A New Approach to Processing Rutile from Ilmenite Ore Utilizing the Instability of Pseudobrookite

Journal Article · Mon Oct 15 04:00:00 EDT 2018 · Metallurgical and Materials Transactions B, Process Metallurgy and Materials Processing Science

DOI:https://doi.org/10.1007/S11663-018-1348-Y· OSTI ID:22857827

Kumagai, Naoki; Hiraki, Takehito ^[1]; Pal, Uday B. ^[2]; Kasai, Eiki ^[3]; Nagasaka, Tetsuya ^[1]

---

1. Tohoku University, Department of Metallurgy, Graduate School of Engineering (Japan)
2. Boston University, Division of Materials Science and Engineering, Department of Mechanical Engineering, College of Engineering (United States)
3. Tohoku University, Graduate School of Environmental Studies (Japan)

Rutile (TiO{sub 2}) is a vital industrial material used in pigments and in many other valuable chemicals. A new production process to synthesize rutile from natural ilmenite ore and therefore overcome the environmental problems associated with conventional rutile extraction processes was developed. Because the simple phase separation of ilmenite (FeTiO{sub 3}) into Fe{sub 2}O{sub 3} and TiO{sub 2} occurs due to air oxidation, extracting TiO{sub 2} by removing Fe{sub 2}O{sub 3} may be possible if pseudobrookite (Fe{sub 2}TiO{sub 5}), known as a stable compound in the Fe{sub 2}O{sub 3}-TiO{sub 2} system at higher temperatures, is of unstable phase in the lower-temperature range. In order to clarify the potential of this new approach, the phase stability of pseudobrookite in the lower-temperature range is discussed. The free energy of formation of pseudobrookite from the respective pure oxides was measured at temperatures ranging from 1073 K to 1473 K by the chemical equilibrium technique using Al{sub 2}O{sub 3} as the reference oxide. The observed free energy is given as a function of temperature: ∆G{sup 0} = 7715 − 7.7T (J/mol). The results indicate that pseudobrookite has an unstable phase below 929 K. This has important industrial implications as a new approach to producing synthetic rutile from ilmenite ore by oxidation at low temperatures and acid leaching.

• OSTI ID: 22857827
• Journal Information: Metallurgical and Materials Transactions B, Process Metallurgy and Materials Processing Science, Journal Name: Metallurgical and Materials Transactions B, Process Metallurgy and Materials Processing Science Journal Issue: 5 Vol. 49; ISSN 1073-5615; ISSN MTBSEO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIR
ALUMINIUM OXIDES
EXTRACTION
FREE ENERGY
ILMENITE
IRON OXIDES
LEACHING
OXIDATION
PHASE STABILITY
PIGMENTS
RUTILE
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TITANATES
TITANIUM OXIDES