Malvern Instruments Mastersizer X, Manual

Page: 64 / 102

Using a slurry
The act of mixing up a small quantity of concentrated sample, dispersant and
additives before it is added to the Dispersion Unit tank is known as preparing a
slurry. Once the particles have been successfully dispersed into a slurry, the
sample may then be added to the system without any additions using a pipette.
The slurry should be continually stirred using the pipette to stop the sample
settling out. If this is a particular problem, a magnetic stirrer may be used.
The use of ultrasonics
Ultrasonics can be used to aid the dispersion of the sample in the suspension
medium.
When mixing the sample in the suspension medium, a visual inspection will often
indicate whether ultrasonics are necessary. If there are large agglomerates of
particles which sink to the bottom of the beaker, then try applying two minutes of
ultrasonics by placing the slurry and its beaker into an ultrasonic bath. It will be
apparent if this has been effective.
%
Caution
Be wary of using ultrasonics with fragile particles as the ultrasonic action may
actually break up the particles themselves. If in any doubt, microscopic
observation before and after ultrasonics should establish whether it has been
beneficial or not.
C H A P T E R 8
Q S S m a l l V o l u m e S a m p l e D i s p e r s i o n U n i t
P a g e 8 . 2
M A N 0 1 6 1