Ferrochrome converter

The purpose of a ferrochrome converter (CRC) is to remove silicon as well as part of carbon from the molten ferrochrome by blowing oxygen into the melt. The CRC process produces raw material for the AOD converter used in stainless steel production, whereas the raw materials of the CRC are molten ferro-chrome with high silicon and carbon contents and stainless steel scrap. Therefore, the CRC process serves effectively as a link between the ferrochrome production and the production of stainless steels. At Process Metallurgy Research Unit, the research has focussed on the chemical reactions and their equilibria in the metal bath.

Highlights

• A fast electrochemical method was tested successfully for determination of the initial silicon content in the ferrochrome converter process. Consequently, it is possible to make more accurate calculations for process control and thereby reduce process variation, environmental burden and operating costs.

Selected publications

• V.-V. Visuri, E.-P. Heikkinen, J. Kaisto, A. Harju, R. Mattila, P. Kupari, T. Ikäheimonen, and T. Fabritius, “The Effect of the MgO Content of Slag on its Penetrability into the Refractory Lining in a Ferrochrome Converter,” Proceedings of the 16th International Ferro-Alloys Congress (A. Wærnes, G. Tranell, M. Tangstad, E. Ringdalen, and C. van der Eijk, eds.), SINTEF/NTNU/FFF, Trondheim, Norway, 2021.
  [View publication]
• H. Pesonen, V.-V. Visuri, T. Ikäheimonen, and T. Fabritius, "In Situ Measurement of Silicon Content in Molten Ferrochrome", Proceedings of the 3rd European Steel Technology and Application Days, The Austrian Society for Metallurgy and Materials, Vienna, Austria, pp. 1218–1227, 2017.
• E.-P. Heikkinen, T. Ikäheimonen, O. Mattila, T. Fabritius, and V.-V. Visuri, “Behavior of Silicon, Carbon and Chromium in the Ferrochrome Converter – A Comparison Between the CTD and Process Samples”, Proceedings of the 6th European Oxygen Steelmaking Conference, Jernkontoret, Stockholm, Sweden, 2011.

Theses instructed

• A. Harju, "Interaction of ferrochrome converter slag with doloma and magnesia-carbon refractories (in Finnish)", Bachelor's thesis, University of Oulu, 2019.
• J. Kaisto, "The effect of CRC slag MgO content on the penetration of slag into refractory lining", Master's thesis, University of Oulu, 2018.
• H. Pesonen, "Determination of the content of silicon in refined molten ferrochrome by an electrochemical measurement", Master's thesis, University of Oulu, 2016.
• A.-M. Heikka, "Measurement of melt temperature at ferrochrome works", Bachelor's thesis, University of Oulu, 2016.