SU1733393A1 - Method of purifying chromium-containing effluents - Google Patents

Abstract

The invention relates to the purification of galvanic production effluent, in particular, to methods for purifying chromium-containing effluent, and contributes to an increase in the duration of the interregeneration period of sorbents. Chromium containing effluents are pretreated on a mechanical filter, then sorption is carried out on the cation exchanger and the anion exchanger in the OH form, followed by regeneration of the sorbents. In this case, the cation treatment is carried out on a carbon sorbent treated with 7–9% boiling sulfuric acid. 1 hp f-ly, 1 tab.

Description

The invention relates to the purification of galvanic production effluent, in particular, to methods for purifying chrome-containing waste.

A known method of purification of chromium-containing drains, including the supply of chromium-containing drains to the cation-exchange filter, the subsequent supply of the solution to the anion-exchange filter, the return of the purified solution to production. With the appearance of chromium in the amount of 8-10 mg / l in the purified solution, the sorbents are regenerated.

The disadvantage of this method is the low service life of the filters before regeneration, due to the limited capacity of the used sorbents - synthetic resins, and their relatively limited service life (mostly 7-8 years) and, as a result, the need to frequently stop the treatment plants. filter regeneration is a big consumption of chemical reagents, simple equipment, time spent on installation and dismantling of equipment, reducing the volume of purified solution, resulting in reduced performance of treatment plants

The aim of the invention is to increase the duration of the inter-regeneration period of the sorbents, as well as reduce the consumption of chemical reagents for the regeneration operation.

PRI me R 1. Purification of chromium-containing drains according to the traditional scheme (in this case, the first filter is filled with cation exchanger KU-2-8 ion exchange resin, and the second filter is filled with AN 18-10P ion exchange resin): the spent aqueous solution is fed along the line vents x. The feed rate of the solution is 400 l / h. The chromium content in the waste wash water is 40 mg / l. Duration of cleaning 16 h / day. After two weeks (ten working days), the chromium content in the purified water at the outlet of the purification plant reached 10 mg / l. The installation is stopped on the regeneration of the anion filter according to the known scheme. After the first regeneration, the unit worked again for 10 days. The chromium content at the exit of the installation again reached 10 mg / l and the anion-exchange filter was subjected to regeneration a second time. This procedure was carried out for 20 working weeks. In this case, the initial content of chromium in the wash water fluctuates

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Elk in the range of 30-50 mg / l. The duration of the cleaning cycle until the chromium content at the exit from the purification plant of 10 mg / l was 9-10 working days. Throughout the test period, the flow rate of the spent solution was 400 l / h.

PRI mme R 2. Purification of chromium-containing drains by the proposed method. The flow pattern of the spent wash water is similar to approx 1. The solution feed rate is 400 l / h. The unit operates 16 hours a day. The chromium content in the spent aqueous solution ranged from 30 to 50 mg / l. At the same time, the chromium content of 10 mg / l at the exit from the unit reached only after 35 working days. After this, the first regeneration of the anion-exchange filter was carried out according to the same scheme. Then a second chromium-containing effluent cleaning cycle was carried out, which lasted 28 working days. From the third to the ninth cycles, the continuous plant operation time was 25 working days. The tenth cycle lasted 23 business days; the eleventh is 20 working days, the twelfth is 14 working days, the thirteenth is 10 working days, the fourteenth is 10 working days: the fifteenth is 9.5 working days.

After the fifteenth cycle, the carbon sorbent was also regenerated.

After regeneration of the carbon sorbent, purification according to the described scheme was carried out again.

The results were almost identical. The test results are shown in the table.

Thus, the cleaning of chromium-containing drains according to the proposed method increases the inter-regeneration cleaning period by more than 2 times.

Claims (2)

1. A method for purification of chromium-containing drains, including their pretreatment on a mechanical filter, sorption on cation exchanger, anion exchanger in OH form, regeneration of sorbents, characterized in that, in order to increase the duration of the inter regeneration period of the sorbents, cation resin treatment is carried out on a carbon sorbent treated 7–9% boiling sulfuric acid. 2. A method according to claim 1, characterized in that, in order to reduce the consumption of chemical reagents for the regeneration operation, the regeneration of the anion exchanger and carbon sorbents is carried out with a frequency of at least 10: 1. Table continuation Regeneration of the carbon sorbent was carried out.