SU1308552A1 - Method of producing sorbent for purifying waste water from silicates - Google Patents

Abstract

The invention relates to the chemical industry, to methods for producing sorbents for the treatment of wastewater from inorganic impurities, and can be used to remove phosphates and silicates. The aim of the invention is to simplify the method of obtaining a sorbent, increase the sorption capacity for phosphates and silicates and increase the specific surface of the sorbent. The method of obtaining the sorbent consists in treating the caustic dolomite with a saturated solution of ferrous oxide-sulfate in a mass ratio of 1: 0.18-0.26. The water is purified by passing through a column filled with a sorbent. The use of a sorbent increases the degree of purification from phosphates and silicates, and the spent sorbent can be utilized as an organophosphorus fertilizer. 1 tab. (C (L with s o 00 01 ate go

Description

The invention relates to methods for the preparation of sorbents used for the purification of waste water from inorganic substances, in particular from silicates and phosphates.

The purpose of the invention is to simplify the method of preparation, to increase the specific surface of the sorbent, to increase the sorption capacity for phosphates while maintaining a high sorption capacity for silicates.

Caustic dolomite of composition CaCOj MgO with a content of magnesium oxide 28 and calcium carbonate 72% is treated with a saturated aqueous solution

ferrous sulfate at a weight ratio of 1: 0.18-0.26. When this occurs, the formation of a sorbent containing magnesium hydroxide, magnesium sulfate, iron hydroxide and calcium carbonate of the following composition, wt.%:

MgSO 11-14

MgCOH) 23-27

Fe (OH) 28-11

CaCO,

52-54

, Iron sulfate acts as a binder and helps solidify the sorbent into a dense porous mass for a day at room temperature. The interaction of MgSOij with the initial MgO as well as with Mg (OH) 2 leads to the formation of a magnesian binder. Calcium carbonate contains the role of filler and pore-forming bodies.

The resulting sorbent has a large, porosity, specific surface area is 560, which is three times more than that of the known sorbent. When Mg (OH), j is above 27%, the cost of the sorbent increases, which is determined by the cost of dolomite, and the phosphate ion sorption capacitance decreases sharply, the pH of the purified water rises, and as a result, the surface of the sorbent becomes covered with carbonate sediment.

calcium.

  Have

When Mg (OH) 2 content in the sorbent is less than 23%, its physicochemical properties deteriorate — the sorbent becomes brittle due to an increase in the magnesium sulfate content.

Example 1. To 75.7 g of crushed caustic dolomite, with stirring, add 50 MP of a solution containing 13.5 g of FeSO (ratio 1: 0.18). Full cure

five

O

five

0

five

35

40 45

50

55

sorbent occurs on the air after a day. The resulting sorbent has a composition, wt.%: MgSO 11, MgCOH) 27, FeCOH) 8, caso, 54.

For the treatment of wastewater, a ground sorbent is used, the grain size of which is 3-5 mm.

The installation, which is a vertical column with a height of 2 m and a diameter of 4 cm, filled with the indicated sorbent in an amount of 2 liters, is fed with wastewater after biochemical cleaning. Water is fed from above the column at a speed of 5 m / h.

Example 2. K72.9 g of caustic dolomite with stirring was added 50 ml of a solution containing 18.6 g of FeSO (ratio 1: 0.26). The composition of the obtained sorbent, wt.%: MgSO4, Mg (OH) 2 23, Fe (OH)., 11, CAS02 52.

The sorbent is loaded into the column and pass the waste water.

Example 3. To 74.2 g of crushed caustic dolomite, 50 ml of a solution containing 16.4 g of FeS04 (ratio 1: 0.22) is added with stirring. The composition of the obtained sorbent, wt.%: MgSO 13; Mg (OH) 2 24.4; Fe (OH) 2 9.7; CaCOj 52.9.

The sorbent is loaded into the column and pass the waste water at a speed of 5 m / h. I

Example 4. K84.2g of caustic dolomite 50 ml of a solution containing 5.1 g of FeSO (ratio 1: 0.06) are added with stirring. The composition of the obtained sorbent, Mac.%: MgS04 4; Mg (OH) 2 33; Fe (OH) 2 3; CaCO 60.0.

The column was filled with the resulting sorbent and cleaned up.

Example 5. K80.8g of caustic dolomite was added with stirring 50 ml of a solution containing 11.8 g of FeS04 (1: 0.15 ratio). The composition of the obtained sorbent, wt.%: MgS04 7; Mg (OH) j 30.2; Fe (OH) 2 5.2; CAS02 57.7.

The column was filled with the obtained sorbent and then proceeded analogously to example 1.

Example 6, To 65.9 g of caustic dolomite, 50 ml of a solution containing 25.4 g of FeSO (ratio 1: 0.39) are added with stirring. The composition of the obtained sorbent, wt.%: MgSO 20; Mg (OH) 2 18; Fe (OHj) 15; CaCO, 47.

The column is filled with the resulting sorbent and is purified as in Example 1.

Example 7 50 ml of a solution containing 33.8 g of FeSO (ratio 1: 0.58) are added to 58.5 g of caustic dolomite with stirring. The composition of the obtained sorbent, wt.%: MgSO 27; Mg (OH) 2 11.3; FeCOH) 20; CAS02 41.7.

The column is filled with the obtained sorbent and is purified as in Example 1.

The data are given in the table.

The sorption capacity of the proposed sorbent for phosphate ions is 50-60 g / kg and 100-110 g / kg for silicate ions, and the sorbent obtained in a known manner can absorb only silicate ions and its sorption capacity is 90 g / kg

When passing sewage through the sorbent layer, not only the removal of silicates and phosphates occurs, but also partial softening and replacement of calcium ions with magnesium ions and a decrease in calcium fluid, which reduces scale formation on the equipment surface.

In addition, the introduction of iron salts into the sorbent increases its water resistance.

VNIIPI Order 1768/18

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bone. When passing through comp. sorbents of the same volume of water change the volume of the proposed sorbent is 1.5 times less than the known one.

The spent sorbent can be used in agriculture as organophosphorus fertilizers. The biological value of the fertilizer is also determined by the presence of calcium and magnesium.

The simplification of the preparation of the sorbent is determined by the possibility of carrying out the process at room temperature, in

while in the well-known it is necessary to heat to 50-60 ° C and the use of concentrated hydrochloric acid.

Claims (1)

Invention Formula A method of obtaining a sorbent for purifying wastewater from silicates, including treating caustic dolomite with an acidic electrolyte, characterized in that, in order to simplify the method, increase the specific surface of the sorbent, increase the sorption capacity of phosphates while maintaining the high sorption capacity of silicates, and processing caustic Dolomite is carried out with a single aqueous solution of ferrous sulfate (2) at a weight ratio of 1: 0.18-0.26. Circulation 511 Subscription