RU203651U1 - Flotation chamber - Google Patents

Abstract

This utility model relates to a flotation cell for separating particles containing valuable material from particles suspended in the slurry. The flotation chamber contains a flotation tank (10) having a center (11), a perimeter (12) and a side wall (13), a chute (2) and an edge (21) of the chute, surrounding the perimeter (12) of the tank (11); and standpipe (4). The height-to-diameter ratio of the flotation cell is 0.9 or less. The standpipe (4) contains an inlet nozzle (41) for feeding the slurry supplied to the standpipe, an inlet (42) for compressed air, an elongated chamber (40) configured to receive feed to the slurry under pressure, and an outlet nozzle (43) configured to restrict the flow of the slurry supplied from the outlet nozzle and to maintain the supply of the slurry in the elongated pressurized chamber. The technical result is the separation of small particles of coal from the surrounding waste rock (ash) during mining. 8 p.p. f-ly, 4 dwg.

Description

FIELD OF TECHNOLOGY

This utility model relates to a flotation cell for separating particles containing valuable material from particles suspended in the slurry.

ESSENCE OF THE USEFUL MODEL

A flotation cell made in accordance with the present utility model differs in what is stated in clause 1 of the utility model claims.

The flotation cell is designed to process particles suspended in the slurry and to separate the slurry into bottom and top products. The flotation chamber contains a flotation tank having a center, a perimeter and a side wall with a vertical portion and a conical bottom portion containing the top; a gutter and an edge of the gutter along the perimeter of the tank; and a standpipe through which slurry feed is supplied to the flotation tank; the ratio of the height, measured as the distance between the top and the edge of the trough, to the diameter, measured as the diameter of the flotation tank along the perimeter of the straight wall part, is 0.9 or less. The flotation chamber is characterized in that the standpipe contains an inlet nozzle for feeding the slurry to the standpipe; a compressed air inlet, the slurry feed being exposed to the compressed air as it exits the inlet nozzle; an elongated chamber configured to receive pulp feed under pressure; and an outlet nozzle configured to restrict the flow of slurry feed from the outlet nozzle, and also to maintain the supply of slurry feed to the elongated chamber under pressure.

In accordance with one aspect of the invention, a flotation line is provided. The flotation line contains a flotation stage and is characterized in that the first flotation stage contains a flotation cell designed in accordance with the utility model.

In accordance with another aspect of the invention, there is proposed the use of a flotation line constructed in accordance with the invention for the treatment of coal particles suspended in a pulp.

By using the utility model described herein, the recovery of fines in the flotation process can be improved. The particles may, for example, contain mineral ore particles such as metal containing particles or coal particles.

In froth flotation of mineral ore, the improvement in the quality of the concentrate is directed to particles with an average size of 40 µm to 150 µm. Thus, fines are particles with a diameter of 0 to 40 microns, and ultrafine particles can be identified as falling in the lower end of the fine particle size range. Large particles have a diameter of more than 150 microns. In froth flotation of coal, improving the quality of the concentrate is aimed at an intermediate range of particle sizes from 40 microns to 300 microns. Fine particles in coal processing are those with a diameter of 0 to 40 microns, and ultrafine particles are those that fall in the lower end of the fine particle size range. Coarse coal particles have a diameter of more than 300 microns.

Recovery of very coarse or very fine particles is challenging because in a traditional mechanical flotation cell, fines are not easily captured by the flotation gas bubbles and can therefore be lost in the tailings. Typically, in froth flotation, the flotation gas is introduced into the flotation cell or tank using a mechanical stirrer. The flotation gas bubbles thus formed have a relatively large size range, typically 0.8 to 2.0 mm or even larger, and are not particularly suitable for collecting smaller particles.

Traditionally, fines recovery has been improved by the use of column flotation cells in which the absence of mechanical agitation and the introduction of wash water from the top of the cell minimizes the entrainment of ore particles by foam. In the column chambers, the slurry contains recirculated material from the bottom of the chamber, which is pumped into a bubbler, where bubbles are attached to the particles. The agglomerates of flotation gas bubbles and ore particles thus formed are pumped back into the flotation cell where the bubbles rise to the foam layer.

In addition, the loading rate of the flotation column, as well as the amount of solids in the slurry to be treated, must be lower than in a mechanical flotation cell to prevent particles from settling on the bottom of the flotation cell.

In mechanical flotation cells and column flotation cells, agglomeration of flotation gas bubbles and ore particles occurs for the most part in the slurry in a flotation tank or other liquid storage tank. Sufficient time should be allowed to allow agglomerates to rise into the foam layer and move in that layer to the upper overflow chute for collection as overhead product or concentrate in the upper overflow chute.

To overcome the aforementioned problems, so-called pneumatic flotation cells are used, in which flotation gas is introduced through a high shear device such as a slurry feed standpipe, thereby creating smaller flotation gas bubbles that can also trap smaller particles already during the formation of bubbles in the standpipe. However, for such a high performance downpipe flotation cell, a vacuum is required to effectively achieve the required bubble rate to capture the desired particles while the slurry feed is briefly in the standpipe.

Upon exiting the dip tube, agglomerates of bubbles and flotation gas particles immediately rise to the froth layer at the top of the flotation cell, and no further particle trapping occurs in that part of the flotation cell below the dip tube outlet. This can cause a significant portion of the particles containing the desired material (mineral or coal) to simply fall to the bottom of the flotation tank and end up in the tailings, which reduces the recovery of the flotation cell.

Typically, however, so-called high-performance flotation cells or pneumatic flotation cells such as Jameson Cells do not contain any flow restrictor to control the pressure inside the standpipe after agglomeration of flotation air bubbles and particles has occurred. Such pressure control is also beneficial in terms of the pressure at which bubbles of the flotation gas are formed (influence on bubble size), as well as for controlling the relative pressure at which they are to be used in the flotation tank. Thus, the coalescence of bubbles after bubble formation can be minimized. This is particularly advantageous because the rate at which the particles are trapped in the flotation gas bubbles decreases as the bubble size increases (assuming the air to liquid ratio remains the same).

In addition, so-called high performance flotation cells can be used in coal recovery operations where there is usually a flotation line containing one or two such flotation cells at the end of the separation loop to recover particularly fine coal particles. In the recovery loop, a process water recirculation system that circulates water from the end of the loop (i.e. from the flotation line and dewatering loop) back to the front loop (start of the recovery loop). Flotation chemicals and especially frothers are usually a source of problems in upstream processes. Problems can be mitigated to some extent by minimizing the use of frothers in the flotation line, but if not enough frother is added to the flotation process, the formation of froth in the prior art standpipes may deteriorate, leading to instability in process conditions and especially to unstable operation. standpipe and froth in the flotation cell, which in turn will adversely affect the recovery of the desired particles, especially large particles.

In known standpipes, the flotation gas is introduced in a self-priming manner under vacuum. The residence time of the flotation air for its entrainment into the slurry is very short, therefore the system is very sensitive to changes in process parameters. Foaming agents should be continually added to overcome the effect of limiting the air flow rate required to maintain or even increase the vacuum inside the dip tube to maintain as constant bubble / particle conditions as possible, as the frothers prevent bubbles from sticking together and rising back into the airspace within the dip tube. not filled with pulp. However, the addition of some of the blowing agent required for continuous use of the standpipe according to the prior art creates problems in other parts of the process, especially when handling coal as described above. Therefore, the solution was to reduce the foaming agent dose, which negatively affected the downpipe vacuum, bubble formation, bubble size and surface area, and also significantly reduces the recovery of the required particles, which makes known high-performance flotation cells ineffective when working with coal.

By using a flotation cell constructed in accordance with the present invention, the amount of foaming agent required to optimize the flotation process can be greatly reduced without significantly impairing bubble formation, bubble-particle interaction, stable foam formation, or recovery of the desired material. At the same time, the problems associated with the recirculation of process water from the downstream circuit to the upstream circuit can be reduced. The pressure standpipe is completely independent of the flotation tank. Better flotation gas flow rates can be achieved, smaller bubbles are created and the use of the frother is optimized since the standpipe operation is independent of the frother dose.

In prior art solutions, problems are associated in particular with the limitations of the amount of flotation gas that can be supplied, relative to the amount of liquid flowing through the standpipe, and the need for relatively high concentrations of blowing agents or other expensive surfactants to create small bubbles.

With the utility model presented here, flotation of fines and ultrafine particles containing, for example, mineral ore or coal can be improved by reducing the size of the flotation gas bubbles introduced into the downpipe slurry feed by increasing the flotation gas feed rate relative to the particle flow rate. suspended in the slurry, and due to an increase in shear force or the rate of energy dissipation, either in the standpipe or adjacent to it. The likelihood that the finer particles will attach to or be trapped in the smaller flotation gas bubbles increases, while the rate of recovery of the desired material, such as mineral or coal, is improved. In a flotation cell constructed in accordance with the utility model, sufficiently small flotation gas bubbles, so-called ultrafine bubbles, can be created to ensure that the fine ore particles are effectively trapped. Typically, ultrafine bubbles can have a bubble size distribution of 0.1 mm to 0.8 mm.

At the same time, recovery of larger particles can be maintained at an acceptable level by achieving a high proportion of flotation gas in the slurry due to the absence of areas of high turbulence in the region below the fourth layer. In addition, the upward movement of the slurry or slurry in the flotation tank increases the likelihood of larger particles rising to the foam bed along with the slurry flow.

By creating fine flotation gas bubbles or ultrafine bubbles, bringing them into contact with the particles and controlling the mixture of liquid and agglomerates of flotation gas bubbles and particles in the slurry, the recovery of hydrophobic particles into the fourth layer and into the overhead product or concentrate of the flotation cell can be maximized, thereby increasing thus, extracting the required material.

In this utility model, the following definitions are used with respect to flotation.

Flotation includes phenomena associated with the relative buoyancy of objects. Flotation is the process of separating hydrophobic materials from hydrophilic materials by adding a flotation gas, such as air, to the process. Flotation can be based on natural differences in hydrophobic / hydrophilic properties, or based on hydrophobic / hydrophilic differences resulting from the addition of a surfactant or chemical reservoir. Gas can be added to the feedstock to be flotation (slurry or slurry) in several different ways. In addition, foaming agents or blowing chemicals are commonly used to promote the formation of a foam layer from which the desired material is collected.

Flotation is mainly aimed at recovering concentrate of ore particles containing valuable material such as mineral or coal. By concentrate herein is meant the portion of the slurry recovered in the overhead product discharged from the flotation cell. A valuable mineral means any mineral, metal or other material of commercial value.

Flotation includes phenomena associated with the relative buoyancy of objects. The term "flotation" includes all flotation processes. The flotation can be, for example, froth flotation, dissolved air flotation (DAF), or induced gas flotation. Froth flotation is the process of separating hydrophobic materials from hydrophilic materials by adding a gas, such as air, to the process. Froth flotation can be based on natural hydrophilic / hydrophobic differences, or based on hydrophilic / hydrophobic differences resulting from the addition of a surfactant or chemical reservoir.

By a flotation line, herein is meant an assembly or device containing a number of flotation assemblies or chambers in which the flotation step is performed and which are located in fluid communication with each other to allow the flow of slurry between the flotation chambers, either by gravity or by using pumping to form a flotation line. In the flotation line, several flotation cells are located in fluid communication with each other, so that the underflow of each previous flotation cell is sent to the next or subsequent flotation cell as feed, up to the last flotation cell of the flotation line, from which the underflow is sent out of the line to in the form of tailings or waste. It is also possible that the flotation line may contain only one flotation stage, carried out either in one flotation cell, or, for example, in two or more parallel flotation cells.

The slurry is fed through the feed port to the first flotation cell of the flotation line to start the flotation process. The flotation line may be part of a larger treatment plant containing one or more flotation lines and a number of other process steps to isolate, purify, and otherwise process the desired material. Consequently, a number of different pre- and post-treatment devices or installations can be operatively associated with the components of the flotation line, as known to the person skilled in the art.

By flotation cell, herein is meant a tank or vessel in which a stage of the flotation process is performed. The flotation cell is generally cylindrical in shape and is delimited by a sidewall or outer wall / walls. Flotation cells are usually circular in cross-section. The flotation cells can have a polygonal, for example, rectangular, square, triangular, hexagonal, or pentagonal, or other radially symmetric cross-section.

By top product, herein is meant that portion of the slurry that collects in the top overflow chute of the flotation cell and thus leaves the flotation cell as a concentrate. The top product may contain foam, foam and slurry, or in some cases only or most of the slurry.

By underproduct, herein is meant a fraction or part of the slurry that does not float to the surface of the slurry during flotation. Bottom product is the effluent or tailings leaving the flotation cell through an outlet, which is usually located at the bottom of the flotation cell.

By concentrate herein is meant a floating portion or slurry fraction of ore particles containing a valuable material such as mineral or coal.

By ultrafine bubbles, herein are meant flotation gas bubbles of 0.1 to 0.8 mm in size, introduced into the slurry in a standpipe.

In contrast, "normal" flotation gas bubbles used in froth flotation range in size from about 0.8 to 2 mm. Larger flotation gas bubbles may tend to coalesce into even larger bubbles while in the mixing zone where collisions occur between particles and flotation gas bubbles and also only between flotation gas bubbles. Since ultrafine bubbles are introduced into the slurry feed prior to entering the flotation tank, such coalescence is unlikely with ultrafine bubbles, and their size may remain smaller throughout their residence time in the flotation cell, thereby affecting the ability of ultrafine bubbles to trap fines.

In one embodiment of the flotation cell, the height to diameter ratio is between 0.3 and 0.9.

In one embodiment of the flotation cell, the outlet nozzle includes a throttle to restrict the flow of the slurry feed.

By forcing the slurry feed through the orifice, the bubbles that have formed in the elongated standpipe chamber are further reduced in size as they pass through the outlet nozzle in the orifice.

In one embodiment of the flotation cell, the outlet nozzle is configured to create a supersonic shock wave in the slurry feed as it exits the elongated cell.

A supersonic shock wave is generated when the feed velocity of the slurry passing through the outlet nozzle exceeds the speed of sound, that is, the feed flow of the slurry is shut off when the ratio of the absolute pressure upstream of the outlet nozzle to the absolute pressure downstream of the outlet nozzle choke exceeds a critical value. When this ratio exceeds a critical value, the slurry feed stream downstream of the outlet nozzle choke becomes supersonic and a shock wave is generated. Small bubbles of flotation gas in the slurry feed mix break up into even smaller ones as they are passed through the shock wave and come into contact with hydrophobic ore particles in the slurry feed, thereby creating agglomerates of flotation gas bubbles and ore particles.

In one embodiment of the flotation cell, the standpipe further comprises an impinger configured to contact the slurry feed stream from the outlet nozzle and direct the slurry feed stream radially outward and upward from the impinger.

In another embodiment of the flotation cell, the impinger comprises an impact surface made of wear-resistant material.

The impinger deflects the slurry feed flow radially outward towards the sidewall of the flotation tank and up towards the top surface of the flotation tank (i.e., toward the foam bed). The pulp is strongly mixed due to the energy of the deflected flow and forms vortices in which the size of the bubbles can be further reduced due to the shear forces acting on them. The favorable high shear conditions also cause a large number of contacts between flotation gas bubbles and particles in the slurry within the flotation tank. As the slurry flow is forced upward towards the foam bed, turbulence decreases and the flow becomes relatively uniform, which can contribute to the stability of already formed bubbles and agglomerates of flotation gas bubbles, especially those containing larger particles.

In one embodiment of the flotation cell, it also includes a preprocessing circuit.

In another embodiment of the flotation cell, the preprocessing circuit comprises a pumping tank in fluid communication with the flotation tank, wherein in the pumping tank fresh slurry feed and a fraction of the pulp taken from the flotation tank through the outlet can be combined into a slurry feed.

In another embodiment of the flotation cell, the preprocessing circuit also includes a pump configured to take a slurry fraction from the flotation tank and feed the slurry further from the pumping tank.

By taking the slurry from the bottom of the flotation cell, it can be ensured that the finer particles deposited on the bottom of the flotation cell can be effectively reintroduced into the active flotation part of the flotation tank before the finer particles are diverted to the tailings. Thus, the recovery rate of valuable material can be improved since particles containing even minimal amounts of valuable material can be collected in a concentrate.

In another embodiment of the flotation cell, the preprocessing circuit also includes a distribution block configured to distribute power.

In one embodiment, the flotation cell comprises 2 to 24 dip tubes, preferably 10 to 24 dip tubes.

In yet another embodiment of the flotation cell, the dip tubes are arranged concentrically to the perimeter of the flotation tank at a distance from the center of the flotation tank.

In yet another embodiment of the flotation cell, the dip tubes are arranged parallel to the side wall of the flotation vessel at a distance from the side wall.

The exact number of standpipes within the flotation cell may depend on the size or volume of the flotation tank, the type of material being collected, and other process parameters. By placing a sufficient number of standpipes in the flotation cell, an even distribution of ultrafine bubbles can be ensured, as well as a mixing effect caused by shear forces within the vessel.

In one embodiment of the flotation cell, the conical bottom portion of the sidewall of the flotation cell has a tilt angle of 10 to 45 °, measured with respect to the horizontal of the flotation cell.

By providing an angle of inclination to the tapered bottom of the sidewall of the flotation tank, tailings removal through the tailings outlet located at the bottom of the flotation tank can be improved. In addition, sanding up the bottom of the tank can be reduced.

In another embodiment of the flotation cell, the tilt angle is between 30 ° and 40 °.

In another embodiment of the flotation cell, the tilt angle is between 15 ° and 25 °.

This design can be especially useful for recovering coal particles suspended in pulp.

In one embodiment of the flotation cell, the vertical wall height of the flotation tank is 1.8 m or less.

In another embodiment of the flotation cell, the volume of the flotation tank is at least 10 m ³ .

By providing the flotation tank with a sufficient volume, the flotation process can be better controlled. The lift distance to the froth layer at the top of the flotation tank does not become too great, which can cause agglomerates of flotation gas bubbles and ore particles to remain together until the froth layer and particle return are reduced. In addition, a suitable bubble rise rate can be achieved to maintain good quality concentrate.

In one embodiment, the flotation line comprises 1 to 2 flotation stages, the first flotation stage comprising a flotation cell configured in accordance with the utility model described herein.

In one embodiment, a flotation line configured in accordance with the utility model comprises two flotation stages, of which at least the first flotation stage comprises a flotation cell configured in accordance with the utility model described herein.

In one embodiment of the flotation line, the flotation stage comprises at least two parallel flotation cells configured in accordance with the utility model described herein.

In one application of the flotation line, frothers are added to the flotation stage in an amount of 12 ppm or less.

By adding even a minimal amount of foaming agent or foaming agents, the problems associated with recycling the process water containing the foaming agent can be reduced or even avoided while maintaining good recovery of the desired material, especially coal.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the present utility model and form part of this description, illustrate embodiments of the utility model and, together with the description, help to explain the principles of the present utility model. In the drawings:

FIG. 1 depicts a three-dimensional view of a flotation cell in accordance with one embodiment of the invention.

FIG. 2 is a top view of a flotation cell in accordance with one embodiment of the invention.

FIG. 3 is a vertical sectional view of the flotation cell shown in FIG. 2, along the cut line A-A, and

FIG. 4a-c are schematic illustrations of flotation lines constructed in accordance with some embodiments of the invention.

DETAILED DESCRIPTION

Embodiments of the present invention are described in detail below, an example of which is illustrated in the accompanying drawing.

The description below discloses some embodiments in such detail that a person skilled in the art can use an apparatus, installation, and method in accordance with the invention. Not all steps of the embodiments are described in detail, as many of them are obvious to a person skilled in the art based on this utility model.

For simplicity, in the case of repeating components, the reference numbers have been retained in the following illustrative embodiments.

In the accompanying FIGS. 1-3, flotation cell 1 is shown in some detail. The drawings are not drawn to scale and many of the components of the flotation cell 1 have not been shown for clarity. FIG. 4a-c schematically show embodiments of a flotation line. The direction of the slurry flows is shown in the figures by arrows.

The flotation cell 1, made in accordance with the present utility model, is designed to treat mineral ore particles suspended in the slurry and to separate the slurry into underflow 400 and overhead 500, the overhead 500 containing the desired mineral concentrate.

The flotation cell 1 contains a flotation tank 10, which has a center 11 and a perimeter 12. The side wall 13 of the tank 10 contains a vertical part 13a and a conical bottom part 13b. The conical bottom part 13b has an apex 130 facing downward with respect to the height of the flotation cell 1.

The flotation cell 1 also contains a trough 2 (not shown in Figs. 1 and 2, but in Fig. 3 for simplicity, only the central trough 2 is shown. It should be understood that the trough 2 may, alternatively or additionally, contain a perimetric trough located the entire perimeter 12 of the reservoir 10 as is known in the art). The overflow 500 is collected in the chute 2 as it passes over the edge 21 of the chute, from the foam layer formed at the top of the tank 10.

The ratio h / d of the height h and the diameter d of the flotation cell is 0.9 or less. The height h is measured as the distance between the top 130 of the tapered bottom 13b of the side wall 13 and the edge 21 of the trough. The diameter d is measured as the diameter of the tank 10 around the perimeter 12 of the straight wall portion 13a as seen in FIG. 3, with the exception of any structures located outside the side wall 13, that is, collecting troughs 2 located outside the side wall 13, such as a perimetric trough. In one embodiment, the ratio h / d of the height h and the diameter d of the flotation tank may range from 0.3 to 0.9. The h / d ratio can be, for example, 0.45 or 0.5 or 0.7.

The conical lower part 13b of the side wall 13 of the reservoir 10 has an inclination angle of 10 ° to 45 °. In one embodiment, the angle of inclination may be between 30 ° and 40 °. This arrangement can be particularly advantageous if the flotation cell 1 is used to treat slurry containing mineral ore particles. In one embodiment, the tilt angle a may be between 15 ° and 25 °. This can be especially advantageous when the flotation cell 1 is used for coal recovery, that is, when flotation of coal particles suspended in pulp.

The height of the vertical wall portion 13a may be 1.8 m or less.

The flotation tank 10 may have a volume of at least 10 m ³ or at least 20 m ³ . The volume of the flotation tank can be from 10 m ³ to 100 m ³ .

In addition, the flotation cell 1 contains at least one dip tube 4 through which the slurry feed 100 is supplied to the flotation tank 11. The flotation cell 1 may be disposed from 2 to 24 dip tubes, or from 10 to 24 dip tubes. In one embodiment, there are 16 standpipes 4 (see FIG. 2). In another embodiment, there are 24 downpipes 4. In another embodiment, there are 10 downpipes 4. The exact number of downpipes 4 can be selected according to the specific operation, for example, the type of slurry processed in the flotation cell 1, with a volumetric the flow rate of the feed supplied to the flotation chamber 1, with the mass flow rate of the feed supplied to the flotation chamber 1 or with the volume of the flotation tank 10.

If the flotation cell 1 has several standpipes 4, they can be arranged concentrically to the perimeter 12 of the tank 10. This is the case when the tank 10 has a circular cross-section. The standpipes 4 can additionally be positioned so that each standpipe 4 is located at a distance from the center 11 of the tank 10, the distance preferably being the same for each standpipe 4.

According to one embodiment of the invention, the standpipes 4 can be arranged parallel to the side wall 13 of the flotation tank 10. This is the case when the tank 10 has a rectangular or square horizontal cross-section. In this embodiment, the standpipes 4 can be further positioned so that each standpipe 4 is located at a distance from the side wall 13, the distance preferably being the same for each standpipe 4. In other words, the standpipes 4 can be located on a straight line lines inside the tank 10.

The standpipe 4 comprises an inlet nozzle 41 configured to supply slurry feed 100 to the standpipe 41, more particularly to the elongated chamber 40. An inlet 42 for compressed flotation gas such as compressed air is configured such that the slurry feed 100 is exposed to the pressurized flotation gas as it exits the inlet nozzle 41. The slurry feed 100 forms a liquid stream which, when it enters the elongated chamber 40, mixes with the compressed flotation gas supplied through the inlet 42.

The flotation gas is entrained by the turbulent mixing action caused by the jet and disperses as small bubbles in the slurry feed 100 as it travels downwardly through the elongated chamber 40 to the outlet nozzle 43 configured to restrict the flow of the slurry feed 100 from the outlet nozzle 43, and also configured to maintain a pressurized slurry feed 100 in an elongated chamber 40.

To restrict the flow, the outlet nozzle 43 includes a throttle, such as a throat-like restricting structure. From the outlet nozzle 43, namely from the throttle, feed 100 of the slurry exits under pressure into the flotation tank 10.

When the slurry feed 100 passes through the outlet nozzle 43, more specifically through the orifice of the nozzle 43, the flotation gas bubbles are reduced in size due to the pressure change and due to the high shear environment behind the nozzle 43. The velocity of the gas-liquid mixture in the orifice of the outlet nozzle 43 may exceed the speed of sound when the flow becomes blocked, and the flow behind the throttle becomes supersonic, while a shock wave is generated in the expanding part of the outlet nozzle 43. In other words, the outlet nozzle 43 is configured to generate a supersonic shock wave in the pulp feed 100.

The slurry feed 100 is shut off when the ratio of the absolute pressure upstream of the outlet nozzle to the absolute pressure downstream of the orifice of the outlet nozzle 43 exceeds a critical value. When this ratio exceeds a critical value, the slurry feed 100 downstream of the throttle of the outlet nozzle 43 becomes supersonic and a shock wave is generated. Small bubbles of flotation gas in the slurry feed 100 are separated into even smaller ones by passing through the shock wave and forced to come into contact with the hydrophobic ore particles in the slurry feed 100, thus creating agglomerates of flotation gas bubbles and ore particles.

The standpipe 4 may further comprise an impinger 44 adapted to come into contact with the slurry feed stream 100 from the outlet nozzle 43. The slurry feed 100 exiting the outlet nozzle 43 is therefore directed to come into contact with the impinger 44. The impinger 44 is configured directing the flow of the slurry feed 100 radially outward and upward from the impinger 44.

The impinger 44 deflects the slurry feed 100 radially outward towards the side wall 13 of the flotation tank and up towards the upper surface (foam layer) of the tank 10. The slurry is strongly mixed by the energy of the deflected flow and forms vortices in which the bubble size can be further reduced by the account of the shear forces acting on them. The favorable high shear conditions also cause a large number of contacts between flotation gas bubbles and slurry particles within the flotation tank 10. As the slurry flow is directed upward towards the foam bed, turbulence decreases and the flow becomes relatively uniform.

Impinger 44 may include a collision surface for contacting slurry feed 100 exiting outlet nozzle 43. The collision surface may be made of a wear resistant material to reduce the need for replacements or maintenance.

The slurry, which is essentially a two-phase gas-liquid mixture, rises from the impinger 44 and enters the top of the flotation tank 10, while the bubbles of the flotation gas rise upward and separate from the liquid, forming a foam layer. Foam rises upward and exits through lip 21 into chute 2 and exits flotation cell 1 as overflow 500. Tails or underflow 400 from which the required material has been substantially removed exits flotation tank 10 through an outlet located in the bottom parts 13b, for example, at apex 130.

Some of the large hydrophobic particles that are carried into the foam may subsequently separate from the flotation gas bubbles and fall back into the tank 10 as the bubbles coalesce in the foam. However, most of these particles fall back into the reservoir 10 in such a way and in such a position that they can be entrained by the bubbles re-entering the reservoir 10 from the dipleg 4 or diplegs 4 and transferred back to the foam layer.

The flotation cell 1 may also contain a preparatory circuit (not completely shown in the drawings). The preparatory circuit may comprise a pumping tank 30 or other such additional tank in which fresh slurry feed 200 and a slurry fraction 300 taken from the flotation tank 10 through an outlet can be combined to form a slurry feed 100. In addition, the preprocessing circuit may comprise a pump 31 configured to take a slurry fraction 300 from the flotation tank 11 and to further transfer the slurry feed 100 from the pumping tank 30 to the standpipe 4 or downpipes 4.

Fraction 300 slurry may contain particles with a low settling rate, such as small, slowly floating particles. A slurry fraction can be taken from the bottom of the tank 10 or near its bottom, the bottom being defined as the portion within the conical bottom 13b of the side wall 13 of the tank 10.

The pump 31 can also be used to further feed the slurry feed 100 into the downpipe 4 or downpipes 4. To evenly distribute the slurry feed 100 into the downpipes 4 (if the flotation cell 1 contains several downpipes 4), a distribution system can be used. block.

FIG. 4a-c shows a flotation line 8. The flotation line comprises a flotation stage 81, that is, a process stage in which flotation is performed in the flotation cell to recover the concentrate. The flotation line 8 may comprise one flotation stage 81 or multiple stages 81, 82 connected in series and in flow connection so that the underflow from the first flotation stage 81 is fed as feed to the next flotation stage 82. Although FIG. 4a-c show only two flotation stages, it should be understood that the flotation line 8 can also have more than two, for example three or four flotation stages.

The flotation line 8 may be preceded by other processes such as grinding, classifying, screening, heavy medium separation, coarse particle recovery, spiral separation and other separation processes, as well as other flotation processes. The flotation line 8 may be followed by a number of processes such as regrinding, cleaning or other flotation processes, centrifugation, filtration, screening or dewatering. For example, when coal is removed from the flotation line 8, a screening process (usually for finer particles in the cyclonic classifying stage) may precede, from which the material to be treated by flotation is sent to the flotation line 8. The top product, i.e. the concentrate of the required material, coal, is then collected and dewatered (eg in a drum filter).

In the flotation line 8, the first flotation stage 81 may be carried out in a flotation cell 1 constructed in accordance with the utility model, as described above (see Fig. 4a). The flotation line 8 may comprise from one to two stages 81, 82, wherein the first flotation stage 81 comprises a flotation cell designed in accordance with the utility model.

In a flotation line 8 comprising two stages 81, 82, both flotation stages can be carried out in a flotation cell 1 (FIG. 4b). In one embodiment, the flotation step 81, 82 may be performed in at least two parallel flotation cells 1 (FIG. 4c). In this case, the slurry feed 100 is divided into both flotation cells 1, and the underflow 400 from the parallel flotation cells can be combined and sent to the next flotation stage 82 as feed. The next flotation stage 82 may also comprise a flotation cell 1. The next flotation stage 82 may also comprise at least two parallel flotation cells 1.

The flotation line 8, designed in accordance with the utility model, can be used to recover coal particles, especially fine or ultrafine coal particles suspended in the slurry. Advantageously, by using a flotation line 8 constructed in accordance with the invention, the amount of foaming agents can be reduced while achieving good coal recovery. In one embodiment, blowing agents can be added in flotation stage 81 in an amount of 12 ppm or less. The foaming reagent or reagents can be added, for example, in an amount of about 5 ppm, 7.5 ppm, or 10 ppm. Foaming reagents are added to the flotation stage by any suitable method known to a person skilled in the art.

The present utility model is described herein in terms applicable to the separation of minerals or coal, in which the mineral ore or coal is either finely ground, or naturally in the form of fine particles forms a slurry or suspension of particles in water, the slurry being conditioned by chemical collectors and foaming agents to so that the required minerals or coals to be recovered by flotation become hydrophobic or non-wettable, while non-wettable or hydrophilic particles must remain in the slurry and discharged from the flotation tank as tailings. An example of this is the separation of fine coal particles from the surrounding waste rock (ash) during mining operations.

The above described embodiments can be used in any combination with each other. Several embodiments can be combined together to form an additional embodiment. The flotation cell to which the invention relates may include at least one of the embodiments described above. It is obvious to a specialist that with the development of technology, the basic idea of a utility model can be implemented in various ways. Thus, the utility model and its embodiments are not limited to the examples described above; instead, they may vary within the scope of the utility model claims.

Claims (9)

1. Flotation chamber (1) for processing particles suspended in the pulp, and for dividing the pulp into a bottom product (400) and an overhead product (500), and the flotation cell contains: a flotation tank (10) containing a center (11), a perimeter (12) and a side wall (13) with a vertical part (13a) and a conical lower part (13b) containing a top (130), a chute (2) and an edge (21) of the chute, surrounding the perimeter (12) of the tank (11), and a standpipe (4), through which it is possible to feed the slurry (100) into the flotation tank (11), while the ratio (h / d) of the height (h), measured as the distance between the specified apex (130) and the edge (21 ) of the trough, and the diameter (d), measured as the diameter of the flotation tank (10) around the perimeter (12) of the straight wall part (13a), is 0.9 or less, characterized in that the downpipe (4) contains an inlet nozzle (41 ) to feed the slurry feed (100) into the standpipe, the compressed air inlet (42), while feeding the bullets pulp is exposed to compressed air as it exits the inlet nozzle, an elongated chamber (40) configured to receive pressurized pulp feed, and an outlet nozzle (43) configured to restrict the flow of pulp feed from the outlet nozzle and maintain pulp feed into elongated pressurized chamber. 2. The flotation cell according to claim. 1, characterized in that the ratio (h / d) of height and diameter is from 0.3 to 0.9. 3. A flotation cell according to claim 1 or 2, characterized in that the outlet nozzle (43) comprises a throttle to restrict the flow of the slurry feed (100). 4. Flotation chamber according to any one of paragraphs. 1-3, characterized in that the outlet nozzle (43) is configured to create a supersonic shock wave in the feed (100) of the slurry when it exits the standpipe (4). 5. Flotation chamber according to any one of paragraphs. 1-4, characterized in that the conical lower part (13b) of the side wall (13) of the flotation tank (10) has an inclination angle (α) of 10 ° to 45 °, measured with respect to the horizontal of the flotation cell (1). 6. The flotation cell according to claim 5, characterized in that the tilt angle (α) is between 30 ° and 40 °. 7. The flotation cell according to claim 6, characterized in that the tilt angle (α) is between 15 ° and 25 °. 8. Flotation chamber according to any one of paragraphs. 1-7, characterized in that the height of the vertical part (13a) of the wall of the flotation tank (10) is 1.8 m or less. 9. Flotation chamber according to any one of paragraphs. 1-8, characterized in that the volume of the flotation tank (10) is at least 10 m ³ .

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