pallmann - John Wood & Associates

Mahlen und Mahltrocknen von Cellulosederivaten
Grinding and dry-grinding of cellulose derivatives
Cellulose derivatives such as MC,
CMC, HEC, HPMC, MHEC etc.
are, depending on the application,
contained as additives in many
products in order to influence their
characteristics.
In the construction industry, they
control the water binding ability of
cement, gypsum and fillers. As
wallpaper paste, CMC is possibly
the most well known product. As
additives in washing detergents,
the derivatives prevent graying
and discoloration. They are also
used as thickeners and when used
in foodstuffs, they enhance composition,
form, structure and consistency.
In the pharmaceutical
industry, CMC is used in tablets
to define active ingredient release
and as a binding agent.
During the production process,
cellulose ether is washed and
granulated after reaction. The
product, still moist, is then precut,
before drying, by means of knife
mills or double-stream mills.
Afterwards it is ground to a fineness
of less than 0,5 mm or pulverized
to less than 0,18 mm, in
a Turbofiner mill, type PLM or a
Contraselector mill, type PPSR,
depending on the requirement.
These explosion pressure-resistant
mills are also used with
hot air induction for simultaneous
grinding and drying, thereby significantly
simplifying the process.
Finest CMC-powders as used in
the pharmaceutical industry are
produced by means of cryogenic
grinding systems with counterrotating
pin mills.
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