cement (2 samples)

Depending on tolerable kind of abrasion, also grinding disk made of steel or zirconium oxide can be equipped for comminution of sample.

With a gap setting of 0,3 mm, ground particles only need to get comminuted to < 0,3 mm in one dimension to pass the gap. For this, still a few particles with a length > 1 mm can be found after grinding.

Regarding the output, a properly filled grinding chamber will show highest output. At the end of the grinding process, when the grinding chamber will slowly get empty, output will sink constantly.

For example: in the first 20 seconds of grinding, about 200 grams of ground sample has been found. After a total of 40 seconds, 322 grams of output have been achieve. After 2 minutes, the amount of sample inside the grinding chamber is getting lower and only 142 g of additional output could be achieved. Finally, the complete sample amount got ground after a total of 2:40 minutes when grinding sound stopped.

Just like in the beginning of the grinding process, we are guessing that an output of ~ 500 g per minute can be realistic by constant feeding of sample.

To determine the achieved fineness, we sieved an aliquot of sample with our Vibratory Sieve Shaker ANALYSETTE 3 and an test sieve of 1,0 mm. We found 99,7 % < 1 mm and ~ 0,3 % > 1 mm. Both fractions have been packed separately.

With this trial, we used a gap setting of 0,15 mm for comminution. With such a gap setting, following output has been found:

40 seconds: 310 g

60 seconds: 364 g

120 seconds: 445 g

180 seconds: 493 g

Typically, about 7 ± 5 grams (depending on sample) of electrostatic charged sample dust can remain inside the grinding chamber. Those particles can be brushed off, or the grinding chamber can be cleaned quickly by vacuuming with a soft brush.

Because ~ 0,17 % of sample is broken to small flakes, we are guessing that even with lowest possible gap setting of 0,1 mm, still a few particles can be found with < 1 mm length.

Ground samples and sieved fractions have been packed separately for demonstration.

Sample II uses to have a higher percentage of fine ground particles. In our third trial, we used a gap setting of 0,5 mm for demonstration.

This way, we found an output of 212 g of ground sample after 15 seconds of grinding. After 1 minutes of grinding, a total of 391 g has been found in the collecting vessel. After 1:45 min, the complete sample amount got ground.

With this sample, we found 99,71 % < 1 mm after sieving. Only 0,29 % of ground particles did not pass the 1 mm mesh of the test sieve.

Ground samples and sieved fractions have been packed separately for demonstration.

In our last trial, we used a gap setting of 0,7 mm. Within 15 seconds, already 400 g of sample has been ground. It took 65 seconds until the grinding chamber has been emptied again.

By grinding this way, highest amount of particles have been found > 1 mm. 93,9 % of ground particles was still able to pass the 1 mm mesh test sieve. Only 6,1 % of material use to be > 1 mm.

Ground samples and sieved fractions have been packed separately for demonstration.