Titanium Dioxide (TiO2) - Comprehensive Technical Overview

Chemical Names:

• Titanium(IV) oxide

• Titania

• Rutile (natural mineral form)

• Anatase (crystal form)

CAS No.:   13463-67-7
Molecular Formula:   TiO2
Molar Mass:   79.87 g/mol

Key Characteristics

1. Physical Properties:

   • Appearance: Bright white powder (most common)

   • Crystal Forms:
     Rutile   (most stable, higher refractive index)
     Anatase   (photocatalytically active)
     Brookite   (rare)

   • Refractive Index: 2.4-2.9 (highest among white pigments)

   • Mohs Hardness: 6-7 (rutile)

2. Chemical Properties:

   • Excellent UV absorption (absorbs <400nm wavelengths)

   • Photocatalytic activity (anatase > rutile)

   • Chemically inert under most conditions

   • Solubility: Insoluble in water/organic solvents; soluble in concentrated acids

Production Methods

1. Sulfate Process:

   • Uses ilmenite (FeTiO3) or titanium slag

   • Sulfuric acid digestion → crystallization → calcination

2. Chloride Process (Superior Grade):

   • Uses rutile/TiCl4 → vapor-phase oxidation at 1000-1400°C

   • Produces finer, purer particles

Applications

1. Pigments & Coatings (90% of global use)

• Paints:   Provides opacity, brightness, and durability

• Plastics:   UV protection and whitening (e.g., PVC, polyolefins)

• Inks & Coatings:   Enhances print quality

2. Cosmetics & Sunscreens

• Physical UV Filter:   Blocks UVB/UVA (micronized forms)

• Opacifier:   In foundations, powders (E171 in EU)

3. Food & Pharmaceuticals

• Food Additive (E171):   Whitener in candies, chewing gum

• Tablet Coating:   Inert excipient

4. Advanced Technologies

• Photocatalysis:   Self-cleaning surfaces, air/water purification

• Solar Cells:   Dye-sensitized TiO2 (Grätzel cells)

• 3D Printing:   UV-curable resins