FRITSCH PULVERISETTE 14 - Manual (Page 32)

For highly temperature-sensitive source material, we recommend
cooling the source material with liquid nitrogen before milling and then
feeding the material into the funnel in very small quantities, e.g. with a
spoon spatula.
CAUTION!
Wear safety goggles and safety gloves!
When milling with liquid nitrogen or dry ice, overpressure
can form in the grinding chamber. Risk of splashing! Addi-
tionally, observe all laboratory guidelines for handling liquid
nitrogen. Only specially trained personnel may be entrusted
with this work.
When milling larger amounts (> 20 g) with external cooling,
always use the conversion kit.
Dry ice (solid carbon dioxide) can also be used for cooling. However,
keep in mind that the surface of dry ice often contains frozen conden-
sate, which can potentially clog or contaminate the sieve ring.
6.8 Grinding with heavy-metal-free or metal-free grinding elements
For the article numbers, please refer to our homepage or the spare parts
catalogue.
To eliminate the influence of even the smallest amounts of iron, it is nec-
essary to install iron-free grinding elements.
The following parts must be installed:
n 12-rib rotor made of titanium (99.8% titanium),
n a sieve ring made of pure titanium with a reinforced edge or
n a sieve ring with a TiN coating,
n a collecting vessel coated with PTFE,
n a lid coated with PTFE.
When using iron‐free grinding elements, keep in mind that
the hardness and abrasion resistance of titanium is signifi‐
cantly lower than that of the tempered special steel. The
Teflon coating of the collecting vessel and lid also has
reduced abrasion resistance. (Ä Chapter 2.2 ‘Scope of appli‐
cation’ on page 7)
Using the device
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