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Sample starts sticking after a dry grinding time of 5 minutes.
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, not much better dry grinding results are expected to be found.
Fineness of sample has been determined afterwards with our Laser Particle Sizer ANALYSETTE 22.
For raising the ratio of desired fraction, it is possible to separate desired fineness fraction and only grinding the coarse fraction until sticking occurs again.
For sure, desired fineness and even smaller fineness can be reached by a grinding in suspension (e.g. with glass).
Usually, we recommend choosing harder materials for grinding bowl and balls as sample use to be – for this, we might recommend taking other ceramics like zirconium oxide for grinding.
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