Alpha-tricalcium phosphate

Planetary Mono Mill PULVERISETTE 6 classic line

main disk speed: 550 rpm

500 ml grinding bowl made of agate (SiO2)

+ 10x 30 mm Øagate grinding balls

By using 160g of sample, the grinding bowl will be filled to the maximum.

Sample already reached a fineness < 500µm as desired. Particles still don’t stick. For this, even longer dry grinding times are plausible (see result 2).

Planetary Mono Mill PULVERISETTE 6 classic line

main disk speed: 600 rpm

500 ml grinding bowl made of agate (SiO2)

+ 25x 20 mm Ø agate grinding balls

For better fine grinding results, ball diameter has been changed to 20mm Ø.

After additional 5 minutes (totally 7 minutes) of grinding at 600rpm, sample is sticking strongly to bowl and balls. This uses to happen after the majority of particles reached a fineness of < 20-30µm. Interacting forces between fine ground particles will become bigger as their own g-force. Therefore, particles will stick to each other and just become compressed by the used grinding balls. These clusters of particles also contain bigger particles which will not be ground any further too.

For this, a longer dry grinding time is not recommended. For achieving a better endfineness, we recommend grinding in suspension (e.g. in alcohol for faster evaporation).

Endfineness has been determined with our Laser Particle Sizer ANALYSETTE 22 NanoTec.