21.11.2001
Retsch GmbH
31
Doc. No E98.014-016.9999 A
Wet sieving
Dry sieving will be possible in the large majority of
cases. There are, however, some materials in which the
adhesive forces between the individual particles can
cause difficulties. These problems can be eliminated by
adding liquid, preferably water, during the sieving
operation (in so far as the additives mentioned in the
chapter on “sieving aids” were not successful). One pre-
condition for wet sieving, however, is that the substances
to be separated will not swell, dissolve or otherwise in-
teract with the liquid.
Required accessories
*
Clamping cover with spray nozzle, matching the sieve
diameter.
*
Base pan with water drain, matching the sieve
diameter.
Preparations
*
Position your AS200 near a water drain.
*
Use a hose to connect the spray nozzle in the clamping
cover to a water faucet.
*
Connect the drain from the base pan with the drain or
a suitable container to receive the liquid.
Operation
*
Apply the solid in the form of a suspension.
*
Set the liquid (water) supply rate so that the spray just
covers the sieve surface completely.
*
Using dispersion agents is advisable. They reduce the
surface tension of the sieve liquids.
*
When dealing with goods which resist forming a slurry
or where more exact separation is required, spray
each individual fraction, one after the other.
*
Following the sieving process, the fractions are to be
transferred from the individual sieves to suitable filters
(
e.g.
filter paper) and dried in a drying cabinet at
80°C.
*
Then clean the sieves in an ultrasonic bath and dry
them, too, in the drying cabinet (without the gaskets).
Do not exceed a maximum drying temperature of
80°C.
