Description
Coatings
Titanium Dioxide pigments produce a high tinting strength, neutral or slightly blue undertone in the pigmentated system. The high reflectivity in the wavelength range of the visible light and their high scattering capacity in the lacquer formulations are other important features. Effective surface treatment leads to high electrostatic stability in various environments at high technical concentrations, which leads excellent product stability. Rutile qualities with higher inorganic surface treatment suppresses decomposition processes of the binder initiated by UV radiation and other weathering influences. This leads to an increase of durability with respect to chalking resistance and glossy posture.
Sulfate process:
- Raw materials: Uses lower-grade ores such as ilmenite and titania slag.
- Process: Digestion with concentrated sulfuric acid to form titanium sulfate, followed by hydrolysis to precipitate hydrated titanium dioxide, and finally calcination.
- Product: Can produce both anatase and rutile pigments.
- Process type: An older, batch-based technology.
- Environmental impact: Has higher waste and pollution control costs, though by-product developments can improve its environmental footprint.ย
Chloride process:
- Raw materials: Uses high-grade ores like natural or synthetic rutile.
- Process: Reacts the ore with chlorine gas and petroleum coke at high temperatures to form titanium tetrachloride (๐๐๐ถ๐4) gas, which is then purified and oxidized to produce pure TiO2.
- Product: Produces a higher-purity rutile pigment with superior whiteness and opacity.
- Process type: A newer, continuous process.
- Environmental impact: Generates hazardous waste (๐๐๐ถ๐4 and ๐ถ๐2) but includes options for chlorine recovery and recycling, making it a more efficient and potentially more environmentally friendly option.ย
Key differences at a glance
| Featureย | Sulfate Process | Chloride Process |
|---|---|---|
| Purity | Lower | Higher |
| Product | Anatase and Rutile | Rutile only |
| Raw Material | Lower-grade ores | High-grade ores |
| Process Type | Batch | Continuous |
| Energy | Higher energy consumption | Lower energy consumption |
| Initial Cost | Lower | Higher |
| Waste | Higher waste generation | Lower waste, but requires chlorine recovery |
