SU994426A1 - Process for purifying water from dispersed activated coal - Google Patents

Description

The invention relates to wastewater treatment and can be used to purify aqueous solutions of activated carbon used to extract precious metals from wastewater, for example, UAF (activated carbon flotation), as well as dispersed substances in the chemical, coal and metallurgical industries. The known method of sewage treatment involves the addition of magnetic powder, iron, flocculant, and the subsequent magnetic separation of G11 into the water. The method allows to increase the cleaning rate by about 2 times, however, the degree of cleaning at the same time practically does not increase. The closest to the proposed technical essence and to the achieved result is a wastewater purification list by electrolytic coagulation in the presence of flocculant with subsequent sedimentation. The disadvantage of this method is the low purification rate. The purpose of the invention is to increase the degree of purification and increase the rate of sedimentation. The goal is achieved by the fact that electrocoagulation in the presence of polyacrylamide is carried out with the application of an external magnetic field of 200-800 Oe with the introduction of magnetite particles with a particle size of up to 1 Mm with stirring at a speed of 16-85 rpm, and 1.0-2.0 mg / l and 0.51, 5 g / l. . , The application of this method allows to obtain by electrocoagulation heavy floccules, almost completely capturing dispersed impurities and having a high deposition rate. Magnetite particles with a particle size of up to 1 mm are used in connection with the fact that heavier magnetite particles are not retained in agglomerates. Magnetite is introduced into the electrocoagulant of a cylindrical formula containing a precipitated substance (active carbon) with constant stirring and a

electrocoagulation with continuous supply of polyacrylamide.

Electrocoagulator in a magnetic field.

In this case, the formation of bulk heavy flakes up to 15 mm in diameter, which completely capture the active coal, is observed.

The role of the magnetic field is to magnetize the magnetite particles, which due to the residual magnetism interlock with each other and form spatial aggregates, the strength and size of which increase in the presence of flakes of bivalent iron hydroxide and polyacrylamide.

It should be noted that the strength and size of the formed conglomerates largely depend on the number of revolutions of the stirrer.

If, during the electrolytic coagulation process, the mixing rate is small (n 16 rpm), a part of the magnetite precipitates and is not included in the structure of the aggregates; at p 85 rpm, flakes are destroyed, their size decreases to 1-2 mm, and with it the degree of sedimentation of active carbon particles decreases.

When the electrocoagula process is carried out by this method, the polyacrylamide feed rate is significant. The feed rate of the polyacrylamide solution is adjusted so that its consumption is 1.02, 0 mg / l of the solution to be purified.

With a lower consumption of polyacrylamide, the technological indicators for the illumination of the solution are sharply reduced. Higher consumption does not improve the process and is not profitable for economic reasons.

The intensity of the magnetic field also Ht-raet a significant role in the implementation of the proposed method. The effect of a magnetic floccule begins to appear at the intensity of a magnetic field of a system of 200 Oe and reaches a maximum at a intensity of 600 Oe.

With an increase in the magnetic field strength up to 1000 Oe, a magnetic stopper is formed in the electrocoagulator and the passage through the system of the formed conglomerates deteriorates. With a voltage of 100 e of a magnetic field, the effect of magnetic flocculation is almost absent.

Example 1. Purified solution containing mg / l:, 0; , 0; Ca2 + l470.0; NaJ 1250.0; HCOg 170.0; SG 320.0; 504,130.0; CN 950.0; active carbon (UAF) with a particle size of 40 μm (1500 mg / l) at pH 8.9 and placed in a cylindrical electrocoagulant placed in a magnetic field and equipped with aluminum electrodes with a surface area of 0.2 dm2.

Magnetite 1.5 g / l is injected into the electrocoagulator with constant stirring (rpm) and with a continuous supply of polyacrylamide 2.0 mg / l, current density 4 A / dm and magnetic field strength of 600 Oe are electrocoagulated within 5 min.

The data on the implementation of the known and proposed methods for various values of operating parameters (speed of transfer: mixing, particle size of magnetite, consumption of polyacrylamide, strength of the magnetic field) are given in the table.

0-0.1 0-0.1 0-0.1 0-0.1 0-0.1 0-0.1

ABOUT

1,4 1,4

O O O O O O 10.7 14.4 15.1 15.1

It follows from the tables that the implementation of electrocoagulation by the proposed method allows a several times increase in the speed of coal flaking, while the optimal operating parameters are not within the range of flow rate of 1.0-2.0 mg / l of purified oil, the size of magnetite particles up to 1 MMf; magnetic magnetic flocculation intensity 200-800 Oe; the rate of agitation of magnetite and polyacrylamide with the solution to be purified in the course of electrocontact 16–85 rpm. ; In this case, according to this method, the deposition rate I increases to

2.0 cm7s. The degree of purification is 98.0%,

The deposition rate of activated carbon according to the method of the prototype was -; is 0.34-0.36 cm / s. The degree of purification does not exceed 94.0%.

Thus, the main advantage of the invention is to increase the deposition rate by 5-6 times and 9% of cleaning by 4.0%.

Claims (2)

Invention Formula The method of water purification from dispersed activated carbon, including 7 994426.8 The electrocoagulation present in the presence of polyacrylamide and magnetite constitutes polyacrylate amide and settling, the p t is 1.0-2.0 mg / l, respectively, and characterized by the fact that C0.5-1.5 g / l. the purpose of increasing the degree of purification and sources of information, increasing the rate of settling, elec. The trocoagulation taken into account during the examination is carried out at the application of 1. Japan Patent 52-25586, external magnetic field 200-800 Ecl. In 03 C 1/00, 1977. with the introduction of large-sized magnetite particles 2. USSR inventor's certificate up to 1 mm under mixing with sk-no. 444404, cl. C 02 F 1/46, 1977 (16–85 rpm, with the number-totip).