glass

The glass flakes with a max. length of up to 20mm use to be too big for a direct grinding with 5mm Ø balls. For this, a pre grinding step needs to be done.

For this, we used 15x 20mm Ø balls and dry ground the complete sample for only 3 minutes. Afterwards, balls can be changed to e.g. 5mm Ø (see result 2).

After pre grinding of sample to < 300µm (see trial 1), balls have been changed to 5mm Ø.

To be able grinding the sample to d90 < 5 µm (as desired) and finer, a grinding in suspension is required. For this, we had to add ~ 100ml of water.

To avoid overpressure, we ground the sample in steps of 5 minutes, followed by a programmed pausing time of 10 minutes. After several cycles, the outside temperature of the bowl should be checked (remain below 80°C); grinding time or programmed pausing time might be readjusted afterwards.

After totally 60 minutes of grinding, the fineness has been checked with our Laser Particle Sizer ANALYSETTE 22 Compact.

The d90 < 2,9µm use to be better as desired. Sample has been packed after totally 60 minutes of grinding.