Retsch ZM 300, Руководство пользователя

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Operating the device
47
Carry out embrittlement of sample material as follows:

Embrittlement of sample material for grinding must be carried out in a suitable vessel. Fill
in the liquid nitrogen and slowly add the sample material. After a suitable cooling time,
remove the sample material and fill it into the ZM 300. It is recommended to use a vacuum
cleaner connected to the pipe sockets of the cyclone separator lid.

Do not fill the mill with liquid nitrogen under any circumstances. The resulting overpressure
when the nitrogen is heated could blow the mill open.
Embrittlement with liquid nitrogen is often not necessary. Sample material that is difficult or
impossible to grind at normal room temperatures (gummy bears, vegetables without additional
water) must be ground cold. Good results are also achieved by mixing the material with dry ice
or storing the sample material for approx. 24 hours at a minimum of -19 °C.
Embrittlement with dry ice (frozen CO
2
) improves the fracture behaviour of such samples. For
this purpose, the sample is mixed with dry ice in a ratio of 1:2 (V:V) and, after a few minutes of
cooling, fed into the machine (dry ice may also be fed).