RU2636727C1 - Device for fluid aeration - Google Patents

Abstract

FIELD: machine engineering.SUBSTANCE: device for fluid aeration contains an aerated fluid capacity, bounded by partitions, a gas storage capacity, open toward the bottom of the capacity of the aerated fluid, a jet directional nozzle located in the gas storage capacity, fluid supply hoses, hoses for gas supply, pipes to drain the gas. In addition, the device comprises an oscillation source connected to a gas storage capacity that allows the dispersion of initial gas bubbles to be created as required by the technology. The capacity of the aerated fluid contains not less than 3 partitions, which form separation chambers of gas bubbles between each other.EFFECT: invention provides the obtaining of any dispersion of initial gas bubbles required by the technology.9 cl, 5 dwg

Description

The present invention relates to the field of mineral processing, and in particular to a flotation process for the separation of mineral particles of any size. It can also be used for wastewater treatment, in the chemical industry and other industries where aeration is needed.

From the existing level of technology, a two-chamber jet aerator is known (RU 2229926, publ. 10.06.2004), comprising a cylindrical manifold and an air channel with at least one inlet, characterized in that the collector is made with holes uniformly spaced along the generatrix, and the air channel is made in the form of a U-shaped profile with outlet openings evenly spaced along the base located on the surface of the collector, the openings of the collector being placed in the cavity of the air channel.

The two-chamber jet aerator is equipped with an input source of water-air pulp, while the aerator collector is made open. The air channel inlets are made with flow controllers. The holes of the air channel are located on the axis of the holes of the manifold. The edges of the openings of the air channel are located on straight lines passing through the edges of the holes of the collector and intersecting on the axis of symmetry of the collector in its cavity. The ratio of the radii of the holes of the collector and the air channel lies in the range of 2.8-1.9.

This two-chamber jet aerator does not generate bubbles of similar sizes, but sets a polydisperse system of bubbles, which is not acceptable for flotation, for example, sludge. This two-chamber aerator is not optimal for wastewater treatment, since the polydisperse system of bubbles contributes to their enhanced coalescence, the emergence of large unloaded bubbles that float without any pollution.

A pulse aerator (RU 2142433, publ. 09/27/2000) containing a reservoir, a circulation pump with a fluid supply pipe and aeration pipes with conical nozzles is known from the prior art. It is equipped with distribution chambers, in each of which a siphon cup with a drain pipe and an air regulator cup with a water seal are installed, while the air tube of the siphon cup is connected to the regulator air cup and the lower end of the branch pipe is made tapering in the form of a nozzle and is located coaxially in the conical nozzle aeration pipe with the formation of an annular gap. The device provides a polydisperse system of bubbles, which is not applicable for flotation separation of nano- and microparticles. Large bubbles form in the pulsed aerator, which mechanically carry all hydrophilic and hydrophobic nano- and microparticles to the surface of the aerated liquid.

The prior art jet-airlift aerator (RU 2156746, publ. 10.12.1999) containing an aeration tank, a supply pipe, airlift aeration column, the airlift column is provided with an aeration pipe, the upper end of which is located in the distribution chamber, and the lower end is known from the prior art. in the first third of the height of the airlift column. The known aerator gives a polydisperse system of bubbles, which is not applicable for flotation separation of nano- and microparticles. Large bubbles form in the jet-airlift aerator, which mechanically remove all hydrophilic and hydrophobic nano- and microparticles to the surface of the aerated liquid.

The prior art method for aeration of a liquid during flotation of materials (A.S. 1284600, publ. 23.01.1987), in which aeration is carried out by trapping a gas bubble through a gas-liquid interface, characterized in that the purpose of increasing aeration efficiency by increasing the gas saturation of the liquid, the jet is directed opposite to the movement of the liquid stream. This method provides a polydisperse system of initial bubbles, which is acceptable for flotation of particles of ordinary flotation size, but not applicable for flotation of nano- and microparticles.

The prior art method for aeration of a liquid during flotation (A.S. 1260026, publ. 09/30/1986), comprising supplying a free stream of liquid to a gas-liquid interface with the formation of a funnel of aerated liquid around a collision zone with a specified surface, characterized in that, in order to increase the gas saturation of the liquid, a free stream is given a rotational movement, and a rotation opposite the direction of rotation of the free stream is given to the rotation of the liquid in the funnel. Due to the high uncontrolled turbulence, this method gives a polydisperse system of small initial bubbles, which, upon subsequent coalescence, form large bubbles suitable for flotation of particles of ordinary flotation size, but not applicable for flotation of nano- and microparticles.

From the existing prior art devices for aeration of a liquid are known Zlobin M.N. and co-authors (A.S. 1561452, publ. 30.08.1994, A.S. 1658577, publ. 30.06.1994). These devices give a polydisperse system of bubbles, since the water-air jet repeatedly falls on many obstacles when leaving the device - air bubbles repeatedly coalesce with each other with the formation of larger bubbles. A less dispersed system in such a device can be obtained only with a high concentration of foaming agent, when the bubbles are armored by the molecules of the foaming agent, their coalescence decreases.

From the current level of technology there is a device for aeration of a liquid Zlobin M.N. and co-authors (AS 1729090, publ. 06/30/1994), in which the gas-liquid system passes repeatedly through a series of hydrodynamic whistles. Such dispersion at a low concentration of the foaming agent gives a polydisperse system of bubbles, since in the process of passing through a series of obstacles (hydrodynamic whistles) both coalescence of the bubbles and their decomposition into smaller ones occur. A finely dispersed system of bubbles is achieved due to a significant concentration of a foaming agent in the aeration device, which leads to an insignificant level of coalescence of bubbles in the pulp volume, but supposedly contributes to the formation of the necessary flotation complex due to the same coalescence ("fusion of air bubbles") of the bubbles on the surface of the mineral particle. In this interpretation, the mineral particle is covered by a finely dispersed system of bubbles that do not coalesce with other small bubbles due to the high concentration of the foaming agent. The volume of finely dispersed air bubbles fixed on a mineral particle, in many cases, will not be sufficient to raise the flotation complex up in the pulp and exit into the foam product (concentrate). Even finely dispersed pulp cannot be passed through this device because it is clogged, and the hydrodynamic whistles will quickly wear out due to the abrasive effect on them. In addition, any hydrodynamic whistle has a whole set of harmonics of its sound spectrum, leading to a polydisperse spray into drops and bubbles. The presence of a large number of obstacles through which the gas-liquid jet passes, significantly increases energy consumption, part of the energy is spent on heating bubbles, drops and liquids.

Of the existing nano- and microbubble aerators, mention should be made of the Nikuni KTM Microbubble Generating Pump (http://www.dafpump.com/applications). This aerator produces micro bubbles with an average size of 5 microns. Microbubbles are created as follows: firstly, liquid and gas are mixed, secondly, the resulting gas-liquid mixture is separated with the release of microbubbles, and large bubbles are discharged through the corresponding nozzle, which is not an optimal solution, since not all gas passes into nano- and micro bubbles. There are a number of similar devices in which nano- and microbubbles are created by separation from a gas-liquid mixture into small and large bubbles. Gas from large bubbles is vented to the atmosphere.

Closest to the claimed technical solution is a liquid aeration device (A.S. 1108078, publ. 15.08.84) containing a container for aerated liquid and an aerator with pipelines for supplying it under excessive pressure of liquid and gas, in which, in order to increase productivity and the efficiency of using the device by increasing the coefficient of ejection of the aerator, reducing wear and ensuring uniform distribution of dispersed gas in the volume of the tank, the aerator is made of aeration and adjustment blocks in the ides of the chambers open from the bottom of the tank’s capacity, while the aeration unit’s chamber is connected to the fluid supply pipe and equipped with a jet nozzle and gas inlet pipe, the control unit’s chamber is equipped with a partition whose lower end is located above the lower ends of the chamber walls, divided by this partition into two compartments, the first of which is connected with the gas supply pipeline and the gas inlet pipe to the aeration unit chamber, and the second compartment is equipped with an excess gas discharge pipe from the control chamber wow block.

The disadvantages of this technical solution are:

1. The polydispersity of the initial bubbles due to the decay of the ejecting liquid stream into a polydisperse droplet system.

2. Uncontrollability of the size of the initial bubbles, since without the necessary resonant action on the jet, bubbles of almost any size are formed that arise during gas ejection through the gas-liquid interface.

3. Emission of excess gas, which reduces the efficiency of the aerator.

The technical problem to be solved by the claimed invention is directed is the creation of a device that allows to obtain any dispersion of the initial gas bubbles required by the technology. For different dispersion of mineral particles during flotation, different initial gas bubbles are required. Ultrafine bubbles are required that are fixed on the mineral surface of the floated particle, as well as large transport bubbles that coalesce with these small bubbles and give the flotation complex the required buoyancy. The diameter of large bubbles should not exceed a certain limit at which, firstly, they can have such a rise rate at which they can interact with any floatation complex and float unloaded, and secondly, large bubbles due to their high kinetic energy of ascent can destroy an already formed flotation complex; thirdly, large bubbles are not applicable for flotation, for example, sludge.

The technical problem is achieved due to the fact that the device for aeration of a liquid containing a container of aerated liquid limited by partitions, a gas container open towards the bottom of the tank of aerated liquid, a nozzle placed in a gas container, nozzles for supplying liquid, nozzles for supplying gas, the pipe for exhausting gas, according to the claimed invention additionally contains a vibration source connected to the gas tank, while the gas tank contains a top cover made in the form of the movable piston, the nozzle is movable in the piston, and the capacity of the aerated liquid contains at least 3 partitions, which form gas bubble separation chambers.

A large number of separation chambers formed by partitions in the tank of the aerated liquid contribute to a better estimate of the dispersion of the initial bubbles created by the aerating device, and also allow the bubbles to be distributed over the chambers in accordance with their size according to a given technology.

The following special cases of the implementation of the claimed invention contribute to the achievement of the specified technical problem.

The nozzle is configured to form a jet through an opening located at the fluid outlet of the nozzle.

The hole of the nozzle is made in the form of a gap.

The hole of the nozzle can be made round or oval.

The hole of the nozzle can be made conical.

As an oscillation source, an electrodynamic sound source, an amplifier and a frequency generator are used. In this case, a gas tank, a nozzle, a generator, an amplifier, an electrodynamic sound source are a source of resonant action on a liquid stream.

The gas pipe is located tangentially with respect to the gas tank.

The capacity of the aerated liquid may be cylindrical, and the separation chambers are separated by cylindrical surfaces.

The directing nozzle is introduced tangentially into the tank of the aerated liquid.

The invention is illustrated by drawings, which depict:

in FIG. 1 shows a liquid aeration device with separation chambers with a polydisperse system of bubbles, where the highest foam height in the last separation chamber with the smallest bubbles;

in FIG. 2 - liquid aeration device with separation chambers with a polydisperse system of bubbles, where the highest foam height in the first separation chamber with large bubbles;

in FIG. 3 - liquid aeration device, where in the middle separation chamber the highest height of the foam with medium-sized bubbles;

in FIG. 4 - liquid aeration device with a close to monodisperse system of bubbles in the penultimate separation chamber with small bubbles of similar size;

in FIG. 5 is a liquid aeration device with a close to monodisperse system of small bubbles in the last separation chamber.

The device consists of the following structural elements:

1 - pipeline;

2 - pump;

3 - the capacity of the aerated liquid (or a liquid solution with foaming agents) and the capacity from which the liquid is supplied;

4 - fluid flow meter;

5 - piston for changing the resonance chamber;

6 - jet forming nozzle;

7 - a gas tank of cylindrical shape (or any other shape);

8 - a source of oscillation (for example, an electrodynamic loudspeaker or any other source of oscillation and vibration);

9 - amplifier;

10 - generator of a given frequency;

11 - chambers for separation of bubbles by size;

12 - adjustable nozzles for supplying and discharging gas;

13 - pipe for tangential gas supply to the resonant gas tank.

A liquid aeration device (acoustic jet aerator) operates as follows.

Through the pipeline 1 through the pump 2, then through the jet nozzle 6 a liquid is supplied, the flow rate of which is determined by the flow meter 4. The jet exiting the jet nozzle 6 is directed at an angle to the gas-liquid phase interface and ejects gas from the gas tank 7 into the tank of the aerated liquid 3. On the generator 10, the frequency is set, which is fed to the amplifier 9 and then to the oscillation source 8 (for example, an electrodynamic loudspeaker) connected to the gas tank 7. The resonance volume is selected gas chamber 7 using a piston to change the gas tank 7 to eject the required dispersed composition of the liquid bubbles, which is estimated using the separation chambers 11. When selecting frequencies on the generator 10 and the volume of the gas tank 7, you can get almost any dispersion of the original bubbles - monodisperse or polydisperse (Fig. 1-5). The dispersion in the separation chambers 11 is estimated by the height of the foam layer. For example, at a flotation concentration of the FSB foaming agent (propylene oxide butyl alcohol) - a mixture of propylene glycol monobutyl ethers equal to 16 mg / l, jet diameter d of the _jet = 0.8 mm, jet velocity V of the _jet = 5 m / s, frequency set by the generator, 3420 Hz in the foam layer of the separation chambers bubbles are created: 80% with a diameter of 0.3 mm; 12% diameter from 0.2 to 0.3 mm; 8% diameter from 0.3 to 0.5 mm. The measurement data are approximate, since they were made from photographs of the foam layer. At low frequencies, larger bubbles and polydisperse ones are obtained. At high frequencies, smaller bubbles of the same size are obtained. A significantly higher foam layer, obtained in one of the separation chambers, shows that it was formed due to close (identical) bubbles in size. Small bubbles of the same size coalesce much less and, therefore, form a high foamy layer of flooded foam.

Separation chambers are designed to assess the dispersed composition of the resulting source gas / air bubbles. Large bubbles enter the nearest separation chamber, smaller into subsequent separation chambers.

For a short-wave spray of the sonic stream into identical droplets ejecting the same bubbles, a vortex whistle was used, formed by a gas tank 7 and a gas pipe 13 tangentially inserted into the gas tank. At frequencies above 10 kHz, a foggy system of bubbles from 5 to 20 microns is formed. The size of the bubbles was estimated by the time of clarification of water. Water clarification occurred from several minutes to several tens of minutes.

To more evenly separate the bubbles by size and reduce their coalescence, the capacity of the aerated liquid 3 can be made in the form of a cylinder and is separated by cylindrical separation chambers coaxial with it.

The injection of a fluid stream through a gas-liquid phase interface is performed tangentially into the tank of the aerated liquid 3 with cylindrical separation chambers separated by coaxial coaxial partitions. This injection of the jet leads to a uniform distribution of bubbles over the capacity of the aerated liquid 3, less than their coalescence and their rapid separation in the separation chambers 11.

Adjustable nozzles 12 are designed to maintain an accurate resonant volume in the resonant chamber 7. The exact volume of the incoming air (gas) cannot be created by only one compressor or other similar device, therefore, some additional air (gas) removal from the resonant chamber 7 is required.

For the needs of a particular flotation of mineral particles of various sizes and fineness, the required system of bubbles can be selected from separation chambers 11.

Thus, this technical solution solves the problem of aeration during coarse-grained flotation with large bubbles and ultrafine bubbles during the flotation of nano- and microparticles without unnecessary energy costs for dispersing gas (air).

Claims (9)

1. A device for aeration of a liquid containing a container of aerated liquid limited by partitions, a gas container open to the bottom of the tank of aerated liquid, a nozzle placed in a gas container, nozzles for supplying liquid, nozzles for supplying gas, nozzles for venting gas, characterized the fact that it additionally contains an oscillation source connected to the gas tank, while the gas tank contains a top cover made in the form of a movable piston, the nozzle is made a movable piston, and the capacity of aerated liquid contains at least 3 partitions, forming between them a separation chamber gas bubbles. 2. The device according to p. 1, characterized in that the nozzle is configured to form a jet through an opening located at the outlet of the liquid from the nozzle. 3. The device according to p. 2, characterized in that the hole of the nozzle is made in the form of a gap. 4. The device according to p. 2, characterized in that the opening of the nozzle is made round or oval. 5. The device according to p. 2, characterized in that the opening of the nozzle is conical. 6. The device according to claim 1, characterized in that an electrodynamic sound source, an amplifier and a frequency generator are used as an oscillation source. 7. The device according to claim 1, characterized in that the branch pipe of the gas occasion is located tangentially with respect to the gas tank. 8. The device according to p. 1, characterized in that the capacity of the aerated liquid has a cylindrical shape, and the separation chamber of the bubbles are separated by cylindrical surfaces. 9. The device according to p. 5, characterized in that the nozzle is introduced tangentially into the tank of the aerated liquid.

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