Patent Application
20210387206
This application relates to the saturation of a multicomponent medium with active microbubbles. Specifically, the described embodiments relate to a method and an agitator for forming a flotation mixture, which may be used when processing ores and man-made mineral formations.
The following is not an admission that anything discussed below is part of the prior art or part of the common general knowledge of a person skilled in the art.
Flotation (floating up, retention on the water surface) is a common method for mineral processing. Flotation is based on a difference in the ability of minerals to hold on an interphase surface in a liquid medium, due to the difference in specific surface energies. During froth flotation, hydrophobic particles may become fixed on air bubbles and carried by them to a pulp surface, forming a layer of mineralized froth, which is a mineral concentrate. During froth flotation, hydrophilic particles remain in the pulp and form a chamber product, i.e., waste (commonly referred to as “tailings”).
Known flotation methods have certain limitations in that they can only be used to efficiently extract minerals from feedstock if the particle size is within a narrow range. It has been found that known froth flotation methods have the inability to effectively extract particles of less than 50 microns into the concentrate due to the existing gravitational and hydrodynamic forces.
Since the reserve of coarsely disseminated free-milling ores is depleting, processing increasingly involves finely disseminated refractory ores, and therefore, the requirement to fine grind minerals. The inability to enrich fine classes of mineral particles remains a shortcoming of known flotation processes.
This section is provided to introduce the reader to the more detailed discussion to follow. This section is not intended to limit or define any claimed or as yet unclaimed subject matter. One or more items of claimed subject matter may reside in any combination or sub-combination of the elements or process steps disclosed in any part of this document including its claims and figures.
In accordance with one aspect of this disclosure, there is provided an agitator for generating a mixture. The agitator may comprise a housing having a first end and a second end, and an impeller that is coupled to a drive shaft and rotatably mounted within the housing. The impeller may have a first end with a first end face, a second end, a sidewall that axially extends between the first and second ends, a plurality of protuberances disposed on the first end face, and at least one compressed gas channel outlet on the first end face of the impeller. The agitator may also comprise a mixing chamber that is located adjacent to the plurality of protuberances, a fluid inlet extending through the housing for supplying a mixing fluid to the mixing chamber, and a fluid outlet extending through the housing for discharging the mixture from the mixing chamber. When the compressed gas and the mixing fluid are supplied to the mixing chamber, the compressed gas may become uncompressed gas and rotation of the impeller may agitate the uncompressed gas and the mixing fluid and may disperse the uncompressed gas and at least a portion of the mixing fluid to generate the mixture.
In at least one embodiment, each compressed gas channel outlet of the at least one compressed gas channel outlet may be located radially inward of each protuberance of the plurality of protuberances.
In at least one embodiment, each compressed gas channel outlet of the at least one compressed gas channel outlet may be located in a central region on the first end face of the impeller.
In at least one embodiment, the plurality of protuberances may be arranged in at least one ring on the first end face.
In at least one embodiment, the fluid inlet may be disposed at the first end of the housing and may supply the mixing fluid to the central region of the first end face of the impeller.
In at least one embodiment, the agitator may further comprise a compressed gas inlet disposed at a sidewall of the housing and extending through the housing.
In at least one embodiment, the impeller may further comprise at least one compressed gas channel connecting the at least one compressed gas channel outlet to a respective one of at least one compressed gas channel inlet on the sidewall of the impeller, the compressed gas inlet may be for supplying compressed gas to the compressed gas channel inlet of each compressed gas channel.
In at least one embodiment, each compressed gas channel of the at least one compressed gas channel may extend from the compressed gas channel inlet to the compressed gas channel outlet along a curved path.
In at least one embodiment, the plurality of protuberances may be between 30 and 200 protuberances.
In at least one embodiment, the plurality of protuberances may be arranged in 4 to 10 concentric rings.
In at least one embodiment, the compressed gas inlet may be a spray nozzle.
In at least one embodiment, the spray nozzle may comprise a non-return valve.
In at least one embodiment, the agitator may further comprise a motor with the drive shaft and a coupling element that couples the drive shaft to the impeller for rotatably driving the impeller.
In at least one embodiment, the mixing fluid may comprise a solution of a multicomponent surfactant and the mixture may comprise gas microbubbles stabilized by a surfactant, emulsion microbubbles stabilized by a surfactant, and/or microdroplets stabilized by a surfactant.
In at least one embodiment, the agitator may further comprise a cooling chamber located intermediate the motor and the housing.
In at least one embodiment, the first end of the housing may comprise an inner front face, defining a portion of the mixing chamber, and the inner front face may comprise a second plurality of protuberances.
In at least one embodiment, the second plurality of protuberances may be arranged in concentric rings.
In at least one embodiment, at least a portion of the first end of the housing may be removable.
In accordance with another aspect of this disclosure, there is provided a flotation system for separating mineral particles from a flow pulp. The flotation system may comprise an agitator having a housing having a first end and a second end, and an impeller that is coupled to a drive shaft and rotatably mounted within the housing. The impeller may have a first end with a first end face, a second end, a sidewall that axially extends between the first and second ends, a plurality of protuberances disposed on the first end face, and at least one compressed gas channel outlet on the first end face of the impeller. The agitator may also comprise a mixing chamber that is located adjacent to the plurality of protuberances, a fluid inlet extending through the housing for supplying a mixing fluid to the mixing chamber, and a fluid outlet extending through the housing for discharging a flotation mixture from the mixing chamber. The flotation system may also comprise a flotation chamber, and a conduit connecting the fluid outlet of the agitator to the flotation chamber.
In at least one embodiment, the conduit may have an inlet disposed upstream of the fluid outlet of the agitator, the inlet being adapted to receive the flow of pulp.
In at least one embodiment, the mixing fluid may be a solution of a multicomponent surfactant and the flotation mixture may comprise gas microbubbles stabilized by a surfactant, emulsion microbubbles stabilized by a surfactant, and/or microdroplets stabilized by a surfactant.
In accordance with another aspect of this disclosure, there is provided a method of producing a flotation mixture having gas microbubbles stabilized by a surfactant, emulsion microbubbles stabilized by a surfactant, and microdroplets stabilized by a surfactant. The method may comprise: (a) providing an agitator having a rotatable impeller, the impeller having a plurality of protuberances extending from a first end face of the impeller into an adjacent mixing chamber; (b) providing a solution of a multicomponent surfactant to the mixing chamber; (c) providing compressed gas to the mixing chamber; and (d) rotating the impeller while the solution of a multicomponent surfactant and the compressed gas are provided, wherein when the compressed gas and the mixing solution are supplied to the mixing chamber, the compressed gas becomes uncompressed gas and rotation of the impeller agitates the uncompressed gas and the mixing solution and disperses the uncompressed gas and at least a portion of the mixing solution to generate the flotation mixture.
In at least one embodiment, the solution of a multicomponent surfactant and the compressed gas may be combined prior to being supplied to the mixing chamber.
In at least one embodiment, the solution of a multicomponent surfactant and the compressed gas may be separately provided to the mixing chamber from opposing directions.
Other features and advantages of the present application will become apparent from the following detailed description taken together with the accompanying drawings. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the application, are given by way of illustration only, since changes and modifications within the spirit and scope of the application will become apparent to those skilled in the art from this detailed description.
For a better understanding of the various embodiments described herein, and to show more clearly how these various embodiments may be carried into effect, reference will be made, by way of example, to the accompanying drawings which show at least one example embodiment of apparatuses, articles, and methods of the present teachings, and which are now described. The drawings are not intended to limit the scope of the teachings described herein.
Further aspects and features of the example embodiments described herein will appear from the following description taken together with the accompanying drawings.
Various apparatuses and methods are described below to provide an example of an embodiment of potentially claimed subject matter. No embodiment described below limits any claimed subject matter and any claimed subject matter may cover apparatuses, components and methods that differ from those described below. The claimed subject matter is not limited to apparatuses and methods having all of the features of any one apparatus or method described below or to features common to multiple or all of the apparatuses or methods described below. It is possible that an apparatus or method described below is not an embodiment of any claimed subject matter. Any subject matter disclosed in an apparatus or method described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and/or owner(s) do not intend to abandon, disclaim, or dedicate to the public any such subject matter by its disclosure in this document.
It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered as limiting the scope of the embodiments described herein.
It should also be noted that the terms “coupled” or “coupling” as used herein can have several different meanings depending on the context in which these terms are used. For example, the terms coupled or coupling can have a mechanical or fluidic connotation. For example, as used herein, the terms coupled or coupling can indicate that two elements or devices can be directly connected to one another or connected to one another through one or more intermediate elements or a fluid pathway, depending on the particular context.
It should also be noted that, as used herein, the wording “and/or” is intended to represent an inclusive-or. That is, “X and/or Y” is intended to mean X or Y or both, for example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof.
It should be noted that terms of degree such as “substantially”, “about”, and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree may also be construed as including a deviation of the modified term, such as by 1%, 2%, 5% or 10%, for example, if this deviation does not negate the meaning of the term it modifies.
Furthermore, the recitation of numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term “about” which means a variation of up to a certain amount of the number to which reference is being made if the end result is not significantly changed, such as 1%, 2%, 5%, or 10%, for example.
As described above, the present teachings relate generally to a method and an agitator for the saturation of a multicomponent medium with active microbubbles forming a mixture. In some examples, this mixture (in this case, a flotation mixture) may be used when processing ores of non-ferrous, noble, and rare-earth minerals, as well as man-made mineral formations.
At least one embodiment of the method and the agitator described herein may generate a flotation mixture having the following flotation-active microbubbles stabilized by a surfactant: gas microbubbles (wherein the gas may be, but is not limited to, air, nitrogen, argon, carbon dioxide, oxygen, and any combination thereof), emulsion microbubbles, and microdroplets. For reasons discussed in detail below, this flotation mixture may improve the floatability of fine particles as compared to known flotation systems.
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The drive shaft 142 may extend through the housing 102 and may be connected to a motor 150 to drive rotation of the drive shaft 142. In at least one example embodiment, the motor 150 may be a 3-phase asynchronous electric motor for general industrial use, from 5.0 to 25.0 kW, 50 Hz, with rotational speed from about 2800 rpm and above. A seal (not shown) may be placed between the housing 102 and the drive shaft 142 to reduce leakage of solution out from the mixing chamber 108 between the drive shaft 142 and the housing 102. In the example illustrated, the drive shaft 142 extends through a removable end wall 152 of the agitator housing 102. It may be desirable for the drive shaft 142 to extend through a removable portion of the housing 102 to facilitate maintenance of the agitator 100, for example, to replace the seal.
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The protuberances 154, 1154, 2154 may be formed by cutting away portions of the impeller 120 using a laser-lathe machine. Accordingly, as shown in
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It has been found that to produce a flotation mixture at a rate of about 10 L/min, between about 3 and 4 L/min of compressed air at a pressure in the range of about 22 psi to about 29 psi may be supplied to the mixing chamber 108. Further, it has been found that six compressed gas channels 172, each having a constant diameter of about 0.2 to 0.4 mm from inlet 174 to outlet 170, are capable of supplying this amount of compressed air to the mixing chamber 108. In other examples, fewer gas channels 172 having a greater diameter may be used to supply compressed gas to the mixing chamber 108; alternatively, more gas channels 172 having a smaller diameter may be used. It may be desirable to include a plurality of smaller compressed gas channel outlets 170 as opposed to one large compressed gas channel outlet 170 to facilitate dispersion of uncompressed gas throughout the mixing chamber 108 at the first end face 128.
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In at least one example embodiment, the spray nozzle 184 may include a non-return valve 192. The non-return valve 192 may ensure that no compressed gas may pass from the mixing chamber 108 back into the spray nozzle 184.
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The agitator 100 may also include a fluid outlet 196 disposed at a first side portion 198 of the housing 102. As shown, the fluid outlet 196 may extend through the housing 102. In some examples of the agitator 100, the fluid outlet 196 may extend through the housing 102, and may extend substantially parallel to the fluid inlet 194. That is, in some examples, the fluid outlet 196 may be disposed at the first end 104 of the housing 102. When in use, the fluid outlet 196 may be used to discharge the solution and uncompressed gas in the form of a mixture from the mixing chamber 108.
To produce a mixture using the agitator 100, a solution to be mixed and compressed gas may each be supplied to the mixing chamber 108 (the examples below are discussed with reference to agitator 100, but agitator 1100 or 2100 may be used). Within the mixing chamber 108, the impeller 120 can create a vortex flow with a high degree of turbulence. Due to the high degree of turbulence, microbubbles may be formed within the mixing chamber 108. These microbubbles and the remaining portion of the solution may then be discharged from the mixing chamber 108 as a mixture. This mixture may be used when processing ores and man-made mineral formations (described in more detail below). Alternatively, this mixture may be used (the following is a non-limiting list of examples): (1) to treat wastewater from oil pollution in the oil and gas industry and wastewater from oil-fat emulsions in the food industry; (2) as a finely dispersed food emulsion when the solution to be mixed is a solution of biologically active compounds and the gas is carbon dioxide or oxygen; (3) in the beauty industry to produce cosmetic microemulsions; (4) in the pharmacological industry for pharmaceutical drug dispersion; and (5) in paint production for pigment dispersion.
In a non-limiting example use of the agitator 100, the solution to be mixed may be an aqueous solution of a multicomponent surfactant consisting of a water-soluble component and an oil soluble component (hereby referred to as a “solution containing a multicomponent surfactant”). Some examples of multicomponent surfactants that may be used include, but are not limited to, dialkyl dithiophosphates, thionocarbamates, xanthates, monobutyl ethers of polyethylene glycols, monobutyl ethers of polypropylene glycols, triethoxybutane, ethoxylated alkyl phenols, and any combination thereof. In other non-limiting examples, the multicomponent surfactant may be prepared using:
It has been found that when a solution containing a multicomponent surfactant is mixed with gas, the resulting mixture has both collective and foaming properties. In contrast, in known flotation methods, the main reagents used are separated according to their purpose; i.e., collectors, foaming agents, and modifiers. That is, in known methods, the main reagents are separately added to the pulp, typically in the following order: (a) modifiers; (b) collectors (to enable hydrophobization of the surface of mineral particles); and (c) foaming agents (so that gas bubbles stabilized by surfactants are more firmly fixed on the surface of hydrophobized mineral particles).
Further, it has been found that the number of gas microbubbles in a flotation mixture produced using known methods may be significantly less than may be desired. That is, it has been found that known flotation methods typically produce mixtures that are less than 7% by volume of gas microbubbles, whereas a desired flotation mixture may be 25-30% by volume of gas microbubbles (“by volume” refers to “by volume of gas bubbles produced” not “by volume of total mixture”). Specifically, a desired flotation mixture may comprise 25-30% of large and medium gas bubbles; 35-40% of small gas bubbles; and 25-30% of gas microbubbles (where large bubbles are generally 2-4 mm; medium bubbles are generally 0.2-2 mm; small bubbles are generally 100 μm-1 mm; and microbubbles are generally 40-70 μm). The composition of gas bubbles within the flotation mixture may be very useful to the flotation of mineral particles because each type of bubble serves a different purpose during the flotation process. Specifically, large and medium gas bubbles may be transporting bubbles, small gas bubbles may fix on the surface of flotation-sized mineral particles (>74 microns), and gas microbubbles may attach to fine mineral particles. Large and medium gas bubbles are referred to as transporting bubbles as they may have a greater lifting ability compared to that of small gas bubbles and gas microbubbles, as they contain more gas.
When mixing a solution containing a multicomponent surfactant in the agitator 100, it has been found that a desired mixture, as described above, may be produced. Further, it has been found that when mixing certain formulations of a solution containing a multicomponent surfactant, it may be possible to obtain small gas bubbles of a cascade structure consisting of several gas microbubbles stabilized by a surfactant. These small gas bubbles of a cascade structure may act as transporting bubbles. Due to their relatively small size, the cascades of gas microbubbles stabilized by a surfactant may move faster and may intensify the flotation process, in comparison to conventional large and medium sized transporting bubbles.
Properties of the mixture, such as the number and size of microbubbles may be controlled by changing the formulation of the solution containing a multicomponent surfactant provided to the agitator. Which multicomponent surfactant to use in the solution containing a multicomponent surfactant may be dependent on the characteristics and/or composition of the pulp to be floated. For example, the size of the ore particles within the pulp may dictate which solution containing a multicomponent surfactant to use. Further, the selected multicomponent surfactant may be dependent on the desired ratio of flotation-active gas microbubbles to small gas bubbles of a cascade structure. For example, by increasing in the proportion of water-soluble micelle-forming surfactant in the solution of a multicomponent surfactant, the fraction by volume of gas microbubbles and small gas bubbles of a cascade structure in the composition of the mixture generated by the agitator 100 may increase. By increasing in the proportion of water-soluble surfactant that does not form micelles (for example, methyl isobutyl carbinol) in the solution of a multicomponent surfactant, the fraction by volume of small gas bubbles of a cascade structure in the mixture generated by the agitator 100 may decrease. The proportion of gas microbubbles stabilized by a surfactant and small gas bubbles of a cascade structure in the generated mixture may also depend on the ratio of the volume of water-soluble surfactant and gas supplied to the mixing chamber per unit time. Characteristics of the multicomponent surfactant that may also affect the properties of the mixture, and therefore may dictate which solution containing a multicomponent surfactant to use, include:
In general, it has been found that when compressed gas and a solution containing a multicomponent surfactant are supplied to the agitator 100, the flotation mixture discharged from the mixing chamber 108 may include the following flotation-active microbubbles stabilized by a surfactant:
It has been found that this flotation mixture has the following effective flotation properties: collective (due to the emulsion microbubbles and microdroplets); foaming (due to the gas microbubbles and their cascades); and aggregating or flocculating fine mineral particles (due to the microdroplets containing an oil-soluble surfactant of oligomeric structure).
A schematic diagram of a gas microbubble stabilized by a surfactant is shown in
During use, within the mixing chamber 108, an oil soluble component of the solution may be broken into a plurality of droplets by the plurality of protuberances 154. A portion of these droplets may acquire sufficient speed for collision and penetration to the non-polar part of a surfactant stabilized gas microbubble by dispersion forces, thereby forming an emulsion microbubble stabilized by a surfactant. Upon penetration, oil-soluble surfactant droplets coalesce to form a layer at the gas/liquid interface. A schematic diagram of an emulsion microbubble stabilized by a surfactant is shown in
The remaining portion of the oil soluble droplets may be stabilized within the mixing chamber 108 by water-soluble surfactant molecules to produce microdroplets stabilized by a surfactant. A schematic diagram of a microdroplet stabilized by a surfactant is shown in
It may be desirable to generate a flotation mixture having the following flotation-active microbubbles stabilized by a surfactant: gas microbubbles, emulsion microbubbles, and microdroplets containing an oil soluble surfactant, as this flotation mixture may improve the floatability of fine mineral particles of ores and man-made mineral formations. The manner in which flotation-active microbubbles may interact with mineral particles to lift those mineral particles to a pulp surface is shown in
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Accordingly, as will be described in detail below, it may be desirable to combine this flotation mixture with pulp having fine mineral particles therein in a flotation chamber to separate the fine mineral particles from the pulp.
A typical flotation process includes three stages: roughing, cleaning, and scavenging. During the roughing stage, pulp may be separated into a rougher concentrate having a maximum amount of mineral particles therein and rougher tailings. According to the principles described above, the agitator 100 (or 1100, 2100) may be used to produce a flotation mixture to be used during the roughing stage. During the cleaning stage, the rougher concentrate from the roughing stage may be further processed to remove undesirable particles and thereby increase the concentration of valuable minerals. During the scavenging stage, the rougher tailings may be further processed to recover desirable mineral particles that were not separated into the rougher concentrate. Again, according to the principles described above, the agitator 100 (or 1100, 2100) may be used to produce a flotation mixture to be used during the scavenging stage. Further, it should be noted that flotation systems may be quite complex, and may include several roughing, cleaning, and scavenging steps, and various options for the enrichment of flotation products, which can be returned to various process stages or processed separately.
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As shown, once the solution of a multicomponent surfactant and the compressed gas are provided to the agitator, at step 308 the impeller of the agitator may be rotated. Rotating the impeller while the solution of a multicomponent surfactant and the compressed gas are provided, may agitate the uncompressed gas and the mixing solution and may disperse the uncompressed gas and at least a portion of the mixing solution to generate the flotation mixture. In some examples, steps 304, 306, and 308 may all be performed conterminously. That is, is some examples of the method 300, the impeller may be constantly rotated for a period of time, and during this period, the solution or a multicomponent surfactant and the compressed gas may be continuously supplied to the mixing chamber at an appropriate rate.
In at least one example embodiment, between 8,000 and 10,000 L/hour of aqueous solution of a multicomponent surfactant, and between 3,500-4,500 L/hour of compressed air at a pressure in the range of from about 22 psi to about 29 psi may be supplied to the agitator 100. In at least one example embodiment, to mix and disperse the compressed air and the multicomponent surfactant, the impeller may be rotated between 2,800 and 3,000 rotations per minute. A motor may be used to drive the impeller.
A series of experiments were conducted to test the following:
The tests were also used to determine features of the flotation mixture produced in (a), such as the size of the generated microbubbles.
Flotation tests (i.e., test 1—basic mode; and test 2—with the method described herein, see Table 1 below) on refractory gold-containing ore were carried out in kinetic mode on a Mechanobr Technika FL-240 flotation machine with a chamber volume of 3 decimeter cubed using a Flotanol C-7 foaming agent. For the basic mode test, aqueous solutions of the Pb(NO3)2, Butyl xanthate, and Flotanol C-7 agents (i.e., modifiers, collectors, and foaming agents) adopted at a mineral processing factory during industrial flotation were fed directly to the Mechanobr Technika FL-240 flotation machine. For the test according to the method described herein, the same aqueous solutions of the agents as used for the basic mode test, excluding the Flotanol C-7 foaming agent, were fed directly to the Mechanobr Technika FL-240 flotation machine, and an aqueous solution of the Flotanol C-7 foaming agent was fed into the mixing chamber of an agitator 100 to generate a flotation mixture containing the following microbubbles stabilized by surfactant: air microbubbles, emulsion microbubbles, and microdroplets. This flotation mixture was then supplied into the Mechanobr Technika FL-240 flotation machine. The flotation results are shown in Tables 1 and 2, below.
As shown, under the basic mode with Flotanol C-7 foaming agent (consumption 7 g/t), 8.06% of gold-containing concentrate with a gold content of 14.08 g/t was obtained with 60.38% recovery. When using the method described herein, 7.89% of gold-containing concentrate with a gold content of 15.14 g/t was obtained with a recovery of 64.31%. That is, gold recovery was increased by 3.93% without compromising the quality of the concentrate.
When using the method described herein with increased consumption of Flotanol C-7 to 10 g/t, 10.36% of gold-containing concentrate with a gold content of 13.50 g/t was obtained with a recovery of 69.32%. That is, gold recovery was increased by 8.94% compared with the basic mode with 7 g/t consumption of Flotanol C-7.
Granulometric analysis of flotation tailings (shown in Table 2) indicates that, as a result of using the method described herein during kinetic tests, the proportion of gold losses in thin size grades less than −0.025+0 mm decreased from 29.27% to 27.37%. At the same time, redistribution of gold to the size grades of more than 0.14 mm was noted from 5.22% to 11.29% of the product. Losses decreased from 0.81 g/t to 0.69 g/t (by 0.12 g/t).
Flotation tests (i.e., test 1—basic mode; and test 2—with the method described here, see Table 3 below) on refractory gold-containing ore were carried out in a locked cycle using Pb(NO3)2, Butyl xanthate, and Flotanol C-7 agents. Roughing and scavenging stages were performed on the Mechanobr Technika FL-240 flotation machine, and cleaning stages were performed on the Mechanobr Technika FL-237 flotation machine. For the basic mode test, aqueous solutions of the Pb(NO3)2, Butyl xanthate, and Flotanol C-7 agents (i.e., modifiers, collectors, and foaming agents (used in that order)) were fed directly to the Mechanobr Technika FL-240 flotation machine during roughing and scavenging operations, and into the Mechanobr Technica FL-237 flotation machine during cleaning operations. For the test according to the method described herein, the same aqueous solutions of the agents as used for the basic mode test excluding the Flotanol C-7 foaming agent were also fed directly to the Mechanobr Technika FL-240 flotation machine during roughing and scavenging operations, and including the Flotanol C-7 into the Mechanobr Technica FL-237 flotation machine during cleaning operations, and an aqueous solution of Flotanol C-7 was also fed into the mixing chamber of an agitator 100 to generate a flotation mixture containing the following microbubbles stabilized by a surfactant: air microbubbles, emulsion microbubbles, and microdroplets. This flotation mixture was supplied into the Mechanobr Technika FL-240 flotation machine during roughing and scavenging operations. The results are shown in Table 3.
The test results show that a concentrate with a gold content of 110 g/t (versus 119 g/t in the basic mode) was obtained using the method described herein in a locked cycle with the recovery of 56.53% (versus 52.13% in the basic mode). That is, gold recovery was increased by 4.40%.
To determine the average size of the microbubbles produced by the agitator 100, a series of photographs were taken using a Phase One XF camera. Based on the pictures, the size of the microbubbles was calculated to be on average less than 50 microns. The aqueous solutions of the following surfactants were passed through the agitator 100 and photographed:
When using the method 300 as described above, the degree of recovery of valuable minerals, the quality of the valuable mineral concentrate, and the velocity of flotation may be increased, as shown in the results of Experiments 1 and 2. As a result of the increased recovery of finely-dispersed mineral particles, which were previously lost in flotation tails using conventional flotation machines, the overall recovery rate of the valuable mineral may be increased as well.
Accordingly, an increase in the efficiency of fine mineral particle recovery may be achieved by:
Further, it has been determined that by changing the formulation of a solution of a multicomponent surfactant and its ratio with gas when supplied to the agitator, it is possible to regulate not only the number and size of microbubbles, but also to obtain small gas bubbles of a cascade structure consisting of several gas microbubbles stabilized by a surfactant. Small gas bubbles of a cascade structure may be transporting bubbles. In contrast to conventional large and medium gas bubbles in the known flotation technology, the cascades of gas microbubbles are much smaller. This allows them to move faster, which intensifies the flotation process.
Further, it has been determined that using the method described herein during scavenging flotation may increase and accelerate the extraction of finely dispersed mineral particles that were not recovered during the roughing flotation stage. Accordingly, the targeted degree of mineral extraction may be achieved with fewer and/or shorter scavenging operations. As a result, by implementing the method described herein, the overall flotation rate may increase due to a decrease in the number of scavenging operations and their duration.
While the applicant's teachings described herein are in conjunction with various embodiments for illustrative purposes, it is not intended that the applicant's teachings be limited to such embodiments as the embodiments described herein are intended to be examples. On the contrary, the applicant's teachings described and illustrated herein encompass various alternatives, modifications, and equivalents, without departing from the embodiments described herein, the general scope of which is defined in the appended claims.
