Diatomite is a lightweight, porous, silica-rich sedimentary rock formed from accumulated microscopic diatom shells. Its pore structure drives many uses and can be altered by aggressive milling.
- Class
- Biogenic siliceous sedimentary rock
- Structure
- Finely porous diatom skeletons
- Main process risk
- Excess damage to pore structure
Functional structure of diatomite
Diatomite consists mainly of amorphous-silica diatom frustules and can contain clay, sand, organic matter and volcanic ash. Purity and pore structure influence use.
Crystalline-silica content can vary with source and calcination history. Occupational and product requirements need analytical verification.
Applications
- Filter aid for liquid processing
- Industrial absorbent and carrier
- Filler in coatings, plastics and dry chemicals
- Insulation, lightweight construction and mild abrasives
Drying, calcination and milling
Raw diatomite can be moist and low in bulk density, so drying and feeding follow volumetric behaviour. Some products are calcined, affecting phase and colour.
Milling may open agglomerates and adjust distribution. In filter-aid duties, excessive breakage of the frustule structure can change permeability and performance.
Selection inputs
- Amorphous/crystalline silica and impurities
- Pore structure and target use
- Natural moisture and calcination route
- Target PSD and permitted structural damage
