SU617381A1 - Method of purification of waste water from fluorine - Google Patents

Description

one

The invention relates to wastewater treatment methods, in particular from fluorine, and can be used in the chemical and glass industries.

A known method for the purification of wastewater from fluorides, based on the binding of fluorine to poorly soluble compounds in the first purification stage, using lime milk, calcined dolomite and other compounds as a reagent. In the second stage, post-treatment is performed with aluminum salts and phosphates, for example, sodium phosphate or superphosphate.

The closest to the described invention by technical sufficiency and the achieved result is a method of purifying drinking water from fluorine, including its treatment with calcium-containing reagent and subsequent filtration of the treated water through an adsorbent - bentonite, pretreated with lime milk.

However, the known method does not allow the deep treatment of wastewater from fluorine due to the fact that the capacity of bentonite in fluorine is 29-36%.

The aim of the invention is to increase the degree of purification of wastewater from fluorine.

To do this, according to the proposed method, the water is treated with a calcium-containing reagent, followed by filtration through a pre-treated lime milk adsorbent, which uses a material selected from the group comprising volcanic tuff, oil shale, perlite or volcanic pumice.

The technology of the method is as follows. The water containing fluoride ions is fed to a neutralizer reactor, where lime milk is simultaneously introduced. After precipitation of fluoride ions in the form of calcium fluoride, the separated water is supplied to the second purification stage in an adsorption column filled with one of the proposed adsorbents: volcanic tuff or combustible shale, perlite or volcanic pumice.

In the adsorption column on the developed surface of the adsorbents, fluoride ions are sorbed to the maximum permissible concentration. When the concentration of fluorine in purified water reaches 1.5 mg / l and higher, the adsorbent is treated with lime milk. Wash water after regeneration of the adsorbent is directed to the first purification stage.

Example I. Water containing fluoride ions is fed to a neutralizing reactor, where lime milk is introduced. After the precipitation of fluoride ions in the form of calcium fluoride, separated water with a fluorine content of 10 mg / l is fed into the adsorption column with the adsorbent — a pre-treated lime milk with volcanic tuff of a fraction of 0.5-15 mm; fluorine adsorption capacity 95%. After soaking for 3 hours, the wastewater is discharged from the column, and the adsorbent is reused to clean new portions of the wastewater. During the test, five cleaning cycles were performed without regeneration of the adsorbent. The cleaning results are as follows:

Fluorine content, mg / l 0.5 0.7

1.1

1.5 1.8

Example 2. The purification is carried out under conditions of example 1, with the adsorbent combustible shale of a fraction of 0.5-15 mm; fluorine adsorption capacity 100%. The fluorine content in the treated wastewater is 0.1-1.5 mg / l.

Example 3. The purification was carried out under the conditions of example 1 with the adsorbent perlite fraction 0.5-3 mm. The fluorine content in the purified wastewater is 0.1-1.5 mg / l.

Example 4. Purification was carried out under conditions of example I with an adsorbent of volcanic minerals, the adsorption capacity was 97% fluorine. The fluorine content in the purified wastewater is 0.3-1.5 mg / l.

Claims (2)

1. Milovanov L.V. Wastewater treatment of non-ferrous metallurgy enterprises. M., “Metallurgists, 1971, p. 146-152. 2. Technologies for the purification of drinking water in Moscow. Sat, M., 1974, p. 73-87.