coke

Because first sample which has been sent in 2011 has been abrasiv, we recommend using grinding disks made of hardmetal tungsten carbide.

With a gap setting of 0,25 mm, all ground particles use to be < 0,25 mm in one dimension. It is possible that some of the particles might be larger or wider as 0,5 mm. For a maximum fineness, a gap setting of 0,1 mm can be set. Output will be lowered then.

During feeding and grinding, a lot of fine sample dust will be formed. To minimize dust exploration, we recommend placing the tube of a vacuum cleaner next to the feeding funnel.

For an optimum feeding, sample pieces should be smaller as 2 cm. Some of the provided particles had shown a maximum length of 35 mm. For this, feeding needs to be supported with a small piece of wood when the feeding funnel will be jammed with sample.

After 2 minutes of grinding, an output of 420 g of sample has been found in the collecting vessel. After 3 minutes of girnding, already 460 g of ground material has been found. A longer grinding time is still possible to achieve a higher output. Usually 8 ± 3 g of sample use to remain loose inside of the grinding chamber.

To determine the fineness of ground particles, we sieved an aliquot with our Vibratory Sieve Shaker ANALYSETTE 3 Pro and a test sieve of 0,5 mm mesh. After 5 minutes of sieving, 6,25 % of particles use to be > 0,5 mm. Already 93,75 % of particles have been ground to < 0,5 mm.

For a rapid grinding of smaller quintiles, next to a planetary ball mill we introduced in 2011, also a Vibrating Cup Mill PULVERISETTE 9 should be capable.

For an optimum feeding, sample should be pre ground to < 8 mm to fill the grinding set. For this, a Jaw Crusher PULVERISETTE 1 Model I or Disk Mill PULVERISETTE 13 can be used. The smaller the pre ground sample, the more sample can be placed into the grinding set.

After just 1 minute at 1500 rpm, sample appears to be fine as desired. By sieving the complete sample amount, 100 % < 0,5 mm has been determined. A longer dry grinding is still possible to improve the grinding result.

Cleaning has been performed rapidly by whipping off. For intensive cleaning, we recommend short time grinding of sand and water (e.g. for 1 minute to maintain a slurry).