Up-grading of natural ilmenite ore by combining oxidation and acid leaching

Takehito Hiraki, Yuichi Maruyama, Yuta Suzuki, Satoshi Itoh, Tetsuya Nagasaka

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Rutile (TiO2) is heavily used in pigments and colorants, and the most abundant source of rutile is ilmenite. Upon oxidation of ilmenite, rutile can be formed with modest energy consumption; furthermore, after leaching, only a few byproducts are formed. Unfortunately, one drawback is the necessarily long oxidative process of typically used methods. In this study, we show that a fluidized bed reactor can be used to oxidize ilmenite ore to rapidly form rutile and pseudobrookite (Fe2TiO5) phases. Ilmenite was oxidized with 5vol% O2 in Ar at temperatures of 1173 K or 1223 K and subsequently leached using a diluted H2SO4 solution to dissolve the pseudobrookite phase. The effects of acid concentration, temperature, and cooling rate after oxidation were investigated. We show that the ilmenite was rapidly oxidized to form rutile and pseudobrookite phases at 1173 and 1223 K in a 5vol% O2/95vol% Ar environment within 40 min. The final maximum rutile yield was 84.2mol% after leaching in (1 + 1) H2SO4 solution at 393 K for 12 h.

Original languageEnglish
Pages (from-to)729-736
Number of pages8
JournalInternational Journal of Minerals, Metallurgy and Materials
Issue number7
Publication statusPublished - 2018 Jul 1


  • acid leaching
  • fluidized bed reactor
  • ilmenite
  • oxidation
  • pseudobrookite
  • rutile

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Geochemistry and Petrology
  • Metals and Alloys
  • Materials Chemistry


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