SU1235825A1 - Method of softening water - Google Patents

Description

The invention relates to water treatment and can be used in complex processing of saline wastewater from ferrous metallurgy enterprises, the chemical industry and in the energy sector.

The purpose of the invention is to reduce the salinity of water and improve the efficiency of the mind process.

Example. Wastewater of Na-cationic faltres of composition, NaCl 7.0; MgCl 1.4; CaSO 1,2; CaClj 1.8, with a mass flow rate of 100 t / h process 4, 1 ton of lime in the reactor. The magnesium hydroxide is clarified and filtered. The pK of the filtrate obtained is 10.5. The filtrate is treated with 100 m O of a 1 M solution of aliphatic amine carbonate of the Co – C fraction in an organic solvent (kerosene, chloroform, carbon tetrachloride) in a mixer. The resulting suspension is settled for 10 minutes in a settling tank, calcium carbonate is separated from the aqueous phase, and the organic phase is sent for regeneration with lime, I

The results of water treatment by the proposed method are shown in the table.

The table shows that the treatment of wastewater Na-cationic. filters with a solution of carbonates of aliphatic ashpüws of the Cg-C fraction in organic solvents in a volume of 0.03-1.0 mol / dm of water after klimkovat-g mass concentration of calcium ions in wastewater decreases from 2.2 to 0.22 g / dm, i.e., the residual concentration of calcium ions does not exceed 10% of the concentration of calcium ions in the source water. If necessary, further removal of the residual Ca concentration is carried out by multi-stage treatment,

According to the proposed method, precipitation and removal of calcium ions in the form of carbonates is carried out using liquid anion exchangers — carbonates of primary aliphatic amines. When using such liquid anion exchangers, the carbonate ion passes into the aqueous phase, which, interacting with calcium ions, forms CaCOj. At the same time, the concentration of the exchanging ion does not increase in the solution being treated. With this treatment, the total salt concentration in

the solution is reduced by one

temporary extraction of 50 ions. The use of solid anion exchangers, for example anion exchangers in the CO form,

These objectives are impossible, since calcium carbonate precipitates on the surface of the resins.

Yrie treated with preliminated source water solutions

carbonates of aliphatic amines, calcium carbonate is formed, which precipitates, and sulphate ions present in the source water, pass into the organic phase, forming

5 amine sulfate salts.

The organic phase, containing sulfate salts of amines, is treated with lime milk and saturated with carbon dioxide to regenerate carbon, amines,

: .Regenerated carbonate is thus re-fed to the treatment of hard natural or waste water.

5 Due to the fact that the salts of the amines are in an organic solvent, only carbonate ions of the liquid ion exchanger molecules participate in the reaction. In addition, as a result

This treatment of water does not lead to an increase in its mineralization, since calcium ions precipitate carbonate-ion-1 of a liquid ion exchanger, and sulfate ions are removed with an organic phase.

 and, therefore, there is no need for further water treatment.

i

Use primary with the number of carbon atoms in the alkyl radical 8-18, Reducing the length

 the alkyl radical results in a significant loss of reagent due to an increase in its solubility in water. The use of amines with a long aJJnl-radical is not advisable due to

 that their carbonate salts are poorly soluble in organic solvents. Carbonates of aliphatic amines of fraction C., in orga d D

These solvents are used in the amount of O ,, 03-1 mol / dm of water after visification. A change in the amount of reagent within the specified limits does not affect the efficiency of water softening. A further increase in the concentration of the aliphatic amine carbonate org anicheno by its solubility, the Use of amine carbonate solutions with a concentration of less than 0.03 mol / dm

3

leads to a decrease in the effectiveness of the mind.

The studied dependence of the precipitation of calcium ions on the pI of the source water suggests that the most complete removal of calcium ions from water occurs at a pH greater than 8, which is typical of water after liming. In this case, the residual content of calcium ions after treatment with a solution of aliphatic amine carbonate does not exceed 10% of its content in the source water.

The advantages of the proposed method compared with the known when taI

2.2 5.32 1.44 0.17

Editor N. Gunko

Compiled by V. Bilinska

T. Fried M. Khodanich Proof-reader V. But ha

Order 3054/19 - Circulation 864 Subscription

V1ShSh1I USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

358254

However, the residual Ca concentrations are that, when treating water under the specified conditions, the salinity of the purified water does not increase due to the extraction of sulphate ions and the efficiency of the process of softening hard wastewater increases.

10 The proposed method is also of ecological importance, especially in the complex processing of saline wastewater from enterprises of the ferrous metallurgy, chemical industry and energy.

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Claims (3)

1. METHOD OF WATER SOFTENING, including liming, treatment with a chemical reagent containing carbonate ions, separation of precipitation, characterized in that, in order to reduce the mineralization of water and increase the efficiency of the process, carbonate of aliphatic amines of the Cd-C fraction is used as a 'chemical reagent ₁₆ in an organic solvent. 2. The method of pop. 1, characterized in that the carbonate of aliphatic amines of the C & —C _1e fraction in an organic solvent is used in an amount of 0.03-1.0 mol / dm ^{3 of} water after liming. 3. The method according to claims 1 and 2, characterized in that kerosene, chloroform, carbon tetrachloride are used as an organic solvent. SU .1235825