RU2376248C1 - Method of removing suspended particles from liquids and device for removing suspended particles from liquids - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: to realise the method, sludge is flocculated with finely dispersed ferromagnetic material and acidified. The flocculant used is an aqueous magnetic liquid with the following composition, wt %: iron (II) sulphate FeSO₄ - 3-3.5; iron (III) sulphate Fe₂(SO₄)₃ - 6-6.5; ammonium hydroxide NH₄OH - 18-22; sodium oleate C₁₈H₃₃O₂₂Na - 1.2-1.7; water - the rest. The solution is acidified to pH 7.5-8.5. The device for realising the method has a tank, inlet pipes for contaminated liquid and outlet of clarified liquid. Inside the tank there is a filtering drum screen, inside of which there is a fixed cylindrical frame, along the generatrices of which are attached permanent magnets with formation of zones which are free from these permanent magnets and are in form of a sector with angle α≈30°-60°. In the zone which is free from permanent magnets, a knife scrapper is pressed to the drum, the other end of the said scrapper of which is linked to a bin for collecting sludge. Inside the drum in the zone free from the permanent magnets, after the knife scrapper there is a pipe carrying washing liquid with sprayers. A holder is fitted in front of the pipe carrying liquid.

EFFECT: easier obtaining magnetic flocculant, possibility of continuous purification of liquid with simultaneous regeneration of the filtering element.

7 cl, 2 dwg

Description

The invention relates to the field of protection of the hydrosphere, in particular to methods and devices for wastewater treatment from suspended particles, and can be used in engineering, chemical, construction and other industries.

Known methods for treating wastewater from mechanical impurities in magnetic filters equipped with a permanent magnet or electromagnet, which are used to remove small ferromagnetic particles with sizes of 0.5-5 microns. As filter elements use a load of ferromagnetic granules with a size of (1-3) mm (D.A. Krivoshein, P.P. Kukin, V.L. Lakin and others. Engineering protection of surface water from industrial effluents. Training manual. M. : Higher School. 2003-344 p., Pp. 109-110) - [1]. This magnetic cleaning method is only suitable for cleaning ferromagnetic contaminants.

There is a method of purification of electrolyte from sludge during dimensional electrochemical processing (Author's certificate No. 1399032, publ. Bull. No. 20 from 05.05.88) - [2], according to which the sludge is flocculated by adding highly dispersed ferromagnetic material to the electrolyte and acidification of the electrolyte to pH 3- 4 by the addition of hydrochloric, sulfuric or nitric acid.

A device for implementing the method is a tank with inlet and outlet pipes. Extraction of the flocculated sludge is carried out by an electromagnet enclosed in a stainless steel shell by immersion in a container.

When implementing the method, iron oxide, barium and strontium ferrites are used as a ferromagnetic material, and carboxymethyl cellulose sodium salt, polymethacrylic acid sodium salt, carboxymethyl cellulose, methyl cellulose, polyvinyl alcohol, and casein are used as flocculants. An aqueous solution of the flocculant is prepared by soaking it in water, highly dispersed ferromagnetic material is introduced with stirring, and then this composition is acidified with acid to pH 3-4.

The technology presented is complex and multi-stage. Another disadvantage is the technology for extracting flocculated pollutants by immersion in a solution of an electromagnetic device. Due to this, the device is a batch device, in addition, with large volumes of cleaned liquid and a significant mass of recoverable sludge, it is necessary to have a special mechanism for immersing, removing and transporting the electromagnetic device to another container.

The technical result to which the claimed invention is directed is to simplify the cleaning technology and expand the range of use for continuous cleaning of liquids with the regeneration of the filter element.

The technical result is achieved by the fact that in the method of purifying liquids from suspended particles, according to which sludge is flocculated with highly dispersed ferromagnetic material and acidified, it is new that an aqueous magnetic fluid prepared on the basis of iron sulfates Fe (II) and Fe ( III) in an aqueous solution with the addition of ammonium hydroxide and sodium oleate, while the components are taken in the following composition, wt.%:

iron sulfate Fe (II) - FeSO ₄ 3-3.5 iron sulfate Fe (III) - Fe ₂ (SO ₄ ) ₃ 6-6.5 ammonium hydroxide NH ₄ OH 18-22 sodium oleate C ₁₈ H ₃₃ O ₂₂ Na 1.2-1.7

the rest is water.

The acidification of the solution is carried out until a pH of 7.5-8.5 is reached.

In the device for purifying liquids from suspended particles, containing a tank, a supply pipe for contaminated liquid and a discharge pipe for clarified liquid, the novelty is that inside the tank there is a filter mesh drum with the possibility of rotation, inside which there is a fixed cylindrical frame along which constants are fixed permanent magnets with the formation of a zone free of these permanent magnets.

The zone free of permanent magnets is a sector with an angle α≈30 ° ÷ 60 °.

A knife scraper is pressed to the filter mesh drum in a zone free of permanent magnets, the other end of which is connected to the sludge collection hopper.

Inside the drum in a zone free of permanent magnets, in the direction of rotation of the drum, there is a flushing fluid pipe with nozzles.

In front of the nozzle for supplying contaminated liquid, a reflector is installed inside the tank.

The invention is illustrated in figure 1, figure 2, where:

figure 1 - device for cleaning liquids from suspended particles.

figure 2 - device for cleaning liquids from suspended particles.

Here: 1 - tank; 2 - nozzle for supplying contaminated liquid; 3 - reflector; 4 - filter mesh drum; 5 - permanent magnets; 6 - knife scraper; 7 - sludge collection hopper; 8 - pipe washing fluid with nozzles; 9 - pipe discharge clarified liquid; 10 - nodes of rotation.

The device for cleaning liquids from suspended particles is a rectangular tank 1 with a pipe for supplying contaminated liquid (supply pipe) 2, in front of which a reflector 3 is installed inside the tank 1. A filter mesh drum 4 is mounted in the tank 1 for rotation, inside which there is a fixed frame, which generators are located permanent magnets 5 in the form of plates. Magnetic plates 5 are installed with the formation of a zone free of magnetic plates in the form of a sector with an angle α≈30 ÷ 60. In the area of sector α, a knife scraper 6 is pressed against the filter drum 4, the other end of which is connected to the hopper for collecting sludge 7. In the same area of sector α, a pipe 8 with nozzle openings is installed on the inside of the drum 4. The filter drum 4 is installed in the nodes of rotation 10 and is driven in rotation from an external drive (not shown).

The device operates as follows.

The liquid to be cleaned is pre-mixed with a flocculant prepared on the basis of magnetic fluid and fed to tank 1 through a nozzle for supplying contaminated liquid 2. Procedure for preparing an aqueous magnetic fluid: a solution of iron sulfate Fe (II) - FeSO ₄ is prepared in distilled water in a concentration of wt.% - 3-3.5%, iron sulfate Fe (III) - 6-6.5%. The resulting solution is mixed with ammonium hydroxide NH ₄ OH - 18-22% with vigorous stirring. The resulting black suspension is washed several times, holding the precipitate until the pH of the solution reaches 7.5-8.5. The resulting mixture is subjected to magnetic treatment to obtain magnetic flocs. After that, the resulting mixture was filtered and the resulting condensed suspension was mixed with 1.2-1.7% sodium oleate C ₁₈ H ₃₃ O ₂₂ Na with heating not higher than 80 ° C. The obtained magnetic flocculant is mixed with waste water in a ratio of 10-20% (wt.), Depending on the type and concentration of suspended pollutants.

The flow of water from the nozzle for supplying contaminated liquid 2 enters the reflector 3, which prevents direct liquid from entering the filter screen 4. The liquid fills the tank 1 to a level not reaching the pipe 8 with nozzles. The filter mesh drum 4 begins to rotate in the nodes of rotation 10 from an external drive (not shown). The direction of rotation of the drum 4 is chosen so that the adherent layer of sludge on the drum crawls onto the knife scraper 6. Under the influence of the pressure drop in front of the mesh drum and inside the drum 4, the liquid to be cleaned from the tank 1 begins to pass through the mesh into the drum. The slocculated sludge is retained on the grid 5 due to the action of magnetic forces generated by the magnetic plates 5. Due to the rotation of the mesh drum 4, a layer of adhering sludge comes out of the liquid and, running onto the knife scraper 6, is collected in the sludge collection hopper 7. Simultaneously with the start of the cleaning process and by rotating the filter mesh drum 4 into the pipeline of the washing liquid 8, the washing liquid begins to be supplied, which, flowing through the nozzles, cleans the filter mesh of the drum 5, which, immersed in the liquid during rotation b Arabana, again included in the cleaning process. The purified liquid is continuously discharged through the outlet pipe of the clarified liquid 9.

Thus, the proposed method and device can simplify the cleaning technology, expand the range of use and carry out continuous cleaning of the liquid with the regeneration of the filter element.

Claims (7)

1. The method of purification of liquids from suspended particles, which carry out flocculation of sludge with highly dispersed ferromagnetic material and acidification, characterized in that the flocculant is an aqueous magnetic fluid prepared on the basis of iron sulfates Fe (II) and Fe (III) in an aqueous solution with the addition of ammonium hydroxide and sodium oleate, while the components are taken in the following composition, wt.%:
iron sulfate Fe (II) - FeSO ₄ 3-3.5 iron sulfate Fe (III) - Fe ₂ (SO ₄ ) ₃ 6-6.5 ammonium hydroxide NH ₄ OH 18-22 sodium oleate C ₁₈ H ₃₃ O ₂₂ Na 1.2-1.7 rest water. 2. The method according to claim 1, characterized in that the acidification of the solution is carried out until a pH of 7.5-8.5 is reached. 3. A device for cleaning liquids from suspended particles, containing a tank, a nozzle for supplying contaminated liquids and a nozzle for draining clarified liquids, characterized in that the filter screen drum is rotatable inside the tank, inside which there is a fixed cylindrical frame along which constants are fixed permanent magnets with the formation of a zone free of these permanent magnets. 4. The device according to claim 3, characterized in that the zone free of permanent magnets is a sector with an angle α≈30 - 60 °. 5. The device according to claim 3, characterized in that a knife scraper, the other end of which is connected to the sludge collection hopper, is pressed against the filter screen drum in a zone free of permanent magnets. 6. The device according to claim 3, characterized in that inside the drum in the area free of permanent magnets, after the knife scraper in the direction of rotation of the drum, there is a washing fluid pipeline with nozzles. 7. The device according to claim 3, characterized in that a reflector is installed inside the tank in front of the nozzle for supplying contaminated liquid.

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