A method of flotation of a rare earth ore

Abstract

The application discloses a flotation method of rare earth ore, and belongs to the technical field of ore dressing. The method provided by the application comprises the following steps: mixing the rare earth ore and water to perform grinding, to obtain a first ore slurry; adding an alkaline adjusting agent into the first ore slurry to perform first-time mixing, to obtain a second ore slurry; adding water glass into the second ore slurry to perform second-time mixing, to obtain a third ore slurry; adding an activator and a collector into the third ore slurry to perform third-time mixing, to obtain a fourth ore slurry; and performing air flotation on the fourth ore slurry, to obtain a rare earth concentrate. The flotation method provided by the application can greatly improve the concentrate grade under the premise of guaranteeing the rare earth recovery rate, and can be implemented only by optimizing the reagent addition and stirring parameters without modifying the existing equipment, and has excellent adaptability and popularization.

Description

Technical Field

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

[0002] In the flotation process of rare earth minerals, water glass is typically added as a gangue depressant to effectively separate rare earth minerals from gangue and harmful associated minerals, thereby improving the quality of the rare earth concentrate. In actual processes, rare earth minerals are first initially enriched by strong magnetic separation, and then water glass is added to the pulp to suppress gangue and niobium-zirconium minerals, thus achieving efficient enrichment of rare earth minerals. The suppression mechanism is as follows: water glass undergoes dissociation and polymerization reactions in the pulp system, forming OH- ions in the pulp. - HSiO3 - H2SiO3, SiO2(OH)2 2- A colloidal-molecular-ionic system composed of equal components adsorbs onto the surface of gangue minerals to enhance hydrophilicity, thereby inhibiting mineral flotation.

[0003] However, in existing rare earth flotation processes, the inhibitory effect of water glass after being added to the slurry weakens significantly with prolonged stirring time, causing a sharp and abnormal increase in the flotation concentrate yield. This results in a severe reduction in the grade of rare earth concentrate, which not only affects the efficiency and product quality of rare earth flotation but also increases the production costs of subsequent smelting processes. This seriously restricts the separation efficiency, separation effect, and industrial application benefits of rare earth flotation processes. Summary of the Invention

[0004] This application discloses a flotation method for rare earth ores, which aims to solve the technical problem of severely reduced grade of existing rare earth concentrates.

[0005] To achieve the above objectives, the technical solution of this application is: The first aspect of this application provides a flotation method for rare earth ores, the method comprising: Rare earth ore is mixed with water and ground to obtain a first slurry; the mass percentage of -0.037 mm particles in the first slurry is 45%~95%, and the concentration of the first slurry is 15%~50%; An alkaline modifier is added to the first slurry and mixed for a first time to obtain the second slurry; Water glass was added to the second slurry and mixed for a second time to obtain the third slurry; An activator and a collector are added to the third slurry, and the mixture is mixed for a third time to obtain a fourth slurry. The fourth slurry was subjected to aerated flotation to obtain rare earth concentrate.

[0006] Preferably, in conjunction with the first aspect, the modulus of the water glass is 3.0-3.5; The amount of water glass added is 500-5000 g / t; The second time is 3-20 minutes.

[0007] Preferably, in conjunction with the first aspect, the amount of water glass added is 1000-3000 g / t; The second time is 5-15 minutes.

[0008] Preferably, in conjunction with the first aspect, the alkalinity adjuster is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; The amount of alkaline adjuster added is 200-1000 g / t; The first time is 1-30 min.

[0009] Preferably, in conjunction with the first aspect, the amount of sodium hydroxide added is 200-500 g / t; The amount of sodium carbonate added is 300-1000 g / t.

[0010] Preferably, in conjunction with the first aspect, the activator is one or a combination of sodium fluorosilicate and magnesium fluorosilicate; The amount of activator added is 200-2000 g / t.

[0011] Preferably, in conjunction with the first aspect, the collector is one or more of oxidized paraffin soap, lauric acid, and oleic acid; The amount of the collector added is 200-2000 g / t.

[0012] Preferably, in conjunction with the first aspect, the third time is 3-15 minutes.

[0013] In conjunction with the first aspect, preferably, the rare earth ore is one or more of the following: genus dahurica, monazite, bastnaesite, and calcite. The rare earth ore is a strongly magnetic concentrate; The strong magnetic concentrate is a concentrate product of rare earth ore through strong magnetic beneficiation, with a rare earth oxide (REO) grade of ≥2%.

[0014] Preferably, in conjunction with the first aspect, the conditions for the aerated flotation are: flotation temperature 25-45 ℃, and aeration rate of 0.1-3.0 m³ / s. 3 / (m 2 The flotation time is 1-40 min.

[0015] Compared with the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following: The flotation method provided in this application involves adding an alkaline modifier followed by water glass. On the one hand, the alkaline modifier creates an alkaline pulp environment, allowing the water glass to complex and dissolve Fe. 3+ Al 3+ The method generates hydroxide precipitates, eliminating the drawbacks of increasing the active sites of collectors and causing gangue to float. Secondly, by controlling the stirring time after adding water glass, abnormal increases in ion concentration and decreases in pulp pH are avoided, thus stabilizing its selective inhibition effect. Thirdly, water glass and alkaline modifiers can synergistically regulate the hydrogen bond structure of water in the pulp, increasing the proportion of polymeric water molecules and reducing the average hydrogen bond strength, thereby strengthening the gangue inhibition effect and improving flotation selectivity. This flotation method can significantly improve concentrate grade while ensuring rare earth recovery. Furthermore, it requires no modification to existing equipment; implementation only requires optimizing reagent addition and stirring parameters. The reagents are inexpensive, readily available, and cost-controllable, making it suitable for the flotation of various rare earth polymetallic ores using water glass as a depressant, demonstrating excellent adaptability and scalability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The diagram shows the pH and SiO2 concentration changes of the third slurry during the flotation process to obtain A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate, as provided in the embodiments of this application. Figure 2 The Fe content of the third slurry in the flotation process for obtaining A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate provided in the embodiments of this application. 3+ Al 3+ Graph showing changes in ion concentration; Figure 3 A slurry filtrate diagram of the third slurry in the flotation process to obtain A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate, as provided in the embodiments of this application; Figure 4 The pH change of the third slurry in the flotation process to obtain A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate is shown in the figure before and after 30 days of settling, according to the embodiments of this application. Figure 5 Technical indicator diagrams of A4-rare earth concentrate and A5-rare earth concentrate provided for embodiments of this application; Figure 6The pH and Fe content of the second slurry in the flotation process for obtaining A3-rare earth concentrate, A4-rare earth concentrate, A5-rare earth concentrate, and A6-rare earth concentrate provided in the embodiments of this application. 3+ Al 3+ Graph showing SiO2 concentration changes; Figure 7 Infrared spectral peak fitting diagrams of water, B1-third slurry, A2-third slurry, and A1-third slurry filtrate provided in the embodiments of this application; Figure 8 Raman spectra of water, A1-third mineral slurry, A2-third mineral slurry, and B1-third mineral slurry filtrate provided for embodiments of this application; Figure 9 Raman spectrum peak fitting diagrams of water, B1-third slurry, A1-third slurry, and A2-third slurry filtrate provided in the embodiments of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0020] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0021] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] It should be noted that all raw materials and / or reagents in the embodiments of this application were purchased on the market or prepared according to conventional methods known to those skilled in the art.

[0024] In a first aspect, embodiments of this application provide a flotation method for rare earth ores, the method comprising: Rare earth ore is mixed with water and ground to obtain a first slurry; the mass percentage of -0.037 mm particles in the first slurry is 45%~95%, and the concentration of the first slurry is 15%~50%; An alkaline modifier is added to the first slurry and mixed for a first time to obtain the second slurry; Water glass was added to the second slurry and mixed for a second time to obtain the third slurry; An activator and a collector are added to the third slurry, and the mixture is mixed for a third time to obtain a fourth slurry. The fourth slurry was subjected to aerated flotation to obtain rare earth concentrate.

[0025] It should be noted that in the first step of the grinding process, this application selects to add water for wet grinding. This method can not only cool down the grinding process, reduce the friction and adhesion between ore particles, and effectively suppress dust pollution generated by dry grinding, but also achieve flexible control of ore particle size, providing a good process foundation for stable and efficient operation in subsequent steps.

[0026] It should be noted that the alkaline modifier provides an alkaline environment to the slurry, allowing the Fe dissolved through the complexation of water glass to be released. 3+ Al 3+ Fe(OH)3 and Al(OH)3 precipitates are formed, and the reaction formula is: Fe 3+ + 3OH - → Fe(OH)3↓、Al 3+ + 3OH -→ Al(OH)3↓ completely eliminates the adverse effects of harmful ions occupying the active sites of the collector and causing gangue minerals to float. Simultaneously, the synergistic effect of water glass and alkaline modifiers regulates the hydrogen bond structure, controlling the hydrogen bond structure of water in the pulp at the infrared and Raman spectral levels, enhancing selective inhibition of gangue minerals and further improving separation accuracy. Practice shows that adding 320 g / t NaOH achieves a concentrate grade of 22.84%, superior to the 15.94% of conventional flotation processes, demonstrating a significant advantage in separation performance.

[0027] It should be noted that by synergistically inhibiting the hydrogen bond structure through the regulation of water glass and alkaline modifier, the hydrogen bond structure of water in the pulp filtrate is changed—at the infrared spectral level, the proportion of aggregated water molecules is increased, forming an associated hydrogen bond network; at the Raman spectral level, the average hydrogen bond strength of the system is reduced, causing water molecules to transform into a loose aggregated water structure. Both of these factors together enhance the flotation inhibition effect on gangue minerals and improve flotation selectivity.

[0028] It should be noted that this application employs the principle of harmful ion precipitation, targeting and precipitating harmful ions to fundamentally solve this core defect. Simultaneously, combined with the principle of water glass's stabilizing performance, the stirring time after adding water glass is strictly controlled to ≤20 min to avoid the formation of SiO2 and Fe due to excessive stirring. 3+ Al 3+ Excessive increase in concentration and decrease in pulp pH effectively maintain the selective inhibition of gangue minerals by water glass, ensuring a stable and controllable flotation process and significantly reducing the risk of fluctuations in separation effect.

[0029] In this embodiment, the modulus of the water glass is preferably 3.0-3.5; the amount of water glass added is preferably 500-5000 g / t, more preferably 1000-3000 g / t; and the second time is preferably 3-20 min, more preferably 5-15 min. The water glass, preferably with a medium-high modulus of 3.0-3.5, after hydrolysis mainly consists of colloidal silicate and polysilicate, which can form a dense hydrophilic hydration film on the surface of gangues such as quartz, feldspar, and mica through hydrogen bonding and hydration, achieving strong selective inhibition; and it has weak adsorption on rare earth minerals, ensuring the rare earth recovery rate.

[0030] Specifically, the amount of water glass added needs to cover the active sites on the gangue surface, achieving an optimal balance between sufficient gangue inhibition and the avoidance of excessive rare earth inhibition, while taking into account both the grade and recovery rate of rare earth concentrate.

[0031] Specifically, water glass needs time to complete hydrolysis, diffusion, and adsorption onto the gangue surface; the stirring time after adding water glass should be controlled to ≤20 min to prevent SiO2 and Fe from reacting. 3+ Al 3+ Excessive increase in concentration and decrease in slurry pH can stabilize the water glass's inhibitory properties.

[0032] In this embodiment, the alkaline modifier is preferably one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; the amount of alkaline modifier added is preferably 200-1000 g / t; and the first time is preferably 1-30 min. By adding the alkaline modifier first and then water glass, the Fe... 3+ Al 3+ Targeted precipitation prevents the premature accumulation of harmful ions. By controlling the amount and timing of the alkaline modifier, an alkaline environment can be ensured in the slurry, allowing the Fe dissolved through water glass complexation to be effectively released. 3+ Al 3+ The formation of hydroxide precipitate completely eliminates Fe. 3+ Al 3+ The adverse effects of increasing the active sites of the collector should be mitigated to prevent gangue minerals from floating to the surface.

[0033] In this embodiment, the preferred amount of sodium hydroxide added is 200-500 g / t; the preferred amount of sodium carbonate added is 300-1000 g / t. NaOH is a strong base, and a small amount can significantly raise the pH; Na2CO3 has a strong buffering capacity, so the amount used is slightly higher.

[0034] In this embodiment, the activator is one or a combination of sodium fluorosilicate and magnesium fluorosilicate; the preferred amount of the activator is 200-2000 g / t. The collector is one or more of oxidized paraffin soap, lauric acid, and oleic acid; the preferred amount of the collector is 200-2000 g / t. The activator releases F upon hydrolysis under alkaline conditions. - It can clean the oxide film and mud coating on the surface of rare earth minerals, expose the surface rare earth cation active sites, activate rare earth minerals, greatly improve the adsorption efficiency of collectors, and increase the rare earth recovery rate; and has no activating effect on gangue, ensuring the selectivity of sorting.

[0035] Specifically, the collector used in this application is an anionic collector. The carboxyl group (-COOH) can chemically chelate and adsorb metal ions such as La, Ce, and Nd on the surface of rare earth, making the surface of rare earth hydrophobic, ensuring sufficient collection of rare earth, and improving the recovery rate.

[0036] In this embodiment, the third time is preferably 3-15 min, which can ensure that the activator and collector diffuse to the mineral surface and complete stable adsorption. The slurry preparation time is short, the process is efficient, and it is suitable for continuous industrial flotation.

[0037] In this embodiment of the application, there are no special requirements for the source and composition of the rare earth ore; any rare earth ore well-known in the art is acceptable. The rare earth ore is preferably one or more of the following: xanthanite, monazite, bastnaesite, and calcite; more preferably, it is a strong magnetic concentrate; the strong magnetic concentrate is the concentrate product of the rare earth ore after strong magnetic separation, with a rare earth oxide (REO) grade ≥2%.

[0038] Specifically, the rare earth ore is preferably an oxygen- or fluorine-containing rare earth mineral with exposed surface metal cations, which readily react with anionic collectors and are suitable for alkaline flotation. Furthermore, the process is highly targeted, has high separation efficiency, is applicable to typical rare earth ore types, and has good industrial versatility.

[0039] Specifically, the raw material for this application is preferably a strong magnetic concentrate with REO ≥ 2%. The strong magnetic separation pre-enriches rare earth elements while discarding a large amount of gangue. This reduces the flotation throughput and reagent consumption; avoids low-grade feed leading to low separation efficiency and large fluctuations in indicators; and facilitates the acquisition of high-grade rare earth concentrates.

[0040] In this embodiment, the aeration flotation process has no special requirements; a flotation process well-known in the art can be used. The preferred conditions for the aeration flotation are: a flotation temperature of 25-45 ℃ and an aeration rate of 0.1-3.0 m³ / s. 3 / (m 2 The optimal flotation time is 1-40 min. By limiting these flotation conditions, this method can significantly improve the concentrate grade while ensuring the rare earth recovery rate. The optimal grade of the roughing concentrate can reach 22.84%, and the grade can be further improved by further refining.

[0041] It should be noted that the flotation method adopted in this application has strong process adaptability and is easy to promote and apply in industrial applications. No modification to existing rare earth flotation equipment is required; process optimization can be achieved simply by adjusting the reagent addition sequence and strictly controlling the water glass stirring time. The operation is low-difficulty, requires no large investment in equipment modification, and is compatible with existing industrial production processes.

[0042] It should be noted that the flotation method used in this application has controllable costs and outstanding economic benefits. The alkaline modifiers (NaOH, Na2CO3) used in the process are all commonly used industrial chemical raw materials, which are inexpensive, widely available, easy to purchase, and have controllable costs. At the same time, the amount of water glass and other flotation reagents used is consistent with that of conventional flotation processes, requiring no additional reagent input and thus not incurring new costs.

[0043] It should be noted that the flotation method used in this application has a wide range of applications and is suitable for various ore types. The core mechanism of this flotation process is universal and applicable to the flotation of all alkaline granite-type rare earth polymetallic ores that use water glass as a gangue depressant. Regardless of the grade of the raw ore, it can play a good regulatory role in strong magnetic concentrates of different grades, effectively solving problems such as unstable gangue suppression and low concentrate grade in the flotation process of such ores. This expands the application scenarios of the process and provides a feasible solution for the efficient flotation of various alkaline granite-type rare earth ores.

[0044] The technical solutions of this application will be further described below with reference to specific embodiments, but they should not be construed as limiting the scope of protection of this invention.

[0045] Example 1 This embodiment provides a flotation method for rare earth ores, specifically including: S101: Select alkaline granite-type rare earth polymetallic mineral strong magnetic concentrate (REO grade 3.85%), weigh 500 g of strong magnetic concentrate, add water and grind until the -0.037 mm particle size accounts for 70%, place it in a 1.5 L single cell flotation machine, and adjust it into A1-first slurry with a solid mass concentration of 30%; S102: Add 320 g / t NaOH as an alkaline adjuster to A1-first slurry and stir for 2 min to obtain A1-second slurry; S103: Add 1600 g / t of industrial water glass with a modulus of 3.5 to A1-second slurry and stir for 6 min to obtain A1-third slurry; S104: Add 600 g / t sodium fluorosilicate and 400 g / t oxidized paraffin soap to A1-third slurry, control the slurry temperature at 30 ℃, and stir for 4 min to obtain A1-fourth slurry; S105: Compressed air is introduced into the flotation machine, where it is sheared into numerous tiny bubbles by the agitator. The rising bubbles carry a large amount of rare earth minerals, forming a layer of mineralized foam on the surface of the A1-fourth ore slurry. This layer of foam is continuously scraped off with a scraper, and after concentration, filtration, and drying, A1-rare earth concentrate is obtained.

[0046] Example 2 The method composition ratio, preparation operation, and process parameters provided in this embodiment are basically the same as those in Example 1. The difference is that 640 g / t Na2CO3 is added as an alkaline adjuster in step S102 to obtain A2-second slurry. A2-third slurry and A2-fourth slurry are obtained sequentially according to the steps in Example 1, and finally A2-rare earth concentrate is obtained.

[0047] Example 3 The method composition ratio, preparation operation, and process parameters provided in this embodiment are basically the same as those in Example 1. The difference is that the stirring time after adding industrial water glass in step S103 is 5 min, 10 min, 20 min, 30 min, and 90 min, respectively, to obtain A3-rare earth concentrate, A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate.

[0048] In addition, to verify the overall performance of the methods provided in the above embodiments, this application provides the following comparative examples for detailed explanation.

[0049] Comparative Example 1 The method, component ratio, preparation operation, and process parameters provided in this comparative example are basically the same as those in Example 1. The difference is that step S103 is omitted in this comparative example, NaOH is not added, and water glass is directly added to the first slurry to obtain B1-third slurry. The following operations are performed to obtain B1-concentrate.

[0050] Comparative Example 2 This comparative example provides a flotation method for rare earth ores, specifically including: S201: Select alkaline granite-type rare earth polymetallic mineral strong magnetic concentrate (REO grade 3.85%), weigh 500 g of strong magnetic concentrate, add water and grind until the -0.037 mm particle size accounts for 70%, place it in a 1.5 L single cell flotation machine, and adjust it into B2-first slurry with a solid mass concentration of 30%. S202: Add 1600 g / t of industrial water glass with a modulus of 3.5 to B2-first slurry and stir for 6 min to obtain B2-second slurry; S203: Add 320 g / t NaOH as an alkaline modifier to B2-second slurry and stir for 2 min to obtain B2-third slurry; S204: Add 600 g / t sodium fluorosilicate and 400 g / t oxidized paraffin soap to B2-third slurry, control the slurry temperature at 30 ℃, and stir for 4 min to obtain B2-fourth slurry; S205: Compressed air is introduced into the flotation machine, where it is sheared into numerous tiny bubbles by the agitator. The rising bubbles carry a large amount of rare earth minerals, forming a layer of mineralized foam on the surface of the B2-fourth slurry. This layer of foam is continuously scraped off with a scraper, and after concentration, filtration, and drying, the B2-concentrate is obtained.

[0051] The difference between this comparative example and Example 1 is that water glass is added first, followed by NaOH.

[0052] Comparative Example 3 The method, component ratio, preparation operation, and process parameters provided in this comparative example are basically the same as those in Example 1. The difference is that step S102 is omitted in this comparative example, that is, NaOH is not added, and ferric chloride is added to make the iron ion concentration the same as the iron ion concentration of the third slurry after stirring for 23 min after adding water glass, so as to obtain B3-concentrate.

[0053] Comparative Example 4 The method, component ratio, preparation operation, and process parameters provided in this comparative example are basically the same as those in Example 1. The difference is that in step S102 of this comparative example, NaOH is not added, and aluminum sulfate is added to make the aluminum ion concentration the same as the aluminum ion concentration of the third slurry after stirring for 23 min after adding water glass, so as to obtain B4-concentrate.

[0054] Comparative Example 5 The method composition ratio, preparation operation, and process parameters provided in this comparative example are basically the same as those in Example 1. The difference is that in this comparative example, 320 g / t NaOH and water glass are added to the first slurry system at the same time to obtain B5-concentrate.

[0055] This application tests the grade and recovery rate of the concentrates after beneficiation in the examples and comparative examples, as shown in Tables 1 and 2.

[0056] Table 1. Grade and recovery rate of concentrate in the examples

[0057] Table 2. Grade and recovery rate of comparative concentrates

[0058] Comparing the test results in Tables 1 and 2, it was found that in Comparative Example 1 and Comparative Example 1, the addition of the alkaline modifier increased the concentrate grade by 6.9 percentage points, while the recovery rate remained essentially unchanged. This confirms that the alkaline modifier can effectively eliminate the influence of harmful ions and improve the sorting indicators. In Comparative Example 1 and Example 2, under the same dosage, NaOH showed better optimization than Na2CO3, with a concentrate grade 4.32 percentage points higher and a recovery rate 6 percentage points higher, making it the preferred alkaline modifier. In Comparative Example 1 and Example 3, the stirring time of water glass was extended to 20 min, resulting in a slight decrease in concentrate grade, confirming that a stirring time ≤ 20 min is the optimal control range. In Comparative Example 1 and Comparative Examples 2 and 5, the order of adding the alkaline modifier first and then the water glass is crucial. Adding them in reverse or simultaneously will lead to premature accumulation of harmful ions and a significant decrease in concentrate grade.

[0059] To further verify the technical principles of the preparation process, the concentrate prepared in the examples was further tested.

[0060] The pH and SiO2 concentration changes of the third slurry obtained in the preparation processes of A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate in Example 3 were tested. Figure 1 As shown, it is evident that as the time of water glass addition increases, the SiO2 concentration rises and the pH decreases.

[0061] Furthermore, the third slurry obtained during the preparation of A4-rare earth concentrate, A5-rare earth concentrate, A6-rare earth concentrate, and A7-rare earth concentrate in Example 3 was tested for Fe content. 3+ Al 3+ Changes in ion concentration, such as Figure 2 As shown in the figure. It can be clearly observed that the addition of water glass prolongs the stirring time, and the Fe... 3+ Al 3+ The concentration gradually increased.

[0062] Furthermore, the third slurry filtrate was observed simultaneously after adding water glass for different stirring times, as shown in the following figures. Figure 3 As shown, a represents the product after adding water glass without stirring; b represents the product after adding water glass and stirring for 10 minutes; c represents the product after adding water glass and stirring for 20 minutes; d represents the product after adding water glass and stirring for 30 minutes; and e represents the product after adding water glass and stirring for 90 minutes. It can be observed that the longer the stirring time, the more mineral dissolution products are produced, and the darker the color of the filtrate.

[0063] Furthermore, the pH change was tested after the above slurry was allowed to stand for 30 days. Figure 4 As shown, a clear decrease in pH can be observed, which is due to Fe 3+ Al 3+ Hydrolysis consumes OH - This is a significant reason for the decrease in pulp pH.

[0064] This application uses water as a blank control and adds Fe. 3+ Al 3+ The B3-concentrate and B4-concentrate were then subjected to flotation, and the results were compared, such as... Figure 5 As shown, 0 on the horizontal axis represents the use of water as a blank control group, and Fe... 3+ Al 3+ These are B3-concentrate and B4-concentrate, respectively. It is clear that Fe... 3+ Al 3+ It will significantly increase concentrate yield and reduce concentrate grade.

[0065] Furthermore, such as Figure 6 As shown, samples were taken from the second slurry obtained in the example and stirred for different times. The pH and different ion concentrations in the slurry after the addition of NaOH were tested over time. The results proved that high pH was not necessarily due to Fe. 3+Al 3+ The reason for the increased concentration; an alkaline environment will actually increase Fe 3+ Al 3+ The decrease in concentration provides a basis for the use of alkalinity adjusters.

[0066] This application uses water as a blank control, and performs infrared spectroscopy tests on B1-third slurry, A2-third slurry, and A1-third slurry prepared in the examples and comparative examples, as detailed below. Figure 7 As shown, the blank control group water is Figure 7 a. B1 - The third slurry is Figure 7 b. A2-Third slurry is Figure 7 c. A1-Third slurry is Figure 7 d, the results are shown in Table 3.

[0067] Table 3 Comparison of Infrared Spectral Peak Areas

[0068] pass Figure 7 The results in Table 3 demonstrate that the hydrogen bond structure of the slurry changed after the addition of the reagent, and the proportion of aggregated water molecules increased significantly, enhancing the inhibitory effect on gangue minerals. The slurry filtrate is essentially an aqueous solution system. Upon addition of water glass, the polar groups of the reagent molecules form hydrogen bonds with water molecules, disturbing the original free hydrogen bond network of water molecules and promoting the association of individual water molecules to form aggregated water molecule clusters. Therefore, the hydrogen bond structure of water is reconstructed, and the proportion of aggregated water molecules increases. Gangue minerals (silicates, carbonates, quartz, etc.) are generally hydrophilic minerals with surfaces rich in hydrophilic groups such as hydroxyl groups, easily forming hydration films with water molecules. With the increased proportion of aggregated water molecules, the degree of water molecule association is enhanced, forming a thicker and more stable hydration film on the surface of the gangue minerals. This significantly increases the hydrophilicity of the gangue, making it difficult for air bubbles to adhere and float, ultimately enhancing the inhibitory effect on the gangue minerals.

[0069] Meanwhile, Raman spectroscopy tests were performed on the A1-third mineral slurry, A2-third mineral slurry, and B1-third mineral slurry prepared using water as a blank control, as well as the examples and comparative examples. Figure 8 and Figure 9 As shown, Figure 8 This demonstrates that the Raman spectral intensity of the filtrate increased after the addition of the reagent, indicating a change in the hydrogen bond structure of water. Furthermore... Figure 9 In the blank control group, water is Figure 9 a. B1 - The third slurry is Figure 9 b. A2-Third slurry is Figure 9 c. A1-Third slurry is Figure 9 d, The data is recorded in Table 4.

[0070] Table 4 Comparison of Raman Spectrum Peak Areas

[0071] The results showed that the Raman spectral intensity of the slurry filtrate water was significantly enhanced after the addition of the reagent, directly confirming the reconstruction of the hydrogen bond structure of water molecules. This structural change was manifested as the deagglomeration of large water molecule clusters with strong hydrogen bonds and the increase of clusters of water molecules with weak hydrogen bonds, which reduced the average hydrogen bond strength of the system. The decrease in average hydrogen bond strength enhanced the ability of water molecules to form a stable hydration film on the hydrophilic gangue surface, further enhancing the inhibitory effect on gangue minerals.

[0072] Therefore, the flotation method provided in this application can significantly improve the concentrate grade while ensuring the rare earth recovery rate. Furthermore, it requires no modification to existing equipment; implementation can be achieved simply by optimizing reagent addition and stirring parameters. The reagents are inexpensive, readily available, and cost-controllable, making it suitable for the flotation of various rare earth polymetallic ores using water glass as a depressant, demonstrating excellent adaptability and scalability.

[0073] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0074] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A flotation method for rare earth ores, characterized in that, The method includes: Rare earth ore is mixed with water and ground to obtain a first slurry; the mass percentage of -0.037 mm particles in the first slurry is 45%~95%, and the concentration of the first slurry is 15%~50%; An alkaline modifier is added to the first slurry and mixed for a first time to obtain the second slurry; Water glass was added to the second slurry and mixed for a second time to obtain the third slurry; An activator and a collector are added to the third slurry, and the mixture is mixed for a third time to obtain a fourth slurry. The fourth slurry was subjected to aerated flotation to obtain rare earth concentrate.

2. The flotation method according to claim 1, characterized in that, The modulus of the water glass is 3.0-3.5; The amount of water glass added is 500-5000 g / t; The second time is 3-20 minutes.

3. The flotation method according to claim 2, characterized in that, The amount of water glass added is 1000-3000 g / t; The second time is 5-15 minutes.

4. The flotation method according to claim 1, characterized in that, The alkalinity adjuster is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; The amount of alkaline adjuster added is 200-1000 g / t; The first time is 1-30 min.

5. The flotation method according to claim 4, characterized in that, The amount of sodium hydroxide added is 200-500 g / t; The amount of sodium carbonate added is 300-1000 g / t.

6. The flotation method according to claim 1, characterized in that, The activator is one or a combination of sodium fluorosilicate and magnesium fluorosilicate. The amount of activator added is 200-2000 g / t.

7. The flotation method according to claim 1, characterized in that, The collector is one or more of oxidized paraffin soap, lauric acid, and oleic acid; The amount of the collector added is 200-2000 g / t.

8. The flotation method according to claim 1, characterized in that, The third time is 3-15 minutes.

9. The flotation method according to claim 1, characterized in that, The rare earth mineral is one or more of the following: genus dahurica, monazite, bastnaesite, and calcite. The rare earth ore is a strongly magnetic concentrate; The strong magnetic concentrate is a concentrate product of rare earth ore through strong magnetic beneficiation, with a rare earth oxide (REO) grade of ≥2%.

10. The flotation method according to claim 1, characterized in that, The conditions for the aerated flotation are: flotation temperature 25-45 ℃, and aeration rate of 0.1-3.0 m³ / s. 3 / (m 2 The flotation time is 1-40 min.

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