Thermodynamic analysis for the oxidation behaviour of manganese in iron-based melts during demanganisation processes

ABSTRACT

In this study, the influences of the solid oxidants and pure oxygen on oxidation behaviour of manganese in hot metal are investigated. The results indicate that the content of manganese in liquid iron decreases faster by using of iron ore fines than that by using of pure oxygen in the first 10 min. Manganese reversion could be happened by using solid oxidant Fe₂O₃, whereas it did not occurr under condition of oxygen blowing within 40 min. Meanwhile, the thermodynamic behaviour of manganese between CaO–SiO₂–MgO–FeO–Fe₂O₃–MnO–Al₂O₃–P₂O₅ slag and molten steel has also been studied by means of IMCT-L_Mn model based on the ion and molecule coexistence theory (IMCT). With the aid of the current model, the effects of basicity on activity coefficient ${\gamma }_{\mathrm{M}\mathrm{n}\mathrm{O}}$ of MnO are investigated, which demonstrate that ${\gamma }_{\mathrm{M}\mathrm{n}\mathrm{O}}$ shows a negative correlation with mass percent of Fe_tO in the range of 18.06–36.52%, indicating that the slag can hold more manganese oxide.

KEYWORDS:

• Hot metal pretreatment
• oxidant
• manganese distribution ratio
• thermodynamic model
• ion and molecule coexistence theory

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [grant numbers U1560203 and 51274031], and Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials at the School of Metallurgical and Ecological Engineering at University of Science and Technology Beijing (USTB), China. The helpful comments, suggestions, and encouragement from editors and anonymous reviewers are gratefully acknowledged.