A cementitious binder from high-alumina slag generated in the steelmaking process

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Linnanmaa, auditorium L10

Topic of the dissertation

A cementitious binder from high-alumina slag generated in the steelmaking process

Doctoral candidate

Master of Science Elijah Adesanya

Faculty and unit

University of Oulu Graduate School, Faculty of Technology, Fiber and Particle Engineering Research Unit

Subject of study

Process Engineering

Opponent

Associate Professor Maria Chiara Bignozzi, University of Bologna, Italy

Custos

Professor Mirja Illikainen, University of Oulu.

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Cementitious binder from slag produced during steelmaking processes – Possibility to reduce 4 million tons of carbon dioxide emissions in Europe

The objective of this doctoral dissertation was to find sustainable circular economy solutions for the utilization of ladle slag produced in steel making process. Finland alone produces tens of thousands of tons of steel slag each year, and Europe produces about 4 million tons. Ladle slag produced in Finland possesses cementitious capabilities and can be utilized in applications where expensive commercial cements having high carbon dioxide (CO2) emissions are currently being used. Therefore, this study investigated the use of slag in high value cement binders: alkali activated materials, hydraulic binder with gypsum and in heat-resistant mortars.

The results showed that ladle slag can be used alone as a precursor in alkali activation or as the sole binder or a co-binder with gypsum in hydraulic binding. Depending on the activation pathway, compressive strength up to 92 MPa can be achieved after 28 days. The results showed that ladle slag has similar or better properties than ordinary Portland cement. In addition, it had the same heat-resistant properties as commercial refractory cement.

The binder can thus be utilized as a high value construction material, such as bricks and high temperature resisting mortars. By utilizing the results of this thesis, landfilling of slag can be avoided, the use of traditional cements can be reduced and around 4 million tons of CO2 emissions can be reduced. This would also contribute to the environmental sustainability of the construction industry.
Last updated: 4.12.2019