Graphite (3 samples)

After only 20 seconds of grinding, grinding sound indicated that the openings of the sieve cassette use to be blocked. Also the airflow which uses to be provided by the cyclone separator is significantly reduced.

Only 10 g of sample have been fed in these 20 seconds.

Probably a grinding with the optional impact bar might achieve finest possible grinding results (see result 2 and following).

Same sample of result 1 has been used for this grinding trial. Instead of a standard sieve ring, an impact bar with 0,08 mm sieve ring has been used.

This way, about 150 g of sample which uses to be ~ 180-190 ml of loose bulk density got ground successfully within 4 minutes.

After grinding, openings of the sieve ring remained free. A grinding of higher amounts of sample is still possible.

For up to 3,5 liters of sample, about 60-80 minutes might be required (depending on the maximum tolerable feed rate). To automatize feeding, we recommend using a Vibratory Feeder LABORETTE 24 which can be connected to the Variable Speed Rotor Mill PULVERISETTE 14.

Achieved fineness has been checked with our Laser Particle Sizer ANALYSETTE 22 NanoTec plus. Already 89,8 % of sample use to be < 50 µm.

Sample # 4 has been used for this grinding trial. It took about 4:30 minutes until the complete sample amount got fed manually.

We are guessing that a automatized feeding with Vibratory Feeder LABORETTE 24 might take up to 80 minutes until the desired amount of 3,5 liters will be ground.

Achieved fineness has been checked with our Laser Particle Sizer ANALYSETTE 22 NanoTec plus. Already 90,5 % of sample use to be < 50 µm.

Sample # 3 appears to be coarser compared to previous ground samples. Few particles can be spotted with ~ 3 mm length.

Here, 100 g of sample have been ground within 105 seconds. After grinding, all openings of the sieve ring remained free, higher amounts of sample use to be grindable.

For this, we are guessing that up to 40 minutes will be required to grind up to 3,5 liters of sample.