M190046 | |
Geology / mineralogy, Mining | |
1.0 mm | |
75.0 % < 50.0 µm | |
1-2 g | |
We recommend using a Planetary Mono Mill PULVERISETTE 6 classic line to rapidly comminute such a type of sample. |
Planetary Mono Mill PULVERISETTE 6 classic linespeed: reduced after 30 sec. 650 revolutions per minute |
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Equipment: |
type of grinding bowl: Grinding bowl 80 ml material: Hardmetal tungsten carbide number of grinding balls: 5x grinding balls: 20 mm dia.grinding balls |
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6,00 g | |
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max. length 16,00 mm | |
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2,00 min | |
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~ 80 % < 45,00 µm | |
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The desired Planetary Mill PULVERISETTE 5 premium line is basically a mill to comminute higher amounts of brittle, pre crushed samples into nano range. Typically samples are already < 3 mm with this type of mill.
For sample amounts of only 6 grams and start sizes as presented (max. length < 16 mm), we recommend using the Planetary Mono Mill PULVERISETTE 6 classic line. Also there, desired hardmetal tungsten carbide equipment is available.
We placed the sample into our 80 ml bowl made of tungsten carbide, which was equipped with 5x 20 mm Ø grinding balls. We started our trial with a setup of 30 seconds at maximum speed (for up to 29x g-force grinding ball acceleration). After this first pre crushing, we reduced the speed to 500 rpm and proceeded grinding for further 90 seconds. With the lower speed setup, we hope that fine ground sample will not start sticking this hard to the grinding equipment (which happens when the majority of particles was ground < 20 µm).
After this two minutes of dry grinding, a few tiny pyrite fragments were found inside the very find ground sample. Surely a d75 < 50 µm as desired should be present. The sample was still easy to brush out; we checked the fineness by sieving the complete sample with our Vibratory Sieve Shaker ANALYSETTE 3 Pro and a test sieve with 45 µm mesh. We found 1,2 g > 45 µm and 5,0 grams of sample < 45 µm (~ 80 % < 45 µm). Both fractions were separately packed and will be returned. A longer grinding time is not required.
Surely a much finer grinding result can be achieved when a wet grinding would be proceeded. For an intensive cleaning, we ground a proper portion of sand and water for two minutes. Afterwards, the equipment was flushed with fresh water and dried afterwards to prevent corrosion.
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Pictures: | Start conditions with our 80 ml bowl (hardmetal tungsten carbide as desired) with 5x 20 mm grinding balls and the provide sample fragment. | |
After two minutes of grinding, the sample was comminuted fine, only slightly compressed to the radius of the bowl. The sample was brushed out easily. | ||
Brushed out sample with a few, tiny pyrite-fragments. |