Evolution behaviour of interfacial structure between quicklime and converter slag: slag-forming route based on Fe_tO component

ABSTRACT

In order to enable the steel companies to achieve carbon peaks and carbon neutrality, the f-CaO content in steel slag should be reduced. For this reason, this study investigates the interface reaction evolution of the quicklime and different slag in the ‘iron’ slagging route of the CaO-FetO-SiO₂-MgO system at the converter steelmaking temperature. The microstructure of the reaction interface was observed by an electron microscope. The results showed that the interface reaction formed CaO-FeO solid solution, (Ca, Mg) olivine phase, and 2CaO·SiO₂. The change in thickness of CaO-FeO and (Ca, Mg) olivine shows a clear trend with the change in slag components.Therefore, the dissolution mechanism of quicklime in the slag was discussed, and the liquid phase mass transfer coefficients in different slags were obtained. The results will provide a theoretical basis for the faster dissolution of lime in slag and reduction of f-CaO content in slag.

KEYWORDS:

• Interfacial structure
• quicklime
• dissolution
• C₂S
• mass transfer coefficient
• f-CaO
• CaO-FeO solid solution
• (Ca,Mg) olivine

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (51974210, 52074197), Hubei Provincial Natural Science Foundation (2019CFB697), and State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [grant number 51974210, 52074197], Hubei Provincial Natural Science Foundation [2019CFB697], and State Key Laboratory of Refractories and Metallurgy WUST.