Synthesis of anatase powder by ilmenite digestion followed by selective thermal decomposition and leaching

Yahya A. Sorkhe, Pegah Bavafa, Ahmet Isa Buldu, Bengi Su Yılmaz, Bora Derin, Cüneyt Arslan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigates an innovative method for producing TiO2 from ilmenite ore through selective thermal decomposition and leaching. The focus lies on understanding the impact of co-existing sulfates on the decomposition temperature of TiOSO4. Insights into the decomposition mechanisms and parameters governing selective leaching efficiency are also presented. Ilmenite concentrate was digested with concentrated sulfuric acid, yielding titanium and iron sulfates. The digested cake was then calcined at different temperatures to induce thermal decomposition. Thermodynamic calculations were employed to model the decomposition reactions and investigate the influence of iron sulfates on TiOSO4 decomposition. Both thermodynamic evaluation and experimental results demonstrate that co-existing iron sulfates play a catalytic role in lowering the decomposition temperature of TiOSO4 from approximately 700 °C to below 500 °C, facilitating its conversion to TiO2. The calcined powder underwent selective leaching, first with water to remove soluble sulfates, followed by dilute acid to obtain a TiO2 precipitate. The precipitate was analyzed by different techniques. The XRD analysis confirmed the successful conversion of TiOSO4 to Anatase TiO2 during calcination and leaching. The SEM images show that the Anatase TiO2 powder displays a near-spherical morphology, with a particle size ranging from 50 to 200 nm. FTIR, DTA, and DTG analyses supported the thermodynamic calculations and XRD results, offering insights into the phase transformations during thermal decomposition and leaching. The thermodynamic evaluation and experimental results demonstrate that co-existing iron sulfates play a catalytic role in lowering the decomposition temperature of TiOSO4. By using the proposed method, anatase powder was successfully produced with minor impurities of iron, SiO2, and other metal oxides.

Original languageEnglish
JournalCeramics International
DOIs
Publication statusAccepted/In press - 2024

Bibliographical note

Publisher Copyright:
© 2024 Elsevier Ltd and Techna Group S.r.l.

Keywords

  • Anatase
  • Hydrometallurgy
  • Leaching
  • Thermal decomposition
  • TiO

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