Amorphous silicic acid

For 100 g of sample (as provided), bowls of 250 ml volume use to be fulfilling for grinding. Higher amounts can be ground with maximum 500 ml girnding bowls (with up to 4 bowls fasteners at PULVERISETTE 5).

To avoid over pressure, 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.

By using 10 mm Ø grinding balls, balls don’t need to be changed during grinding to fulfill the desired fineness of d90 < 10 µm. After a total grinding time of 2 hours. The desired fineness has been achieved.

It is plausible that the total grinding time can be reduced, when grinding balls will be changed after a pre grinding with 10 mm Ø balls (e.g. for 15 minutes) to 2 mm Ø. Because of the higher amount of girding balls, grinding will be improved. We recommend using balls which use to be 20x bigger as the present particle size.