Mineral surface selective dissolution-based micro-fine particle lepidolite reinforced recovery method

Abstract

The invention aims to disclose a micro-fine particle lepidolite reinforced recovery method based on mineral surface selective dissolution. The method comprises the following steps that (1) surface dissolution is conducted, specifically, a selective solvent WX-R is added into ore pulp, selective dissolution is conducted on the mineral surface under ultrasonic stirring, and the selective solvent WX-R comprises citric acid, oxalic acid and ethylenediaminetetraacetic acid; and (2) flotation is conducted, specifically, an inhibitor WX-I is added into the dissolved ore pulp, full stirring is conducted, then a collecting agent WX-C is added for air inflation flotation, micro-fine-particle lepidolite concentrate and tailings are obtained, the inhibitor WX-I comprises water glass, dextrin and carboxymethyl cellulose, and the collecting agent WX-C comprises oleic acid, dialkyl phosphoric acid, lauryl amine and sodium dodecyl sulfate. According to the method, surface property modification and strengthening of the lepidolite are achieved, the reagent effect is achieved, the recovery rate and grade of Li2O are remarkably improved, and the problem that the recovery efficiency of micro-fine particle lepidolite is low through traditional flotation is solved.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, and in particular to a method for enhanced recovery of fine-grained lepidolite based on selective dissolution of mineral surfaces. Background Art

[0002] Mica, a key lithium resource, is widely used in industries such as batteries, ceramics, and glass. However, with the continued rapid growth in global lithium demand, the efficient recovery of lepidolite has become increasingly critical. Micro-particle lepidolite, in particular, faces numerous challenges in traditional flotation processes due to its fine particle size, large surface area, and high surface energy. This small particle size makes it prone to agglomeration in the slurry, making it difficult to achieve good dispersion. This severely impacts its effective contact with the collector, thus reducing flotation efficiency. Furthermore, its high surface area and high surface energy increase its surface activity, making separation from gangue minerals extremely difficult. In traditional flotation processes, commonly used flotation reagents and equipment struggle to precisely target micro-particle lepidolite, failing to fully utilize its flotation properties. This ultimately results in low lepidolite recovery and a low concentrate grade. These issues severely hinder the effective utilization of lepidolite resources and the sustainable development of related industries.

[0003] Traditional methods for recovering fine-grained lepidolite currently focus on optimizing flotation reagent systems and improving flotation equipment. For example, in the flotation reagent sector, attempts to improve lepidolite capture efficiency have been made by adjusting the type and dosage of collectors such as fatty acids and amines. However, due to their limited selectivity, these efforts have struggled to fundamentally resolve the difficulty in separating lepidolite from gangue minerals. Regarding flotation equipment improvements, several new flotation machines have been developed that, by optimizing slurry flow patterns and bubble generation, have improved the flotation environment to some extent. However, these efforts remain unable to effectively address the agglomeration and surface activity issues of fine-grained lepidolite.

[0004] Therefore, there is an urgent need to develop innovative technologies to enhance the recovery of fine-grained lepidolite to meet the growing demand for lithium and promote the healthy development of related industries. Summary of the Invention

[0005] To solve the above problems, the present invention discloses a new method for enhanced recovery of fine-grained mica based on selective dissolution of mineral surfaces. By selectively dissolving surface elements of lepidolite, its surface properties are changed, and its interaction with flotation agents is enhanced, thereby improving the recovery rate and concentrate grade of lepidolite during flotation.

[0006] A method for recovering fine-grained lepidolite based on selective dissolution of mineral surfaces comprises the following steps: (1) Surface dissolution: Add a selective solvent WX-R to the slurry of lepidolite and gangue minerals, and fully react under ultrasonic stirring. The selective solvent WX-R includes citric acid, oxalic acid and ethylenediaminetetraacetic acid; (2) Flotation: Add inhibitor WX-I to the dissolved slurry, stir thoroughly, and then add collector WX-C and stir to perform aeration flotation to obtain fine-grained lepidolite concentrate and tailings. The inhibitor WX-I includes water glass, dextrin and carboxymethyl cellulose, and the collector WX-C includes oleic acid, dialkyl phosphoric acid, dodecylamine and sodium dodecyl sulfonate.

[0007] Specifically, the samples of the fine-grained mica with a particle size of less than 800 mesh account for more than 40%.

[0008] Preferably, the selective dissolving agent WX-R is prepared by compounding citric acid, oxalic acid, and ethylenediaminetetraacetic acid in a mass ratio of (1-5):(0.5-3):(0.5-3).

[0009] Preferably, the selective dissolving agent WX-R is composed of citric acid, oxalic acid, and ethylenediaminetetraacetic acid in a mass ratio of (1-4):(1-2):(1-2).

[0010] Preferably, the inhibitor WX-I is prepared by compounding water glass, dextrin and carboxymethyl cellulose in a mass ratio of (1-5):1:(1-5), preferably, the mass ratio is (1-3):1:(1-3).

[0011] Preferably, the collector WX-C is prepared by compounding oleic acid, dialkyl phosphoric acid, dodecylamine and sodium dodecyl sulfonate in a mass ratio of (1-5):2:(1-5):(2-6), preferably, the mass ratio is (2-4):2:(1-3):(3-5).

[0012] Specifically, in step (1), the slurry concentration is 20% to 40%, and the concentration of the selective dissolving agent WX-R is 30 to 100 g / t.

[0013] Specifically, in step (1), the slurry concentration is 25% to 30%, and the concentration of the selective dissolving agent WX-R is 30 to 60 g / t.

[0014] Specifically, the ultrasonic stirring time in step (1) is 1-10 minutes, preferably, 3-7 minutes.

[0015] Specifically, in step (2), the concentration of the inhibitor WX-I is 50-150 g / t, the concentration of the collector WX-C is 50-300 g / t, the stirring time after the inhibitor WX-I is added is 3-15 min, the stirring time after the collector WX-C is added is 3-20 min, and the aeration time during the aeration flotation process is greater than 30 s.

[0016] Specifically, in step (2), the concentration of the inhibitor WX-I is 60-120 g / t, the concentration of the collector WX-C is 80-160 g / t, the stirring time after the inhibitor WX-I is added is 3-7 min, and the stirring time after the collector WX-C is added is 8-15 min.

[0017] Principle of the present invention: Mineral surface properties play a key role in flotation efficiency. Fine-grained lepidolite, with its small particle size, large specific surface area, and high surface energy, is difficult to separate from gangue minerals. The present invention utilizes a selective solvent, WX-R, to modify the surface properties of both lepidolite and gangue minerals. When the selective solvent WX-R is added to a slurry of lepidolite and gangue minerals, intense ultrasound promotes full contact between the solvent and the minerals. At an appropriate slurry concentration (20-40%), the solvent's components are fully effective. The selective solvent WX-R is composed of citric acid, oxalic acid, and ethylenediaminetetraacetic acid in a mass ratio of (1-4):(0.5-3):1. Citric acid contains multiple carboxyl groups, oxalic acid exhibits reducing properties and high carboxyl activity, and ethylenediaminetetraacetic acid exhibits strong chelating properties. These components react chemically with metal ions on the lepidolite surface, forming complexes or undergoing replacement reactions with metal ions such as lithium and aluminum, thereby dissolving some of the elements on the lepidolite surface. The synergistic effect of these different components allows for selective dissolution of the lepidolite surface, while dissolving gangue mineral surfaces to a lesser extent. The ultrasonic dissolution time is controlled between 3 and 10 minutes, ensuring that the solvent fully reacts with the lepidolite, altering its surface properties, while preventing excessive dissolution that could lead to excessive lepidolite loss or adversely affect subsequent flotation.

[0018] After selective dissolution of the lepidolite surface, inhibitor WX-I is added. Inhibitor WX-I is composed of water glass, dextrin, and carboxymethyl cellulose in a mass ratio of 2:(0.5-1.5):(1-3.5). Water glass hydrolyzes in the slurry to form silicate colloid, which adsorbs to the surface of gangue minerals, increasing their hydrophilicity and making them less susceptible to collector binding. Dextrin and carboxymethyl cellulose contain numerous hydrophilic groups that can adsorb to the surface of gangue minerals through hydrogen bonding and other interactions, further enhancing their hydrophilicity while hindering collector adsorption. The concentration of inhibitor WX-I is 50-150 g / t. After addition, stirring is continued for 3-15 minutes to ensure full dispersion of the inhibitor and its interaction with the gangue surface, selectively inhibiting its flotation.

[0019] After the inhibitor has reacted, collector WX-C is added. Collector WX-C is composed of oleic acid, dialkylphosphoric acid, dodecylamine, and sodium dodecylsulfonate in a mass ratio of (1-4):2:(1-3):(2-6). The carboxyl groups in oleic acid chemically adsorb with metal ions exposed on the surface of dissolved lepidolite, forming hydrophobic fatty acid metal salts. Dialkylphosphoric acid forms stable chemical bonds with metal ions on the lepidolite surface through its phosphate groups, enhancing the surface's hydrophobicity. Dodecylamine, after protonation under acidic conditions, electrostatically adsorbs onto the lepidolite surface, rendering it hydrophobic. Sodium dodecylsulfonate is an anionic surfactant whose hydrophobic groups adsorb onto the lepidolite surface, while its hydrophilic groups face the aqueous phase, further enhancing its hydrophobicity. The collector WX-C concentration is 50-300 g / t. Stirring for 3-20 minutes after addition allows the collector to fully bind to the lepidolite surface, forming a stable hydrophobic layer. After adding the collector and stirring, aeration flotation is performed for more than 30 seconds. At this point, because the lepidolite surface has become hydrophobic due to the collector, bubbles collide with and adhere to the lepidolite during the aeration process, carrying the lepidolite to the surface of the slurry, forming a foam layer. This separates the lepidolite from the gangue minerals, resulting in a fine-grained lepidolite concentrate and tailings. This method, based on selective dissolution of the mineral surface, alters the surface properties of the lepidolite and gangue minerals, enhances the interaction between the lepidolite and the flotation reagent, and improves the lepidolite recovery rate and concentrate grade during flotation.

[0020] Beneficial effects of the present invention: (1) Compared with the traditional flotation method, the recovery rate of fine-grained lepidolite is significantly improved, and the loss of lepidolite resources in the mineral processing process is effectively reduced.

[0021] (2) This method has good adaptability to different types of fine-grained lepidolite ores and can flexibly adjust the types and dosages of dissolving agents and flotation agents according to the properties of the original ore. It is easy to operate and easy to apply industrially. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely illustrative and do not constitute any limitation on the scope of protection defined by the claims of the present invention.

[0023] It should be understood that the terms described in the present invention are only for describing particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges in the present invention, it should be understood that the upper and lower limits of the ranges and each intermediate value therebetween are specifically disclosed. Each smaller range between any stated value or intermediate value within a stated range and any other stated value or intermediate value within the stated range is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0024] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

[0025] Preparation of the selective dissolving agent WX-R in the present invention: citric acid, oxalic acid, and ethylenediaminetetraacetic acid are compounded in a mass ratio of 2:1:1, and when used, a solution with a mass concentration of 5% is added, and the dissolving agent and lepidolite are ultrasonically dissolved for 5 minutes.

[0026] The preparation of the inhibitor WX-I in the present invention is as follows: it is prepared by compounding water glass, dextrin, and carboxymethyl cellulose in a mass ratio of 2:1:2. When used, the concentration of the inhibitor WX-I is 50-150 g / t, and stirring is performed for 3-15 minutes after addition.

[0027] The preparation of the collector WX-C in the present invention is prepared by compounding oleic acid, dialkylphosphoric acid, dodecylamine, and sodium dodecylsulfonate in a mass ratio of 3:2:2:4. When used, the collector WX-C concentration is 100-300 g / t. After addition, stirring is performed for 3-20 minutes to enable the collector to fully bind to the surface of the lepidolite to form a stable hydrophobic layer. After adding the collector and stirring, aeration flotation is performed, and the aeration time is greater than 30 seconds.

[0028] Example 1 This example uses fine mud from a lepidolite mine in Jiangxi Province. The Li2O grade in the fine mud product is 0.3%. The specific steps and reagent system are as follows: 1) Surface dissolution: Add 50g / t of selective dissolving agent WX-R to the slurry of lepidolite and gangue minerals (slurry concentration 30%) and fully react for 5 minutes under ultrasonic stirring to selectively dissolve the surface of lepidolite and gangue minerals.

[0029] 2) Flotation: Add 75g / t of depressant WX-I to the dissolved slurry, stir for 5 minutes, then add 150g / t of collector WX-C and stir for 10 minutes, and perform aeration flotation to obtain fine-grained lepidolite concentrate and tailings.

[0030] The test results are shown in Table 1. It can be seen that the final Li2O grade in the lepidolite concentrate is 2.02%, the recovery rate is 91.20%, and the Li2O loss rate in the tailings is only 8.80%.

[0031] Table 1. Test results

[0032] Comparative Example 1 The fine mud of a certain lepidolite mine in Jiangxi Province in Example 1 was used as the raw ore, and the same reagent system as in Example 1 was adopted to investigate the effect of non-surface selective dissolution on the flotation index of lepidolite.

[0033] The test results are shown in Table 2. It can be seen that under the conditions of no surface selective dissolution flotation, the Li2O grade in the lepidolite concentrate is only 0.43%, the recovery rate is 13.20%, and the loss rate in the tailings is 86.80%, with almost no enrichment.

[0034] Table 2. Results of flotation test without surface selective dissolution

[0035] Comparative Example 2 The fine mud of a certain lepidolite mine in Jiangxi Province in Example 1 was used as the raw ore, and the same flotation process as in Example 1 was adopted to investigate the effect of the type of reagent on the flotation index of lepidolite.

[0036] The test results are shown in Table 3. It can be seen that the use of selective solvents, inhibitors or collectors other than those of the present invention cannot achieve effective enrichment of coarse and fine lepidolite.

[0037] Table 3. Test results of drug types

[0038] Example 2 This example uses a lepidolite mine in Hunan. The Li2O grade in the lepidolite mine product is 0.25%. The specific steps and reagent system are as follows: 1) Surface dissolution: Add 45g / t of selective dissolving agent WX-R to the slurry of lepidolite and gangue minerals (slurry concentration 30%) and fully react for 5 minutes under ultrasonic stirring to selectively dissolve the surface of lepidolite and gangue minerals.

[0039] 2) Flotation: Add 100g / t of depressant WX-I to the dissolved slurry, stir for 5 minutes, then add 100g / t of collector WX-C and stir for 10 minutes, and perform aeration flotation to obtain fine-grained lepidolite concentrate and tailings.

[0040] The test results are shown in Table 4. It can be seen that the Li2O grade in the final lepidolite concentrate is 2.01%, the recovery rate is 92.89%, and the Li2O loss rate in the tailings is only 7.11%.

[0041] Table 4. Test results

[0042] The method for enhanced recovery of fine-grained lepidolite based on selective dissolution of the mineral surface disclosed in the present invention has good adaptability to different types of fine-grained mica ores. Compared with traditional flotation methods, it significantly improves the recovery rate of fine-grained lepidolite and effectively reduces the loss of lepidolite resources in the mineral processing process.

[0043] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for recovering fine-grained mica based on selective dissolution of mineral surfaces, characterized in that: The following steps are involved: (1) Surface dissolution: Add a selective solvent WX-R to the slurry of lepidolite and gangue minerals, and fully react under ultrasonic stirring. The selective solvent WX-R includes citric acid, oxalic acid and ethylenediaminetetraacetic acid; (2) Flotation: Add inhibitor WX-I to the dissolved slurry, stir thoroughly, and then add collector WX-C and stir to perform aeration flotation to obtain fine-grained lepidolite concentrate and tailings. The inhibitor WX-I includes water glass, dextrin and carboxymethyl cellulose, and the collector WX-C includes oleic acid, dialkyl phosphoric acid, dodecylamine and sodium dodecyl sulfonate.

2. The method according to claim 1, characterized in that The samples of the fine-grained mica with a particle size of less than 800 mesh account for more than 40%.

3. The method according to claim 1, characterized in that The selective dissolving agent WX-R is prepared by compounding citric acid, oxalic acid, and ethylenediaminetetraacetic acid in a mass ratio of (1-5):(0.5-3):(0.5-3), preferably, the mass ratio is (1-4):(1-2):(1-2).

4. The method according to claim 1, wherein The inhibitor WX-I is prepared by compounding water glass, dextrin and carboxymethyl cellulose in a mass ratio of (1-5):1:(1-5), preferably, the mass ratio is (1-3):1:(1-3).

5. The method according to claim 1, wherein The collector WX-C is prepared by compounding oleic acid, dialkyl phosphoric acid, dodecylamine and sodium dodecyl sulfonate in a mass ratio of (1-5):2:(1-5):(2-6), preferably, the mass ratio is (2-4):2:(1-3):(3-5).

6. The method according to claim 1, characterized in that In step (1), the slurry concentration is 20% to 40%, and the concentration of the selective dissolving agent WX-R is 30 to 100 g / t.

7. The method according to claim 6, characterized in that In step (1), the slurry concentration is 25% to 30%, and the concentration of the selective dissolving agent WX-R is 30 to 60 g / t.

8. The method according to claim 7, characterized in that The ultrasonic stirring time in step (1) is 1 to 10 minutes, preferably 3 to 7 minutes.

9. The method according to claim 1, characterized in that In step (2), the concentration of the inhibitor WX-I is 50-150 g / t, the concentration of the collector WX-C is 50-300 g / t, the stirring time after the inhibitor WX-I is added is 3-15 min, the stirring time after the collector WX-C is added is 3-20 min, and the aeration time during the aeration flotation process is greater than 30 s.

10. The method according to claim 9, characterized in that In step (2), the concentration of the inhibitor WX-I is 60-120 g / t, the concentration of the collector WX-C is 80-160 g / t, the stirring time after the inhibitor WX-I is added is 3-7 min, and the stirring time after the collector WX-C is added is 8-15 min.

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