[Non approuvé] Slurry filtration characteristics of five categories
According to the formation rate of the filter cake, the filtration properties of the filter pulp can be divided into the following five categories.
1, good filtering pulp, fine ore, quartz sand, crystal products and coal slurry and other solid liquid mixture, are good filtering pulp. The filter pulp is fast and can form a thick filter cake in a few seconds. Can use the internal feeding type rotary drum vacuum filter, can also use the horizontal belt type vacuum filter with a horizontal filter surface. However, the deposition of filter slurry in horizontal pipeline should be considered.
2, medium filter pulp, starch, acetate gypsum, toner, aluminum hydroxide and sulfurized concentrate mixture, belong to the medium filter pulp, after slow mixing, can maintain the suspension state. The forming speed of the filter cake is more than 25mm/min, with a medium filtering speed. The rotary drum vacuum filter can be used.
3, poor filter pulp, calcium carbonate, cement, zinc orange ore, zinc sulfate, sodium chloride and sodium hydroxide, solid and liquid mixture, all stage in poor filter pulp: as long as a little slow mixing, it is easy to suspend. The formation speed of the filter cake is no more than 6mm/min, and the filtration speed is very slow. For such a filter, pressure or vacuum filter can be used.
4, rarefied filter pulp, solid volume fraction of less than 5% of the filter pulp, as rarefied filter pulp. The formation rate of the filter cake is no more than 1mm/min. For example, the solid liquid mixture c of waste activated carbon, fermentation medium, clay, protein and hydrogen oxidation, etc., can be used for such a filter slurry by various pre-coating filters or intermittent pressurized oil filters. With pressure precompress layer filter, can get rid of the water in the swimming pool escherichia coli (1 around m) : because the embarrassed layer is very thick. So it is suitable for mud with a wide range of concentrations.
5, extremely thin filter pulp, volume fraction less than 0.1%, such as colloidal dispersion system, belongs to this kind of filter pulp. It does not form filter cake at the time of filtration, and solid particles are cut inside the medium, which belongs to the medium filtration mechanism. When the particle size is above 5 meters, you can choose the filter press, filter element filter and pre-layering filter. These machines can also be used for filter pulps with high strength. When the handiwork degree is low, can use the intermittent preapplied layer pressure filter. For the high viscosity filter slurry under the particle size of 5 meters, filter press can be used. Polymer high viscosity liquid, can use a specially designed simple filter filter.
It should be noted that when the filtration volume fraction is less than 1%, the filtration accuracy is usually required. The substance and particle size to be removed and its concentration in the filtrate should therefore be specified. The filtration accuracy is improved in the following order: general filtration, precision filtration, ultrafiltration and reverse osmosis.
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