METHOD FOR PRODUCING GRANULAR FILTER MATERIAL Russian patent published in 2017 - IPC B01D39/06 B01J20/14 

FIELD: technological processes.

SUBSTANCE: diatomite rock (kieselguhr, trefoil, flask, infusorial ground and etc.) is ground to particles size of less than 1 mm and classified into 3 fractions (up to 5 mcm, 5 to 100 mcm and over 100 mcm) which are then mixed in a different ratio of fractions to control properties and characteristics of the granular filter material. Ground rock particles (one fraction or mixes of 2 or 3 fractions) having a moisture content of 15-18% are mixed with binders: for example, with water, increasing the moisture content of the ground particles to 38-42%, or with substances containing carbon, for example with aqueous 5% solution of carboxymethylcellulose (0.08% carboxymethylcellulose by weight of the granules). Starch, modified starch and methylcellulose can also be used as a binder additive containing carbon. A mix of diatomite particles with binder additives is sent to a layer-by-layer granulation in a disc granulator or a fluid bed granulator to obtain spherical isotropic granules which average diameter exceeds the average equivalent diameter of the ground diatomaceous rock particles by at least 8 times. The resulting granules are dried and fired at a temperature of 700 to 1200°C.

EFFECT: improving quality of the finished product.

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