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It was mentioned to use the Disk Mill PULVERISETTE 13 for grinding the sample. In this case, ground particles only need to be < 100 µm (smallest gap setting) in one dimension to pass the gap between the grinding disks. Therefore, you will found particles with a length up to ~ 300 µm with that machine.

We recommend a Variable Speed Rotor Mill PULVERISETTE 14 where ground particles usually use to have a mean size which correlates to the half of the trapezoidal perforated openings. With a 0,12 mm sieve ring (as used in this trial), a particle size of d50 < 0,06 mm (60 µm) is expected to be found.

The complete sample got ground within 2 minutes. After grinding, a couple of openings use to be clogged with sample. This is not uncommon when brittle sample will be ground. Probably a lower feed rate will made it possible to grind higher amounts.

Also the usage of the accessories for grinding large quantities will optimize the air flow inside the grinding chamber and less sticking particles should be found on the sieve ring (generally recommended equipment when > 50 g of sample should be ground).

Also the usage of the active sample exhauster system with cyclone separator is possible. With its air flow of ~ 2800 L/min, the sample will get sucked out of the grinding chamber and very high amounts of sample can be ground rapidly (> 1 Liter).