coal

With a gap setting of 0,1 mm (smallest possible gap), particles can be ground in one dimension to < 0,1 mm. Resulting particles can be longer and wider as the gap which was set. Usually about 2-3 x longer pieces can be found afterwards.

With the 200 g of sample which have been provided, grinding took less as a minute until the grinding sound stopped. With a properly filled grinding chamber, much higher output can be achieved.

To determine the fineness, we used our Vibratory Sieve Shaker ANALYSETTE 3 and test sieves of 160 µm and 250 µm mesh. We found the following fractions after grinding: 63,9 % of sample use to be > 250 µm; 28,1 % of sample use to be < 160 µm. 8 % of sample use to be in the very narrow desired fraction.

To maximize the output of desired fraction, it is still possible to separate coarse particles and feed a further time.