The ceramics industry uses zircon sand for glazes and thereby
makes a fundamental distinction between two products:
 zircon flour, fineness of d 45 µm
and opacifier, fineness of d 1.2 µm
Generally speaking, zircon flour is manufactured using dry ball
mills in circuit with a classifier, whereas up until now, the
opacifier has been wet-ground.
With our new grinding system, however, comprising the S.O.-SF
ball mill in combination with the Turboplex multi-wheel
classifier, we have succeeded in dry-grinding opacifier, thus
eliminating the system-related disadvantages of wet grinding
such as high drying costs, flat particle size distribution with
risk of oversize particles, and waste water disposal problems,
etc.
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All-important when dry-processing opacifier is exact control
of the grinding system if a constant high product quality
is to be guaranteed. One of the measures we apply is a precise
control of the filling level by means of load cells, which
continuously weigh and regulate the amount of product in the
mill.
It is essential that glazes used for ceramics are free from
contaminants such as iron abrasion. Our mills are therefore
lined with aluminium oxide and equipped with top-quality aluminium-oxide
grinding elements for this application. The classifying wheels
are fully ceramic and the classifier housing is equipped with
ceramic wear-protection elements. Over and above this, assuming
proper handling and operation, additional contamination of
the opacifier with aluminium oxide can be kept way below the
critical level. Empirical values attest to a max. increase
of the Al203
portion of only < 0.6% and of the Fe203
portion of < 20 ppm.
Below is a typical example of a processing system designed
and delivered for processing zircon sand (opacifier). The
following specifications were used as a basis for laying out
the system:
Feed product: Zircon sand
Feed size: < 300 µm
Feed moisture: <= 0.05% H20
Demanded and guaranteed end-product fineness:
99% < 4.5 µm ± 0.1 µm
50% < 1.2 µm ± 0.05 µm
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Legend
1 = Feed bin
2 = Proportioning belt weigher
3 = Metal separator
4 = Change-over flap (sampling)
5 = Ball Mill So-SF
6 = Load cells
7 = Grinding aid supply
8 = Grinding pearl supply
9 = Rotary valve
10 = Ultrafine Classifier ATP
11 = Auxiliary air supply |
12 = Butterfly valve and fan
13 = Automatic reverse jet filter
14 = Fan
15 = Flap valve
16 = End-product bin with activated discharge and shut-off
element
17 = Control cabinet
A = Feed product
B = End product
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The advantages of this grinding system have already convinced
a great number of market leaders on the zircon sand sector,
and they now use our systems for production in the USA, in England,
Germany, Spain, India and Australia.
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