SU891578A1 - Method of purifying waste water from selenium - Google Patents

Description

one

The method relates to the treatment of wastewater and can be used to remove selenium and other impurities from wastewater and dilute solutions of non-ferrous metallurgy and other industries.

A known method of purifying aqueous solutions from selenium is that silver ions are introduced into a solution containing selenium in a 2-fold molar amount relative to selenium, then acidified to pH 2 and iron powder is added. As a result, silver and selenium O are reduced and precipitated.

The disadvantages of the method are the use of expensive silver salts, the consumption of acid to create the required pH value of the medium and the insufficient degree of purification of the solution.

There is also known a method based on the introduction of manganese dioxide into the solution in the presence of hydrogen peroxide at pH 3-5. As a result of the purification, a residual selenium concentration of 10 mg / l C2 is achieved.

The disadvantage of the method is the high consumption of expensive reagents, such as manganese dioxide and hydrogen peroxide, and the need to create a pH in the range of 3-5.

The closest in technical essence to the invention is a method

10 of wastewater treatment with salts of iron and copper, in which purification is carried out by adding iron salt to wastewater twice a molar amount relative to the village and adding salt at a pH of 3-5 in between 0.5-1 multiple molar amount. Deposition of oxidized hydroxide of iron, selenium and copper is carried out at 2Q pH 5-6. The degree of purification solutions 60-80 3.

The disadvantages of the method are insufficient depth of wastewater purification from selenium, additional consumption of 3 reagents to create the required pH value of the medium and pollution of wastewater with toxic copper ions, cleaning up to MPC is a difficult and technical task and leads to a significant increase in the cost of the process. The purpose of the invention is to increase the depth of wastewater purification from selenium. This goal is achieved by introducing metallic iron into the waste water and treating it with atmospheric oxygen and sulfurous anhydride. Preferably, treat the waste water with sulfuric anhydride in the amount of mg / l. The method is carried out as follows. To the column equipped with an air dispersant, water containing selenium is poured, iron scrap is charged, 5-30 mg / l of sulfur dioxide is introduced, after which air is blown through the solution for 60 minutes. The precipitate obtained is settled and then separated. Example. 200 ml of a solution containing 0.5 mg / l of selenium is poured into the column, iron scrap is loaded and 10 mg / l of sulfur dioxide is added. Air flow 1.0 l / min, OH 3. The solution is purged with air for 60 minutes. After settling for 2 hours, the decantate contains 0.002-0.001 mg / l selenium. The table presents comparative data on the purification of waste water containing selenium after purification, according to the method known and proposed.

Claims (2)

Claim 1. A method of treating wastewater from selenium, comprising treating with an iron-containing reagent, characterized in that, in order to increase the degree of purification, the wastewater is treated with atmospheric oxygen and sulfur dioxide, and metal iron is used as 40 iron-containing reagent. 2 “The method according to claim 1, available in that the wastewater is treated with sulfur dioxide in the amount of 5“ 30 mg / l.