Reduction equilibria of ternary calcium ferrite with CO-CO2 gas mixture

Takayuki Maeda, Yoichi Ono

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3 Citations (Scopus)

Abstract

The reduction behaviors of CaO-Fe2O3 binary calcium ferrite and CaO-Fe2O3-SiO2-Al2O3 quaternary calcium ferrite are known to be quite different from each other. To clarify the difference, the reduction sequence and reduction equilibrium with CO-CO2 gas mixture were investigated by using two kinds of synthesized CaO-Fe2O3-Al2O3 ternary calcium ferrite. One of the samples had an Al2O3 content as high as 16 mass% and a composition of CaO·3(Fe0.74Al0.26)2O3. The other had a low Al2O3 content of 2 mass% and was essentially CaO·Fe2O3 containing Al2O3 as solid solution. The results are summarized as follows: 1) The reduction behavior of the ternary calcium ferrite with higher Al2O3 content was essentially the same as that of the quaternary calcium ferrite. It was reduced to iron stepwise via magnetite and wustite, both containing Al2O3 and CaO as solid solution. In the course of reduction, a calcium aluminate, CaO·Al2O3, was precipitated. The equilibrium gas composition vs. temperature curve, of each reduction step was almost the same as the corresponding curve for the quaternary calcium ferrite. 2) The reduction behavior of the ternary calcium ferrite with lower Al2O3 content was essentially the same as that of the binary calcium ferrite. But the equilibrium CO contents were considerably higher than those of the binary calcium ferrite. 3) From the results, the difference in reduction behavior between the binary and the quaternary calcium ferrites was attributed to the difference in their crystal structures.

Original languageEnglish
Pages (from-to)21-26
Number of pages6
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume80
Issue number6
Publication statusPublished - Jun 1 1994

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

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