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| Main
Processes and Equipment |
1. Wet Grinding
The process adopts the two-stage grinding
and separation technology that combines
rod mill open grinding, ball mill closed
grinding and hydrocyclone separation. The
technology has apparent merits – the
manifested large scale installation fully
exerts the capabilities of rod mill and
ball mill, combines rational process configurations,
and achieves efficient cyclone separation
and low grinding power consumption. The
overflow type of rod mill and the overflow
type ball mill are from China Mining Machinery
and Equipment Co. Ltd. and the hydrocyclone
is from France. Performance assessment shows
that the productivity and the technical
performance of the installation comply with
the design requirements.
2. High-pressure Digestion
The process adopts the technology of mono-tube
pre-heater, indirect heating autoclaves
and reinforced digestion technology. The
autoclave uses energy saving mechanical
agitator with its CMD drive unit imported
from Citroen in France. Steel materials
were imported from Germany for the manufacture
of pre-heating mono-tube, autoclave, flash
evaporation vessel, and pulse buffer. The
technology is specially developed for the
fact that diaspore is difficult to dissolve
and has the following advantages: realization
of indirect steam heating and low energy
consumption; high thermal recycling; high
equipment operation rate. In this installation,
the relative digestion rate of alumina from
bauxite is as high as 95%, the highest level
among similar installations in China.
3. Precipitation
This process adopts an advanced sandy alumina
production technology that features “high
concentration, high solid content, and one-step
precipitation process”. Large-scale
flat-bottom mechanical agitating tanks are
employed in the process. Its stirring propeller
design is the best in China and its gear
box and hydrate classification equipment
are both imported from France. For higher
precipitation output rate, wide-channel
plate heat exchangers are installed at proper
location on top of the precipitation tanks
and serve as an intermediate cooling device.
The average extraction output in the precipitation
process is above 95kg/m3, a leading level
in China. |
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4. Evaporation Station
6-effect falling film evaporators with
forced circulation crystallization are
used in the evaporation station. The
station has an evaporation capacity
of 220 tons/unit • hour. The installation
is good for its simple process, low
evaporation temperature, wide operation
scope, stable operation, long working
hours, and low steam consumption rate.
At present the average operation rate
of these evaporators is above 90% and
the steam consumption is only 0.28t
for each ton of water. |
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5. Calciner
The calciner adopts the advanced calcination
technology and has the merits of low power
consumption, high availability and productivity,
low maintenance costs, and low space requirements.
The calciner uses ESP for gas purification
and is able to reduce the dust concentration
in gas to no more than 50mg/m3 and thus achieves
low alumina losses and low pollution to the
environment. |
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6. Red Mud Settlers/Washers
Hi-Rate Settlers/Washers manufactured
by DORR-OLIVER EIMCO Germany, which
features high liquid and solid flow
rate, good red mud separation and washing
performance, thick underflow, and low
space requirement. |
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7. Red Mud Drum Filter
120m2 large-scale drum filter manufactured
by Dorr-Oliver EIMCO Germany, which features
high productivity, low water content in cakes,
and low alkali loss. Red mud is piled through
dry type storage technology, which features
low water consumption, low pollution, and
easy storage yard management. |
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8. Disc Filter
Gaudfrin 180m2 disc filter, which features
long disc diameter, efficient filtration,
high slurry processing capacity, long
filter cloth life, high automation,
low space requirement, and low water
content in cakes. |
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9. Diaphragm Pump
ZPM1700 diaphragm pump manufactured by GEHO
Pumps in Netherlands, flow rate: 420-520m3/h,
pressure: 6.8bar.
10. Aluminate Liquor Diastar Filter
The filter is manufactured by Gaudfrin in
France and is the most advanced fine filtration
equipment in the world. Diastar filter,
with productivity above 1.5m3/m2/h, is capable
of continuous operation, automatic cake
discharge, high output, and low labor requirements.
11. Pan Filter
The 62 m2 triple counter washing pan filter
is made by Dorr-Oliver EIMCO Germany. The
equipment is known for efficient washing,
high quality product, low water consumption,
high production capacity, and low water
content in its cake.
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