6 Methods to Improve Disc Filter Efficiency

Disc filter is the common dewatering equipment in mineral processing plant. Reasonable operation of the filter machine is one of the important conditions for good dewatering effect. Each mineral processing plant should determine the best filter working conditions according to the nature of the ore and the dewatering experiment. This article will introduce 6 ways to improve disc filter efficiency.

Generally, when the pressure difference is not large, increasing the vacuum degree can reduce the moisture of the filter cake. However, when processing the pulp composed of fine particles, the large pressure difference will cause the fine particles to drill into the holes of the filter gauze and plug up the holes, so that the filtering speed will be reduced within a certain period of time. At this time, the best way is to use a certain minimum suction pressure, as long as the pressure can maintain the necessary slurry filtration rate and help the filter cake to meet a certain moisture requirement. It is also possible to use thin filter cake for filtration and extend the filtration time to prevent clogging of the filter cloth. Different suction pressures can also be used to complete the filtration and further dewatering of the filter cake. For example, use a lower pressure in the filter zone to ensure that the filter cake has a larger porosity and a higher filtration rate.

And use a higher suction pressure in the dewatering zone to increase the compression force on the filter cake, so as to squeeze out the remaining water.

A good filter cloth should have the following effects:

• There is no suspended particle in the filtrate

• The filter cloth should have the smallest filtration resistance, sufficient mechanical strength, chemical stability, corrosion resistance and long service life

• Not easy to block, easy to clean and replace

• When the filter cake is thickened, the sediment can be firmly adsorbed on it, and it is easy to fall off during discharge

For the slurry composed of flat colloidal solid, it is easy to block the filter holes during filtration. You can precoat the press cloth with a layer of hard granular material that will not deform under ordinary pressure, such as diatomite, activated carbon, paper foil, etc. Such precoat materials are filter aid. The surface of filter aid can absorb colloid and prevent it from blocking the filter hole. After filtration, the filter aid will be removed together with the filter cake. Sometimes in order to change the solid particle size composition of the slurry, the filter aid can also be evenly mixed in the slurry, and then into the filter machine. Or mix the coarse product with the fine product into the filter machine, coarse material can play the role of filter aid.

Heating the slurry can reduce its viscosity and increase the filtration rate. Mineral processing plants generally use steam to heat the filter. It is proved by production practice that the working temperature of the filter is proportional to the amount of pulp processed when other conditions remain unchanged. But when the temperature is too high, its viscosity change will not be significant. It will not only corrode machinery, but also waste steam. The appropriate heating temperature must be determined by experiment.

Increasing the feed concentration can reduce the filtrate volume that needs to be discharged per unit filtration area. In addition, increasing the slurry viscosity will reduce the resistance of the filter cloth and increase the filtration speed, thereby shortening the filtration time and improving the filtration efficiency. For this reason, it is necessary to strengthen the slurry concentration process and keep the resistance of the filter cake layer stable to improve the processing capacity of the filter machine.

Fine material will increase the pulp viscosity and make filtration difficult. Adding flocculants can make the fine particles agglomerate into a larger aggregate (flocculation), increase the particle size and reduce the size range, so as to avoid the blockage of the filter hole. Commonly used flocculants are lime, sulfuric acid, starch and other synthetic agents. After adding the flocculants, the thickness of the filter cake can be increased, but the moisture of the filter cake cannot be reduced since the capillary moisture is still attached to the filter cake. But using filter press can overcome this problem.

The above are 6 ways to improve the efficiency of the disc filter. Improving the efficiency of the filter can not only directly increase the dewatering speed of the pulp, but also promote the operation of the entire mineral processing plant. In actual production, various indicators should be adjusted according to specific conditions.

If you want to know more about the operation of the disc filter, or want to buy a filter machine, you can consult the online customer service or submit a message, we will contact you as soon as possible!