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For a grinding of organic materials, we recommend using bowls and balls made of sintered corundum (Al2O3). Fibrous materials will be comminuted much more efficient, compared to smooth surfaced grinding materials.

With its rough surface, Al2O3 uses to produce also higher abrasion (compared to smooth surfaced grinding materials).

After 4 minutes of dry grinding, sample starts to stick lightly to bowl and grinding balls. This uses to happen after the majority of particles reached a fineness of < 20-30 µm. Interacting forces between fine ground particles will become bigger as their own g-force. Therefore, particles will stick to each other and become compressed by the used grinding balls. These clusters of particles also contain bigger particles which will not be ground any further.

Within the ground sample, also small fibrous materials from the shell of the corn use to be present (with up to 300 µm length).

Much longer dry grinding times are not recommended. To achieve a better fineness, a grinding in suspension is recommended.

For a grinding of higher amounts, bowls of 250 ml and 500 ml volume use to be available. By grinding with 30 mm Ø grinding balls instead of 20 mm Ø (as shown in result 1), the sample use to stick to bowl and grinding balls after a dry grinding time of 4 minutes too.

Still fibrous pieces with up to 300 µm length can be found in the fine ground powder.

As recommended in result 1, to achieve a better fineness, a grinding in suspension should be performed.