Installation and method for improving ore floatability in a flotation process

Abstract

The present invention pertains to the field of ore flotation, in particular, that of injecting gas nanobubbles into the ore flotation process. This invention provides a facility and a method for improving ore floatability in a flotation process by increasing the retrieval of fine and ultrafine particles due to the presence of nanobubbles. These nanobubbles can be injected into the flotation liquid or directly into the ore pulp.

Description

[0001] INSTALLATION AND METHOD FOR IMPROVING THE FLOTABILITY OF MINERALS IN A FLOTATION PROCESS

[0002] Technical field of the invention

[0003] The present invention belongs to the area of ​​mineral flotation, in particular, that of injecting gas nanobubbles into the mineral flotation process.

[0004] Background of the invention

[0005] Within the state of the art, there are various techniques for injecting gases and generating micro or nano bubbles in flotation processes which, unlike the invention, do not allow for low operational impact implementation in currently installed plants or direct injection into mineral pulp lines with controlled and homogeneous diffusion.

[0006] The nanobubble injectors used in the state of the art work in three ways:

[0007] 1. Injecting nanobubbles using a tank with an integrated injector.

[0008] 2. Generating the nanobubbles in a flotation cell with the nanobubble generator integrated within the cell.

[0009] 3. Generating nanobubbles on the surface of the mineral by saturating the aqueous medium.

[0010] Application CL202001458 discloses the use of surfactants (specifically quillaia saponin) and one or more adjuvant gases in the hydrometallurgy and pyrometallurgy processes in which it is applied, which are added to it in a state of nanobubbles and microbubbles. In addition, it understands that both the gases used and the nanobubbles and microbubbles thereof, are present in a variable proportion depending on the physicochemical requirements of each of the stages of the process where it is applied. The nanobubbles and microbubbles of the proposed composition make it possible to significantly increase the physicochemical properties of these gases, such as: flotation speed, oxidizing power, reducing power, contact area provided, and coalescence speed.

[0011] Document CN108499746 presents a nanobubble flotation device comprising a rectangular tubular container, a basin for receiving the discharge, and a bubble-generating device. A nanofoam generator is arranged at the bottom of the device and comprises a cavity, a horizontal dividing plate, a conical filter plate, and microflow pipes; the microflow pipes comprise inner and outer tubes and copper foil coils. Waterproof bearings are fixedly arranged at both ends of the inner tubes, and rotating shafts are arranged in the waterproof bearings; and gates are arranged at the upper ends of the rotating shafts to cut off the air flow discharged by the copper foil coils.The size of the nanobubbles generated by the nanobubble flotation device can be modified by controlling the diameters of the air microflow channels and the rotation speed of a first motor. The generated nanobubble sizes are uniform, the nanobubble volume is large, the flotation efficiency is high, and the mineral recovery rate is high; and the nanobubble flotation device has a simple overall structure and low manufacturing cost.

[0012] US10155229B2 discloses a mineral flotation method using nanobubbles to enhance gas-solid interaction. The nanobubbles are used to connect microbubbles and non-floating particles, thereby creating sufficient capillary forces between the particles and microbubbles so that relatively large and heavy particles can be separated from the slurry. The nanobubbles form on the surfaces of the hydrophobic particles. The microbubbles, functioning as collecting air bubbles, adhere to the particles. The nanobubbles create additional capillary adhesion forces between the particles and the microbubbles, allowing the microbubbles to rise, along with the adhered particles, to the top of the suspension for separation and recovery.Finally, document 2023020661 presents a method for leaching minerals containing precious metals assisted by injecting oxidizing nanobubbles into pulp. In this case, nanobubbles are used due to their ability to maintain their chemical characteristics: high oxygen transfer efficiency and high reactivity. Furthermore, the present invention describes the use of air nanobubbles in pulp, where they maintain their physical properties: high stability, high collision probability with fine and ultrafine hydrophobic minerals, and high Z potential.

[0013] Summary of the invention

[0014] Essentially, the present invention provides a first object of the invention, which consists of an installation for improving the floatability of minerals in a mineral flotation process, characterized in that it comprises the installation of at least one nanobubble generator in a pulp or liquid line within an installation where a mineral flotation process is carried out.

[0015] Additionally, the present invention provides a second object of the invention, which consists of a method for improving the floatability of minerals in a flotation process, characterized in that it comprises the steps of: a. providing at least one nanobubble generator; b. installing said generator in a facility as previously described; c. connecting the nanobubble generator to a gas source; d. turning on the nanobubble generator and allowing the flow of pulp or liquid to pass through said generator; and e. sending the pulp or liquid with nanobubbles to a flotation system. Description of the figures

[0016] FIG. 1. Illustrates how nanobubbles act as secondary collectors.

[0017] FIG. 2. Illustrates the installation (1 ) for improving the floatability of minerals in a mineral flotation process in the pulp feed line (111 ) to the flotation process in primary pre-flotation cells (21 ) (pre-rougher).

[0018] FIG. 3. Illustrates the installation (1 ) for improving the floatability of minerals in a mineral flotation process in the pulp feed line (111 ) to the flotation process in primary flotation cells (22) (rougher).

[0019] FIG. 4. Illustrates the installation (1 ) for improving the floatability of minerals in a mineral flotation process in the pulp feed line (111 ) to the flotation process in a collective flotation system (25).

[0020] FIG. 5. Illustrates the installation (1 ) for improving the floatability of minerals in a mineral flotation process in the pulp feed line (111 ) to the scavenger flotation process (23).

[0021] FIG. 6. Illustrates the installation (1) for improving the floatability of minerals in a mineral flotation process in the liquid line (112) that goes to a flotation system (2), which could be the adjustment of solids in flotation.

[0022] FIG. 7. Illustrates the installation (1) for improving the floatability of minerals in a mineral flotation process in the liquid line (112) that is recirculated from the thickeners (26).

[0023] FIG. 8. Illustrates the installation (1) for improving the floatability of minerals in a mineral flotation process in the recirculation of liquids (112) of the flotation process in a reservoir which feeds the plant.

[0024] FIG. 9. Shows an example of flotation kinetics of primary flotation cells (22) (rougher) for copper ore.

[0025] FIG. 10. Shows an example of copper flotation kinetics without nanobubbles, with nanobubbles, and with nanobubbles plus foaming. FIG. 11. Shows an example of molybdenum flotation kinetics without nanobubbles, with nanobubbles, and with nanobubbles plus foaming.

[0026] FIG. 12. Shows an example of copper flotation kinetics without nanobubbles (Une basis) and with nanobubbles.

[0027] FIG. 13. Shows an example of copper recovery without nanobubbles (Une base) and with nanobubbles.

[0028] FIG. 14. Shows an example of copper flotation kinetics without nanobubbles (Une basis) and with nanobubbles.

[0029] FIG. 15. Shows an example of copper recovery without nanobubbles (Une base) and with nanobubbles.

[0030] Detailed description of the invention

[0031] Essentially, the present invention provides a first object of invention, which consists of an installation (1) for improving the floatability of minerals in a mineral flotation process that is characterized in that it comprises the installation of at least one nanobubble generator (10) in a line (11) of pulp (111) or liquid (112) within an installation where a process that uses a mineral flotation system (2) is carried out.

[0032] For the purposes of the present invention, but not limited to it, a feed line shall be understood to be a pipe through which a liquid or pulp circulates, which is part of a mineral flotation system (2). In a preferred embodiment of the present invention, said liquid may be water.

[0033] For the purposes of the present invention, without limiting it, a mineral flotation system (2) shall be understood as a system comprising at least one flotation cell or column, where said system (2) may be primary pre-flotation cells (21) (or pre-rougher), primary flotation cells (22) (or rougher), sweeping flotation cells (23) (or scavenger), cleaning flotation cells (24) (cleaner), collective flotation system (25), thickener (26), water reservoir for flotation (27), selective flotation system (28), reverse flotation system (29).

[0034] For the purposes of the present invention, without limiting it, the expressions “pulp feed line (111)” and “pulp line (11) (111)” will be used interchangeably, since line (11) refers to a line that can generally carry either liquid or pulp. In that sense, for the purposes of the present invention, without limiting it, the expressions “liquid feed line (111)” and “liquid line (112)” will be used interchangeably.

[0035] In a preferred embodiment of said installation (1 ), without limiting the present invention, said nanobubble generator (10) is installed in a pulp feed line (111 ) of a mineral flotation system (2) that is selected from primary pre-flotation cells (21 ) (or pre-rougher) (as in FIG. 2), primary flotation cells (22) (rougher) (as in FIG. 3), sweeping flotation cells (23) (scavenger) (as in FIG. 5), cleaning flotation cells (24) (cleaner).

[0036] In a preferred embodiment of said installation (1 ), without limiting the present invention, said nanobubble generator (10) is installed in a pulp feed line (111 ) of a collective flotation system (25), as in FIG. 4).

[0037] In a preferred embodiment of said installation, without limiting the present invention, said nanobubble generator (10) is installed in a liquid feed line (112) of a mineral flotation system (2) that is selected from primary pre-flotation cells (21) (pre-rougher) (as in FIG. 2), primary flotation cells (22) (rougher) (as in FIG. 3), sweeping flotation cells (23) (scavenger) (as in FIG. 5), cleaning flotation cells (cleaner) (24).

[0038] In a preferred embodiment of said installation, without limiting the present invention, said nanobubble generator (10) is installed in a liquid feed line (112) of a collective flotation system (25).

[0039] In a preferred embodiment of said installation, without limiting the present invention, said nanobubble generator (10) is installed in a recirculated liquid feed line (122) coming from a thickener (26), as in FIG. 7, or from a water reservoir for flotation (27), as in FIG. 8.

[0040] In a preferred embodiment of said installation, without limiting the present invention, said nanobubble generator (10) is installed in a recirculated pulp feed line (111) coming from a water reservoir for flotation (27).

[0041] The invention allows controlling the addition of air in the mineral flotation process, injecting the gas in the form of nanobubbles directly into the pulp and / or water that is added to the process. Said nanobubbles have a high Z potential, causing them to repel each other and increasing the probability of bubble-mineral collision, acting as secondary collectors for fine and ultrafine particles of hydrophobic minerals or minerals treated with chemical reagents (collectors) that increase the hydrophobicity of said minerals, which increases the floatability of the minerals in a flotation process, and, consequently, the recovery in the flotation processes, as illustrated in FIG. 1.

[0042] The invention involves the installation of a nanobubble generator (10) in a line, pipe and / or tank of aqueous solution (pulp and / or water) in mineral processing operations such as: Pulp feed lines to the processes of primary pre-flotation cells (21) (pre-rougher), primary flotation cells (22) (rougher), sweeping flotation cells (23) (scavenger) and collective flotation (25), regardless of the type of flotation device (cell or column) used in the process.

[0043] The equipment does not work through a tank but rather works directly in the line (11) (or pipe) or treating the solution in existing reservoirs (or ponds), which allows the direct treatment of the mineral pulp and the water that is added to said pulp during the flotation process.

[0044] In a preferred embodiment of the present invention, the nanobubble generator (10) has a tubular shape that does not generate physical impediments to the passage of pulp or solution, since the nanobubbles are injected around the tube that transports said pulp or solution. Unlike the state of the art, the installation (1) for improving the floatability of minerals in a mineral flotation process described can be installed directly in:

[0045] 1. Pulp transport pipelines: During pulp transport, the solution can be passed through the nanobubble generator, which is installed directly in the transport line, without the need for additional stages.

[0046] 2. Water transport pipes: During the transport of water from the flotation process, it can be passed through the nanobubble generator, which is installed directly in the transport line, without the need for additional stages.

[0047] 3. Liquid and / or pulp reservoirs: In many production processes, reservoirs or tanks are used for storage or pretreatment of liquid (or pulp) from which different stages or processes are fed. In these cases, the nanobubble injector can be installed in such a way that the contents of the tank are recirculated through the nanobubble injector, generating the nanobubbles before said liquid is fed to flotation.

[0048] Additionally, the present invention provides a second object of the invention, which consists of a method for improving the floatability of minerals in a flotation process, characterized in that it comprises the steps of: a. providing an installation as previously described; b. connecting the nanobubble generator (10) of said installation to a gas source; c. turning on the nanobubble generator (10) and allowing the flow of pulp or liquid to pass through said generator (10); d. sending the pulp or liquid with nanobubbles to the line (11) of pulp (111) or liquid (112). The method in which the nanobubbles act is to increase the probability of collision between microbubbles, bubbles and fine and ultrafine sized mineral as shown in FIG. 1 , acting as secondary collectors for said particles, improving the recovery of copper, molybdenum, gold, silver and iron among other species of interest.

[0049] In either case, the injected nanobubbles have a diameter of less than 1 micrometer, usually less than 200 nm, depending on the medium. The injected gas can be air, enriched air, ozone, oxygen, or any other type of gas. The gas can be bottled or generated on-site using a compressor, blower, or other mechanical device, as appropriate. The gas injection flow rate varies between 0 and 10% of the volumetric flow rate of the pulp or treated water, where this flow rate can be:

[0050] Maximum: In order to saturate the medium with nanobubbles.

[0051] Determined by an operator based on the characteristics of the mineral being treated and the holdup of the flotation cell or column, with the option of measuring and controlling the amount of gas present in the system.

[0052] It converts the gas only into nanobubbles with sizes between 50 and 500 nm, with the majority being between 100 and 350 nm.

[0053] The invention does not propose generating the nanobubbles in a pond.

[0054] The invention does not require a solid-liquid separation system.

[0055] The invention does not consider microbubbles.

[0056] The invention can be integrated into any established flotation process.

[0057] The invention includes the ability to inject the nanobubbles directly into the pulp.

[0058] The invention does not require the consumption of additional chemicals (surfactant) except those already used in the flotation process.

[0059] The proportion of gases used to achieve the results is between 5 and 10% of the volumetric flow rate of the solution or pulp to be treated. In the present invention, a nanobubble injector such as the one described in patent application CL 202200088 can be used as a preferred embodiment of the invention, but other types of injectors that allow direct injection into the mineral pulp line can also be used.

[0060] Steps for the implementation of the invention in pulp transport pipelines:

[0061] 1. The pulp line that will be passed through the nanobubble generator must be intervened.

[0062] 2. The bubble generator is connected to a gas source, which can be a compressor, gas cylinders or gas produced on site.

[0063] 3. The generator is turned on and the pulp is passed through it, at the same time the volumetric flow of gas that will be added to the pulp is selected.

[0064] 4. The pulp is sent directly to the flotation stage.

[0065] Steps for the implementation of the invention in liquid transport pipelines:

[0066] 1. The liquid line that will pass through the nanobubble generator must be intervened.

[0067] 2. The bubble generator is connected to a gas source, which can be a compressor, gas cylinders or gas produced on site.

[0068] 3. The generator is turned on and the liquid is passed through it, at the same time the volumetric flow of gas that will be added to the pulp is chosen.

[0069] 4. The liquid is sent directly to the flotation stage.

[0070] Steps for the implementation of the invention in pulp or liquid reservoirs:

[0071] 1. A line of pulp or liquid is added from the reservoir and passed through the nanobubble generator using a pump. 2. The bubble generator is connected to a gas source, which can be a compressor, gas cylinders, or gas produced on-site.

[0072] 3. The generator is turned on and the pulp or liquid is passed through it, at the same time the volumetric flow of gas to be added is selected.

[0073] 4. The pulp or liquid is returned to the reservoir from which the nanobubble generator is fed.

[0074] The present invention can be used in the flotation process of minerals containing copper, molybdenum, gold, silver, iron and other metals.

[0075] The gas to be injected in the present invention, in a preferred embodiment, without being limited by this, is air, which can be provided by compressed air containers or mechanical systems such as compressors, blowers or the like.

[0076] The nanobubble generator (10), in a preferred embodiment of the present invention, without limiting it, can be mechanical such as cavitation (in any of its types), microbubble compression, gas supersaturation in the pulp or through porous membranes. The injection method must be by passing the pulp or water through a nanobubble generator.

[0077] Within the framework of the present invention, without limiting it, it is possible to install the nanobubble generator in one or more intermediate stages of the flotation process, in series or in parallel, where the gas injection method and solution flow may vary as previously described.

[0078] For the purposes of this invention, mineral pulp is understood as a mixture of solid and liquid in suspension form. In other words, within the mining sector, pulp refers to a fluid composed of one or more mineral vapors (in a liquid).

[0079] For the purposes of the present invention, primary pre-flotation cells (21) (or pre-rougher cells, also known as flash cells) are understood to be the cell that treats the circulating load of the grinding. This cell is used to increase the efficiency of the mills and hydrocyclones in addition to recovering part of the material that has already been released. The material that is not floated in this stage returns to the mill and goes through a size classification process before entering the conventional rougher stage.

[0080] For the purposes of the present invention, primary flotation cells (22) (or Rougher Cells) will be understood as the cells that receive the head pulp that comes from the mill conditioners, in them most of the objective minerals float, from these cells both concentrates and "provisional" tailings are obtained since the concentrates still contain many impurities and the tailings in turn still carry objective minerals or values.

[0081] For the purposes of the present invention, cleaning cells (24) will be understood as the cells that receive the foams from the Rougher cells, and their function is to eliminate the greatest possible amount of impurities. For this purpose, they are used in first cleaner, second deanery and third cleaner batteries, the final concentrate of the third cleaner flotation is sent to the concentrate thickener.

[0082] For the purposes of the present invention, Scavenger Cells will be understood as the cells that receive the tailings from the primary flotation cells (22) and their function is to float the target minerals that did not do so either due to lack of time, addition of reagents or some mechanical effect, however the foam obtained from these cells cannot be sent to the concentrate thickener since it still contains many impurities, and they cannot be discarded either since they also contain values, so they are returned to the circuit, in the flotation head part.

[0083] For the purposes of the present invention, the collective flotation system (25) will be understood as the flotation system where the concentrate that goes through the flotation process contains two or more valuable minerals of a single mineralogical type (for example: sulfides), and which together come out in the foam.

[0084] For the purposes of the present invention, without limiting it, a mineral flotation system (2) shall be understood as a system comprising at least one flotation cell or column, where said system (2) may be primary pre-flotation cells (21) (or pre-rougher), primary flotation cells (22) (or rougher), sweeping flotation cells (23) (or scavenger), cleaning flotation cells (24) (cleaner), collective flotation system (25), thickener (26), water reservoir for flotation (27), selective flotation system (28), reverse flotation system (29).

[0085] For the purposes of the present invention, the selective flotation system (28) will be understood as the system where the mineral that goes through the flotation process contains more than one species of interest, which are separated by a flotation process.

[0086] For the purposes of the present invention, the reverse flotation system (29) will be understood as the system where the gangue is floated in the flotation process, while the species of interest are recovered in the tails of the flotation process.

Claims

CLAIMS 1. An installation (1) for improving the floatability of minerals in a mineral flotation process, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a line (11) of pulp (111) or liquid (112) within an installation where a process using a mineral flotation system (2) is carried out.

2. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a pulp feed line (111) of a mineral flotation system (2) that is selected from primary pre-flotation cells (21), primary flotation cells (22), sweeping flotation cells (23), cleaning flotation cells (24).

3. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a pulp feed line (111) of a collective flotation system (25).

4. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a pulp feed line (111) of a selective flotation system (28).

5. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a pulp feed line (111) of a reverse flotation system (29).

6. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a liquid feed line (112) of a mineral flotation system (2) that is selected from primary pre-flotation cells (21), primary flotation cells (22), sweeping flotation cells (23), cleaning flotation cells (24).

7. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a liquid feed line (112) of a collective flotation system (25).

8. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a liquid feed line (112) of a selective flotation system (28).

9. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a liquid feed line (112) of a reverse flotation system (28).

10. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a recirculated liquid feed line (112) coming from a thickener (26) or from a water reservoir for flotation (27).

11. The installation of claim 1, CHARACTERIZED in that it comprises at least one nanobubble generator (10) installed in a recirculated pulp feed line (111) coming from a water reservoir for flotation (27).

12. A method for improving the floatability of minerals in a flotation process, CHARACTERIZED in that it comprises the steps of: a. providing at least one nanobubble generator (10); b. installing said generator (10) in an installation as described in any of claims 1 to 11; c. connecting the nanobubble generator (10) to a gas source; d. turning on the nanobubble generator (10) and passing the flow of pulp or liquid through said generator; and e. sending the pulp or liquid with nanobubbles to a flotation system

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