SU1608133A1 - Method of cleaning waste water from aliphatic amines - Google Patents

Abstract

The invention relates to methods of ion-exchange wastewater treatment from aliphatic amines in the enrichment processes of non-ferrous, heavy and rare metals, where amines are used as flotation agents. The aim of the invention is to more completely remove the amines in solution. Wastewater treatment is carried out by treatment with cation exchangers, then sequentially regenerating the cation exchanger, first with sodium chloride solution, then with 3-5% sodium hydroxide solution, passing from top to bottom solutions, then removing the amines by supplying water to counter cation exchanger. The method provides an increase in the degree of desorption of amines 9.8-9.9 times compared with the prototype

a significant simplification of the technology for the utilization of desorbed amines and a reduction in the consumption of reagents and the possibility of utilization of an alkali solution for repeated regenerations. 1 hp f-ly, 1 tab.

Description

The invention relates to ion exchange wastewater treatment and can be used in the treatment of waste water from aliphatic amines in the enrichment processes of nonferrous, heavy and rare metals, where amines are widely used as flotation agents, as well as in rubber, textile , chemical-pharmaceutical, polymeric materials, pesticides, synthetic rubber for sewage treatment from aliphatic amines.

The purpose of the invention is a more complete extraction of amines in solution.

The method is carried out as follows.

Wastewater containing aliphatic-. Concentrated amines at concentrations of 20–80 mg / l are treated in fixed-bed cation-exchange filters. To ensure the degree of purification of circulating water up to 1 mg / l, at concentrations of amine before purification of 40-50 mg / l, a sulfo-coal cation exchanger is used, which has a capacity in relation to amines of 272 g-eq / m and is the least expensive with a synthetic synthetic cation exchanger with a sorbent, the fougol ensures the duration of the operation of the facilities with the given parameters for 20-25 hours. At higher concentrations of amines, the use of cation exchanger is advisable & KU-23 type based on macroporous styrene-divinylbenzene matrix, the capacity of which is 1.5 times higher than that

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allows to provide the necessary degree of sewage treatment.

The speed of waste water through a fixed layer of cation exchanger is maintained within 4-10 m / h. Increasing the filtration rate above 10 m / h impairs the amine absorption conditions, as the contact time of water decreases and the cleaning effect decreases. Low transmission rates, i.e. less than 4 m / h, are unacceptable under production conditions of the factory where there are significant costs of recycled water.

The spent cation exchanger is sequentially regenerated with an 8–12% solution of sodium chloride by direct filtration through the cation exchanger from top to bottom at a speed of 4–6 m / h and a specific flow rate of 4–5 cation exchangers, then 3-5% ng. sodium hydroxide solution by direct filtration through the cation exchanger from top to bottom at a speed of 1-2 m / h with a specific flow rate of 2.0-2.5 cation exchanger. I Preliminary treatment with sodium chloride is necessary because the partial absorption of Ca and Mo ions from wastewater by cationite causes them to be expelled into the amino-containing solution during regeneration with caustic soda and contaminated with the regeneration solution and wash water. In addition, treatment with sodium chloride solution is necessary to prevent calcium and magnesium hydroxides from clogging the cation exchanger.

When the cation exchanger is treated with a solution of caustic soda, a double process occurs: the desorption of amines and the transition of the amino groups to the neutral state. The regeneration product, a neutral amine, is deposited on the cation exchanger grains as a fine precipitate. The passage of the regeneration solution, the alkali must be conducted from the top down.

The use of caustic soda solution of 3-5% concentration provides the maximum effect of regeneration of the cation exchanger. A decrease in the concentration of the applied solution worsens the desorption of the amine, thereby reducing the degree of its utilization. An increase in this concentration is impractical because in this case the specific value of the desorption substance per unit of the regeneration solution decreases.

The specific consumption of alkali for effective regeneration should be 2.0 - 2.5 m / t. Increase in svpie 2, .5 m / t

ten

five

0

five

0

five

0

five

0

five

does not increase the effect, and liish to additional consumption of the reagent. The data presented in the table.

The alkali solution used contains almost no regeneration products. The concentration of amine in it does not exceed 0.02 mg / l; therefore, it is collected and reused in subsequent regenerations of cation exchangers. A fine precipitate of neutral amine remains in the body of the cationite charge.

The desorbed amines are removed by washing the cation exchanger with clean water, passing water in a countercurrent, i.e. from the bottom up with a flow rate of 8 - 10 l / s m. The specific consumption of wash water 48 cation exchanger. The first 20-25% of the total wash water is separated and disposed of as a 0.8% strength solution of aliphatic amine and sent for reuse to the main production. The rest of the wash water in the amount of 75-80% of the total volume, containing amine not higher than 4 mg / l, is reused during the operation of washing the cation exchanger. PRI me R. Sewage water from a quartz concentrator containing 80 mg / l of aliphatic amines is treated with a cation-exchange filter (cation exchanger KU-23). The spent cation exchanger is regenerated in the following phase: 10% sodium chloride solution is directly filtered through a cation exchanger from top to bottom at a speed of 5 m / h and a specific consumption of 5 cation exchanger; A 3% sodium hydroxide solution is directly filtered through the cation exchanger at a speed of 2 m / h with a specific flow rate of 2, cation exchanger. The desorbed amines are removed from the cation exchanger by washing with clean water. m specific consumption of 48 cation. The first 25% of the total wash water is separated and disposed of as a 1% aliphatic amine solution and sent for reuse to the main production.

The use of the proposed method allows to achieve the almost complete removal of highly toxic aliphatic amines from wastewater at their concentrations in the range of 20-8 ° C) mg / l and makes it possible to ensure

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non-waste process technology. According to the proposed method, the extraction of amine is 9.8-9.9 times more than the known. The degree of desorption of the proposed method is 98.0-99.0%.

Claims (2)

1. The method of sewage treatment from aliphatic amines, including their treatment on cation exchangers, regeneration of cation exchangers, extraction of amines in solution, about t and t 336 In order to extract the amines more completely, the regeneration of the cation exchangers is carried out by sequential treatment of the cation exchangers from top to bottom with sodium chloride solution and sodium hydroxide solution, while removing the amines into the solution by countercurrent treating the cation exchangers with water. 2. A method according to claim 1, characterized in that a 3-5% solution of caustic soda is used with a specific consumption of 2-2.5 cation exchangers.