Yanpai can customize filter cloths for aluminium enterprises. Our filter cloths are widely used in all processes in alumina industry, such as red cement separation, crude liquid separation, crystal washing, chemical alumina, etc. They are also suitable for all machines, including rotary drum machines, belt filter, vertical leaf filter, horizontal leaf filter, tilting disc machines, flat disc machines, etc.

Special filter cloth for leaf filter:

Yanpai’s special filter cloth for alumina leaf filter are finely woven by imported raw materials. With heat-setting and calendering under the high temperature, the cloth mesh is evenly distributed on the surface, so that the air permeability is stable, and the cloth surface is smooth. The filter bag for a leaf filter is of normal size and exquisite workmanship. If the machine is in good condition, its life span can be up to 3 months, and the floating suspended matter can be reduced to less than 5mg/L within 5 minutes.

Leaf filter working conditions:

Each filter needs to handle a minimum liquid flow: 510m3/h
Maximum feed solid content: 300-600mg/l
Caustic soda concentration (expressed as Na2Ok): 165-175g/l
Concentration of Al2O3: 188g- 195g/l
Concentration of Na2CO3 in Na2Ok3: 20g/l
Cl concentration: 12g/l
Liquid temperature: 105°C
Solid content of filtered material: 15mg/l

Special filter cloth for vertical disc filter:

Yanpai’s special filter cloth for alumina vertical disc filters has a typical life span of 1800-2000 hours. We now supply professional customized services for domestic alumina plants, which can be adjusted according to the actual working conditions.

Vertical disc filter working conditions:

Filtering medium: aluminium hydroxide
Slurry solid content: 700~1200g/L
Slurry Nk concentration: 160~200g/ L (aluminium hydroxide)
Blowback pressure: 0.1MPa≤P≤0.6MPa
Operating temperature: 42~50℃
Operation mode: continuous operation indoors
Vacuum level: ≤-0.025MPa

Special filter cloth for flat disc filter:

Yanpai’s specialized filter cloth for alumina flat disc filter, used on top of the flat disc filter for finished alumina filtration, has a typical life span of 2 months. The floating matter is less than 0.7g-4g/L and the drying rate of the filter cake is about 4%-8%.

Working conditions of flat disc filter:

Working medium: alkali (aluminium hydroxide slurry, filtrate), hot water
Working temperature: -30℃-150℃
Vacuum degree, back-blowing wind pressure: 0.03-0.06MPa
Alkali concentration: 0-320g/L
Slurry flow: 0-180m³/h

Red mud washing:

Red mud still has a high viscosity after sedimentation which is difficult to be separated from solid during the washing process and is also hard to detach from the filter media. Chamber filter is a kind of traditional filter, and single filter cloth is very difficult to be washed. Nowadays, rotary strand filter are often used and some of which uses additional back roller to unload the filter cake, making washing and separation effect more ideal. Some manufacturers also use horizontal vacuum belt filter, but the effect is not ideal.

Recommendation filter cloths :

 Most of the filter cloths used are mono-filament polypropylene filter cloths with a mesh size around 30-50um. Yanpai and research institutes of the major alumina manufacturers have developed and successfully evaluated the 2815-type mono-filament filter cloth, which can be used on the transfer machine by changing the process and improving the efficiency of the filter cloth.


The advantages of this type of polypropylene filter cloth: filter cloth would have a good mesh stability and cake unloading ability if made from uniform and clean mono-filament, ensuring both the product’s quality and the maximum washing effect.

Crystal Wash:

The decomposed aluminium acid solution is separated from the solution and aluminium hydroxide in the concentration aluminium hydroxide graded in the classifier. The small-size aluminium hydroxide is returned as particles to decompose the sodium chlorate solution and large-size particles are selected for calcination after washing and filtration. The vertical disc filters, as well as vacuum belt filters, are usually used for washing crystalline.

Filter cloth recommendation:

Mono-filament filter cloth or non-woven fabric is recommended with material of polypropylene and polyamide. The filter cloth with 50-60um mesh, pa1420, pa1666, PP750G is highly recommended.


The type of filter cloth, with good resistance and strong regeneration, has span life of approximately 1800 hours, reducing the downtime caused by filter cloth replacement.