SU1736944A1 - Method of cleaning sewage from polymerization processes - Google Patents

Abstract

Use: wastewater treatment from polymers. SUMMARY OF THE INVENTION: Waste water containing polyvinyl chloride and a copolymer of vinyl chloride with tetrachlorethylene is treated with copper, iron or aluminum sulfate or ferric chloride, after which alkali is introduced at a ratio of 1: (0.1-4) and in an amount of 0.01 - 0, 5 wt.%. 4 tab.

Description

The invention relates to wastewater treatment and can be used in plants producing polymeric materials.

Methods for clarifying wastewaters of various industries are known, including the treatment with coagulants. For example, aluminum sulphate, cationic polyelectrolyte and cellulose are used sequentially to clean industrial wastewater.

There is also known a method for treating waste water from the production of latex and adhesives. It is carried out according to a complex scheme by sequential treatment of water with three reagents in separate containers with strict observance of the pH value: in the 1st tank with aluminum sulphate to a pH of 4.5; in the 2nd caustic soda to pH 6.5 and in the 3rd tank, flocculation is carried out using anionic and cationic electrolytes, followed by separation of the precipitate.

This clarification method has significant drawbacks; For a complex reagent mode with exact adherence to processing conditions, it requires cumbersome instrumentation, which makes it difficult to use in industry. The use of this method for the treatment of wastewater containing suspended polyvinyl chloride and similar resins is also limited.

The closest in technical essence and achieved results is the method of clarification of the waste water of the polymerization process by treatment with coagulant; lime is used as expensive. At the same time, phosphoric acid is used to adjust the pH, during the addition process which is fed first with cationic or non-ionic and then anionic

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water-soluble polymer. In fact, sequential treatment with lime, cationic and anionic flocculants is carried out.

This method of clarifying waste water has drawbacks: it does not give deep cleaning, most of the polymer remains in suspension; The known reagent mode includes the supply of four reagents, which is difficult to implement under industrial conditions, since a system is necessary to allow contact with each of them; Polymeric water soluble flocculants (cationic, anionic and non-ionic) used are scarce and expensive.

The purpose of the invention is to increase the degree of wastewater treatment and simplify the process.

In order to achieve this goal, the wastewater of polymerization processes is sequentially treated with reagents, which are salts of mineral acids and alkali at a ratio of 1: (0.1-4) and in an amount of 0.01-0.5 wt.%, With alkali being added t after salts of mineral acids. After deposition, the sediment is separated from the clarified layer by traditional methods.

The experiments were carried out on two types of wastewater polymerization processes, where the solid phase is represented by polyvinyl chloride ... CH2-CHCI.,. (hereinafter referred to as PVC) with a content of 245 mg / l and a pH of 9.6; and a copolymer of vinylchloride with tetrachloroethylene ... CH2-CHCI-CCl2-CCl2 ... (CTX3) with a content of 990 mg / l and a pH of 4.85.

As salts of mineral acids, copper sulfates (pH of 5% solution of 4.1), iron (pH of 5% solution of 3.2) and aluminum (pH of 5% solution of 3.85), ferric chloride (pH of 5% aqueous solution 1.95), alkali - caustic soda.

PRI me R 1. The waste water of STHE is treated successively with copper sulfate and caustic soda in a ratio of 1.1 with a total dosage of 0.2 wt.%. Received: the content of the suspended phase in the clarified layer mg / l, the degree of clarification, 5%.

PRI mme R 2. PVC wastewater after flotation processed on the proposed

method consistently with copper sulfate and caustic soda in the ratio of 1: 1 with a total dosage of 0.1 wt.%. Received: mg / l, 7%.

Froze The waste water of STHE is treated by a known method: lime at a dosage of 0.2 wt.%, Phosphoric acid 120 mg / l with simultaneous feeding of the cationic polymer VPK-402 in the amount of

100 mg / l, and then anionic polyacrylamide 25 mg / l. No stratification was observed on the clarified layer and sediment. With 560 mg / l, 3%.

EXAMPLE 4 PVC wastewater is treated in a known manner as in Example 3. No separation was observed in the clarified layer and sediment, mg / l, 9%,

The effect of salt ratio was determined.

mineral acid and alkali on the indicators of clarification (Table 1).

As can be seen from the results of Table 1, a positive effect is observed at a ratio of 1; (0.1-4).

The effect of the consumption of reagents at the optimum ratio (Table 2) was determined.

A positive effect is observed at a cost of 0.01-0.5 wt.%.

Examples of the effect of other salts of mineral acids are given in Table 3.

Another method of feeding or exposure of each reagent separately does not give a positive effect (Table 4).

The method allows to increase the degree

wastewater treatment of polymerization processes up to 98% with a significant simplification of the process, which is achieved by reducing the number of reagents used and eliminating water treatment with expensive flocculants,

Claims (1)

The invention The method of purification of wastewater polymerization processes by sequential introducing reagents, precipitating and separating a precipitate, characterized in that, in order to increase the degree of purification and simplify the process, mineral salts and alkali at a ratio of 1: 0.1 - 4 and in an amount of 0.01-0.5 wt.%, and the alkali is introduced after salts of mineral acids. Table 1 The effect of the ratio of copper sulfate and caustic soda on the clarification of waste water STHE at a dosage of 0.2 May. % table 2 Effect of consumption of copper sulfate and caustic soda at a ratio of 11 to the clarification of waste water STHE The effect of sequential processing of various salts mineral acids and caustic soda at a ratio of 1: 1 and consumption 0.2 May. % for clarification of waste water STHE The effect of different methods of feeding copper and alkali sulphate with a total dosage of 0.2 May. % and the ratio of 1: 1 and individual reagents for clarification of waste water STHE Table 3 Table 4 Continued table. four