Coal

*1: After the first 15 minutes of grinding, an aliquot has been sampled to determine the fineness by sieving. About 19% uses to be < 20µm; 24% 20-63µm and 57% > 63µm have been found (see sample 1a).

After 60 minutes of grinding, 48,5% use to be < 20µm; 38,1% 20-63µm and 13,4% > 63µm have been found. The sample does not stick; still longer grinding times are possible.

*2: The fineness was determined by sieving an aliquot with our Vibratory Sieve Shaker ANALYSETTE 3 Pro and sieves of mesh size 20µm and 63µm (10min, ampl. 2mm + 5mm agate balls as sieving aides).

*1: The fineness < 20µm rose from 3’ 15%; to 7’ 27%; to 12’ 74% to 20min 94%; the sample does not stick; even longer grinding times are possible.

*2: Determined by sieving an aliquot with ANALYSETTE 3 Pro.

Summary: A grinding with our Mortar Grinder PULVERISETTE 2 (trail 1) is possible. A much faster result can be achieved by using a Planetary Mono Mill PULVERISETTE 6 with 20mm or 30mm balls (trail 2).