Metals and Materials International

, Volume 25, Issue 1, pp 248–256 | Cite as

A Study on the Formation Mechanism of the Interfacial Layer Between Solid CaO and Molten Iron Alloys

  • Sunghee Lee
  • Dong Joon MinEmail author


The present study aims to clarify the formation mechanism of the interfacial layer between solid CaO and molten iron through SEM–EDS analysis. The interfacial layer formed between CaO and molten iron is observed by SEM–EDS for different compositions of molten iron (CaO/Fe–C–S interface: CaS layer; CaO/Fe–C–Si–S interface: CaS and Ca2SiO4 layers; CaO/Fe–C–Si interface: no interfacial layer; CaO/Fe–S–Si interface: Ca2SiO4 and CaS layers). The effect of S and Si concentrations on layer formation is discussed using the following proposed mechanism.
$$ {\text{CaO}}\left( s \right) + \underline{\text{S}} = {\text{CaS}}\left( s \right) + \frac{1}{2}{\text{O}}_{2} $$
$$ 2{\text{CaO}}\left( s \right) + \underline{\text{Si}} + {\text{O}}_{2} = {\text{Ca}}_{2} {\text{SiO}}_{4} \left( s \right) $$
In the case of the Fe–C–Si–Al–S/CaO interface, CaS and Ca3Al2O6 layers are observed. The formation mechanism of a reaction layer for Al-containing iron melts is also proposed as below.
$$ {\text{CaO}}\left( s \right) + \underline{\text{S}} = {\text{CaS}}\left( s \right) + \frac{1}{2}{\text{O}}_{2} $$
$$ 3{\text{CaO}}\left( s \right) + \underline{{2{\text{Al}}}} + \frac{3}{2}{\text{O}}_{2} = {\text{Ca}}_{3} {\text{Al}}_{2} {\text{O}}_{6} \left( {\text{s}} \right) $$


Calcia Dicalcium silicate Calcium sulfide Desulfurization 



The study was supported by the Korea Evaluation Institute of Industrial Technology project no. 10076604.


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Copyright information

© The Korean Institute of Metals and Materials 2018

Authors and Affiliations

  1. 1.Department of Material Science and EngineeringYonsei UniversitySeoulRepublic of Korea

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