Process for preparing a flotation reagent, flotation reagent and method for the flotation of rare earth ores

Abstract

The embodiment of the application discloses a flotation reagent preparation method, a flotation reagent and a flotation method of a rare earth ore. The flotation reagent preparation method is characterized in that the method comprises the following steps: mixing a plurality of flotation reagents to obtain a mixed fatty acid collector; adding a sodium hydroxide solution to the mixed fatty acid collector to obtain a collector solution; and electrolyzing the collector solution and oxidizing the collector solution to make the collector solution generate nanobubbles and hydroxyl radicals, thereby obtaining a flotation reagent. The flotation reagent preparation method can simultaneously realize dispersion activation and in-situ oxidation modification of the fatty acid collector, can generate hydroxyl radicals without additional addition of a Fenton reagent, and can avoid problems such as impurity pollution of ore slurry and unstable oxidation effect caused by an exogenous reagent.

Description

Technical Field

[0001] This application relates to the field of mineral processing technology, and in particular to a method for preparing flotation reagents, flotation reagents, and a flotation method for rare earth ores. Background Technology

[0002] Fine-grained rare earth polymetallic ores are typical complex and difficult-to-process strategic resources in mineral resource development. Constrained by their fine particle size, complex symbiotic components, and high gangue mineral content, conventional beneficiation processes are difficult to separate and have low resource utilization rates. Flotation technology, with its advantages of high separation accuracy and wide adaptability, is currently an important process for the enrichment and separation of fine-grained minerals. Traditional flotation processes rely on millimeter-micron level bubbles and conventional reagent systems, which have extremely poor adaptability for separating fine-grained rare earth minerals with a particle size of less than 40 μm. They suffer from prominent problems such as low probability of gas-solid collision and adhesion, severe interference from slime capping, and low flotation recovery and concentrate grade, making it difficult to achieve efficient resource utilization of complex fine-grained rare earth ores.

[0003] To overcome the bottleneck of traditional flotation technology in separating fine-grained minerals, micro-nano bubble flotation technology is gradually becoming a new technical approach for separating fine-grained ores. Compared with conventional bubbles, micro-nano bubbles have the characteristics of small particle size, high number density, high interfacial activity, and excellent mass transfer performance. They can effectively improve the contact probability between fine minerals and bubbles, weaken the interference of slime, and significantly optimize the flotation conditions of fine-grained minerals. Currently, most existing micro-nano bubble flotation processes adopt a single foaming mode, mainly using methods such as hydraulic cavitation, pressurized dissolution, and single electrolytic foaming. They can only rely on small-particle-size, high-number-density bubbles to improve the gas-solid contact effect. The technology enhancement dimension is singular, and it cannot simultaneously achieve the performance modification and upgrading of flotation reagents. The flotation enhancement effect has a clear upper limit and is difficult to adapt to the high-precision separation requirements of complex fine-grained rare earth polymetallic ores.

[0004] Fatty acid collectors are the mainstream preferred reagents for rare earth mineral flotation, possessing advantages such as low cost and strong adaptability, and are widely used in rare earth ore flotation production. However, for fine-grained rare earth ores with complex compositions and polymetallic coexistence, conventional fatty acid collectors have inherent defects such as poor water dispersibility, insufficient surface activity, and weak targeted adsorption selectivity. This easily leads to problems such as low reagent utilization and poor separation selectivity. Typically, they need to be used in conjunction with heating processes and multiple chemical modifiers to barely maintain basic flotation effects, resulting in cumbersome processes, high energy consumption, and poor separation stability. To improve the flotation performance of fatty acid collectors, existing research often uses the traditional Fenton system to generate hydroxyl radicals, optimizing the surface activity and dispersion performance of the reagent through appropriate oxidative modification, effectively improving the flotation indicators of rare earth ores. However, the traditional Fenton system requires the addition of chemical reagents such as ferrous salts and hydrogen peroxide, which can easily introduce impurity ions into the flotation system, causing slurry pollution and increasing the pressure on subsequent water treatment. At the same time, the dosage of reagents is difficult to control precisely, the oxidation modification effect is unstable, and it is difficult to achieve stable industrial application.

[0005] Existing publicly available microbubble flotation technologies for fine-grained minerals, such as "Micro-nano bubble generation device suitable for fine mineral flotation separation" (CN202410627234.2) and "A flotation method and flotation system for fine-grained ilmenite" (CN202111161204.X), all employ a single hydraulic cavitation foaming mechanism, focusing only on optimizing the number and particle size of micro-nano bubbles. They can only achieve a single physical enhancement of the flotation process, without combining chemical enhancement methods such as reagent modification. They cannot fundamentally solve the core problems of poor compatibility and insufficient performance of fatty acid collectors, and it is difficult to meet the dual needs of physical separation optimization and reagent performance upgrading.

[0006] In summary, current flotation technology for fine-grained complex rare earth polymetallic ores has two major shortcomings: First, the micro-nano bubble foaming mode is singular, which can only achieve physical flotation enhancement with limited efficiency improvement; second, the modification of fatty acid collectors relies on the traditional Fenton chemical system, which requires the addition of external reagents, resulting in problems such as impurity introduction, unstable modification, and high process costs, and failing to achieve green, efficient, and stable flotation enhancement effects. Summary of the Invention

[0007] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This part of the invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0008] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0009] Therefore, a first aspect of the present invention provides a method for preparing flotation reagents.

[0010] A second aspect of the present invention provides a flotation reagent.

[0011] A third aspect of the present invention provides a flotation method.

[0012] In view of this, a method for preparing flotation reagents is provided according to a first aspect of the embodiments of this application, comprising: Multiple flotation reagents are mixed to obtain a mixed fatty acid collector; Add sodium hydroxide solution to the mixed fatty acid collector to obtain a collector solution; The collector solution is electrolyzed and oxidized to generate nanobubbles and hydroxyl radicals, thereby obtaining a flotation reagent.

[0013] In one feasible embodiment, the mass concentration of the sodium hydroxide solution is 0.5% to 2%; The mass concentration of the collector solution is from 0.1% to 10%.

[0014] In one feasible embodiment, the steps of electrolyzing the collector solution and oxidizing the collector solution to generate nanobubbles and hydroxyl radicals to obtain the flotation reagent include: A cathode electrode plate and an anode electrode plate are placed in a container, with a distance of 0.5 cm to 3 cm between the cathode electrode plate and the anode electrode plate; The materials used to prepare the cathode electrode plate include nickel-based or boron-doped diamond; The materials used to prepare the anode electrode plate include boron-doped diamond, graphite, or titanium-based materials; The electrolysis voltage is 5V to 30V, and the electrolysis time is 0.5min to 10min.

[0015] A flotation reagent is provided according to a second aspect of the embodiments of this application. The flotation reagent is prepared by the flotation reagent preparation method described in any of the above technical solutions.

[0016] In one feasible implementation, the raw materials for preparing the mixed fatty acid collector in the flotation reagent include oxidized paraffin soap, tall oil, and RA935 collector.

[0017] A flotation method is proposed according to a third aspect of the embodiments of this application, comprising: The rare earth ore is crushed and ground to obtain a slurry; Add the flotation reagents described in any of the above technical solutions to the slurry and perform flotation.

[0018] In one feasible implementation, the step of crushing and grinding the rare earth ore to obtain a slurry includes: Rare earth ore is crushed using a double roll crusher; The crushed ore is ground using a stirred mill, and the particle size D80 of the ground ore is 10μm to 75μm. The grinding media consists of ceramic balls with a diameter of 2 mm to 4 mm.

[0019] In one feasible implementation, the step of adding flotation reagents to the slurry and performing flotation includes: Control the slurry concentration to 10% to 50%, adjust the slurry temperature to 25℃ to 50℃, and stir for 1 min to 5 min; Add pH adjuster to the slurry to adjust the pH to 8 to 9.5, and stir for 1 to 5 minutes; Add water glass to the slurry at a dosage of 200g / t to 800g / t; Magnesium fluorosilicate or sodium fluorosilicate is added to the slurry at a dosage of 100g / t to 500g / t. The flotation reagent is added to the slurry at a dosage of 100 g / t to 600 g / t. The slurry is circulated through the Venturi tube by a peristaltic pump. The air inlet valve of the Venturi tube is closed. The flow velocity at the throat of the Venturi tube is 10 m / s to 20 m / s. The circulation and stirring time is greater than or equal to 3 min. Open the venturi inlet valve and adjust the air intake to 1% to 10% of the slurry volume. Under the action of hydraulic cavitation, mineralized bubbles appear in the slurry, and flotation is carried out.

[0020] In one feasible implementation, the flotation method further includes: Add flotation water during the flotation process to keep the slurry surface at the flotation interface.

[0021] In one feasible implementation, the step of preparing the flotation water includes: Water is circulated through a peristaltic pump, and the air inlet valve of the venturi tube is opened. The volume ratio of air to water is adjusted from 1% to 10%, and the flow velocity at the throat of the venturi tube is 10 m / s to 20 m / s. The water is circulated and stirred for more than 3 minutes, generating a large number of tiny bubbles in the water, thus obtaining flotation water containing micro-nano bubbles.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: The flotation reagent preparation method provided in this application can simultaneously achieve the dispersion activation and in-situ oxidation modification of fatty acid collectors. It generates hydroxyl radicals without the need for additional Fenton reagent, avoiding problems such as pulp impurity contamination and unstable oxidation effects caused by exogenous reagents. The mixed fatty acid collector, combined with sodium hydroxide solution for alkaline dissolution, significantly improves the water solubility of the reagent, solving the defects of poor water dispersion and easy agglomeration of conventional fatty acid reagents. The electrolysis process utilizes hydroxyl radicals to moderately oxidize reagent molecules, enhancing the surface activity of the collector and the targeted adsorption selectivity of rare earth minerals, thus reducing reagent dosage. Simultaneously, it generates nanobubbles in situ, pre-constructing a micro-nano bubble system to enhance the diffusion and mass transfer of the reagent in the pulp. The entire preparation process is simple and easy to control. The modified flotation reagent can significantly weaken the interference of fine-particle slime covering, increase the adhesion probability of rare earth minerals to bubbles, and ultimately simultaneously improve the grade of rare earth concentrate and flotation recovery rate. The process is green and low-consumption, suitable for the industrial separation of complex fine-particle rare earth ores.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic flowchart illustrating the steps of a flotation reagent preparation method according to an embodiment of this application; Figure 2 A schematic flowchart illustrating the steps of a flotation method according to an embodiment of this application; Figure 3 A schematic structural block diagram of an apparatus corresponding to a flotation method provided in this application.

[0025] in, Figure 3 The correspondence between the reference numerals and component names in the attached drawings is as follows: 210 Venturi tube, 220 anode electrode plate, 230 cathode electrode plate. Detailed Implementation

[0026] The following description provides numerous specific details to offer a more thorough understanding of the technical solutions provided by this invention. However, it will be apparent to those skilled in the art that the technical solutions provided by this invention can be implemented without one or more of these details.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0028] Exemplary embodiments according to the present invention will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the invention is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0029] According to a first aspect of the embodiments of this application, a method for preparing flotation reagents is provided, comprising: Step 101: Mix multiple flotation reagents to obtain a mixed fatty acid collector; Step 102: Add sodium hydroxide solution to the mixed fatty acid collector to obtain the collector solution; Step 103: Electrolyze the collector solution and oxidize it to generate nanobubbles and hydroxyl radicals to obtain flotation reagent.

[0030] The flotation reagent preparation method provided in this application can simultaneously achieve the dispersion activation and in-situ oxidation modification of fatty acid collectors. It generates hydroxyl radicals without the need for additional Fenton reagent, avoiding problems such as pulp impurity contamination and unstable oxidation effects caused by exogenous reagents. The mixed fatty acid collector, combined with sodium hydroxide solution for alkaline dissolution, significantly improves the water solubility of the reagent, solving the defects of poor water dispersion and easy agglomeration of conventional fatty acid reagents. The electrolysis process utilizes hydroxyl radicals to moderately oxidize reagent molecules, enhancing the surface activity of the collector and the targeted adsorption selectivity of rare earth minerals, thus reducing reagent dosage. Simultaneously, it generates nanobubbles in situ, pre-constructing a micro-nano bubble system to enhance the diffusion and mass transfer of the reagent in the pulp. The entire preparation process is simple and easy to control. The modified flotation reagent can significantly weaken the interference of fine-particle slime covering, increase the adhesion probability of rare earth minerals to bubbles, and ultimately simultaneously improve the grade of rare earth concentrate and flotation recovery rate. The process is green and low-consumption, suitable for the industrial separation of complex fine-particle rare earth ores.

[0031] In one feasible embodiment, the sodium hydroxide solution has a mass concentration of 0.5% to 2%; the collector solution has a mass concentration of 0.1% to 10%.

[0032] In this technical solution, controlling the NaOH solution concentration to 0.5% to 2% and the collector solution concentration to 0.1% to 10% ensures sufficient saponification and stable electrolytic modification of the reagents. Below the lower limit, fatty acid saponification is incomplete, resulting in poor water solubility and easy stratification and aggregation of the reagents. Too high a concentration leads to excessive alkalinity, exacerbating side reactions during electrolysis, and excessive alkali can damage the effective functional groups of the reagents, reducing selectivity. This range allows for sufficient saponification and dispersion of the mixed fatty acids, ensuring a uniform and stable electrolytic system. It facilitates the uniform action of hydroxyl radicals on the reagents to complete controlled oxidation, simultaneously and stably generating nanobubbles, avoiding reagent failure or uneven modification, improving reagent activity and separation stability, reducing reagent loss, and adapting to subsequent rare earth ore flotation conditions.

[0033] like Figure 3 As shown, in one feasible embodiment, the collector solution is electrolyzed, and the collector solution is oxidized to generate nanobubbles and hydroxyl radicals to obtain flotation reagents. The steps include: placing a cathode electrode plate 230 and an anode electrode plate 220 in a container, with a distance of 0.5 cm to 3 cm between the cathode electrode plate 230 and the anode electrode plate 220; the material for preparing the cathode electrode plate 230 includes nickel-based or boron-doped diamond; the material for preparing the anode electrode plate 220 includes boron-doped diamond, graphite, or titanium-based materials; wherein the electrolysis voltage is 5 V to 30 V, and the electrolysis time is 0.5 min to 10 min.

[0034] This technical solution further provides specific electrolysis process steps. The electrolysis process parameters and electrode design ensure efficient and stable modification of the collector and continuous production of hydroxyl radicals and nanobubbles. The distance between the anode electrode plate 220 and the cathode electrode plate 230 is limited to 0.5 to 3 cm. If the distance is too small, it will easily cause current concentration, local overheating and electrode burnout, and aggravate ineffective side reactions; if the distance is too large, the electric field strength between the plates will be insufficient, the amount of free radical generation will decrease significantly, and the reagent modification will be insufficient. The cathode is made of nickel-based or boron-doped diamond, which has excellent conductivity and hydrogen evolution foaming performance and can stably produce nanobubbles; the anode is made of boron-doped diamond, graphite, or titanium-based materials, which have strong oxidation catalytic ability, can continuously generate hydroxyl radicals, are corrosion-resistant, have a long service life, and are suitable for alkaline collector systems.

[0035] In this technical solution, the electrolysis voltage is controlled between 5V and 30V, and the electrolysis time is between 0.5min and 10min. Low voltage and short time cannot generate sufficient active free radicals, resulting in insufficient activation of the reagent surface. Excessive voltage and long electrolysis time will cause excessive oxidation of fatty acids, destroying the effective functional groups for collection and significantly reducing the selectivity of rare earth separation. This parameter range achieves controllable and moderate oxidation, uniformly improving the dispersibility of fatty acids and the targeted adsorption capacity of minerals, while simultaneously generating a large number of nanobubbles to enhance reagent diffusion. No exogenous oxidants are added, the system is clean and free of impurities, significantly improving the recovery rate of subsequent flotation of fine-particle rare earth ores. The process has low energy consumption, stable and controllable modification effects, and is suitable for continuous industrial production.

[0036] According to a second aspect of the embodiments of this application, a flotation reagent is provided, which is prepared by a flotation reagent preparation method as described in any of the above technical solutions.

[0037] The flotation reagent preparation method provided in this application is prepared by adopting any of the flotation reagent preparation methods described above. Therefore, the flotation reagent has all the beneficial effects of the preparation methods described above, and will not be elaborated here.

[0038] In one feasible implementation, the raw materials for preparing the mixed fatty acid collector in the flotation reagent include oxidized paraffin soap, tall oil, and RA935 collector.

[0039] This technical solution further provides the raw materials for a mixed fatty acid collector, which is prepared by compounding oxidized paraffin soap, tall oil, and RA935, achieving complementary performance of the three types of reagents. Oxidized paraffin soap is readily available and inexpensive, possessing basic collecting ability for rare earth minerals, but its dispersibility and selectivity are poor. Tall oil can improve the water solubility and foam stability of the reagent, and alleviate the interference of sludge capping. The RA935 collector specifically enhances the adsorption of rare earth minerals, improving separation selectivity. The compounding of the three compensates for the shortcomings of single fatty acid reagents, significantly improving overall water dispersibility and increasing the number of adsorption active sites. After subsequent electrolytic oxidation modification, the synergistic effect of the compounded system is further amplified, requiring lower reagent dosage, exhibiting stronger capturing ability for fine-grained rare earth minerals, effectively distinguishing rare earth from gangue minerals, simultaneously improving concentrate grade and rare earth recovery rate, and reducing the overall cost of flotation reagents.

[0040] It is understandable that RA935 collector is an existing collector that can be purchased on the market, such as through Wuhan Xianghui Mineral Processing Technology Co., Ltd., or it can be prepared by itself using rosin acid soap, oxidized petroleum fatty acid soap, sodium alkyl ether sulfate and alkylphenol polyoxyethylene ether. Among them, the mass ratio of rosin acid soap and oxidized petroleum fatty acid soap in RA935 collector is 75% to 85%, the mass ratio of sodium alkyl ether sulfate and alkylphenol polyoxyethylene ether is 8% to 15%, the mass ratio of nonionic emulsifier and organic modifying agent is 8% to 15%, and the balance is an alkaline aqueous solution carrier and trace additives.

[0041] like Figure 2 As shown, a flotation method is proposed according to a third aspect of the embodiments of this application, comprising: Step 201: Crush and grind the rare earth ore to obtain a slurry; Step 202: Add flotation reagents according to any of the above technical solutions to the slurry and carry out flotation.

[0042] The flotation method provided in this application first prepares rare earth ore into a suitable particle size slurry through crushing and grinding, and then completes the separation with flotation reagents containing self-modified mixed fatty acids via electrolysis, achieving synergistic effects of physical pretreatment and chemical reagent modification. The crushing and grinding process dissociates rare earth monomer minerals and reduces gangue intergrowths, creating the basic conditions for reagent adsorption and bubble mineralization. The matching modified reagents are activated by in-situ electrolytic generation of hydroxyl radicals, possessing both excellent dispersibility and rare earth selectivity, and can weaken the interference of fine-particle slime. With the combination of the two, the probability of collision and adhesion between fine rare earth minerals and bubbles is greatly increased, eliminating the need for additional oxidizing agents, preventing the introduction of impurities into the system, and significantly improving flotation selectivity and rare earth recovery rate. This simplifies the on-site process, reduces reagent consumption and water treatment pressure, and is suitable for the efficient and green separation of various fine-particle complex rare earth ores.

[0043] In one feasible implementation, the steps of crushing and grinding rare earth ore to obtain slurry include: crushing the rare earth ore by a double roll crusher; grinding the crushed ore by a stirred mill, wherein the particle size D80 of the ground ore is 10μm to 75μm; wherein the grinding media are ceramic balls with a diameter of 2mm to 4mm.

[0044] This technical solution further provides specific process steps for crushing and grinding. It employs a double-roll crusher for coarse crushing combined with a stirred mill for fine grinding, using 2-4mm ceramic ball milling media. The grinding process, with a D80 control of 10-75μm, effectively liberates fine-grained rare earth minerals. The double-roll crusher achieves uniform pre-crushing of the ore, avoiding the difficulty in grinding large pieces. Ceramic balls replace steel balls, eliminating iron ion contamination of the slurry and interference with reagent selective adsorption. By limiting the D80 range, excessively coarse particles result in incomplete liberation of rare earth minerals, making separation and enrichment difficult; excessively fine particles lead to excessive slime accumulation, causing severe capping and inhibiting flotation. This particle size range balances the degree of monomer liberation and slime formation, significantly reducing slime interference, allowing modified fatty acid reagents to fully contact rare earth minerals, improving bubble mineralization efficiency, and simultaneously improving concentrate grade and rare earth recovery rate. The grinding conditions are stable and compatible with subsequent micro / nano bubble flotation systems.

[0045] In one feasible embodiment, the flotation steps of adding flotation reagents to the slurry include: controlling the slurry mass concentration to 10% to 50%, adjusting the slurry temperature to 25°C to 50°C, and stirring for 1 to 5 minutes; adding a pH adjuster to the slurry to adjust the slurry pH to 8 to 9.5, and stirring for 1 to 5 minutes; adding water glass to the slurry at a dosage of 200 g / t to 800 g / t; and adding magnesium fluorosilicate or sodium fluorosilicate to the slurry at a dosage of... 100g / t to 500g / t; Add flotation reagent to the slurry at a dosage of 100g / t to 600g / t; circulate the slurry through a venturi tube using a peristaltic pump, close the venturi tube air inlet valve, maintain a flow velocity of 10m / s to 20m / s at the throat of the venturi tube, and circulate for a duration of 3 minutes or more; open the venturi tube air inlet valve and adjust the air intake to 1% to 10% of the slurry volume. Under the action of hydraulic cavitation, mineralized bubbles appear in the slurry, and flotation is carried out.

[0046] This technical solution further provides flotation process steps. The flotation process involves segmented pulp conditioning, reagent addition, and Venturi hydraulic cavitation flotation parameters to form a synergistic adaptation system, comprehensively optimizing the separation environment for fine-grained rare earth minerals. A pulp concentration of 10% to 50%, a temperature of 25 to 50°C, and short-term stirring for 1 to 5 minutes ensure sufficient contact between the mineral particles and the reagents while avoiding excessive mud formation caused by prolonged stirring. Suitable temperatures enhance the activity of modified fatty acid reagents; too low a temperature reduces reagent dispersion and adsorption capacity, while too high a temperature increases energy consumption and easily damages reagent functional groups. A pH range of 8 to 9.5 is the optimal range for the fatty acid collector, and a weakly alkaline environment ensures stable adsorption of rare earth minerals and inhibits gangue flotation.

[0047] In this technical solution, the water glass dosage is controlled between 200 g / t and 800 g / t to selectively suppress silicate gangue such as quartz and feldspar, while the fluorosilicate dosage is between 100 g / t and 500 g / t to further suppress calcium-containing gangue such as calcite and fluorite. The combination of the two significantly improves the separation selectivity and reduces gangue inclusions. The modified flotation reagent dosage range of 100 g / t to 600 g / t balances separation effect and reagent cost. The electrolytically modified reagent has higher activity and can reduce the dosage compared to conventional fatty acid reagents.

[0048] In this technical solution, the slurry is first circulated in a sealed venturi tube at a flow rate of 10 m / s to 20 m / s for more than 3 minutes, relying on hydraulic shearing to break up the slurry flocs and remove the fine slurry covering. Then, 1% to 10% of the volume of air is introduced, and hydraulic cavitation generates a large number of micro-nano mineralization bubbles. The micro-nano bubbles have a large specific surface area, which significantly increases the probability of collision and adhesion of fine rare earth particles. Together with the modified highly active collector, they form a dual physical and chemical enhancement, effectively improving the grade and recovery rate of rare earth concentrate. The entire parameter range is stable, requiring no complex heating or external oxidizing agents. It is green and low-consumption, and suitable for industrial flotation production of complex fine-particle rare earth ores.

[0049] In one feasible implementation, the flotation method further includes adding flotation water during the flotation process to keep the slurry surface at the flotation interface.

[0050] In this technical solution, the flotation process continuously replenishes the flotation water to stably maintain the standard pulp level in the flotation cell. This avoids the froth layer drying out, the pulp concentration continuously increasing, causing the froth to become sticky and increasing gangue entrainment, thus ensuring the smooth floating and separation of mineralized bubbles.

[0051] like Figure 3As shown, in one feasible embodiment, the steps for preparing flotation water include: circulating water through a peristaltic pump to a Venturi tube 210, opening the air inlet valve of the Venturi tube 210, adjusting the volume ratio of air to water to 1% to 10%, setting the flow rate at the throat of the Venturi tube 210 to 10 m / s to 20 m / s, circulating and stirring for more than 3 minutes, generating a large number of micro bubbles in the water, and obtaining flotation water containing micro-nano bubbles.

[0052] In this technical solution, Venturi hydraulic cavitation is used to prepare micro-nano bubble flotation water. With a throat flow velocity of 10 m / s to 20 m / s, an air-to-water volume ratio of 1% to 10%, and a circulation time of at least 3 minutes, a large number of fine-sized, highly active micro-nano bubbles can be stably generated. When the flow velocity is below 10 m / s, the hydraulic shear force is insufficient, the cavitation effect is weak, and the bubble generation is low; when the flow velocity exceeds 20 m / s, the equipment energy consumption increases significantly, and bubbles are prone to rapid coalescence and failure. An air-to-water ratio below 1% results in insufficient bubble quantity, while a ratio above 10% leads to large bubbles, reducing the adsorption efficiency of fine mineral particles. A circulation time of at least 3 minutes ensures uniform and stable bubble density in the water. This flotation water is used as makeup water for flotation, continuously replenishing the slurry system with micro-nano bubbles, increasing the contact probability between fine rare earth minerals and bubbles, breaking up sludge flocs, and alleviating the problem of fine particle smearing. No additional foaming agents are required, making it green and pollution-free. It can stabilize the bubble environment of the flotation system throughout the entire process, reduce fluctuations in separation indicators, and work synergistically with modified fatty acid collectors to improve the rare earth flotation recovery rate. The process is simple and easy to achieve for continuous industrial production.

[0053] Example 1 This application provides a flotation method to solve the problems existing in the flotation of fine-grained rare earth polymetallic ores. It provides a high-efficiency and green flotation system with dual-mode micro-nano bubble coupling and in-situ reagent modification to achieve high-precision, high-recovery, low-cost and pollution-free separation and utilization of complex and difficult-to-process fine-grained rare earth polymetallic ores.

[0054] Specifically, the existing technologies suffer from two main shortcomings: First, traditional flotation processes for fine-grained rare earth ores suffer from low gas-solid collision adhesion probability, low flotation recovery rate, and low concentrate grade. Existing micro-nano bubble flotation technologies mostly employ hydraulic cavitation and pressurized dissolution, which can only optimize bubble size and quantity at the physical level. The technology enhancement is limited in scope and has a significant upper limit, making it unsuitable for the high-precision separation requirements of complex and fine-grained rare earth ores. Second, mixed fatty acid collectors such as oxidized paraffin soap and RA935 suffer from poor water dispersibility and weak targeted adsorption selectivity. When applied to the separation of complex fine-grained rare earth ores, the reagent utilization rate is low and the separation effect is poor. They require heating processes and various modifiers to assist in the operation, resulting in cumbersome processes, high energy consumption, and poor stability. Existing fatty acid reagent modification methods, such as the traditional Fenton system, require the external addition of chemical reagents such as ferrous salts and hydrogen peroxide, which can easily introduce impurity ions and contaminate the slurry. Furthermore, the oxidation modification effect is difficult to control precisely and has poor stability.

[0055] Meanwhile, existing publicly available microbubble flotation technologies for fine particles only focus on the enhancement of physical foaming through hydraulic cavitation, without combining chemical modification of reagents. This makes it difficult to effectively solve the core problem of insufficient collector compatibility and to meet the dual needs of optimizing flotation physical conditions and upgrading reagent performance, thus restricting the efficient, green, and large-scale resource utilization of fine-particle rare earth polymetallic strategic resources.

[0056] The flotation method specifically includes the following steps: (1) Ore crushing and grinding 1.1 The lumpy ore is crushed to -2 mm using a double roll crusher.

[0057] 1.2 Add the crushed ore to a stirred mill. The grinding media are ceramic balls with a diameter of 2-4 mm to avoid iron contamination of the surface of useful minerals. Grind until the particle size D80 (referring to the proportion of ore below a certain particle size of 80% wt, the same below) is 10-75 μm.

[0058] (2) Preparation of the collector Weigh out appropriate amounts of oxidized paraffin soap, tall oil, and RA935, and mix them in any proportion to obtain a mixed fatty acid collector; Weigh out an appropriate amount of NaOH and add water to prepare a NaOH solution with a mass concentration of 0.5% to 2%. Add an appropriate amount of NaOH solution to the mixed fatty acid collector to obtain a collector solution with a mass concentration of 0.1-10% for the mixed fatty acid collector.

[0059] (3) Collector pretreatment The collector solution is pretreated using an electrolysis device. Micro-nano bubbles are generated through electrolysis, and hydroxyl radicals (·OH) are generated to oxidize and modify the fatty acid collector.

[0060] 3.1 Fix two electrode plates in the container, with a spacing of 0.5~3cm between the electrode plates, to form a foaming unit. Multiple foaming units can be set in the container. The cathode material is selected as nickel-based or boron-doped diamond electrode, and the anode material can be boron-doped diamond electrode, graphite, or titanium-based material.

[0061] 3.2 Pour the collector solution into the electrolytic foaming device, and energize the electrode plates with a DC power supply, setting the voltage to 5~30V.

[0062] 3.3 During the energizing process, a large number of fine bubbles are generated on the electrode surface and in the solution, as well as some hydroxyl radicals (·OH). Electrolytic foaming treatment for 0.5~10 min yields a moderately oxidized modified mixed fatty acid collector solution, which improves the sorting and selectivity of the collector.

[0063] (4) Preparation of water for flotation Place an appropriate amount of water in a beaker, and circulate the water through a venturi tube (any commercially available one will do) using a peristaltic pump. Open the air inlet valve of the venturi tube, adjust the volume ratio of air to water to 1-10%, and set the flow rate at the throat of the venturi tube to 10-20 m / s. Circulate and stir for more than 3 minutes to generate a large number of tiny bubbles in the water, thus obtaining flotation water containing micro- and nano-bubbles. This helps to enhance the dispersion of fine mineral particles and the probability of contact with bubbles during the flotation process.

[0064] (5) Micro-nano bubble flotation 5.1 Pour the slurry obtained in step (1) into the flotation machine (or flotation column), add the flotation water obtained in step (4) until the slurry mass concentration is 10~50%, adjust the slurry temperature to 25~50℃, and stir for 1~5 minutes.

[0065] 5.2 Add Na2CO3 to the slurry, adjust the pH of the slurry to 8~9.5, and stir for 1~5 minutes.

[0066] 5.3 Add water glass to the slurry at a rate of 200~800g / t (relative to dry ore weight, the same below).

[0067] 5.4 Add magnesium fluorosilicate (or sodium fluorosilicate) to the slurry at a rate of 100~500g / t.

[0068] 5.5 Add the modified mixed fatty acid collector solution obtained in step (3) to the slurry, with a collector dosage of 100~600g / t.

[0069] 5.6 Circulate the slurry through the Venturi tube using a peristaltic pump, close the air inlet valve of the Venturi tube, maintain the flow velocity at the throat of the Venturi tube at 10~20m / s, and circulate and stir for 3 minutes.

[0070] 5.7 Open the venturi inlet valve and adjust the air intake to 1-10% of the slurry volume. Under the action of hydraulic cavitation, a large number of fine mineralization bubbles will appear in the slurry.

[0071] 5.8 Start flotation to separate the foam product from the surface of the slurry until there is no obvious foam. During the flotation process, add the flotation water from step (4) to keep the slurry surface basically stable.

[0072] 5.9 The foam product obtained is flotation concentrate, and the product retained in the flotation equipment is flotation tailings.

[0073] 5.10 As needed, you can scan or select again.

[0074] The flotation method provided in this application overcomes the limitations of traditional single foaming technology and exogenous reagent modification. This invention generates a large number of small-particle-size, high-density micro / nano bubbles through hydraulic cavitation foaming, significantly improving the contact mass transfer efficiency between fine rare earth minerals and bubbles at the physical level, solving the problems of difficult capture of fine ores and severe interference from sludge. Simultaneously, it utilizes electrolytic foaming to generate hydroxyl radicals in situ, constructing a Fenton-like oxidation system without the need for additional Fenton reaction reagents. This allows for controllable and moderate oxidative pretreatment of fatty acid collectors, effectively improving collector dispersibility, surface activity, and targeted adsorption performance.

[0075] This invention achieves green, efficient, and low-cost flotation separation of fine-grained complex rare earth polymetallic ores by combining the physical flotation enhancement of dual-mode micro-nano bubbles with the synergistic effect of in-situ free radical chemical modification. The two promote each other and avoid the drawbacks of traditional processes, such as single efficiency enhancement, reagent modification pollution, and poor separation index. It effectively solves the industry pain point that existing technologies cannot simultaneously achieve bubble separation optimization and collector impurity-free modification.

[0076] Example 2 The Balzhe uranium-rare earth deposit in Inner Mongolia is a large-scale radioactive polymetallic deposit, associated with various metals such as niobium, tantalum, and zirconium. The ore type is shallow-intrusive mineralized alkaline granite. Due to mineralization and subsequent geological processes, the ore has fine-grained minerals, is severely weathered, and is prone to mudification. The main valuable minerals are rare earth minerals (xinganite, bastnaesite, monazite, etc.), in addition to various associated valuable minerals such as columbite and uranium-bearing zircon. The main gangue minerals are quartz, potassium feldspar, and sodium-iron amphibole. In the existing development process, the raw ore undergoes strong magnetic separation under a background field of 2.4T to obtain a magnetic product with preliminary rare earth mineral enrichment (strong magnetic concentrate, the ore in this example), which is then recovered by flotation. The grades of REO, ZrO2, Nb2O5, and U in the strong magnetic concentrate are 2.98%, 5.84%, 1.15%, and 0.033%, respectively.

[0077] (1) Ore crushing and grinding ① Weigh 2.5 kg of strong magnetic concentrate (slightly agglomerated) and crush it to -2 mm using a double roll crusher.

[0078] ② Add the crushed ore to a stirred mill, using ceramic balls with a diameter of 2-4 mm (weight ratio 3:1) as the grinding media, and grind until the particle size D80 is 40 μm.

[0079] (2) Preparation of the collector Weigh out appropriate amounts of oxidized paraffin soap, tall oil, and RA935, and mix them in a 1:1:1 ratio to obtain a mixed fatty acid collector. Weigh 20g of NaOH and add water to prepare 2L of NaOH solution with a mass concentration of 1%; Add 980g of NaOH solution to 20g of mixed fatty acid collector to obtain a collector solution with a mass concentration of 2% for the mixed fatty acid collector.

[0080] (3) Collector pretreatment The collector solution was pretreated using an electrolytic device. Micro-nano bubbles and hydroxyl radicals were generated to modify the mixed fatty acid collector.

[0081] ① Fix the two electrode plates in the container, with a distance of 1.5 cm between them. Both the cathode and anode are made of boron-doped diamond electrode plates.

[0082] ② Pour the collector solution into the electrolytic foaming device, and energize the electrode plates with a DC power supply, setting the voltage to 16V.

[0083] ③ During the energizing process, a large number of tiny bubbles are generated on the electrode surface and in the solution. After electrolytic foaming treatment for 3 minutes, a mixed fatty acid collector solution with appropriate oxidation modification is obtained.

[0084] (4) Preparation of water for flotation Take an appropriate amount of water into a beaker, circulate the water through a venturi tube (25mm diameter) using a peristaltic pump, open the venturi tube air inlet valve, adjust the air-to-water volume ratio to 5%, and set the flow rate at the venturi tube throat to 15m / s. Continuously circulate and stir the water to generate a large number of tiny bubbles, which can be used as flotation water.

[0085] (5) Micro-nano bubble flotation ① Pour the slurry obtained in step (1) into the flotation machine, add the flotation water obtained in step (4) until the slurry mass concentration is 20%, adjust the slurry temperature to 40℃, and stir for 3 minutes.

[0086] ② Add Na2CO3 to the slurry, adjust the pH of the slurry to 8.5±0.3, and stir for 3 minutes.

[0087] ③ Add water glass to the slurry at a rate of 400 g / t.

[0088] ④ Add magnesium fluorosilicate to the slurry at a dosage of 300 g / t.

[0089] ⑤ Add the modified mixed fatty acid collector solution obtained in step (3) to the slurry, with a collector dosage of 400 g / t.

[0090] ⑥ Circulate the slurry through the Venturi tube using a peristaltic pump, close the air inlet valve of the Venturi tube, set the flow rate at the throat of the Venturi tube to 15 m / s, and circulate and stir for 3 minutes.

[0091] ⑦ Open the venturi inlet valve and adjust the air intake to 5% of the slurry volume. Under the action of hydraulic cavitation, a large number of fine mineralized bubbles will appear in the slurry.

[0092] ⑧ Start flotation to separate the foamed product from the surface of the slurry until there is no obvious foam. During the flotation process, replenish the flotation water obtained in step (4) in a timely manner to keep the slurry surface basically stable.

[0093] ⑨ The foam product obtained is flotation concentrate, and the product retained in the flotation machine is flotation tailings.

[0094] The test results of Example 2 are shown in Table 1.

[0095] Table 1. Test results of Example 2

[0096] Comparative Example 1 Select the same ore sample as in Example 2 and compare the difference in rare earth mineral flotation effect of strong magnetic concentrate when the collector solution is not treated by electrolytic foaming process compared with Example 2.

[0097] During the experiment, step (3) was cancelled, and step (5) was adjusted as follows. The remaining operations were the same as in Example 2.

[0098] (5) Micro-nano bubble flotation ① Pour the slurry obtained in step (1) into the flotation machine, add the flotation water obtained in step (4) until the slurry mass concentration is 20%, adjust the slurry temperature to 40℃, and stir for 3 minutes.

[0099] ② Add Na2CO3 to the slurry, adjust the pH of the slurry to 8.5±0.3, and stir for 3 minutes.

[0100] ③ Add water glass to the slurry at a rate of 400 g / t.

[0101] ④ Add magnesium fluorosilicate to the slurry at a dosage of 300 g / t.

[0102] ⑤ Add the mixed fatty acid collector solution obtained in step (2) to the slurry, with a collector dosage of 400 g / t.

[0103] ⑥ Circulate the slurry through the Venturi tube using a peristaltic pump, close the air inlet valve of the Venturi tube, set the flow rate at the throat of the Venturi tube to 15 m / s, and circulate and stir for 3 minutes.

[0104] ⑦ Open the venturi inlet valve and adjust the air intake to 5% of the slurry volume. Under the action of hydraulic cavitation, a large number of fine mineralized bubbles will appear in the slurry.

[0105] ⑧ Start flotation to separate the foam product from the surface of the slurry until there is no obvious foam. During the flotation process, add the flotation water obtained in step (4) to keep the slurry surface basically stable.

[0106] ⑨ The foam product obtained is flotation concentrate, and the product retained in the flotation machine is flotation tailings.

[0107] The experimental results of Comparative Example 1 are shown in Table 2.

[0108] Table 2 shows the experimental results of Comparative Example 1.

[0109] Comparative Example 2 Select the same ore sample as in Example 2 and compare the difference in rare earth mineral flotation effect of strong magnetic concentrate when the flotation process does not use hydraulic cavitation foaming.

[0110] Cancel step (4) and adjust step (5) as follows, the rest is the same as in Example 2.

[0111] (5) Flotation ① Pour the slurry obtained in step (1) into the flotation machine, add the flotation water obtained in step (4) until the slurry mass concentration is 20%, adjust the slurry temperature to 40℃, and stir for 3 minutes.

[0112] ② Add Na2CO3 to the slurry, adjust the pH of the slurry to 8.5±0.3, and stir for 3 minutes.

[0113] ③ Add water glass to the slurry at a rate of 400 g / t.

[0114] ④ Add magnesium fluorosilicate to the slurry at a dosage of 300 g / t.

[0115] ⑤ Add the modified mixed fatty acid collector solution obtained in step (3) to the slurry, with a collector dosage of 400 g / t.

[0116] ⑥ Stir the slurry for 3 minutes.

[0117] ⑦ Open the air inlet valve of the flotation machine and adjust the air intake to 5% of the pulp volume. A large number of mineralized bubbles will appear in the pulp.

[0118] ⑧ Start flotation to separate the frothy product from the surface of the slurry until there is no obvious froth. During the flotation process, add rinsing water in a timely manner to keep the slurry surface basically stable.

[0119] ⑨ The foam product obtained is flotation concentrate, and the product retained in the flotation machine is flotation tailings.

[0120] The experimental results of Comparative Example 2 are shown in Table 3.

[0121] Table 3 shows the experimental results of Comparative Example 2.

[0122] Comparative Example 3 Select the same ore sample as in Example 2, and compare the differences in the flotation effect of rare earth minerals in strong magnetic concentrate when using conventional flotation process and the technology recommended in this invention with Example 2.

[0123] Cancel steps (3) and (4), and adjust step (5) as follows, the rest is the same as in Example 2.

[0124] (5) Flotation ① Pour the slurry obtained in step (1) into the flotation machine, add an appropriate amount of water to make the slurry mass concentration 20%, adjust the slurry temperature to 40℃, and stir for 3 minutes.

[0125] ② Add Na2CO3 to the slurry, adjust the pH of the slurry to 8.5±0.3, and stir for 3 minutes.

[0126] ③ Add water glass to the slurry at a rate of 400 g / t.

[0127] ④ Add magnesium fluorosilicate to the slurry at a dosage of 300 g / t.

[0128] ⑤ Add a mixed fatty acid collector solution to the slurry, with a collector dosage of 400 g / t.

[0129] ⑥ Circulate the slurry through the Venturi tube using a peristaltic pump, close the air inlet valve of the Venturi tube, set the flow rate at the throat of the Venturi tube to 15 m / s, and circulate and stir for 3 minutes.

[0130] ⑦ Open the venturi inlet valve and adjust the air intake to 5% of the slurry volume. Under the action of hydraulic cavitation, a large number of fine mineralized bubbles will appear in the slurry.

[0131] ⑧ Start flotation to separate the frothy product from the surface of the slurry until there is no obvious foam. During the flotation process, add rinsing water in a timely manner to keep the slurry surface basically stable.

[0132] ⑨ The foam product obtained is flotation concentrate, and the product retained in the flotation machine is flotation tailings.

[0133] The experimental results of Comparative Example 3 are shown in Table 4.

[0134] Table 4 shows the experimental results of Comparative Example 3.

[0135] Supplement steps in a timely manner The Weishan rare earth deposit in Shandong Province is a quartz-barite-carbonate rare earth deposit with a complex and diverse mineral composition. The main rare earth minerals are bastnaesite, bastnaesite, and monazite, while the main gangue minerals include abundant fine-grained calcite, as well as quartz, celestite, barite, feldspar, and fluorite. The REO content in the ore ranges from approximately 5% to 18%, with significant variations in ore grade across different sections. Due to the predominant presence of carbonate minerals (mainly calcite) in the ore, beneficiation is necessary to separate the gangue minerals (carbonates and other minerals) from the rare earth minerals before development and utilization. The sample in this example was taken from vein No. 12 and, after mixing, was used for testing.

[0136] (1) Ore crushing and grinding ① Weigh 1 kg of raw ore and crush it to -2 mm using a double roll crusher.

[0137] ② Add the crushed ore to a stirred mill, using ceramic balls with a diameter of 2 mm (weight ratio 3:1) as the grinding media, and grind until the particle size D80 is 50 μm.

[0138] (2) Preparation of the collector Weigh out appropriate amounts of oxidized paraffin soap, tall oil, and RA935, and mix them in a 2:1:1 ratio to obtain a mixed fatty acid collector. Weigh 20g of NaOH and add water to prepare 2L of NaOH solution with a mass concentration of 1%; Add 1980g of NaOH solution to 20g of mixed fatty acid collector to obtain a collector solution with a mass concentration of 1% for the mixed fatty acid collector.

[0139] (3) Collector pretreatment The collector solution was pretreated using an electrolytic device. Micro-nano bubbles and hydroxyl radicals were generated to modify the mixed fatty acid collector.

[0140] ④ Fix the two electrode plates in the container, with a spacing of 1.0 cm between them. Both the cathode and anode are made of boron-doped diamond electrode plates.

[0141] ⑤ Pour the collector solution into the electrolytic foaming device, and energize the electrode plates with a DC power supply, setting the voltage to 12V.

[0142] ⑥ During the energizing process, a large number of tiny bubbles are generated on the electrode surface and in the solution. After electrolytic foaming treatment for 3 minutes, a moderately oxidized and modified mixed fatty acid collector solution is obtained.

[0143] (4) Preparation of water for flotation Take an appropriate amount of water into a beaker, circulate the water through a venturi tube (25mm diameter) using a peristaltic pump, open the venturi tube air inlet valve, adjust the air-to-water volume ratio to 6%, and set the flow rate at the venturi tube throat to 17m / s. Continuously circulate and stir the water to generate a large number of tiny bubbles, which can be used as flotation water.

[0144] (5) Micro-nano bubble flotation ⑩ Pour the slurry obtained in step (1) into the flotation machine, add the flotation water obtained in step (4) until the slurry mass concentration is 20%, adjust the slurry temperature to 35℃, and stir for 3 minutes.

[0145] Add Na2CO3 to the slurry to adjust the pH of the slurry to 8.5±0.3, and stir for 3 minutes.

[0146] Add water glass to the slurry at a rate of 800 g / t.

[0147] Magnesium fluorosilicate is added to the slurry at a dosage of 200 g / t.

[0148] Add the modified mixed fatty acid collector solution obtained in step (3) to the slurry, with a collector dosage of 350 g / t.

[0149] The slurry is circulated through the Venturi tube using a peristaltic pump. The air inlet valve of the Venturi tube is closed, and the flow velocity at the throat of the Venturi tube is 17 m / s. The slurry is circulated and stirred for 3 minutes.

[0150] Open the venturi inlet valve and adjust the air intake to 5% of the slurry volume. Under the action of hydraulic cavitation, a large number of fine mineralization bubbles appear in the slurry.

[0151] Start flotation to separate the foam product from the surface of the slurry until there is no obvious foam. During the flotation process, replenish the flotation water obtained in step (4) in a timely manner to keep the slurry surface basically stable.

[0152] The resulting foam product is flotation concentrate, and the product remaining in the flotation machine is flotation tailings.

[0153] The test results of Example 3 are shown in Table 5.

[0154] Table 5. Experimental results (%) of Example 3

[0155] In summary, it can be seen that by combining the flotation method and flotation reagents provided in the embodiments of this application, a dual-mode micro-nano bubble flotation preparation method of electrolytic foaming coupled with hydraulic cavitation foaming is proposed, which breaks through the technical limitations of traditional single foaming technology and exogenous reagent modification.

[0156] This invention utilizes an electrolytic foaming method to generate micro-nano bubbles and hydroxyl radicals with oxidative modification function, thereby obtaining a Fenton-like oxidation system without the addition of external reagents. This enables controllable and moderate oxidative pretreatment of fatty acid collectors, effectively improving the dispersibility, surface activity, and targeted adsorption performance of the collectors.

[0157] By generating a large number of small-diameter, high-density micro-nano bubbles through hydraulic cavitation foaming, the contact mass transfer efficiency between fine rare earth minerals and bubbles is significantly improved from a physical perspective, solving the problems of difficult capture of fine ores and serious interference from mineral slime.

[0158] The synergistic effect of physical flotation enhancement and in-situ free radical chemical modification promotes each other and avoids the drawbacks of traditional processes such as single efficiency enhancement, reagent modification pollution, and poor separation index. It realizes green, efficient, and low-cost flotation separation of fine-particle complex rare earth polymetallic ores and effectively solves the technical pain point of existing technologies that are difficult to balance bubble separation optimization and collector impurity-free modification.

[0159] Addressing the technical challenges of weak reagent selectivity and poor flotation efficiency in fatty acid flotation systems for fine-grained rare earth polymetallic ores, this invention provides a flotation reagent preparation method and flotation method that combines electrolysis and hydraulic cavitation. This method enhances the flotation effect of fine-grained rare earth ores by generating micro-nano bubbles and increasing the activity of fatty acid reagents. By constructing a dual-mode micro-nano bubble flotation system coupled with electrolytic foaming and hydraulic cavitation foaming, the system achieves physical enhancement of fine mineral flotation through hydraulic cavitation foaming. Electrolytic foaming is used to construct a Fenton oxidation-like system without external reagents, enabling controllable modification of the fatty acid collector. Through the synergistic coupling effect of physical separation enhancement and reagent modification, this invention effectively solves the technical problems of traditional processes, such as single-dimensional enhancement, reagent modification pollution, poor separation indicators, and insufficient stability. This significantly improves the flotation efficiency and separation accuracy of fine-grained complex rare earth polymetallic ores, enabling the green, efficient, and stable resource development and utilization of this type of difficult-to-process strategic mineral resource. Under the condition that the REO grade of the raw ore is 2.1% to 18%, the "one-stage roughing" process of this technology can recover rare earth concentrates with REO grades of 22.12% and 56.76%, respectively, with recovery rates of 52.99% and 88.10%, respectively. The rare earth grade enrichment ratio is more than 10 times. Compared with the conventional flotation process under the same conditions, the REO recovery rate is increased by 10 to 17 percentage points.

[0160] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0161] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0162] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0163] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing flotation reagents, characterized in that, include: Multiple flotation reagents are mixed to obtain a mixed fatty acid collector; Add sodium hydroxide solution to the mixed fatty acid collector to obtain a collector solution; The collector solution is electrolyzed and oxidized to generate nanobubbles and hydroxyl radicals, thereby obtaining a flotation reagent.

2. The method for preparing flotation reagents according to claim 1, characterized in that, The sodium hydroxide solution has a mass concentration of 0.5% to 2%; The mass concentration of the collector solution is from 0.1% to 10%.

3. The method for preparing flotation reagents according to claim 1, characterized in that, The steps of electrolyzing the collector solution and oxidizing the collector solution to generate nanobubbles and hydroxyl radicals to obtain the flotation reagent include: A cathode electrode plate and an anode electrode plate are placed in a container, with a distance of 0.5 cm to 3 cm between the cathode electrode plate and the anode electrode plate; The materials used to prepare the cathode electrode plate include nickel-based or boron-doped diamond; The materials used to prepare the anode electrode plate include boron-doped diamond, graphite, or titanium-based materials; The electrolysis voltage is 5V to 30V, and the electrolysis time is 0.5min to 10min.

4. A flotation reagent, characterized in that, The flotation reagent is prepared by the flotation reagent preparation method as described in any one of claims 1 to 3.

5. The flotation reagent according to claim 4, characterized in that, The raw materials for preparing the mixed fatty acid collector in the flotation reagent include oxidized paraffin soap, tall oil, and RA935 collector.

6. A flotation method, characterized in that, include: The rare earth ore is crushed and ground to obtain a slurry; Add the flotation reagent as described in claim 4 or 5 to the slurry and perform flotation.

7. The flotation method according to claim 6, characterized in that, The steps of crushing and grinding rare earth ore to obtain slurry include: Rare earth ore is crushed using a double roll crusher; The crushed ore is ground using a stirred mill, and the particle size D80 of the ground ore is 10μm to 75μm. The grinding media consists of ceramic balls with a diameter of 2 mm to 4 mm.

8. The flotation method according to claim 6, characterized in that, The steps of adding flotation reagents to the slurry and carrying out flotation include: Control the slurry concentration to 10% to 50%, adjust the slurry temperature to 25℃ to 50℃, and stir for 1 min to 5 min; Add pH adjuster to the slurry to adjust the pH to 8 to 9.5, and stir for 1 to 5 minutes; Add water glass to the slurry at a dosage of 200g / t to 800g / t; Magnesium fluorosilicate or sodium fluorosilicate is added to the slurry at a dosage of 100g / t to 500g / t. The flotation reagent is added to the slurry at a dosage of 100 g / t to 600 g / t. The slurry is circulated through the Venturi tube by a peristaltic pump. The air inlet valve of the Venturi tube is closed. The flow velocity at the throat of the Venturi tube is 10 m / s to 20 m / s. The circulation and stirring time is greater than or equal to 3 min. Open the venturi inlet valve and adjust the air intake to 1% to 10% of the slurry volume. Under the action of hydraulic cavitation, mineralized bubbles appear in the slurry, and flotation is carried out.

9. The flotation method according to claim 8, characterized in that, Also includes: Add flotation water during the flotation process to keep the slurry surface at the flotation interface.

10. The flotation method according to claim 9, characterized in that, The steps for preparing the flotation water include: Water is circulated through a peristaltic pump, and the air inlet valve of the venturi tube is opened. The volume ratio of air to water is adjusted from 1% to 10%, and the flow velocity at the throat of the venturi tube is 10 m / s to 20 m / s. The water is circulated and stirred for more than 3 minutes, generating a large number of tiny bubbles in the water, thus obtaining flotation water containing micro-nano bubbles.

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