Gras (wet)

A comminution of the moistened sample is not possible. The sample uses to be too sticky and will stay attached to the pestle or will start to build up in front of the scraper.

Only when sample will be dried previously, or when additional water will be added, this sticky character of coarse particles will be removed.

Possibly a planetary mill might be capable to grind the moistened sample to a paste (see following report).

Because of its moisture contend, the grass sample sticks together. The impact force of the used 20 mm Ø grinding balls does not seems to be big enough to comminute such balls of sample.

Without additional adding of water, this sample is not grindable with 20 mm grinding balls.

Even after 5 minutes of grinding, still intact sample can be found. Probably 30 mm Ø grinding balls will be more suitable for grinding (see result 3).

Comminution with 30 mm Ø grinding balls is possible. After 5 minutes of comminution at maximum speed, only a few fibers can be spotted with > 1 cm length. Most of ground particles already use to be < 3 mm (smaller as desired).

Because of its ruff surface, sintered corundum will have a rapid grinding success when organic, flexible particles should be ground. Because of its ruff surface, also more abrasion will be found after comminution compared to other ceramic grinding materials.

In most cases, a comminution with a planetary mill will deliver a wide spectrum of particles. To achieve a maximum output of particles in range of 5-6 mm, we recommend to dry the sample previously, a comminution with a cutting mill.

With the sieve cassettes available in different sizes, output fineness can be steered somehow. Probably also a rotor speed mill might come into question as well when sample can be dried previously.