RU2334559C2 - Device for centrifugal-gravity flotation and desulphurisation of fine coal - Google Patents

Abstract

FIELD: engines and pumps, mining operations.

SUBSTANCE: device for centrifugal-gravity flotation and desulphurisation of fine coal includes a scumming chamber, a hydrocyclone consisting of a casing, made up of the upper cylinder-taper, middle cylinder and lower taper parts flanged together with bolts and nuts. A cylinder-taper crushed-coal aerator with a neck and Laval nozzles is flanged to the hydrocyclone input branch pipe, the hydrocyclone being tangentially inserted into the casing upper cylindrical part. The upper scumming pipe is arranged long the casing upper cylinder-taper part, the end of the latter being furnished with an annular cylindrical crushed coal perforated damper. A cylinder-taper wear-resistant material foamed product support is arranged along the lower taper part of the casing to be moved along the vertical by the screw-nut mechanism. The screw furnished with a cylinder-taper anti-wear cap is attached to the said support. The air chamber arranged in the hydrocyclone is formed by solid inner and outer perforated cylinders closed by an upper solid cover and a lower annular cover. The said chamber is divided by rectangular vertical partitions into equal number of sections all along the perimeter. The lower cover every section has a round threaded hole made along its lengthwise axis to receive the Laval nozzle screwed, via an inner thread boss, to the vertical air-feed pipe connected to the spreader pipe and, via compressed air line with a check valve and a receiver. Every section with the Laval nozzle and inner perforated wall represents an additional aerator. The lower taper hydrocyclone part communicates, via a stepwise chute, with the 1.5 m-wide 2 m-deep rectangular flotation chamber incorporating the air-lift with the aerator and is divided into two flotation sections, the chamber bottom terminating in a pyramid narrowing.

EFFECT: higher machine and flotation efficiency, fine coal desulphurisation, simpler machine design.

3 cl, 1 dwg

Description

The invention relates to the beneficiation of minerals, namely, machines for flotation of minerals, and can be used in coal, ferrous and non-ferrous metallurgy in processing plants, as well as in the beneficiation of rare metals and non-metallic materials.

Known "Device for flotation and desulphurization of coal fines."

This device includes a hydrocyclone with an inlet pipe and a perforated drain pipe, an aerator with a Laval nozzle, and a contact vat. It is equipped with a camera for fine fractions, which has a curved pipe with perforations. The pipe has an end cut at an acute angle in the direction of flow. It also has a chamber for coarse fractions, a flexible pipe connecting the aerator to the inlet of the hydrocyclone, which allows you to change the angle of inclination of the hydrocyclone relative to the horizontal axis. The inlet nozzle of the hydrocyclone is equipped with a curved partition installed with the possibility of regulation, and is made along an arc of a circle. The chamber for coarse fractions is equipped with a curved pipe with hollow walls, in which the pulp aerator is mounted coaxially in the form of a conical shape umbrella with acute-angled cutouts around the perimeter and a pipe for supplying compressed air.

The device aerator consists of a mixing chamber, a neck and a diffuser. Two pipes tangentially powered by a contact tub and a Laval nozzle located in the end part of the aerator mixing chamber along its central axis are brought tangentially to the mixing chamber of the aerator. A pipe for supplying compressed air is connected to the Laval nozzle.

This device is a combination of two copyright certificates of E.P. Yachushko. (see Pulp Aerator. Aut. St. No. 12212588. B03D 1/14. BI No. 7 of 02.23.1986. Author EP Yachushko. Device for flotation and desulfurization of coal fines. Aut. St. No. 1215749. B03D 1 / 14. BI No. 9 dated 03/07/1986.)

Unfortunately, the device was not tested in laboratory conditions and has not been put into commercial operation. A well-known American latest model of highly efficient dispersed air cyclone (ASH), which can be used for the selective flotation of small particles of coal. The ASH hydrocyclone consists of two concentric straight vertical pipes, the head of a conventional cylindrical cyclone with a tangential inlet pipe and a drain pipe connected to an outlet pipe bent at an angle at the top, and a foam product stand at the bottom. The cyclone head is connected to the outer pipe on the flanges and bolted together.

The support for the foam product of a cylindrical shape is located coaxially with the housing in the inner pipe with a gap and is held by a bracket connected by four posts to the lower pipe flange. The inner pipe is porous.

[Not good I.Kh., Sipotenko A.A., Tarasova G.N. The main directions of development of engineering and technology for coal enrichment p. 81-85, VINITI. Results of science and technology. Mineral processing. Volume 23, 1989.]

The hydrocyclone works as follows.

Food (pulp treated with reagents) is supplied tangentially through the usual head of the cyclone to the inside of the porous pipe, and a vortex flow of a certain thickness is created, adjacent to the pipe wall, leaving an air column in the center.

Dispersed air is introduced into the vortex flow through the wall of the porous pipe, forming small air bubbles.

Hydrophobic particles (coal) in suspension collide with these bubbles and, after sticking to them, move to the center of the cyclone.

The air zone becomes a foam zone. The hydrophilic particles mainly remain in the suspension phase, which is discharged in the form of a vortex layer through the annular opening for the condensed product between the wall of the porous tube and the foam product stand.

The foam phase is stabilized and restrained by the foam product stand as a condensed product and thus moves to the head of the cyclone and is discharged as a drain product through the pipe.

The pressure difference between the stand and the outlet of the foam product can be controlled, and it is the actual driving force of the axial movement of the foam phase. In addition, with a normally running process, the concentration of solid particles by mass is highest in the center of the foam zone and decreases in radius to the concentration of the suspension phase. This is an important feature of the flotation process in a hydrocyclone, which is controlled by structural and operational parameters.

Previous experiments have shown that the ASH system actually functions under limited conditions, when the annular hole is usually less than the thickness of the vortex layer, thus providing a difference in pressure required to move the foam.

Due to the fact that small particles of a mineral substance (rock) remain in suspension, water directed to the drainage stream (foam) should be controlled at a minimum level. This can be done by applying the optimum ratio of the area of the drain hole and the hole for the condensed product at the appropriate air flow rate. To minimize the transport of small rock particles to the drain stream (along with transport water), a small drain area is recommended.

These conclusions, affecting the mineral separation technological process, are not fully taken into account in the design of the ASH system hydrocyclone, which is its drawback.

The proposed design of the hydrocyclone of the ASH system does not allow the removal of rock fines trapped in the foam. In addition, as experiments on the enrichment of coal in the ASH system hydrocyclone have shown, when enriched in one stage, it produces low ash waste. So, the second stage of their enrichment is required.

Known deep airlift flotation machine Institute "Mechanobr" (AFM-2.5).

It consists of a bathtub with a depth of 2.5 m, which has foam chutes on its sides, a loading device and an unloading pocket for tails. An axial lift is located along the axis inside the bathtub, above which there is a reflector, above it there are baffle walls with an air pipe. Above them is a receiver, from which air supply nozzles ending in slotted gates are lowered down on both sides of the airlift (Meshcheryakov NF Flotation machines. M., "Nedra", 1972, p.136).

It differs from other types of airlift machines in the design of the airlift and the presence of slotted shutters on the air supply pipes, which exclude the ingress of pulp into the air duct system.

These features of the machine made it easy to operate.

The capacity of the pulp stream reaches 10 m ³ / min, air flow 5-7 m ³ / min per 1 m of machine length with an average particle size of the floated material, air pressure 2.5 · 10 ⁴ -3 · 10 ⁴ Pa.

The machine has several advantages compared to small airlift machines: a higher efficiency of the airlift, which increases the intensity of circulation and mixing of the pulp and allows you to float coarse-grained material; higher productivity per unit volume of the machine; occupies a significantly smaller area. Energy consumption for AFM-2.5 is approximately 40% less than for small airlift or mechanical flotation machines (Abramov A.A. Flotation enrichment methods. M., "Nedra", 1984, p. 326).

The AFM-2.5 machine has the disadvantage that its air supply pipes are mostly immersed in the pulp and are subject to wear from the abrasive action of solid particles.

Known airlift flotation machine with a supersonic speed of air flow (see Vorbanov R. Gaydarzhiev S. Airlift flotation machine with a supersonic speed of air flow. VIII International Congress on Mineral Processing. 1968, vol. 1. Ed. Mechanobr, 1969).

The machine consists of a rectangular bath with a square section of 2 × 2 m, along the longitudinal axis of the bath is an airlift chamber with vertical partitions, with a distance between it of 200 mm. In its center are vertical air supply tubes connected to the receiver and ending in Laval nozzles not reaching the bottom of the bathtub by 150 mm. On top of the airlift with a gap is a pulp reflector with vertical baffles submerged in the pulp. These partitions are located at a distance of 375 mm from the center of the airlift chamber and direct the pulp from the airlift to the flotation compartments of the bath. The bath has longitudinal foam gutters on both sides of it. The machine has a loading device and an unloading pocket and a tail chute.

The machine has two features.

The first is that the tubes of the airlift chamber end with Laval nozzles. They provide air supply to the airlift chamber at speeds exceeding the speed of sound, whereas in conventional airlift machines it is 10-15 m / s.

The main purpose of Laval nozzles is to convert the static pressure of the supplied compressed air into an air stream having a speed greater than the speed of sound, with its subsequent transition to subsonic in the pulp itself.

The supersonic air supply to the pulp leads to its dispersion directly in the zone of exit from the constriction. The supersonic air stream is the carrier of complex wave processes associated with the nature of the flow. At these speeds, the jet is very labile and continuously pulsates with a change in the pressure gradient, and therefore the dispersion of air is intensified as a result of high turbulence at the boundary of the jet and pulp.

The outflow of a jet with supersonic speeds is accompanied by complex acoustic effects that have a positive effect not only on the dispersion of air, but also mass transfer processes in the machine and on the adhesion of mineral particles to air bubbles.

Laval nozzles with different diameters of the critical section were studied, the speed of the air stream was measured at different pressures of compressed air from 1 to 6 atm and its flow rate. Under these conditions, the jet velocity varied from 335 to 400 m / s. The most effective are Laval nozzles with a critical section diameter of 3 mm, as they turned out to be the best in terms of dispersing air and the lowest energy consumption. The optimal excess air pressure was 1 atm with a power consumption of 2-3 kW per 1 m ³ of bath volume.

Industrial testing of the machine was carried out on copper sulfide ore.

The machine worked successfully at an increased pulp density of 43% solid (with a content in the pulp up to 55% of the class - 0.074 mm).

A slight improvement in the flotation of small classes was noted; reagent consumption is reduced by 20% and water by the same amount; power consumption is lower than in mechanical machines by 30%; the area of the flotation department is reduced by 40-50%; Easy adjustment of the machine.

It is noted that the aerators worked without failures when the machine stopped suddenly, the water, air, etc. were cut off. No clogging of nozzles was observed.

Another feature is the width of the airlift chamber. Good results were obtained with a width of 200 mm. But the authors believe that its width can be reduced to 150 mm. At the same time, air consumption is further reduced and flotation of large classes is improved by increasing the ascending pulp speeds in the chamber.

The disadvantage of the machine is that the air supply tubes located in the machine airlift are located in the pulp and are subject to abrasion from the solid particles circulating in the airlift.

In the coal industry, the enrichment of fine coal has a technical problem - the desulfurization of flotation concentrates, especially coking coal.

In mechanical flotation machines, this coal fines desulfurizes inefficiently, since in them the process is carried out in the gravitational field.

Sulfur in coal is represented mainly by coal pyrite, which, unlike ore pyrite, is almost as flotated as coal. The use of pyrite depressant reagents does not help much. At the same time, the density of coal pyrite is 5000 kg / m ³ , pure coal - 1350 kg / m ³ and rocks - 1800-2200 kg / m ³ . In gravitational flotation, the difference in the densities of coal pyrite and coal cannot be used. If flotation is carried out in a centrifugal field, then this density difference can be used taking into account the use of pyrite depressant reagents. Flotation machines and devices built using centrifuges and hydrocyclones, as their basis, will allow desulfurization of coal fines by flotation.

Closest to the invention is the "Centrifugal pneumatic flotation machine" (patent No. 2051754, author E.P. Yachushko).

A centrifugal pneumatic flotation machine, including a cylindrical conical body with flanges located in its cylindrical part, the outer continuous and inner perforated walls forming an air chamber in which a porous partition is placed, a foam product removal pipe, an inlet pipe made in a horizontal plane in the form of a circular arc with a partition installed with the possibility of movement, the inner perforated wall is made of end rings with recesses and grates, made socked from wear-resistant material, while the grates are fixed with their ends in the recesses of the end rings, the end rings are connected to the flanges of the cylindrical part of the body, the grates in the cross section are made in the form of successively conjoined trapezoid and two rectangles, the large sides of which are mutually perpendicular, while the grates are installed with the formation of a gap having a zigzag section. The machine is also equipped with a cylindrical conical stand for the foam product, an aerator with Laval nozzles and a chamber for removing foam, while the cylindrical conical stand for the foam product is made of wear-resistant material and is mounted in the lower conical part of the body with the possibility of movement along the vertical axis. The machine is also equipped with a cylindrical perforated pulp dampener installed with a gap at the end of the pipe to remove the foam product, in order to facilitate the adjustment of the process, it is equipped with devices for changing the inner diameter of the pipe to remove the foam product from the set of cylindrical inserts.

The machine has the following disadvantages:

1. It is equipped with different types of aerators, which complicates its design.

2. The design of the inlet to the hydrocyclone is complicated.

The aim of the invention is the addition of a device for gravitational flotation of the condensed hydrocyclone product diluted with liquid sediment to the foam removal chamber, which is not in the prototype, and also that the device uses the same type aerators, air dispersers in which are Laval nozzles, simplification of the prototype design, all this improves the flotation process by improving its hydro- and aero-hydrodynamic parameters, and most importantly, the device allows the desulfurization of fine coal.

This is achieved by the fact that the device for centrifugal gravity flotation and desulphurization of fine coal is equipped with the same type aerators with air dispersers in the form of Laval nozzles. An additional aerator located in the cylindrical part of the hydrocyclone body, including an outer continuous cylinder and an inner cylinder with perforations, blocked from above by a continuous annular cover and a lower annular cover, an air chamber is formed between the cylinders, divided by vertical rectangular partitions into an equal number of compartments around the entire perimeter, in the lower the cover of each compartment is made a round hole with a thread where the Laval nozzle is screwed in, a round hole is made in the flange of the lower conical part for the passage of lugs connecting the Laval nozzle with a short air supply tube connected with an annular distributor pipe, connected through the air pipe compressed air receiver, all parts of the housing are fastened together by means of flanges with gaskets between them and the bolts and nuts.

The flotation of the condensed product from the hydrocyclone diluted with liquid sediment from the foam removal chamber is carried out in the chamber. The technical result is achieved in that a chamber having a width of 1.5 m and a depth of 2 m with a pyramidal narrowing at the bottom, including a foam chute, an airlift located along its longitudinal axis, having vertical partitions, dividing the chamber into two flotation compartments, including an aerator, consisting from vertical air supply tubes connected by bosses to Laval nozzles, which are air dispersers for bubbles in the pulp, the tubes are connected by welding to a distribution pipe connected through a compressed air duct with a non-return valve with a receiver, a pulp reflector located above the airlift with a gap, made in a figured shape, over the pulp reflector there are baffle plates with an U-shaped air outlet, having a loading device and an unloading pocket connected to the tail chute, according to the invention, the airlift is equipped with an aerator located under the bottom of the chamber and consisting of vertical air supply tubes located along the longitudinal axis of the bath with a distance between each other of 100-200 mm, connected to the nozzles Laval through lugs, the ends of which protrude to a small height above the bottom of the chamber, an air supply tube connected to the horizontal distribution pipe, which through air line compressed air with a check valve connected to the receiver.

The drawing shows a device for centrifugal gravity flotation and desulphurization of fine coal.

The device consists of a hydrocyclone 1, a chamber for removing foam 2 and a chamber 3 for gravitational flotation of the condensed product exiting the hydrocyclone.

The hydrocyclone body includes an upper cylindrical part 4, a middle cylindrical part 5 and a lower conical part 6.

The upper cylindrical part 4 has a flange 7, a vertical pipe 8 to remove the foam product. It has four round holes 9, used to remove gases that accumulate inside part 4 and disrupt the process in the housing 1.

An inlet pipe 30, rectangular in shape and made along an arc of a circle, is tangentially attached to the upper cylindrical part 4. A pulp aerator 31 having a cylindrical shape with a neck is attached to it on flanges, two Laval nozzles 16 are attached to its cylindrical part on the bosses 17 connected by welding with it, one of which is connected opposite the device power supply pipe 32 tangentially attached to the cylindrical part of the aerator. Another Laval nozzle 16 is mounted in the center of the end cylindrical part of the aerator.

The middle part 5 includes an outer continuous cylinder 10 and an inner cylinder 11 with perforations. An air chamber is formed between them, which is divided by vertical rectangular partitions 12 into an equal number of compartments around the entire perimeter.

Cylinders 10 and 11 are overlapped by ring caps: the upper continuous cover 13 and the lower cover 14. The cylinder 10 has flanges 15 at the ends. A round hole is made in the passage of the boss 17 into each compartment in the flange 21 of the conical part 6. Each compartment with a Laval nozzle has an additional aerator. A threaded hole is made in each compartment along the longitudinal axis in the bottom cover 14, into which the Laval nozzle 16 is screwed. It has an external thread, it is connected through the boss 17, which has an internal thread of the same pitch as the thread of the Laval nozzle, to the end of the vertical air supply pipe 18. In this case, the following condition must be observed: the Laval nozzle must be connected to the air supply tube without a gap, so as not to create unnecessary resistance to the passage of compressed air into the Laval nozzle. The tube 18 is connected by welding with an annular distribution pipe 19, which is connected through a compressed air duct with a non-return valve to the receiver 20. The air ducts in the drawing are conventionally shown by lines with arrows.

If necessary, Laval nozzles with bosses and air supply tubes and an annular distribution pipe can be arranged in the upper cylindrical part 5. The arc shape of the inlet pipe 30 allows this.

In the lower conical part 6 along the axis of the housing 1, there is a gap relative to its side walls of the part 6 and the inner cylinder 11, a support 22 of a cylindrical shape, hollow of the foam product day and made of wear-resistant material. Inside it, a sleeve 23 with a female thread is fixed for welding, where the screw 25 enters at its end, passed through a nut 26, mounted on the bottom of the cylinder 24, preventing the spraying of the thickened product. The screw ends with the helm 27. To protect against wear of the screw 25, a cylinder-shaped cap 28 is used, which is fastened by welding to the bottom of the stand 22. Using the screw-nut mechanism, the centrifugal flotation process in the housing 1 is adjusted by moving the stand 22 "up and down »What regulates the annular gap of the release of condensed product.

The output of the condensed product is carried out using a square hole in the cylinder 24, the cylinder is connected to the stepped groove 29. The conical part 6 has a flange 21.

Using the flanges 7, 15 and 21, as well as using gaskets and bolts with nuts, the parts of the housing 1 are fastened together as a whole.

Since the hydrodynamics of the pulp flows in the housing 1 is not quite ordered, small rock particles that contaminate the concentrate inevitably fall into the drain along with the foam and transport water; therefore, chamber 2 serves to separate the foam from the transport water containing small rock particles. foam removal. It has a rectangular pyramidal shape with an inclined bottom, rolling in its front part in a horizontal bottom. It has a vertical front wall 33, not reaching the horizontal bottom and having a gap with it, overlapped by the gate 35. The chamber has a foam chute 34, as well as a scraper foam 37. Liquid sediment is removed from the chamber using a cylindrical pipe 36.

The supply of foam with transport water into the chamber 2 is carried out using a vertical pipe 8. It has a turbulent character. A prerequisite is that the end of the pipe 8 should enter the foam layer of the chamber 2, thereby reducing the resistance to the exit of foam with transport water from the housing 1. In order to reduce the turbulence of the discharge entering the chamber 2, it is strengthened at the end of the pipe 8 with a gap around the perimeter of the pipe cylindrical annular damper 38 pulp with perforations.

The housing 1 is equipped with a set of interchangeable inserts 39, for example, 3 sizes.

They should be made of the same length with the pipe 8, have an outer diameter that allows them to enter it without a gap, connect to it using a bayonet connection. These inserts 39 must be grooved on the cone in order to reduce the resistance to the inlet of the drain into the tube 8, and also have four round holes, when connected to the pipe 8, they must be combined with its holes.

Chamber 3 is used for gravitational flotation of the condensed hydrocyclone product. Chamber 3 has a rectangular shape 1.5 m wide and 2 m deep, ending in a pyramidal narrowing at the bottom. In the front side wall there are rectangular openings 41 located at different levels. Through them, the condensed product enters the flotation compartments of the chamber from the housing 1 through a step chute 29, to the beginning of which a liquid precipitate is supplied from the chamber 2 through a pipeline to dilute it. The chute 29 to the pulp level in the chamber 3 must be closed, and from it through closed chutes through the rectangular holes 41, power is supplied to the chambers 3. The chutes 29 are not shown in the drawing, and the pipeline for supplying liquid sludge to the chute 29 is conventionally shown by arrows. The chamber 3 has on the sides of the chute 42 for foam.

On the longitudinal axis of the chamber 3 there is an airlift 43 with vertical partitions 44 dividing the chamber 3 into two flotation compartments. The distance between the vertical partitions 44 should be 150-200 mm. Above the airlift 43, there is a gap of a pulp reflector 45 made in a figured shape, which divides the stream of aerated pulp from the airlift 43 into two streams, directing them to the flotation compartments of the chamber. Above the pulp reflector 45, there are baffle walls 46 with an air outlet, directing the flows of aerated pulp from the airlift 43 under the foam into the flotation compartments of the chamber 3.

The airlift aerator 43 consists of vertical air supply tubes 47, bosses 17 and Laval nozzles 16.

The air supply tubes 47 are connected by welding to the distribution pipe 49. The distribution pipe 49 with the air supply pipes 47 is located under the bottom of the chamber along the longitudinal axis. Boss 17 enter through the holes in the bottom of the chamber to a small height. The gap between them and the bottom is closed. The bosses 48 are made with an internal thread of the same pitch as the external thread of the air supply tubes. Laval nozzles 16 have the same external thread. Laval nozzles are screwed into the bosses. In this case, the following conditions must be met: Laval nozzles 16 must enter the boss 17 without a gap with the ends of the air supply tubes 47 in order to exclude excessive resistance to the passage of compressed air into the Laval nozzles 16. The air supply tubes 47 are located at a distance of 100-200 mm from each other. Laval nozzles 16 and boss 17 are made of wear-resistant material, for example, manganese steel. The distribution pipe 48 must be of sufficient diameter to provide all Laval nozzles with compressed air. It is connected by a compressed air duct with a check valve to the receiver 20. In the drawing, the air duct is conventionally shown by lines with arrows.

The camera 3 is mounted on a low frame 49 made of channels. On the Laval nozzles 16, hose valves can be installed to ensure that the pulp does not enter them when the camera stops suddenly.

The camera 3 has a discharge pocket, which is not shown in the drawing. It is a compartment connected to the rear wall of the camera, a cutout is made in the rear wall, covered by an electric drive gate. An unloading pocket connects to the tail chute.

The device requires a compressor with a pressure of 1.5-3 bar. Its air ducts are equipped with lowering pressure reducers, pressure gauges and valves as necessary.

A device for centrifugal gravity flotation and desulfurization of fine coal works as follows. The device is powered by pulp treated with reagents in the pulp preparation unit or in the contact tub, located 12 meters higher than the device’s air lift 31 by gravity through pipe 32 and tangentially flows into the cylindrical chamber of the aerator 31, where compressed air is supplied through the Laval nozzles 16 through the bosses 17 . Expiring from Laval nozzles at a supersonic speed into a rotating pulp, it disperses almost instantly into small bubbles, to which hydrophobic particles adhere, having managed to meet them. The aerated pulp from the cylindrical-conical part of the aerator 31 through the mouth and inlet 30 enters the cylindrical-conical part 4 of the housing 1, receiving a rotational movement, passing further into the cylindrical part 5. Here it is saturated with air bubbles generated by additional aerators consisting of compartments into which the Laval nozzles are screwed 16, from which air flows out at a supersonic speed and is fragmented into small bubbles. This is facilitated by small perforations of the cylinder 11, which overlaps the compartments of additional aerators.

Due to the rotation of the pulp in the cylindrical part, a centrifugal force is formed - the largest on the axis of the body and smaller at the walls of the cylinder 11, which forms the arrangement of solid particles in the pulp in their "orbits": large and heavy are closer to the wall of the cylinder 11, small and light particles behind them . Under the action of centrifugal force in the center of the cylindrical part, the continuity of the pulp ruptures, as a result of which an air column forms, supported by stand 22, where mineralized bubbles rush, forming a foam in it. Since the density of pyrite particles is almost 4 times higher than the density of coal particles and more than 2 times higher than rock particles, plus the use of pyrite depressant reagents, which reduce the ability of coal pyrite particles to adhere to air bubbles, pyrite particles do not swallow here and go into condensed the product through an annular gap formed between the inner side of the conical part 6 and the foam product stand 22. The foam product support can be moved vertically using the screw-nut mechanism, is smart Shai or increasing the annulus for discharging the condensed product. It enters the cylinder 24, which is connected to the groove 29 to release it.

The difference in pressure between the stand 22 and the outlet of the drain pipe 8 can be controlled, and it is the actual driving force of the axial movement of the foam phase due to the difference in pressure between the stand for the foam product 22 and the outlet of the pipe 8, since they are at different levels height.

For flotation of the condensed product of the housing 1, diluted with liquid sludge from the chamber 2, the chamber 3 serves. It enters the flotation compartments of the chamber through the openings 41 through a closed stepped groove 29 and through hermetic chutes.

Compressed air is supplied to the airlift aerator 43 from the receiver 20 through the distribution pipe 48, air supply tubes 47, boss 17 and the Laval nozzle 16, which, flowing out of the Laval nozzles at a supersonic speed, is fragmented into small air bubbles that float. Aerial pulp creates a density of aerated pulp lower than in flotation compartments. This causes the pulp to flow from the flotation compartments to the airlift. Thus, multiple pulp circulation through an airlift is carried out. In it, hydrophobic particles meet with air bubbles and adhere to them. Mineralized bubbles along with the pulp rise in the airlift, thanks to the reflector 45, it is sent to the flotation compartments and, using the baffles 46, the aerated pulp is introduced into them under the foam. Mineralized bubbles float, forming a layer of foam, which is gravity removed in the groove 42 for foam.

Unflotted particles together with the pulp through the discharge pocket are removed into the tailings chute.

The technical and economic efficiency of the device consists in the fact that impellers are not required for its operation. The use of aerators with a Laval nozzle, more productive than slotted and more durable rubber tubular aerators, reduces operating costs.

Finally, this device solves to some extent the technical problem of desulphurization of fine coal, especially coking coal.

The device is designed for flotation of coal fines, but it can be used for flotation of ores of ferrous, non-ferrous, rare metals, as well as for the enrichment of non-metallic raw materials.

Claims (3)

1. A device for centrifugal gravity flotation and desulphurization of fine coal, including a chamber for removing foam, a hydrocyclone, consisting of a housing made of bolts and nuts fastened together by bolts and nuts of the upper cylindrical, middle cylindrical parts and lower conical part, pulp aerator a cylindrical-conical shape with a neck, having Laval nozzles connected to the flanges with an inlet of a hydrocyclone made along an arc of a circle tangentially entering the upper cylindrical part of the body a mustache, a vertical pipe for removing foam product located along the axis of the upper cylindrical conical part of the body, at the end of which an annular cylindrical pulp dampener with perforations is placed with a gap, a hollow support for the cylindrical-shaped foam product made of wear-resistant material located on the axis of the conical lower part, and installed with the ability to move vertically using a screw-nut mechanism, the screw of which is protected from wear by a cylinder-conical cap and fastened with a stand, an air chamber located in the hydrocyclone and formed by a continuous outer and inner cylinder with perforations overlapped by an upper continuous and lower annular cover, divided by vertical rectangular partitions into an equal number of compartments around the perimeter, a circular axis is made along the longitudinal axis of each of them in the lower cover a threaded hole for screwing in a Laval nozzle, which is connected through a boss with an internal thread on the thread to the end of a vertical air supply tube, fixed to a distribution pipe, which is connected to the receiver through a compressed air duct with a non-return valve, each compartment with a Laval nozzle and a perforated inner wall is an additional aerator, while the lower conical part of the hydrocyclone is connected via a stepped trough to the gravity flotation chamber of the condensed hydrocyclone product containing an airlift with an aerator and made rectangular in shape with a width of 1.5 m and a depth of 2 m with a pyramidal narrowing at the bottom, divided by a vertical partition and two flotation compartment. 2. The device according to claim 1, characterized in that to prevent the sprayed condensed product from hydrocyclone from splashing, it is equipped with a hollow cylinder with a bottom having a square opening for discharging the condensed product made of wear-resistant material and connected to the stepped trough. 3. The device according to claim 1, characterized in that the aerator of the gravity flotation chamber of the condensed product is located under the bottom of the chamber and consists of vertical air supply tubes located at a distance of 100-200 mm from each other, and through the bosses entering the chamber are connected to Laval nozzles, air supply tubes are connected to a horizontal distribution pipe located along the longitudinal axis of the chamber, and connected through a compressed air pipeline to a non-return valve and receiver, while Laval nozzles and bosses are made from wearproof material.