Application of Belt Filter Press in Tailing Coal Dehydration
Introduction of tailing coal dehydration
In recent years, with the increase of domestic coal mining depth and the change in coal quality conditions, the content of high ash and fine mud in coal slime water has been increasing, which has brought great difficulties to tailing coal dehydration. Conventional dehydration methods are difficult. Meet the needs of high ash fine mud dehydration.
As a new type of dehydration equipment, the belt filter press gradually shows its advantages in the dehydration of high-ash fine mud due to its unique design of the dehydration method.
Structure of belt filter press
The belt filter press is mainly composed of a driving device, frame, press roller, upper filter belt, lower filter belt, filter belt tensioning device, filter belt cleaning device, unloading device, air control system, electrical control system, etc.
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The process of tailing coal dehydration
1. Gravity filtration dehydration section
In the gravity filtration and dehydration section, the coal slime from the system is fully mixed with the chemical agent through the static mixer and then flows to the filter belt through the pressurized “turbulent flow” and decompressed expanded “steady flow” device. Then, it passes through the sludge trap to adjust and limit the thickness of the filter layer so that the material can be evenly distributed, and then the plow-shaped micro-pressure dehydration is performed on the coal slime in order to achieve the maximum removal of free water in the gravity dehydration section.
2. Prepress dehydration section
That is to use the wedge-shaped changes of the upper and lower filter belts to gradually apply pre-pressure to the coal slime from the gravity dewatering section to further remove the surface water of the coal slime, reduce the water content of the coal slime entering the pressing zone, and completely lose the fluidity.
According to the characteristics of coal slime, the pre-compression section of the belt filter press is divided into two-stage pre-compression devices: flexible pre-compression and rigid pre-compression. The dehydration efficiency of the two-stage pre-pressing device is more than twice that of the pre-pressing dehydration only relying on the wedge shape change of the upper and lower filter belts, which lays the foundation for the dehydration of the next stage of pressing and dehydration.
3. Press the dehydration section
Since a two-stage pre-pressing device is adopted in the pre-pressing dehydration section, six dewatering rollers are set in this section to form an S-shaped movement mode so that the coal slime can reach an ideal dehydration state in the process of repeated extrusion.
In summary, using the belt filter press as the check equipment for flotation tailings dehydration can achieve good results. The processing capacity and dehydration effect are less affected by the size of the coal slime, and the operating cost is low. Especially when the flotation tailings with high fine mud content are dehydrated, the advantages are more obvious.