven tested briquettes were deemed suitable for an electric arc furnace, three of the briquettes were considered unsuitable, and two of the briquettes were considered of limited use.
Last updated: 23.1.2024