charcoal

For a grinding of sample with Cross Beater Mill PULVERISETTE 16, it is important that the all sample pieces use to be < 2 cm. A feeding of longer particles will block the feeding funnel.

During grinding, we placed a tube of a vacuum cleaner next to the feeding funnel, because during grinding, a lot of coal dust will escape the feeding funnel. No other opportunity is possible to remove dusts.

All sample has been ground within 30 seconds. Afterwards, only a small quantity of pre ground sample use lye loose on top of the bottom sieve and can be found on the inserts ribs. No sample use to stick inside of the openings of the bottom sieve, so a grinding of the desired amount of 500 g should be possible without problems.

Cleaning can be performed by vacuuming with a soft brush.

Rotor with V-cutting edges and fixed knives made of hardmetal tungsten carbide has been used for this trial. It has a much longer durability as the standard rotor with V-cutting edges, which should be usable for this kind of application as well.

Also in this trail, the tube of a vacuum cleaner has been placed next to the feeding funnel to remove escaping dust.

After the first minute of grinding, an output of 100 g has been found in the collecting vessel. After 90 seconds, 115 g of output has been found. After a total grinding time of 2 minutes, already 122 g of sample have been ground.

Just as with the previous trial, a small amount of sample use to lye loose on top of the sieve cassette. The sieve cassettes openings are not blocked with sample, a grinding of higher amounts is possible.

By using the optional active sample exhauster system with cyclone separator, sample will be removed directly when it is able to pass the sieve cassettes openings, also fine dust will be removed by the high air flow of ~ 2800 L/min. With a cyclone separator, longer particles with up to 3cm diameter can be fed. With the protected funnel with sample pusher (cannot be combined with the cyclone), up to 5-6 cm long and wide particles can be fed. Protected funnel will reduce the dust exploration too (still a bit of dust will escape).

Without the accessories for grinding large quantities, the collecting pan should be emptied after each 50 g of sample has been ground. The accessories also improve the airflow. Sample and air will be pressed into the attached paper filter bag. For this, no dust of fine ground sample will escape the feeding funnel.

All sample has been ground within 100 seconds. Usually, ground sample shows a d50 (50% of particles) which is half of the size of the sieve rings trapezoidal openings. Especially for such a brittle sample, d50 should be < 100 µm after grinding.

The impact rotor is free of residues; the openings of the used sieve ring are not blocked with sample too. A grinding of higher amounts should be possible.

Also with Variable Speed Rotor Mill PULVERISETTE 14, a cyclone separator can be mounted for a faster grinding of higher amounts of sample.