Anhydrit

Provided sample was much too wide to be ground with Cross Beater Mill PULVERISETTE 16 or Disk Mill PULVERISETTE 13 directly. We used our Jaw Crusher PULVERISETTE 1 Model I (for up to 60 mm Ø start size with Model I; up to 95 mm large fragments can be fed with Model II).

The complete sample was fed slowly into the mill. The mill was adjusted to gap setting 1,5 mm for comminution. We expect that all sample should pass with ~ 1 cm max. length with this setup.

Feeding was finished after ~ 45 seconds and the grinding sound vanished shortly afterwards. We stopped the mill after a total grinding time of 50 seconds. The grinding chamber was empty and all sample was transferred with mostly < 8 mm length into the collecting vessel of the mill.

There is no significant clogging of gap etc. Surely even higher amounts of sample can be ground this way.

Pre crushed sample from result one was used for this test. Because of the slightly harsher grinding sound of our Jaw Crusher PULVERISETTE 1, we recommend using a Disk Mill PULVERISETTE 13. If sample would be ground on a regular basis, we recommend using disks made of hardmetal tungsten carbide for a much longer durability.

The pre crushed sample was transferred into the feeding funnel completely. The grinding sound was slightly rough; but not critical. After two minutes of grinding, we already found an output of ~ 1,07 kg of sample inside the collecting vessel.

While the grinding chamber becomes emptier, less of output would be achieved. After a total grinding time of six minutes, output rose to 1,75 kg. We interrupted the grinding process after 1,83 kg of output after eight minutes of grinding.

There was a slightly higher amount of sample, left inside the grinding chamber. Cleaning was performed rapidly by vacuuming with a soft brush. Residues in the area of the feeding funnel can be minimized when such particles which build up were pushed into the grinding chamber with a long stick / brush. A desired amount of 5 kg of sample can be ground to this level of fineness only batch wise.

We checked the particle size distribution of the ground sample, using our Laser Particle Sizer ANALYSETTE 22 NanoTec. A d50 < 16 µm was already determined. The d90 value of the ground sample was already < 38 µm.