SU916482A1 - Process for producing diatomaceous powder - Google Patents

Description

The invention relates to a production technology of diatomite powders and, in particular, can be used to obtain diatomite filter powders used in medicine, chemicals, petrochemicals, Lee winemakers ^5, in the production of beer and fruit juices. Powders can also be used in the production of chromatographic media.

A known method for the production of diatomaceous filtering powder, including crushing, drying, grinding, firing, cooling and classification of baked diatomite with the release of filtering powder. <

The known method is as follows. Diatomite crushed pieces of the particle size of 50-60 mm and fed to the inclined conveyor for drying a go- _m rizontalny rotary drum dryer, a 'which is also fed with a temperature of a drying agent 550

6OO ° C. In the process of drying humidity

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diatomite is adjusted to 15-18%. Then the diatomite is fed for grinding in a hammer mill SM-218. The resulting grains (coarsely chopped diatomite) are fed for firing into a horizontal rotating drum, where they are calcined at 900-1000 ° C. After firing, the grains are cooled in a rotating drum, irrigated with water, and fed to the classification. In the process of classification, the filtering powder is separated from the diatomite working fraction, and the rest (the sum of fractions placed on the upper and lower limits of the particle size of the filtering powder) is at least 50% used as a by-product for another purpose.

The known method of producing filtering powder determines the presence of waste caused by the use of horizontal rotating drums for drying and firing, which are also characterized by an increased consumption of 916482

home fuel. The increased fuel consumption is due to the lack of heat recovery from burnt raw materials and flue gases. Wastes are the result of dust carried away from the drums, losses between technological conversions and by-products formed during the classification process of baked diatomite and separation of working fractions of filtering powder from its composition. To reduce waste and increase the specific yield of the product, additional grinding of waste is used · classifications, some of which, after re-classification, are added to filter powders 03 ·

However, additional grinding of burnt diatomite grains reduces the filtering properties of the powder. This is explained by the fact that the calcined diatomite acquires a rigid structure and repeated grinding leads to the destruction and residual deformation of the elementary particles of the diatomite of the armors of diatoms.

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The purpose of the invention is to increase the specific removal of the product, improving quality and reducing specific fuel costs.

This goal is achieved by the fact that the method of production of diatomite powder, including crushing, drying, grinding, firing, cooling, the selection of the product of a given particle size composition, the last produced after grinding, before firing, preheat, and the firing is carried out in a cyclone-vortex furnace.

The invention is illustrated by the scheme.

The crushing of raw materials is carried out in a roller crusher 1. The resulting grains with particle sizes up to 5 ^- 6 mm are collected in a hopper 2, from where they are fed into a rotary dryer 3 ,. where its su ~ _o shat at an average temperature of 300-500 C, to a humidity of 3 “5%. Dried grains through pneumatic conveying served in the system of cyclone-separators 4.

After separation, the grains are collected in a buffer tank 5. The final dedusting of the pneumatic agent is carried out in filter 6. The dust-free gases are sucked off by the fan 7, and the isolated fine fraction of the diatomite with particle sizes less than the allowable limit of the filter specification 4

This powder is used as a by-product. Next, diatomaceous grains from the buffer tank 5 is fed through the screw to the grinding in the mill 8.

In the process of grinding carry out the operation of preliminary preparation of the powder of a given size of grinding. The final stage of obtaining a powder of a given final particle size distribution is carried out in cyclone separators 9 and a filter 10, in which particles with sizes that do not correspond to the lower limit of technical conditions per filter porosity 15 are separated from the powder. The dust-free pneumatic agent is sucked off by the fan 11, and the prepared diatomaceous powder is collected in the buffer tank 12. Through the air supplied by the blower 13, the powder (air mixture) is fed to the surface-type heat exchanger 14.

In the recuperator, the aerosol mixture is preheated to at least 200-400 ° C due to the 25 heat of the gas suspension withdrawn from the cyclone-vortex furnace 15 less than 1250 "1b00 ° C. The gas suspension formed, as noted above, is sent to the heat exchanger 14 and further to the cyclone-separator system 16 and the filter 17. The dust-free gases are sucked out by a smoke exhauster 18, and the working product (filter powder) is fed to the storage. To optimize the roasting of the powder, this option also provides for the possibility of heating only the air supplied to the furnace to the furnace 40. In the event of a temporary failure of the heat exchanger 14, it is also possible to operate the furnace on a cold 45 blast. and powder are provided for the gate.

Technical and economic efficiency of the process is determined by increasing the specific yield _{of 50} cm of the product for every ton of raw materials, improved product quality and a reduction in specific fuel consumption.

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Claims (1)

Claim Method for the production of diatomite powder, including crushing, drying, 5 Λ 1.6482 6 grinding, firing, cooling, the selection of the product of a given granulometry composition, characterized in that, in order to increase the specific removal of the product, improve quality and reduce specific fuel costs, the selection of the product of a given particle size distribution is produced after crushed, before "but firing is carried out before heating, and firing is carried out in a cyclone-vortex furnace.