Titanium Dioxide (TiO₂): Production Process & Industrial Applications

Section 1: Key Uses of Titanium Dioxide

White Pigment

Titanium dioxide (TiO₂) is primarily used as a white pigment in coatings, masterbatches, and color formulations, providing bright color, gloss, and exceptional opacity. Additionally, it acts as a UV shield to protect paint films and enhance weather resistance.

TiO₂’s key function lies in its ability to cover underlying colors while seamlessly blending with new hues. This opacity stems from its high refractive index (2.71 for rutile grade, 2.52 for anatase) and its capacity to reflect nearly all visible light.

Section 2: Sulfate Process Production 

Stage 1: Raw Material Preparation

1. Ore Crushing

- Ilmenite (FeTiO₃) ground to 200-300 mesh

- Equipment: Raymond mill → Output: Fine powder

2. Acid Digestion

- 98% H₂SO₄ reacts at 250°C (exothermic)

- Reaction: FeTiO₃ + 2H₂SO₄ → TiOSO₄ + FeSO₄

Stage 2: Purification

3. Settling

- Gravity separation of undigested solids

- Flocculants added for colloidal impurities

4. Residue Washing

- Filter press recovers soluble Ti⁴⁺

- Waste slag removed (contains unreacted ore)

5. Crystallization

- Freeze or vacuum method to remove FeSO₄

6. Filtration

- Precision filtration with activated carbon

Stage 3: TiO₂ Formation

7. Concentration

- Vacuum evaporation to increase TiOSO₄ density

8. Hydrolysis

- TiOSO₄ + H₂O → TiO(OH)₂ (pH-controlled)

9. Washing

- Removes residual H₂SO₄ and metal ions

10. Bleaching

- Al powder reduces Ti⁴⁺ → Ti³⁺ for purity

Stage 4: Final Processing

11. Calcination

- Rotary kiln at 800-1000°C → Anatase TiO₂

12. Milling & Packaging

- Raymond mill for particle size control

- Bulk bags (1-ton) or 25kg sacks