The selection of filter material is the key to the operation of the filter, and is also the main component of the filter press. Variety, property, shape and gradation of filter material are the main factors determining the ability of filter to intercept impurities.
The following aspects should be considered in the selection of filter materials.
(1) Satisfactory mechanical strength: It is necessary for filter material of press to have satisfactory mechanical strengthening to prevent excessive abrasion of particles and breakage of bentonite waterproof blanket during washing. Because the broken fine particles enter the filter water simply, and the wear and tear make the particle size smaller, which increases the head loss of the filter head, and will be carried out of the filter by the water flow during the washing process, increasing the loss of the filter material, it is necessary to meet the mechanical strength, such as quartz sand.
(2) Have satisfied chemical stability: Satisfied chemical stability can prevent the pressure filter from occurring in the process of filtration, dissolved and filtered water scene, leading to deterioration of water quality. Strictly speaking, the general filter material has a very small amount of dissolved scene, but does not affect the general water quality requirements.
(3) It can be used locally and inexpensively: quartz sand is commonly used as filter material in water treatment of filter press. It can make river sand, sea sand, and so on. However, the need for strict cleanliness, can not contain harmful substances to human health and production.
(4) The shape is close to spherical shape, rough and sharp in appearance: so the adsorption surface is relatively strong, and the adsorption force at the sharp point is the strongest. There are certain grain size distribution and appropriate porosity of filament Geotextiles to improve filtering power. The particle size of filter material refers to the pore size when the particle just passes through a sieve hole.