Granulating is the process of turning a material into grains — granulate — with a more or less uniform grain size. This is done by crushing, grinding, pelletising or by rapidly cooling a liquid material. Granulating makes a material easier to process, dose and reuse.
Examples in construction
Granulating occurs in various processes:
- Blast-furnace slag — liquid slag from the blast furnace is rapidly cooled with plenty of water (“granulated”), forming glassy grains. Ground down, this provides the basis for blast-furnace cement
- Rubble and concrete — demolition waste is crushed and screened into granulate for foundations and concrete
- Plastics — residual material is turned into grains so it can be reprocessed
- Fertilisers and binders — powders are pressed into grains for easier handling
Why granulate?
- Processability — grains are easier to transport, dose and mix than powder or large lumps
- Reactivity — rapidly cooled slag becomes a reactive, glassy material suitable as a binder
- Reuse — granulating turns waste into a usable raw material, in line with circular building
Point of attention
The way of granulating determines the grading and the properties of the end product. For binders, for example, rapid cooling is essential.
Related Terms
- Granulate
- Blast-furnace slag
- Blast-furnace cement
- Grading
- Building material recycling
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