Titania Particles and a Process for their Production

A process for the production of titania particles with a desired morphology, the process comprising:

• providing a titania sol;
• and then
• drying the sol to provide dried titania particles;
• characterised in that the morphology of the dried titania particles is controlled by applying one or more of the following criteria:
• (a) the titania sol is produced from a TiO2 containing slurry obtained using a precipitation step in a sulphate process, wherein the size of micelles formed during the precipitation is controlled,
• (b) the titania sol is produced from a TiO2 containing slurry and the pH of the slurry is controlled in order to affect the extent to which the titania sol is flocculated,
• (c) the titania sol is produced from a TiO2 containing slurry and the iso-electric point of the titania is adjusted in order to affect the extent to which the titania sol is flocculated,
• (d) the titania sol is dried by application of heat and the temperature used during the drying step is controlled.

A process for the production of titania particles, wherein the process comprises:

• providing a titania sol;
• and then
• spray drying the sol to provide dried titania particles;
• characterised in that the morphology of the dried titania particles is controlled by:
• (i) producing the titania sol from a TiO2 containing slurry and controlling the pH of the slurry to be 3 pH units or more from the iso-electric point of the titania, by the addition of peptising agent, in order to reduce the extent to which the titania sol is flocculated;
• or
• (ii) producing the titania sol from a TiO2 containing slurry and adjusting the iso-electric point to be 3 pH units or more from the pH of the slurry, by the addition of dispersant, in order to reduce the extent to which the titania sol is flocculated.

Titania particles formed by:

• providing a titania sol;
• and then
• spray drying the sol to provide dried titania particles;
• characterised in that the morphology of the dried titania particles is controlled by:
• (i) producing the titania sol from a TiO2 containing slurry and controlling the pH of the slurry to be 3 pH units or more from the iso-electric point of the titania, by the addition of peptising agent, in order to reduce the extent to which the titania sol is flocculated;
• or
• (ii) producing the titania sol from a TiO2 containing slurry and adjusting the iso-electric point to be 3 pH units or more from the pH of the slurry, by the addition of dispersant, in order to reduce the extent to which the titania sol is flocculated,
• wherein the particles each have a continuous exterior convex surface, the particles have a diameter of 30 μm or less, and a BET specific surface area of 50 m2/g or more, and wherein the particles are porous.