SU1154216A1 - Method of removing fluorine from waste water - Google Patents

Abstract

1. METHOD FOR CLEANING WASTE WATER from fluorine, including electrical treatment and a soluble aluminum anode, characterized in that, in order to increase the degree of purification and speed up the process, electrical treatment is carried out in the presence of a polyvinyl acetate emulsion. 2. Method POP.1, characterized in that the polyvinyl acetate emulsion is introduced in an amount of 5-20 mg / l of purified water.

Description

ate

4 1C

The invention relates to the purification of industrial wastewater, in particular the water from the mines of the fluorite-spar subsector from fluorine.

A known method of purification of wastewater from fluorine by treating them with a mixture of liquid glass and aluminum sulphate. The method is based on the precipitation and sorption of fluorine by the precipitated silica precipitate (sol).

The disadvantage of this method is that water purification from maximum permissible concentrations (л1.5 mg / l) of fluorine is achieved only with one component ratio of 1: 3 during the formation of active sol, which, under production conditions, makes it difficult to obtain stable results. The cleaning rate decreases as the temperature of the treated water decreases, and the adsorption capacity of the sol decreases when the sediment is stored for more than a day.

The closest to the technical essence of the invention is a method of electrochemical treatment of wastewater from fluorine with A-anode at a current density of IQ, 0.35-1.5 A / dm, cleaning time 1-8 ml / min

The disadvantage of this method is its low productivity.

The aim of the invention is to increase the degree of purification of water from fluorine and accelerate the process.

The goal is achieved by the fact that according to the method of purification of water from fluorine, which includes electrical treatment with a soluble aluminum anode, electrical treatment is carried out in the presence of polyvinyl acetate. emulsion.

In addition, the polyvinyl acetate emulsion is preferably administered in the amount of 5-20 mg / l of water to be purified.

The method is carried out as follows.

Wastewater from mine mines, fluoride ions, is subjected to electrolysis in the presence of a soluble aluminum anode at a current density of 1o, 0.5-2.5 A / dm2, 3-8 in the presence of 520 mg of polyvinyl acetate emulsion / l of purified water. The analysis of fluorine in water before and after its treatment is carried out by a potentiometric method using a fluoride selective method.

electrode. At the same time, they monitor the transparency of the water. Water treatment leads to deep purification of water from fluorine.

The choice of the interval, 5-8 during the purification of wastewater from fluorine, is related to the fact that in this pH range the content of anodic-dissolved aluminum in purified water does not exceed 1 mg / l, while the content of A in the solution reaches 12 mg / l and is a source of re-contamination of water.

PVA, which is introduced in the form of a 2% aqueous solution in an amount of 520 mg / l, promotes the complete precipitation of fluorine with aluminum hydroxide at a high rate.

Introduction of PVA in an amount of less than 5 mg / l impairs purification rates, and more than 20 mg / l is impractical.

The current density is limited to 0.5–2.5 A / dm due to the fact that at lower current densities, the cleaning rate is low, and at higher densities, water is strongly heated.

The results of experiments on the treatment of wastewater from fluorine without the introduction of PVA and in its presence are presented in the examples.

Example 1. Processing is subjected to mine-water with an initial fluorine content of 9.66 mg / l. The electrolysis is carried out at a current density of 0.5 A / dm, 35 in the presence of PVA in an amount of 5 mg / l. The cleaning rate of 6.6 ml / mi residual fluorine content is 0.53 mg / l. The degree of purification of water from fluorine is equal to 94.5%.

Example 2. The treatment is subjected to the same solution and under the same conditions as in Example 1, only without introducing PVA into the purified water. The residual fluorine content at a purification rate of 6.6 ml / min is 2.45 mg / l. The degree of purification is 74.6%.

Example 3. Processing is subjected to mine water with an initial fluorine content of 5.75 mg / l at a current density of 2.5 A / dm and 4 in the presence of PVA in an amount of 20 mg / l.

With a basic fluorine content of 55 0.98 mg / l, the purification rate is 6.3 ml / min. The transparency of the water layer (after a standing time of 1 hour) is 30.0 / 100 (cm /%).

An example. Under the same conditions as in example 3, but without the introduction of PVA with a residual fluorine content of 0.96 mg / l and a transparency of the water layer of 30.0 / 100 (cm /%), the purification rate is 5.0 ml / min.

From the above examples, it follows that due to the introduction of PVA in the amount of 5-20 mg / l of purified water, the degree of purification of water from fluorine and the purification rate increases by approximately 1720%.

PVA does not impair the transparency of water, completely settled with the precipitate Ae (OH) s.

The advantages of the proposed purification method in comparison with the known ones completely precipitated with aluminum hydroxide precipitate; purification of water does not lead to a significant change in the pH of the mine water and, accordingly, does not require additional administration of the reagent to neutralize it.

Claims (2)

1. METHOD FOR CLEANING WASTE WATER FROM FLUOR, including electrical treatment with a soluble aluminum anode, characterized in that, in order to increase the degree of purification and speed up the process, the electrical treatment is carried out in the presence of a polyvinyl acetate emulsion. 2. The method according to claim 1, characterized in that the polyvinyl acetate emulsion is administered in an amount of 5-20 mg / l of purified water. >