Kinetics in reduction of synthetic ilmenite with carbon monoxide

Satoshi Itoh, Takeshi Azakami

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

In order to elucidate the kinetics and mechanism of synthetic ilmenite reduction with carbon monoxide, reduction experiments were carried out using thermogravimetric technique in the temperature range between 1173 and 1373 K. The reduction rate was analyzed in terms of the mixed-control kinetics by applying the isothermal shrinking unreacted-core model, on the basis of the observation of cross section of the partially reduced ilmenite and reduction reaction path in the Ti-Fe-O ternary phase diagram. Reaction rate constant kc and effective diffusivity De determined are expressed by the following equations: kc/m·s-1=exp {-129.9×103/(RT)+7.149}, De/m2·s-1=exp (-4331/T-6.158), where R: gas constant (J·mol-1·K-1), T: temperature (K). The activation energy of the reaction was 130 kJ· mol-1. The calculated reduction curves using the rate parameters finely reproduced the experimental data. The reduction rate increases as the reduction temperature increases. In the initial stage of reduction, the overall rate is controlled by a mass transfer step through the gas film and a chemical reaction step, while in the final stage both the diffusion step of carbon monoxide through pores of the product layer (Fe+TiO2) and the chemical reaction sten determine the overall reaction rate.

Original languageEnglish
Pages (from-to)177-183
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume60
Issue number2
DOIs
Publication statusPublished - 1996

Keywords

  • Ilmenite
  • Mixed-control kinetics
  • Rate-determining step
  • Reduction kinetics
  • Shrinking unreacted-core model
  • Titanium
  • Upgrading

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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