SU1281514A1 - Method of preparing liquid for washing highly dispersed silicon dioxide - Google Patents

Abstract

The invention relates to methods for the preparation of a liquid (wash water) for washing highly dispersed silicon dioxide and allows the process to become cheaper and increase the specific surface area of silicon dioxide. The method is carried out as follows. Technical water coming, for example, from artesian wells, is mixed with industrial effluents. white carbon black production in the ratio (3: 1) - (15: 1) depending on the salt content in. industrial effluent, which ranges from 1-50 g / l to 1-30 g / l NaHCOg; 0.1-50 g / l of Na 80, so that the concentration of the total salt in the resulting mixture is 3-5 g / l, and the mixture is contacted with a white carbon black spray dryer waste gas containing 400-600 mg / m dust dispersed SiO, at 50-80 0 and the mass ratio of gas and liquid is 1: 1. The liquid prepared in this way is used to wash the precipitate of SiO obtained by carbonizing liquid glass (sodium silicate solution) with a gas containing 20% CO ,, and separating the mother liquor. The washed filter cake is repulped in water to obtain a suspension with a content of 8-10% solid and, depending on the quality requirements of highly dispersed silicon dioxide, is sent directly to the dryer in a spray dryer, or pretreated with ion-exchange resin and then dried. 2 hp f-ly, 1 tab. i (L 1CHE 00 ate

Description

This invention relates to methods.

preparation of the liquid (wash water)

for washing highly dispersed silicon dioxide and may find application in the chemical industry, in particular in the production of the mineral filler white carbon by the carbonic method,

I:

The purpose of the invention is to make the process cheaper and to increase the specific surface area of silicon dioxide.

Example 1. About 3m of industrial wastes containing 1 g / l, 1 g / l of NaHCO and 50 g / l of Na, jSO are mixed with 4.7 m of industrial water (ratio of water and industrial wastes 15: 1), and the resulting mixture containing 3 g / l of the amount of salts is subjected to countercurrent gas treatment, containing 1 m 200 mg / m of highly dispersed SiOj. Gas and liquid are taken in a mass ratio of 1: 1 and the treatment is carried out at 50 C.

The liquid thus prepared at the same temperature is used to wash the precipitate of dispersed silicon dioxide obtained by carbonizing a 20 m aqueous solution of sodium silicate with a density of 1035 kg / m at 82 ° C with lime-kiln gas supplied in an amount of 1200 and containing 14 % carbon dioxide. The resulting suspension is settled, and 1.5 m of the thickened suspension is filtered on a FPAKM-25 filter press. Obtained on the filter press precipitate dispersed SiO in the amount of 120 kg (in terms of dry substance) rinse on the same filter liquid obtained in this way.

Washed and pressed on the filter; The sediment with total alkalinity in terms of 5-6% in dry residue is repulped in water to obtain an 8% suspension of SiO and treated with strongly acidic cationite to a pH of 6.5 to 7.5, and then after separation of the cation exchanger is fed to Where the product is dried by flue gases formed during the combustion of natural gas. The finished dried product is separated from the flue gases in bag filters (purification level 85-90%). The gas after the filters is used to treat the wash liquid. The specific surface of the soot obtained in this way is shown in the table.

Example 2. Liquid for washing highly dispersed SiO is prepared as in Example 1, but treated with gas containing 1000 mg / m of highly dispersed SiO5 and used for washing the SiO precipitate obtained in Example 1. The washed precipitate is processed as in Example 1 to obtain white carbon black with a specific surface. ,

given in the table.

Example 3. The washing liquid is prepared according to example 1, treated with a gas of the same dust content, but at. After washing the precipitate and further processing it into white carbon black in Example 1, a product with a specific surface is shown in the table.

Example 4. Wash liquid prepared by mixing

components of the same composition and in the same ratio as in example 1, is treated with a gas containing 600 mg / m of highly dispersed SiO at 60 C. After washing the obtained precipitate with this liquid and further processing it as in example I, a product with a specific surface is given, given in the table.

Example 5. The washing liquid was prepared by mixing 0.3 m of effluent containing 50 g / l of Na, CO, 30 g / l of NaHCO and 0.1 g / l with

4.7m of technical water. Received 5 m mixture containing 5 g / l amount

NanCOg, Na, CO, and gas are treated under the conditions of Example 4 and used to wash the resulting precipitate. Specific surface white

soot obtained by processing the washed precipitate is shown in the table.

Example 6. The washing liquid was prepared by mixing 1.2 m of effluent containing 5 g / l of Na, CO,

3 g / l NaHCO and 5 g / l, and

3.8m of industrial water (ratio of industrial stock: water 1: 3) to obtain a mixture containing 3 g / l of the amount of salts NaHCOg, NagCO, and. The mixture is treated with a gas under the conditions of Example 4 and used to rinse the resulting precipitate. The specific surface of the white carbon black obtained by processing this precipitate in example 1 is given

in the table.

Example 7. The washing liquid was prepared by mixing 0.5 m of effluent containing 10 g / l,

NaHCOjHlO g / l Na, S (, with 4.5 m of technical water (industrial stock ratio: water 1: 9) to obtain a mixture containing 3 g / l of the amount of NaHCO salts, and Na SO. The mixture is treated with gas under the conditions of example 4 and used for washing the precipitate obtained in example 1. The specific surface of white carbon black obtained by processing this precipitate in example 1 is shown in the table.

Example 8 Wash liquid was prepared by mixing 0.72 m of industrial wastes containing 50 g / l of Na CO, 30 g / l of NaHCO and 0.1 g / l with 11.28 m 3 of industrial water (ratio of industrial drains: water 1 :15). Get the mixture with the concentration of the amount of salts

Sh

15

NaHCO 3, Ka, CO2, 5 g / l. Mixture

treated with gas under the conditions of example 4 and used to wash the precipitate, obtained as in example 1.

Next, the washed dispersed silicon dioxide is repulped to form a suspension containing 8% SiO ,, and is fed to the dryer directly to the spray dryer. The specific surface of the soot obtained in this way is shown in the table.

Example 9. A washing liquid was prepared by mixing 2.88 m of industrial wastes containing 5 g / l, 3 g / l of NaHCO and 5 g / l with 9.12 m of technical water (1: 3 ratio) to obtain a mixture containing 3 g / l of the sum of salts, NaHCOj and, the mixture is treated with gas under the conditions of example 4 and used to wash the precipitate with dispersed SiOj, obtained as in example I. The specific surface of white soot obtained by processing the washed precipitate in example 8 is shown in the table.

Example 10. Washing liquid was prepared by mixing 1.2 m of effluent containing 10 g / l, 7 g / l NaHCO and 10 g / l with 10.8 m of technical water (ratio 1: 9) with obtaining a mixture containing 3 g / l of the amount of salts. The mixture is treated with a gas under the conditions of example 4 and washed with the resulting precipitated-dispersed silicon dioxide liquid prepared in example 1. The specific surface of white soot obtained by processing the washed precipitate as in example 6 is shown in the table.

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The proposed method makes it possible to eliminate the deterioration of the primary structure of the precipitate of dispersed SiO, which results in an improvement in the quality of the product. This eliminates the cost of expensive reagents and heating of the washing liquid, which reduces the cost of its preparation.

Thus, the technical and economic advantages of the proposed method of preparing a liquid for washing highly dispersed silica include improving the quality of the finished white soot product by increasing its specific surface from 110-130 to 125-140, reducing the number of discharged industrial wastes, and eliminating the costs i reagents and charge heat for water treatment and replacement of expensive filter equipment made of acid-resistant alloys made of cheap carbon steel.

Claims (3)

1. Method of preparing liquid for washing highly dispersed silicon dioxide produced by carbon dioxide a method that includes mixing water with a chemical reagent containing ion sulfate, characterized in that, in order to reduce the cost of the process and increase the specific surface of silicon dioxide, a solution containing carbonate, bicarbonate and sodium sulfate is used as a chemical reagent. 3-5 g / l are carried out until the said salts are contained in the liquid, after which the liquid is treated with gas containing highly dispersed silica dust in an amount of 200-1000 mg / m at 50-. 815146 2. The method according to p., Characterized by the fact that as a solution containing carbonate, bicarbonate and sodium sulphate, use is made of the production of highly dispersed silicon dioxide produced by the carbon dioxide method, containing: 1-50 g / l Sh /five Na jCO, NaHCO, 1-30 g / l 0.1-50 g / l, Na SO g 4 the offset is carried out at a ratio of water: industrial stocks 3-15: 1. 3. Method POP.1, characterized in that the liquid is treated with gas at a mass ratio of 1: 1.