SU1274713A1 - Method of cleaning waste water of etching process - Google Patents

Abstract

The invention relates to the non-processing of waste from pickling, can be used in mechanical engineering and other industries, and allows an increase in the degree of purification. The goal is achieved by the fact that in a known method of sewage treatment of pickling, including treating wastewater with a reagent, separating sludge and treating wastewater in an electrodialyzer according to the invention, before introducing the reagent and separating sludge, purifying wastewater in an electrodialysis apparatus 5.0-6.0 cm / s, and carbon dioxide is used as a reagent. 1 h. apt. 2 tab.

Description

Yu

four

The invention relates to the treatment of pickling waste, which can be used in the machine-building and other sectors of the industry for the disposal of waste from pickling processes and passivation, namely, highly concentrated acidic effluents containing metal ions, such as chromium, zinc, magnesium, and calcium.

The purpose of the invention is poE) Feeding the quality of purification by removing heavy metal ions.

Research has shown that electrodalysis of highly concentrated acid wastewater containing heavy metal ions at a flow rate of 5.0-6.0 cm / s is 10 stars; 1 it is impossible to remove hydrogen ions from wastewater. Heavy metal ions; 1; Yuv of this speed do not enhance ironing through the electrodialysis membrane due to lower mobility and are removed from solution in the form of insoluble carbonates and heavy metal hydroxides as a result of interaction with flue gases to which carbon dioxide is added. The presence of carbon dioxide, nitrogen, etc. in the flue gases; With the simultaneous addition of carbon dioxide, it is necessary to make this mixture more reactive and to completely remove heavy metal ions from wastewater.

Example. Wastewater having a pH of 3 is fed to the anode chamber of a two-chamber ion-diaphragm electrolytic dialyzero. The flow rate of wastewater is 5.5 cm / s. At the outlet from the electrodialysis apparatus, the pH of the wastewater is 7. The cathode chamber is washed with running technical water, which is acidified, but does not require further neutralization. From the anode chamber flowing water is fed into the reactor. It maintains a pressure of 20 atm and a temperature of 25 ° C, necessary for the complete dissolution of carbon dioxide and flue gas in the waste water. Flue gas to which carbon dioxide is added is circulated to the reactor. The H: is carried out, with it, gas m. Moisture is separated in a condenser installed in the pipeline. Purified wastewater is fed from the reactor to the sump, where sludge is separated.

Similarly, tests are carried out at the rate of movement of wastewater through the electrodialysis apparatus 4.5; 5.0; 6.0; 6.5 cm / s. The test results are summarized in table. I.

Table 1

15000 2900

4.5

2.3 3.6 0.01 0.02 5.0

6.0 0.025 0.02 6.5 2.15 3.02 5.5 0.01 0.02

From tab. 1 that the quality of sewage treatment of etching production is the best at the speed of movement of the stop water in the electrodialyzer 5.0-6.0 cm / s.

1800

2.5

12.7

6.5

Not detected, Gzheno 7.1

0,0010,027,9

5,02,25,6

Not Detected Not Detected7.0 Rouge

The results of comparative tests of the proposed and known methods are summarized in table. 2

Source water

Proposed

the way

Famous

Claims (2)

method From table. 2 it follows that the proposed method has a higher quality of wastewater treatment - highly concentrated effluent than the known one. Thus, the use of the proposed method allows an increase in the quality of purification of highly concentrated acidic effluents by an average of 16 times. Claims. The method of purification of wastewater pickling, including processing table 2 1800 2300 0.086 0.073 waste water with a reagent, sediment separation and treatment in an electrodialyzer, characterized in that, in order to increase the degree of purification before introducing the reagent and separating the sediment, waste water is treated in the electrodialyzer with the latter being fed into the desalting chamber at a flow rate of 5.0 -6.0 cm / s, and carbon dioxide is used as a reagent. 2. A method according to claim 1, characterized in that carbon dioxide is introduced together with flue gases.