ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Activity of Chromium Oxide in Calcium Silicate Bearing Molten Slag for Highly Clean Chromium Steel Refining Process
Yuxing Liu Zhi LiYoshinao Kobayashi
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JOURNAL OPEN ACCESS Advance online publication

Article ID: ISIJINT-2022-368


Thermodynamic properties of chromium oxide in molten slags are essential to optimizing stainless steel refining processes and reduction processes of chromium ores. The present study conducts chemical equilibrium experiments at 1823 K (1550 °C) under different oxygen partial pressures in order to investigate chromium oxide activity coefficient in CaO-CaF2-MgO-Al2O3-SiO2-MnO-CrOx slags with low chromium content taking the effect of MgO addition into consideration. An increase in MgO initial content from 0 to 20 mass % increases the activity coefficient of CrO𝑥 under the oxygen partial pressures of 6.38×10-12 atm and 1.60×10-10 atm. It is found that lower oxygen partial pressure may reduce solid phase formation. The present study recommends the usage of 29 mass % CaO-5 mass % CaF2-20 mass % MgO-10 mass % Al2O3-29 mass % SiO2-5 mass % MnO-2 mass % Cr2O3 slag to reduce chromium loss at 1823 K (1550 °C) under the oxygen partial pressure of 6.38×10-12 atm, where the activity coefficient of CrO𝑥 is the highest in the slags without solid phase.

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© 2022 by The Iron and Steel Institute of Japan

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