SU1496817A1 - Method of producing filtering material - Google Patents

Abstract

A method of obtaining a filtering material comprising granulating a suspension of natural aluminosilicate raw materials in a fluidized bed followed by calcining the granules at 800-900 ° C, characterized in that sapropel is used as a natural aluminosilicate raw material.

Description

The invention relates to a method for producing a filtering material and can be used in the purification of natural waters and the purification of wastewater in filtering structures both in descending and in ascending filtration.

A known method for producing filtering material for water purification filters includes granulation of a suspension of alumo-calcium silicate raw materials (natural clays) in a fluidized bed with subsequent calcination of the obtained granules at 1050-1250 C.

The disadvantage of this method is the low filtration capacity due to the low specific surface area of the granules (1.0-1.2).

The closest to the proposed technical essence and the achieved result is a method of obtaining a filtering material, including the introduction of crushed magnetite into the clay suspension, followed by granulation in the fluidized bed and roasting the obtained granules at 600-900 C.

The disadvantage of the method is insufficient filtration capacity of the material.

The aim of the invention is to increase the filtration capacity of the material.

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This goal is achieved by the fact that according to the proposed method, including granulation of a suspension of aluminosilicate raw materials in a fluidized bed with a subsequent calcination of granules at HEO-EOO C, sapropel is used as a primary aluminosilicate raw material.

Sapropel forms at the bottom of a 4l press. lakes from dead organisms and plants, as well as transported mineral impurities. The content of the organic part per unit volume of sapropel is from 5 to 10 to 70%, and the mineral part from 90 to 30%, depending on the deposit.

The chemical composition of the mineral part (ash) sapropel,%: SiO 24.1- 20 76.4, CaO 2.6-52.2, Al-jOg 2.5-11.4 the rest (, MgO,, O3, PjOj) 9.6-18.5.

The organic substances that make up the sapropel, during calcination, burn out and contribute to the formation of the microporous structure of the granules with a developed specific surface and roughness.

Example. To obtain a filtering material, sapropel of the following composition is used,%: organic part 23, mineral part 77,

The chemical composition of the mineral part,%: SiO 49.3i CaO 38.1; 7.4., 3.5i MgO 1.2; , SOj, P, 050.9.

Based on 200 kg of sapropel with a moisture content of 24%, a suspension of 70% moisture is obtained (0.72 kg of the solid phase per liter of suspension). It is then sprayed with a nozzle and granulated in a counter-flow of hot gases (in the fluidized bed).

The obtained granules are burnt in a muffle furnace at 800-900 s.

Data on mechanical strength and specific surface of the granules, depending on the firing temperature are given in, Table. 1.50

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Technological tests of granulated filter material were carried out on an experimental bench, consisting of two filter columns with a diameter of 50 mm and a height of 2000 mm. One of the columns is loaded with the material obtained by the proposed method, the other with the material obtained in accordance with the prototype. In both columns the grain size is 1.0-1.2 mm, the loading thickness is 1.0 m. The water is filtered in the direction of top down. The filtration rate is kept constant at 8 m / h.

The quality of water supplied to the filtration is characterized by the following indicators: suspended solids 6 mg / l, chromaticity - 41 degrees, pH 7.1. Immediately before being fed to the columns, coagulant - sulfuric acid aluminum in an amount of 23 mg / l is added to the source water.

The criterion for the effectiveness of filter materials is the amount of water cleaned by the filter cycle. The duration of the filter cycle of each filter (column) is determined by the period during which the filter produces water that meets the requirements of GOST 2874-73 Drinking water, namely: color 20 degrees, turbidity 1.5 mg / l, pH 7 , 0. The results of technological tests are presented in Table. 2

From tab. 2 it follows that the duration of the filter cycle and, consequently, the amount of water purified per filter cycle on the filter with loading from granulated and baked sapropel is 57% more than on the filter with loading according to the prototype.

Thus, according to the proposed method, a filtering material with an increased filtering capacity is obtained, which makes it possible to increase the efficiency of the filtering structures.

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Claims (1)

A method for producing a filtering material, including granulation of a suspension of natural aluminosilicate raw materials in a fluidized bed followed by calcining the granules at 800,900 ° C, is characterized by using sapropel as a natural aluminosilicate raw material.