База данных протоколов измельчения: детали

Protocol number:		M002128
Industry:		Mechanochemistry
Feed Size:		< 30µm
Desired Fineness:		mechanochemical reaction
Quantity:		20-40 g
Recommendation:		As desired, a Vario-Planetary Mill PULVERISETTE 4 has been used for grinding with several grinding sets. A mechanochemical synthesis can not be determined with our laboratory equipment; therefore, we please to check yourself if desired chemical compound can be found.

Vario-Planetary Mill PULVERISETTE 4 classic line

Result 1

main disk speed: 400 rpm
transmission ratio: 1/-1

80 ml grinding bowl made of tempered steel
+ 5x 20 mm Ø tempered steel grinding balls

Feed quantity:	20 g
Feed Size:	< 30 µm
Grinding time:	5 min
Final fineness:	sticks heavily!
Comments:	The start size of your sample mixture use to be < 30 µm; so a rapid sticking of sample is expected. Interacting forces between fine ground particles will become bigger as their own g-force. Therefore, particles will stick to each other and become compressed by the used grinding balls. These clusters of particles also contain bigger particles which will not be ground any further. Usually we don’t recommend to proceed dry grinding when sample will only stick stronger to the bowls wall. If the balls use to be free of sticking sample, balls will hit themselves and will produce higher abrasion (until a barrel form will show). When balls will be covered in sample too, higher abrasion is not expected to be found. With the desired machine setting, the sample was heavily sticking after a total grinding time of 5 minutes. It is not possible to check how many of reactant has been transformed with our laboratory equipment. For this, sample have been scratched off and send back.

Result 2

main disk speed: 400 rpm
transmission ratio: 1/-1

250 ml grinding bowl made of tempered steel
+ 50x 10 mm Ø tempered steel grinding balls

Feed quantity:	40 g
Feed Size:	< 30 µm
Grinding time:	5 min
Final fineness:	sticks heavily!
Comments:	This result has been performed equally to result 1. For the higher amount of sample, a 250 ml grinding bowl has been used. Also with lighter 10 mm Ø grinding balls, the sample is sticking heavily to the bowl and balls. Usually no longer dry grinding is recommended. For a finer grinding result, grinding should be proceeded in suspension. Because we cannot determine the amount of desired compound, sample has been scratched off and sent back.