cement

After a total grinding time of 5 minutes, the sample starts to stick lightly.

This uses to happen after the majority of particles reached a fineness of < 20 µm. Interacting forces between fine ground particles will become bigger as their own g-force. Therefore, particles will stick to each other and become compressed by the used grinding balls. These clusters of particles also contain bigger particles which will not be ground any further.

For a better fineness, a grinding in suspension might be required.

Present fineness has been determined with Laser Particle Sizer ANALYSETTE 22 Compact and small volume dispersing unit. We found a d50 < 9,3 µm and d90 < 42 µm. The desired fineness has been achieved.

Because the desired fineness has been reached, the grinding trial has been aborted after 5 minutes.