Stone Wool

The desired Universal Cutting Mill PULVERISETTE 19 is not capable to reach the desired level of fineness with 90 % < 100 µm. The knife gap inside its grinding chamber is about 200 µm wide and only brittle samples like e.g. coal would achieve finer grinding results.

To reach such a fineness, we would recommend to use a Vibrating Cup Mill PULVERISETTE 9 and 2 grinding sets simultaneously (to comminute higher amounts). While one grinding set would be used inside the mill, the second could be emptied and refilled to maximize the throughput.

We used a 250 ml steel grinding set and fed about 50 grams of the mineral wool without problems. If the sample would be manually compressed, even more of sample might be grindable at a time.

We programmed the mill to comminute the sample for just 60 seconds which already ground the sample into a level of fineness, where it starts to stick lightly (typically when d50 < 20 µm is present). The sample was ground to a fine powder which could be brushed off relatively easy. No interlocking of fibers was observed in packed sample.

For an intensive cleaning of the grinding set, we comminuted a proper portion of sand and water for one minute. Afterwards, the grinding set was flushed with fresh water and dried off to prevent corrosion.

Optionally, also grinding sets in hardmetal tungsten carbide are available with a much longer durability than steel equipment.