Structural Investigation of Titanyl Sulfate Dihydrate and Intermediates Formed During Thermal Decomposition

  • Miss Hailey Reynolds, Royal Melbourne Institute of Technology University, Australia
  • Prof Suresh Bhargava, Royal Melbourne Institute of Technology University, Australia
  • Mr Frank Antolasic, Royal Melbourne Institute of Technology University, Australia

    • Titanyl sulfate dihydrate (TiOSO4.2H2O), is one possible intermediate formed during the production of Titanium dioxide, a commonly used pigment. The crystal habit of this compound causes subsequent pumping and separation steps extremely difficult. To understand the conditions which lead to the formation of TiOSO4.2H2O, there is a need to examine its solid state structure and what influences atomic arrangement.

    This study aimed to define the solid state structure of TiOSO4.2H2O via an indirect, retrospective method, investigating thermal phase changes and intermediate structures formed during decomposition. Related compounds (TiOSO4.H2O and TiO(OH)2) were also investigated to aid structural identification.
    Using techniques such as TGA, High Temperature-XRD, High Temperature-FTIR and SEM two structures for TiOSO4.2H2O were proposed, which are variations of one another, exhibiting bidentate and binuclear sulfate bonding as well as hydrogen bonding between the sulfate ion and adjacent water molecule. A mechanism by which TiOSO4.2H2O thermally decomposes was also proposed.
    A further aim of this study was to push the boundaries of in-situ High Temperature-FTIR analysis. The custom built in-situ High Temperature-FTIR cell aimed to push the boundaries of in-situ High Temperature-FTIR analysis with the ability to reach temperatures of 1100oC. It is hoped that results from this study will stimulate further interest in this area and eventually lead to conclusive structure analysis and improved industrial processes.