Slag

Sample has been dry ground for ~ 2 minutes. A stronger sticking of sample to bowl and balls occurred.

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.

Fineness has been determined with our Laser Particle Sizer ANALYSETTE 22 Compact. A d50 < 10,5µm and d99 < 51µm has been detected.

To achieve an endfineness of < 30µm as desired, we recommend grinding in suspension (see result 2).

Because of rapid sticking of sample in dry grinding, a grinding in suspension is recommended to achieve the desired endfineness of < 30µm. For this, we added ~ 7ml of test benzine (boiling point 100-140°C).

The used 20mm balls can be picked easier as 5-10mm Ø balls after grinding.A separation of balls and sample will be easier. Smaller balls should be quicker in delivering the desired endfineness.

After 5 minutes of grinding, the desired endfineness has been achieved.