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| One of the oldest mineral binders
is gypsum. Natural gypsum is obtained as a sediment by
precipitating evaporated sea water. Heating serves to
extract combined water from the raw gypsum. At a temperature
of approx. 100°C, the so-called building plaster and
plaster of Paris forms. Besides this natural gypsum, the
environmental technology industry is also a supplier of
the raw material. Gypsum is yielded during flue-gas desulphurisation
processes in coal-fired power plants. |
Gypsum is used:
in the building industry as gypsum plaster boards, building
and facing plaster
in the fine ceramics industry as plaster of Paris
in medicine and pharmacology for tooth restorations and plaster
casts, etc.
in the field of art for models and sculptures, etc.
A processing system for natural gypsum is shown below. The system
configuration is based on the following requirements:
Feed size: less than 2 mm with a moisture content of below 0.8%.
Required end-product fineness: 97% < 100 µm.
End-product output: approx. 800 – 1000 kg/h at the above
fineness.
Because natural gypsum can always contain a certain amount of
abrasive contaminants, we use our AWM table roller mill for
the grinding. The micron classifier integrated into the machine
top section guarantees a sharp top-size limitation.
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1 = Shut-off valve
2 = Change-over valve
3 = Rotary valve
4 = AWM 400 Table Roller Mill with MS Micron Classifier
5 = Automatic reverse jet filter
6 = Fan with silencer
7 = Rinsing air fan
8 = Hydraulic unit
9 = Lube oil supply
10 = Control cabinet
A = Feed product
B = End product
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If the moisture content of the feed material is above 0.8 %,
impact drying with the AWM is a good option. The product is
dried during the grinding process to a residual moisture of
0.5 %, whereby the flow of heated classifying air is used.
The energy consumption is low because the heat from the fan,
the mill and the classifier is utilised. Energy savings of up
to 25 % are possible!
This system is naturally also suitable without the drying step
for processing other types of gypsum such as FGD gypsum, etc.
As a means of expanding the application properties, the pure
gypsum types can be ground with our UPZ fine impact mill subsequent
to calcining. If a sharp top-size limitation is demanded in
this case, an ultrafine classifier from the MS series can be
installed downstream of the mill.
Fine impact mill UPZ |
Micron classifier MS |
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