EA045025B1 - DEVICE AND METHOD OF SEPARATION BY FOAM - Google Patents

Description

Field of technology to which the invention relates

The present invention relates to a flotation separation apparatus and method that can be used for separating substances having different hydrophobicity, for example, for particle separation, in particular for mineral processing purposes, for example, for coal processing, and also for environmental protection purposes, recycling and water treatment to achieve solid separation, solid-liquid separation, or liquid separation.

State of the art

Flotation separation machines, also called flotation cells, are known in which the separation of elements can occur using the hydrophilicity or hydrophobicity characteristics of specific elements. In the mining industry, such machines are known as flotation cells. Separation cells typically collect a liquid stream containing the substances to be separated, which is hereinafter also referred to as slurry when it also contains solids, and gas and/or air bubbles generated and/or injected that are capable of separating hydrophobic material from hydrophilic material.

The hydrophobic material adheres to the bubbles and is carried to the liquid/air interface, thereby forming foams that will tend to aggregate and accumulate at the top of the cell, while the hydrophilic material will remain in the slurry, which is then discharged to the outside, e.g. at the bottom .

A variety of types of flotation cells have been developed, with the following being the best known and most common:

mechanical separation cells;

column-type separation cells, also called separation columns;

pneumatic separation cells;

Dissolved Air Flotation (DAF). These separation cells operate in a gravitational field, and the force that causes the separation between foam and pulp is gravity.

Centrifugal cells have also been developed in which the force that causes the separation of foam and pulp is centrifugal force. Centripetal acceleration can be obtained by feeding material and pulp into the cell tangentially, or can be created, for example, by rotating the flotation cell body around the axis of rotation.

Reagents can be added to the slurry to promote separation, improve foam stability, increase the hydrophobicity of materials that are to be recovered, and reduce the hydrophobicity of those materials that are not intended to be present in the foams.

For example, foams with enormous thicknesses, or high foams, can be produced using large amounts of foaming agent or many stable foaming agents. Large amounts of foaming agent can improve flotation separation results, but usually also have some detrimental effects on other parts of the plant and on the environment.

The flotation cell is usually a processing unit built into the unit and very often large amounts of foaming agent will reduce the overall performance of the system. Environmental restrictions may also limit the type and amount of reagents that can be used for flotation separation, and complete processing and then recycling of the effluent may be required, resulting in higher production costs.

Mechanical type flotation cells typically consist of walls that define a processing chamber into which the slurry or liquid is fed. The pulp is kept in a mixed state using a paddle mixer. The movement of the agitator blade, in combination with the stator, converts the forced air entering at the base of the rotor into fine bubbles as a result of shear forces.

Flotation columns are known which include, usually at their bottom, air bubble generators which introduce bubbles which, as they rise, pick up hydrophobic substances in the pulp and carry them upward. The separation columns are also typically equipped with a foam enrichment assembly to increase the purity of the foam so that a purer concentrate can generally be produced.

In centrifugal separation cells, which are usually round in shape, the pulp containing the material to be separated is fed tangentially to impart centrifugal acceleration. The air, converted into tiny bubbles, for example using a Venturi tube, is forced into the supply material and slurry pipeline.

Mechanical cells have shown that they can provide good results in terms of recovery of hydrophobic material, but they are unlikely to produce high purity concentrates from foam.

Separation columns and pneumatic cells produce higher foams than mechanical cells, and the foams can be washed to remove impurities contained in the liquid between the bubbles to achieve higher purity.

Centrifugal cells have a higher unit capacity than flotation cells

- 1 045025 other types of cells, but they are less efficient in terms of separation.

It has been demonstrated that separation selectivity increases with foam height; on this basis, thicker froths in flotation cells will produce cleaner products without any froth washing at all, as is the case with the above-mentioned flotation columns.

One disadvantage of the known separation cell technology is that the thickness of the foam reduces its stability, which should be understood as the ability of the bubbles not to collapse.

If the bubbles do not collapse, a certain stability and height of the foams can be obtained that will allow or more continuously reach the intended outlet channel so that the hydrophobic material can be effectively separated and released.

One object of the present invention is to provide a device for flotation separation of hydrophobic materials, which allows the height of foams to be increased while at the same time preventing their collapse.

It is yet another object of the present invention to provide a particle flotation separation device that can be used in any type of flotation cell known in the art to improve the performance of individual flotation cells and the entire plant.

A further object is to provide a device that is easy to mount on and/or away from flotation cells and that allows for simple and rapid maintenance.

A further objective is to develop a process for flotation separation of hydrophobic materials that provides more efficient separation of hydrophobic and hydrophilic materials, as well as large quantities of foams, in particular higher foams than those that can be obtained according to the prior art.

Last but not least is another object of the invention, which is to provide a method and/or apparatus for detecting foam properties during the separation process.

For reasons of overcoming the disadvantages of the prior art and achieving these and additional objects and advantages, the Applicant of the present invention has conceived, tested and implemented the present invention.

The essence of the invention

The present invention is presented and characterized by independent claims. Dependent claims disclose other features of the present invention or variations of the basic idea of the invention.

In accordance with the above objectives, a flotation separation apparatus includes a flotation cell and at least one modular foam support element that can be associated with said flotation cell, preferably being movable and/or removable during the separation process.

The flotation separation apparatus advantageously includes multiple modular elements interconnected to form a three-dimensional structure having large capacity and support volumes that provide a large additional support surface for the foams.

Said supporting structure may have a constant or variable cross-section along one or multiple extension directions.

The modular elements may be in the form of sheets whose thickness is much less than the dimensions defining the extent of the surface, or they may be elongated with one predominant dimension, for example elongated and/or thread-like elements, or small diameter hollow tubes.

The modular elements may have, in front view, an oval, round, square, polygonal, regular or irregular shape, or any other possible shape. The modular elements may have a substantially flat shape, or they may be curved along one or more axes, or be partly flat and partly curved.

Modular elements can have a constant or variable cross-section along the longitudinal or transverse directions of extension.

The modular elements may be arranged parallel to the vertical extent of the flotation cell, or they may be inclined, arranged in parallel and/or transverse rows, or arranged in a sunburst pattern, or in concentric rings of variable diameter.

For example, modular elements can be mutually aligned in a line, concentric or inclined.

In some embodiments, the modular elements may be combined with each other in terms of average bubble size and/or particle size of the materials being separated.

The modular elements may be solid, or they may have through-holes or grooves to allow lateral movement of foams and/or pulp or liquid. Thus, the device can still operate even when one or many volumes of passing foam have been blocked by the material contained therein.

- 2 045025

In some embodiments, the device includes a foam support module formed by one or more interconnected modular elements.

The foam supporting module has peripheral surfaces and internal surfaces. The interior surfaces are defined by numerous interconnected modular elements. The outer surfaces may be defined by the same modular elements, or a casing may be provided to enclose said modular elements.

In some embodiments, the foam support modules may include a specialized device for air recirculation and bubble introduction and generation to enhance overall bubble formation, providing higher foams. In some alternative embodiments, which may be combined with other embodiments, the foam support modules may be associated with flushing devices, which may be either connected to or separate from the flushing system, being part of, for example, column-type cells, thus thereby providing improved foam enrichment and washing.

Modular elements and/or foam support modules can be used in any existing type of flotation cell. They can also be structurally integrated into new machines.

In any case, the modular elements and/or foam support modules can preferably be mounted movable and/or removable, even during the separation process, so that they can be moved or removed in order to take foam samples or carry out maintenance, cleaning and things like that.

In some embodiments, modular elements and/or foam support modules are mounted on top of the flotation cells and may be partially placed within or on top of the slurry. Modular elements and/or foam support modules may be applied to or associated with the edge of the flotation cell, or suspended relative to the pulp.

Modular elements and/or foam support modules can be arranged to cover all or only a portion of the free interface area between the liquid containing the material to be separated and the foams in the flotation cell.

The foams can be collected by overflow from the top of the foam support modules, or through drainage channels leading to holding tanks or manifolds, or they can be transferred through connecting pipes to a subsequent foam support module, and a concentrate can be withdrawn from the last foam support module in the series.

According to a preferred embodiment, the invention includes a device for sampling foam so that properties of the foam, such as composition, purity and the like, can be determined.

According to the claims, a device for flotation separation is provided, comprising: a separation flotation cell equipped with a processing chamber into which a liquid stream containing the material to be separated can be introduced;

and one or more devices for introducing and/or generating air bubbles, for carrying out flotation separation of hydrophobic material and hydrophilic material, characterized in that said device contains at least one modular foam supporting element removably associated with the separation flotation cell, so that at least one modular foam support element (30) can be removed to take foam samples or carry out maintenance, cleaning or replacement work, and the like, during the separation process, and wherein the at least one modular foam support element comprises modular wall elements placed in parallel or transverse directions to form a structure in the form of a three-dimensional lattice.

Preferably, the modular elements are connected to each other to form an internal foam support module structure for providing additional support surfaces for the foams, said foam support module being movable and/or removable during the separation process.

Preferably, said modular foam support elements have, in front view, an oval, round, square, polygonal, regular or irregular shape, or any other possible shape, and that said modular elements have a flat and/or curved shape.

Preferably, said modular elements have a constant or variable cross-section along the longitudinal and/or transverse extent.

Preferably, said structure is a mesh or lattice, or a structure having a toroidal or circular crown shape, or a three-dimensional structure having any shape, configured to create flow volumes and additional supporting surfaces to support the foams and encourage their upward flow.

Preferably, said at least one modular element and/or foam support module comprises a bubble generating and/or introducing device configured to generate and/or introduce air bubbles to enhance overall bubble flow

- 3 045025 and stimulate the growth and stability of foams in the device.

Preferably, said at least one modular element and/or foam support module comprises a foam recirculation loop for allowing the concentrate in the foams to be recirculated.

Preferably, said at least one modular element and/or foam support module comprises one or more flushing devices configured to supply water and/or liquid at different heights within said foam support module.

Preferably, said modular elements and/or said foam supporting modules are arranged to cover the entire free surface of the liquid in said separation flotation cell, or only a portion thereof.

Preferably, said modular elements and/or said foam support modules are mounted on top of the separation flotation cells, and may be partially placed within or on top of the slurry or liquid.

Preferably, the modular elements and/or modules can be mounted on the edge of the separation flotation cell, or otherwise connected thereto, or suspended in the slurry or liquid, or left to float in the latter.

Also according to the claims of the invention, a method of flotation separation in the above-mentioned device for flotation separation is proposed, comprising:

introducing a stream containing the material to be separated into the processing chamber;

generating and/or introducing air bubbles into said processing chamber;

separating from the hydrophilic material hydrophobic material which adheres to the bubbles and is transferred towards the free surface of the liquid in said processing chamber.

Moreover, the method provides:

forming very deep foams, while maintaining them by at least one modular element and/or one foam supporting module associated with the separation flotation cell in the above device;

removing at least one modular element and/or one foam support module from the separation cell to collect a sample of foam to be analyzed during the method.

Preferably, one or more operational parameters of the separation cell are controlled depending on the properties of the analyzed foam sample.

In addition, according to the claims, there is provided a device for controlling flotation separation in the above method, comprising a modular element and/or a foam support module removably associated with said separation cell during operation of the separation cell so that at least one modular foam support element can be removed to take foam samples or carry out maintenance, cleaning or replacement work, and the like, during the separation process, and wherein the at least one modular foam support element comprises modular wall elements arranged in parallel or transverse directions to form structures in the form of a three-dimensional lattice.

Brief description of drawings

These and other features of the present invention will become apparent in light of the following description of certain exemplary embodiments thereof, in which reference will be made to the accompanying drawings, in which:

fig. 1 is a schematic front cross-sectional view of a flotation separation apparatus in accordance with certain embodiments described herein;

fig. 2 is a top view of a device in accordance with some embodiments described herein;

Figures 3a-3b are schematic views of embodiments of combinations of modular elements in accordance with certain embodiments described herein;

fig. 4 is a schematic perspective view of a foam support module in accordance with certain embodiments described herein;

Figures 5a-5c are schematic views of some embodiments of the foam support module of FIGS. 3;

fig. 6 is a schematic view of some flotation separation devices in accordance with some embodiments described herein, connected in series with each other;

fig. 7 is a schematic front cross-sectional view of an embodiment of a flotation separation apparatus in accordance with certain embodiments described herein;

fig. 8 is a top view of a flotation separation device according to the embodiment of FIG. 7;

fig. 9 is a schematic front cross-sectional view of an additional embodiment of a flotation separation apparatus in accordance with certain embodiments described herein.

For better understanding, the same reference code numbers have been used throughout the drawings as much as possible to denote identical common elements. Moreover, it goes without saying that elements and features of one embodiment may also be readily applicable to other embodiments.

Description of some embodiments of the invention

Reference will now be made to details of various embodiments of the invention, one or many examples of which are illustrated in the accompanying drawings. Each example is provided to illustrate the invention and is not to be construed as limiting thereof. For example, features of an embodiment illustrated or described herein may be valid in or linked to other embodiments to create an additional embodiment. It is understood that the present invention includes all such modifications and variations.

In accordance with the present invention, the flotation separation device 10 can generally be used to separate hydrophobic materials, for example, for mineral processing purposes, particularly coal processing, or in environmental protection, recycling and water treatment applications to achieve separation of solid materials, solid material and liquid, or separation of liquids.

In embodiments according to the present description, the expression flotation separation refers to a chemical process that falls within the category of processes referred to in the industry as adsorption-bubble separation. Specifically, two examples of flotation separation methods are the froth flotation method and the froth fractionation method. The device 10 according to the present invention includes a flotation cell 12, 112, 212, and at least one modular foam support module 30, which is movably and/or removably connected, also during the process, to the flotation cell 12, 112, 212.

In some embodiments, multiple modular elements 30 are provided that are interconnected to form a three-dimensional foam supporting structure.

The modular elements 30 may have an elongated, flat or curved shape, and may be mutually aligned, concentric or inclined, forming a lattice, or have a toroidal or ring shape, or any possible three-dimensional structure 28 that can be obtained by combining and intersecting modular elements. elements 30 to allow the foam to flow upward.

The support structure 28 may have foam accommodating and supporting volumes that provide large additional support surfaces for the bubbles so that they are not supported only by underlying bubbles, and thus can form more stable and higher or deeper foams.

In some embodiments, the modular elements 30, combined with each other to form a structure 28, may form the internal structure of the foam support module 14.

In the embodiments described herein with reference to FIGS. 1, mechanical flotation cell 12 includes a processing chamber 13 defined by outer side walls 16 and bottom wall 17 for containing slurry or liquid and for performing separation of hydrophilic material from hydrophobic material. The flotation cell 12 includes an opening 18 for supplying a stream of material to be separated, and an outlet 20 for removing an effluent stream, i.e., liquid containing hydrophilic material, which is typically located near the bottom 17.

The flotation cell 12 also includes a rotor 22 coupled to and driven by a motor 24 that maintains the slurry in a state of agitation and prevents settling of the material contained therein. An air supply device 27 may also be present, for example associated with the rotation of the engine or connected to a supercharger or compressor; this air is necessary to form bubbles to which the hydrophobic material will adhere. For example, the combined action of the rotor and stator of the paddle mixer 22 can be used (the stator is not shown) to generate fine bubbles.

Typically, the mechanical separation cell 12 is also provided with a support structure, also referred to as a bridge, 25 for supporting the assembly including the paddle mixer 22 and the motor 24. The bridge 25 may be a frame or a support plate.

The bubbles rise toward the top of the flotation cell 12 and, when they reach a height greater than the outer walls 16, they can fall into suitable skimmers 26 from which they will be discharged to recover the separated concentrate of material.

In addition and/or alternatively, near the edge of the side wall(s) 16 of the separation cell 112, there may be one or more channels (not shown in the drawings) for draining or releasing foam from the cell 12 into the reservoirs 26.

In some embodiments, modular elements 30 and/or foam support modules 14 are built into the top of flotation cells 12 and may be partially located within or on top of the slurry. Modular elements 30 and/or foam support modules 14 may be attached to or associated with the edge of flotation cell 12, or suspended relative to the pulp or

- 5 045025 liquid, or float on it.

The modular elements 30 and/or foam support modules 14 are advantageously connected to the separating cell 12 by being movable and/or removable. Thanks to this, they can be moved or removed even when the cell 12 is in operation during the flotation process according to the invention.

This will make it possible to take action as soon as required: for example, in the event of a malfunction, failure or the like, or to replace one or more modular elements 30 or foam support modules 14, or to check the progress of the separation process, or to take foam samples for examination .

In essence, removing, lifting, or moving in any way one or more modular elements 30 or foam support modules 14 will also remove foam deposited thereon.

The foam thus obtained can then be analyzed separately in the laboratory or visually by an operator to evaluate its properties (eg density, purity, composition, etc.) and obtain information regarding the progress of the separation process; In this way, it will be possible to check whether the process is proceeding correctly, or whether some changes in the process parameters are required (for example, the number of bubbles injected, the speed of rotation of the paddle mixer 22 for mixing the pulp, the residence time in the separator, etc.). In some embodiments, the foam support module 14 may be tightly or loosely connected to the flotation cell 12, 112, 212; in both cases the foams will rise due to the wall effect reinforced by the internal structure 28.

In accordance with the embodiments described herein, with reference to figures 1 and 2, modular elements 30 and/or foam support modules 14 can be associated with the flotation cell 12 so as to cover all or only a portion of the free surface of the pulp.

For example, the right side of Figures 1 and 2 shows an exemplary solution in which six modular elements 30 or foam support modules 14 cover the entire free surface of the pulp (from the center to the wall 16) and collect all the foam and concentrate that rises to the top of the flotation cell 12; in this case the coating is almost dense.

The left side of figures 1 and 2 shows an exemplary technical solution in which four modular elements 30 are placed so that they do not cover the entire free surface, but only the inner part, which is furthest from the foam collector 26. Thus, foams can be removed in the traditional way, with particles and fibers, including large ones, are collected in foam collectors 26, while the innermost part is cleaned in the foam support module 14 to create a cleaner concentrate. These two technical solutions can be used separately or in combination with each other or with additional options.

The solution illustrated on the left allows the foam support module 14 to be used as a foam accumulator in conventional flotation cells 12, 112, 212 so that deeper foams can also be formed near the outer walls 16.

The froths should not be too deep in the outermost portion as this would reduce the average residence time in the flotation cells 12, 112, 212 as the usable volume would be reduced, resulting in reduced recovery of hydrophobic material in the froths. The modular elements 30 and/or foam support modules 14 provide the advantage that very high foams can be obtained while maintaining the same average residence time of the slurry or liquid in the flotation cells 12, 112, 212. The average residence time can also be increased by if the slurry or liquid level rises, and the corresponding modular elements 30 and/or foam support modules 14 are positioned to tightly cover the entire free surface. This may in any case be useful in existing flotation cell systems 12, 112, 212, which cannot provide satisfactory results due to their insufficient size.

According to the embodiments described herein, with reference to FIGS. 3a, modular elements 30 may include modular wall elements 30a, 30b arranged in parallel or transverse directions to form a structure 28, for example, in the form of a three-dimensional lattice. The modular elements 30a, 30b can be placed in orthogonal directions or inclined relative to each other at an angle other than 90°.

The modular elements 30a, 30b can either be aligned vertically or placed obliquely.

In some embodiments, the modular elements 30 may have smooth surfaces, or be provided with through holes or grooves to allow bubbles and foam to flow laterally.

The modular elements 30a, 30b form foam flow volumes having a relatively narrow cross-section. Such sections may become clogged with solids or fibers contained in the pulp.

The presence of perforated modular elements 30a, 30b will allow slurry, foam and/or bubbles to flow in a transverse direction to ensure self-levelling of the slurry level or

- 6 045025 fluids within the structure 28. This means that lateral movements and higher efficiency can be obtained when a channel or duct becomes clogged by allowing the contents themselves to be redistributed into adjacent ducts.

According to an alternative embodiment described herein with reference to FIG. 3b, the structure 28 may include modular elements 30a arranged parallel to each other with interposed interconnecting modular elements 30c having an elongated shape and a thickness that is much smaller than the dimensions that define their surface. In some embodiments, the connecting modular elements 30c may be placed in an orthogonal direction or obliquely at an angle α other than 90° relative to the modular elements 30a.

A bubble and/or particle moving in a vertical direction has a weight that is equal to its mass multiplied by the acceleration due to gravity (mxg). The inclined connector 30c can provide bubble support equal to mxgxcosa in a direction perpendicular to the surface of the connector 30c, that is, less than or equal to the value of mxg. The weight of the bubbles and the particles contained therein will thereby be reduced not only due to the wall effect created by the modular elements 30a, but also by the reaction force exerted by the inclined connecting element 30c.

In additional embodiments, the structure 28 may consist of a lattice formed by multiple solid or hollow modular elements 30a having one predominant size.

In some possible embodiments, the modular wall members 30a, 30b may be fabricated as a single integral piece extending from the bottom to the top of the interior structure 28, or along its transverse extent, or they may be fabricated from multiple modular elements 30 mutually layered. on top of each other and combined, or connected and held apart from each other by additional connecting elements 30c, such as connecting rod spacers.

Fig. 4 is used here as a reference to describe a foam support module 14 that includes at least one modular element 30, in particular multiple modular elements.

The foam support module 14 may have peripheral surfaces and internal surfaces defined by modular elements 30 that provide additional support surfaces for the foams.

In some embodiments, the foam support module 14 may include side walls 36 that define a housing 38 that externally encloses the modular elements 30. The side walls 36 may also be configured to allow the foam support module 14 to be connected to the top of the flotation cell 12.

The housing 38 may be defined by a lower edge 37 and an upper edge 39. The lower edge 37 may be immersed in or suspended above the pulp or liquid, while the upper edge 39 may be contained within or extend beyond the outer walls 16 of the processing chamber 13.

When the foam support module 14 is partially inserted into the processing chamber 13, the side walls 36 may have through holes or grooves at least on their lower portions flush with the liquid to allow lateral movement in and out of the foam support module 14. In the portion located outside the liquid, the side walls 36 may be formed as solid walls to retain the foams and support them until they reach the top edge 39 where they are then removed.

In some embodiments, the side walls 36 may be formed as a single integral piece, or they may be formed from segments joined and fused together to form a housing 38.

In some embodiments, the housing 38 may have a constant or variable cross-section between the lower edge 37 and the upper edge 39. The cross-section may also vary more than once.

For example, the cross-section defined by the lower edge 37 of the foam support module 14 may have dimensions A1 and B1, while the cross-section defined by the upper edge 39 may have dimensions A2 and B2, respectively equal to the dimensions A1 and B1. The dimensions A2 and B2 of the top edge 39 can be selected depending on the vertical foam speed achieved. If the speed of air flow through a section remains constant, the average speed will be inversely proportional to the area of the section.

In some embodiments, the modular elements 30 may be firmly secured and secured to the side walls 36 using suitable known fasteners. Some examples of fasteners may be welds, bolts, hooks, hinges, flanges, or the like.

Said fastening means preferably allow the modular elements 30 and/or foam support modules 14 to be removed even during the separation process, that is, when the separation

- 7 045025 cell 12 is in operating mode.

In one alternative embodiment, a support member 40 may be used to support the modular members 30 in a desired position and secure them to the side walls 36. The support member 40 may be located at the bottom edge 37 or at a predetermined distance h1 from the bottom edge 37.

One alternative embodiment may provide a stop element 42 for limiting the vertical movement of the modular elements 30. The stop element 42 can be placed near the top edge 39, that is, at a distance h2 from the latter.

In some embodiments, the support member 40 and/or the stop member 42 may include beams, grids, or other elements suitable for supporting the modular members 30 while allowing both liquid and air bubbles to flow.

In some embodiments, the support member 40 and/or the locking member 42 may be removably secured to the side walls 36 so that the modular members 30 can be quickly removed for cleaning and maintenance operations.

Some embodiments may provide only one support member 40 and only one stop member 42 for the entire internal structure 28, or additional support members 40 and/or limit members 42 may be placed at intermediate positions between some of the modular members 30.

In some embodiments, the foam support modules 14 may include bubble generation and/or distribution devices 50 for introducing additional bubbles to make the separation process more efficient. In this way, bubbles will be introduced both into the flotation cells 12, 112, 212 through known generators 21, 27, and into each individual foam support module 14. In this way, a large number of bubbles can be supplied and forced into the foam support module 14 to control the separation and recovery of hydrophobic material.

Additional bubbles can also be generated by forcibly recycling a portion of the material exiting the flotation cells 12, 112, 212 into additional flotation cells 12, 112, 212. This solution is typical of bubble generators incorporating Venturi devices or in-line mixers.

In some embodiments, the foam support module 14 may include a foam recirculation loop 52 for recirculating foam collected from upstream and/or downstream flotation cells 12 and for removing foam at various heights of the foam support module 14.

The foam support module 14 may also include its own foam washing circuit 54 configured to wash the foams supported by the module elements 30 to improve their purity, that is, to obtain a purer concentrate of the separated material.

The foam washing circuit 54 may include one or more washing devices 56 for dispensing water or another suitable liquid into the foam support modules 14, for example, at different heights. Wash devices 56 can be used in addition to existing wash devices, such as those housed in column-type flotation cells 112 (FIG. 7).

In some embodiments described herein, with reference to FIGS. 4, the foam support modules 14 may be equipped with handles 58, lugs, or other elements designed to allow the foam support modules 14 to be easily picked up and mounted.

In some embodiments described herein, with reference to FIGS. 4, the foam support modules 14 may include support members 60 for connecting the foam support modules 14 to the flotation cells 12, 112, 212, for example, at the ends of the outer walls 16 of the flotation cells 12, 112, 212 and/or near them, and/or suspended over pulp or liquid. The support members 60 may also be configured to connect two or more foam support modules 14 to each other.

The support members 60 may include side or corner projections, seams, hooks, and removable fasteners, and may be positioned at any height of the foam support module 14 for insertion into and/or connection with the flotation cell 12, 112, 212. with an additional foam support module 14, and/or with a support bridge 25, and to hold it in the desired position.

The support elements 60 may be directly connected to the walls 16 or the bridge 25, or they may be associated with and/or connected to suitable support structures 62 secured within the processing chamber 13 of the flotation cells 12, 112, 212. The support structures 62 may be configured for supporting individual modular elements 30 and/or foam supporting modules 14.

In some alternative embodiments, the modular elements 30 and/or foam support modules 14 may be supported by flotation cells 12, 112, 212 so that they can move freely in a vertical direction, for example, using floats. With this technical solution, the height of the foams can be maintained constant in the structure 28, regardless of the liquid level in the flotation cell 12, 112, 212. Stop elements may be present to limit movement and to prevent damage to the modular elements 30 and/or the foam supporting modules 14 of the flotation parts cells 12, 112, 212, for example, a paddle mixer or anti-wear coatings.

In some embodiments, which may be combined with all of the embodiments described herein, the foam support modules on one or more side walls 36 of the casing 38 may be provided with side doors 57 designed to allow concentrate to be removed from the foam support module 14 if it becomes clogged and obstructs proper flow of foams and concentrate towards the upper edge 39. Thus, in the event that the foam support module 14 becomes blocked, it will be possible to continue to use the separating device 10 as a traditional flotation cell 12, 112, 212.

Figures 5a-5c are useful for describing various methods for collecting foam at the top edge 39 of the foam support module 14.

The foams may be collected, for example, by overflowing into suitable manifolds 44, which are then discharged through a collection line 46 (FIG. 5a), or through an outlet from the manifold 44 into an underlying container, reservoir, or reservoir (FIG. 5b).

In some embodiments, the foams may be collected and discharged directly through one or more collection lines 48 located on top of the foam support modules 14 (FIG. 5c).

Collection lines 46 and/or 48 may be connected to corresponding skimmers 26 of flotation cells 12, 112, 212.

Fig. 6 is provided to describe an exemplary embodiment of an array 100 including multiple separating devices 10, each of which includes a flotation cell 12, such as a mechanical cell (some portions of which, such as the paddle agitator, are not shown for clarity), and a foam support module 14, connected with each other to allow pulp and hydrophobic material to flow between them.

It has been experimentally demonstrated that process throughput increases when hydrophobic material recovered from a bank of flotation cells 12, 112, 212 is fed directly into the froths of preceding flotation cells 12, 112, 212 to recycle the concentrate collected therein.

The technical problem encountered in industrial installations according to the prototype is, in fact, the impossibility of achieving a depth of foam that would allow recycling of the collected concentrate directly into the foams, not to mention the subsequent disposal of the hydrophilic material still present therein.

The foam support module 14 allows deep foams to be formed by wall effect, and then hydrophobic material to be supplied directly into the foams, as shown in FIG. 6, which shows by way of example how concentrate is recycled directly from one foam support module 14 to another between flotation cell 12 and the preceding cell, via foam recirculation loop 52.

For example, the pulp is fed into the first flotation cell 12 on the left side (arrow IN), in which the first separation between foam and pulp occurs, then the foams holding the hydrophobic material will rise up, while the foam containing the hydrophilic material will be fed into the next flotation cell 12 (arrow D) to be further processed during the separation process. Finally, when the last flotation cell 12 in the series or group of system 100 is reached, an effluent containing almost exclusively hydrophilic material will be finally removed (arrow OUT1).

Instead, the froths containing the separated hydrophobic material will follow the reverse path as they are discharged from the top of the last flotation cell 12 through the collection line 48 and recirculated into the froths collected in the upstream flotation cell froth support module 14 through the froth recirculation loop 52. and so on until they return to the foam support module 14 of the first flotation cell 12, from which the separated concentrate will be recovered (arrow OUT2).

In general, or preferably in part, recycling of the material floating in the foam support modules 14 can also be accomplished in various ways using a pump or an airlift. In addition, a choice can be made whether to recycle only the concentrate collected in the modules 14 or the entire amount of foam generated.

It will be clear that this type of feeding can also be carried out between different groups 100, not necessarily between flotation cells 12 of the same group 100.

Flotation cells 12, 112, 212 are typically arranged in groups 100 in a flotation unit, and may act as roughing, refining, or finishing flotation cells 12, 112, 212

- 9 045025 groups. For example, they may be configured to perform a first rough separation of hydrophilic and hydrophobic materials, or subsequent separation steps to recover additional hydrophobic material from the effluent, and/or to remove any hydrophilic material that may still be present in the concentrate obtained from upstream flotation tanks. cells 12, 112, 212.

In some alternative embodiments described herein, with reference to FIGS. 7, apparatus 10 includes a column-type flotation cell 112 including a processing chamber 13 formed by outer walls 16 and bottom wall 17 for containing pulp and performing separation of hydrophilic material from hydrophobic material.

Column-type flotation cell 112 includes an inlet 18 for introducing slurry or liquid, and an outlet 20 for removing effluent.

Typically, the column flotation cell 112 also includes an air bubble generator 21 for generating bubbles of a desired size within the processing chamber 13.

In addition, the column-type flotation cell 112 includes a rinsing device 23 that supplies water in countercurrent to the froths to encourage any hydrophilic material remaining on the air bubbles to slide toward the bottom 17.

In some embodiments described herein, with reference to FIGS. 7, foam support modules 14 may be positioned to cover, in whole or in part, the top surface of flotation cell 112. Foam support modules 14 can either be inserted into the processing chamber 13 (on the left side in FIG. 7) or attached to the top outer walls 16 (on the right side in FIG. 7) so that they are still in fluid communication with the treatment chamber 13. Foam flow channels 64 may be provided between adjacent foam support modules 14 to transport the foam toward the headers. 44 and/or to additional collectors.

As the foam support modules 14 protrude upward from the processing chamber 13, the overall volume of the device 10 will increase, thereby improving its performance.

As an example, assuming that it is necessary to generate 3 m of foam in a column-type flotation cell 112 that has a height of 6.5 m, which typically operates to generate foam with a height of approximately 0.5 m, the useful volume of liquid in the flotation cell 112 will be reduced to only 3 m, that is, by half. If the foam support module 14 protrudes from the flotation cell 112, 2.5 m of foams can be formed on the outside of the flotation cell 112 while keeping the average residence time of the slurry or liquid constant, thereby creating six times higher foams.

The formation of deeper foams is also stimulated when the foam support modules 14 are submerged under the foams. Moreover, the modules 14 can dampen turbulence and waves that can occur if too much air is blown in. Thanks to wave suppression, the modules 14 allow very shallow foams to be handled since the slurry or liquid will not be discharged directly into the concentrate.

Fig. 8 is useful for describing a schematic top view of a particle separation apparatus 10 that includes a column-type flotation cell 112, the surface of which is almost completely covered by multiple foam support modules 14, the cross-section of which in this case is a sector of a circular rim. According to this technical solution, the foam-supporting modules 14 have a cross-section in the form of a sector of a circle and are placed connected to each other in the form of round rims.

In some alternative embodiments described herein, with reference to FIGS. 9, apparatus 10 includes a centrifugal flotation cell 212 including a processing chamber 13 formed by outer side walls 16 and top walls 19 for separating hydrophilic material from hydrophobic material. The pulp or liquid is introduced through the opening 18 and the effluent is discharged through the outlet 20. The processing chamber 13 may have a cylindrical shape at its top and a truncated cone shape tapering at its bottom towards the outlet 20.

The bubbles will rise to the top of the flotation cell 212 and, when they reach a certain height within the processing chamber 13, they will tend to fall back down into suitable skimmers 26 located within the processing chamber 13.

In this solution, one or more modular elements 30 and/or foam support modules 14 can be attached to the top wall 19 of the flotation cell 212, for example, by attaching a support element 40 to the support structure 62. A closure element 66 for closing the mouth of the skimmer 26 is also may be attached to the support structure 62 and/or to the support member 40 to cause any bubbles to rise upward toward the foam support module 14.

The closure member 66 may be configured to switch from a closed neck position to an open neck position and, in the closed position, may be supported by stop members 68 that are present in the sump 26.

From the above description it can be understood that the originality of the invention lies in the use of one or more modular elements 30 and/or foam support modules 14, which are movable and/or removable during the flotation process, which makes it possible to remove them from the separation cell 12, 112, 212, even when the latter is working.

On the one hand, this allows maintenance work, cleaning and replacement of modular elements 30 or modules 14; on the other hand, it also makes it possible to sample the foam deposited on such modules.

In fact, foam retained by the modular elements 30 or modules 14 can be collected when they are lifted (by floats or by an operator) or removed from the cell 12, 112, 212; such foam can then be analyzed (for example, in a laboratory or visually by an operator) to obtain useful information about its composition, purity, etc., which information will allow the progress of the separation process to be monitored and any necessary changes made if any deviations in relation to desired conditions.

In this regard, it must be emphasized that it is important for the invention that the modular elements 30 and/or the foam support modules 14 are accessible from the outside of the flotation cell 12, 112, 212; they can preferably be handled from above by an operator or by means of a lifting device (crane, overhead crane, or the like): this is due to the fact that the separating cell 12 is preferably open from above.

It is clear that the particle separation apparatus and method described herein may undergo modifications and/or additions of parts without departing from the scope of the present invention.

It is also understood that although the present invention has been described herein with reference to certain specific examples, one skilled in the art will certainly come up with many other equivalent embodiments of a particle separation apparatus and method having the features set forth in the claims, and thereby located within the scope of legal protection determined by them.

List of symbols:

- device for flotation separation;

- mechanical flotation cell;

- processing chamber;

- foam supporting module;

- external walls;

- bottom wall;

- inlet;

- upper outer walls;

- outlet;

- air bubble generator;

- paddle mixer;

- washing devices;

- engine;

- bridge;

- foam collectors;

- device for introducing air;

- internal structure;

- modular elements;

a - modular walls;

b - modular walls;

c - connecting modular elements;

- side walls;

- bottom edge;

- casing;

- top edge;

- supporting element;

- locking element;

- collectors;

- collection pipeline;

- pipelines;

- bubble generators;

- foam recirculation circuit;

- foam washing circuit;

- washing device;

-

Claims (8)

57 - doors; 58 - handles; 60 - supporting elements; 62 - support structures; 64 - flow channels for foam; 112 - column-type flotation cell; 212 - centrifugal flotation cell; A1 - size; A2 - size; B1 - size; B2 - size; D - arrow; h1 - distance; h2 - distance; α - angle; IN - inlet channel for pulp; OU T1 - outlet channel for outflow; OU T2 - outlet channel for concentrate. CLAIM 1. A device for flotation separation, containing: a separation flotation cell (12; 112; 212) equipped with a processing chamber (13), into which a liquid stream containing the material to be separated can be introduced; and one or more devices (21, 27) for introducing and/or generating air bubbles, for carrying out flotation separation of hydrophobic material and hydrophilic material, characterized in that said device contains at least one modular foam supporting element (30), with the possibility of removal associated with the separation flotation cell (12; 112; 212), so that at least one modular foam support element (30) can be removed to take foam samples or carry out maintenance work, cleaning or replacement, and the like, during separation process, and wherein the at least one modular foam support element (30) comprises modular wall elements (30a, 30b) arranged in parallel or transverse directions to form a structure (28) in the form of a three-dimensional lattice. 2. The device according to claim 1, characterized in that the modular elements (30) are connected to each other to form an internal structure (28) of a foam support module (14) designed to create additional supporting surfaces for foams, wherein said foam support module (14 ) is movable and/or removable during the separation process. 3. The device according to any of the preceding claims, characterized in that said modular foam support elements (30) have, in front view, oval, round, square, polygonal, regular or irregular shape, or any other possible shape, and that said modular elements (30) have a flat and/or curved shape. 4. A device according to any of the preceding claims, characterized in that said modular elements (30) have a constant or variable cross-section along the longitudinal and/or transverse extent. 5. A device according to any of the preceding claims, characterized in that said structure (28) is a mesh or lattice, or a structure having a toroidal or circular crown shape, or a three-dimensional structure having any shape, configured to create flow volumes and additional supporting surfaces to support foams and stimulate their upward flow. 6. A device according to any one of claims 1 to 5, characterized in that said at least one modular element (30) and/or foam supporting module (14) contains a device (50) for generating and/or introducing bubbles, configured to forming and/or introducing air bubbles to enhance the overall flow of bubbles and stimulate the growth and stability of foams in the device. 7. Device according to any one of claims 1 to 6, characterized in that said at least one modular element (30) and/or foam support module (14) contains a foam recirculation circuit (52) designed to enable the recirculation of concentrate in foams . 8. A device according to any one of claims 1 to 7, characterized in that said at least one modular element (30) and/or foam supporting module (14) contains one or more flushing devices (56) configured to supply water and /or liquids at different heights inside said foam support module (14). -