Lepidolite flotation collector as well as preparation method and application thereof

Abstract

The invention provides a lepidolite flotation collecting agent and a preparation method and application thereof, and relates to the technical field of mineral flotation. The preparation method of the lepidolite flotation collecting agent comprises the following steps that S1, methyl alcohol and concentrated sulfuric acid are evenly mixed to obtain a solution A; s2, adding modified salicylhydroxamic acid into the solution A, and uniformly mixing to obtain a solution B; s3, adding water, sulfonated oleic acid and fatty alcohol-polyoxyethylene ether into the solution B, uniformly mixing to obtain a solution C, and heating and stirring the solution C to obtain the lepidolite flotation collecting agent. According to the lepidolite flotation collector, effective flotation of lepidolite is achieved, and the recovery rate of lepidolite is increased.

Description

Technical Field

[0001] The invention relates to the technical field of mineral flotation, and in particular to a lepidolite flotation collector and a preparation method and application thereof. Background Art

[0002] As the world's attention to clean energy continues to increase, new energy industries such as electric vehicles and energy storage systems have developed rapidly. As a key energy storage component in these fields, the demand for lithium-ion batteries has exploded. As one of the important sources of lithium resources, the study of lepidolite ore is an inevitable requirement to meet the growing demand for lithium. For example, the lithium-ion battery required for an ordinary electric car contains a certain amount of lithium, and the rich lithium resources in lepidolite ore can provide a guarantee for battery production.

[0003] Lithium is regarded as a strategic resource in modern industry. All countries are aware of the importance of lithium resources, not only in the energy field, but also in many high-tech fields such as aerospace, electronics, etc. The traditional supply of lithium resources mainly depends on salt lake brine and spodumene, but with the rapid growth of market demand, these resources are facing problems such as increased difficulty in mining, rising costs and gradual scarcity of resources. Lepidolite ore is relatively widely distributed, which can alleviate the tight supply of lithium resources to a certain extent. Through the study of lepidolite ore, more efficient mineral processing and extraction processes can be developed to expand the supply channels of lithium resources. Lepidolite and spodumene differ in mineral structure, physical and chemical properties, etc., which requires collectors to have different selectivity and collection capacity. For different minerals, the design and formulation of collectors need to be adjusted accordingly to achieve the best flotation effect and improve the overall utilization efficiency of resources. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a lepidolite flotation collector and a preparation method and application thereof.

[0005] The present invention provides a method for preparing a lepidolite flotation collector, comprising the following steps:

[0006] S1, mixing methanol and concentrated sulfuric acid uniformly to obtain solution A;

[0007] S2, adding modified salicylic hydroxamic acid to solution A, and mixing evenly to obtain solution B;

[0008] S3, adding water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether to solution B, mixing evenly to obtain solution C, heating and stirring solution C to obtain a lepidolite flotation collector.

[0009] The lepidolite flotation collector prepared by the invention has stable properties, and can realize effective flotation of lepidolite by means of the synergistic effect between different reagents, thereby improving the recovery rate of lepidolite.

[0010] Preferably, in S1, the mass ratio of methanol to concentrated sulfuric acid is (2-4):1.

[0011] When the mass ratio of methanol to concentrated sulfuric acid is controlled within a certain range and mixed, the mixture has better solubility and is beneficial to the subsequent reaction.

[0012] Preferably, in the S2, the content of modified salicylic hydroxamic acid in solution B is 40-80 g / L.

[0013] Preferably, in S2, the preparation method of modified salicylic hydroxamic acid comprises the following steps: dissolving salicylic hydroxamic acid in a solvent, adding acetic anhydride and concentrated sulfuric acid, heating and stirring evenly, cooling to room temperature, adding pH buffer solution to adjust the pH to neutral, washing, separating the organic phase, drying and evaporating to obtain modified salicylic hydroxamic acid.

[0014] By introducing the acetyl group in acetic anhydride into the modified salicylic acid molecule through esterification reaction, its chemical structure and properties can be changed. This modification can enhance the selectivity and capture ability of modified salicylic acid for specific minerals and improve the flotation effect.

[0015] More preferably, the solvent is selected from one or more of toluene, cumene, propanol and isopropanol.

[0016] More preferably, the mass volume ratio of salicylic hydroxamic acid to the solvent, acetic anhydride and concentrated sulfuric acid is (80-120):(100-300):50:(1-10).

[0017] More preferably, the heating temperature is 80-150° C. and the heating time is 6-10 hours.

[0018] More preferably, the stirring speed is 200-500 r / min.

[0019] More preferably, the pH buffer solution is a sodium hydroxide solution.

[0020] More preferably, the washing detergent is selected from one or more of saturated saline solution and ethyl acetate.

[0021] Preferably, in S3, the mass ratio of water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether is (1-3):1:1.

[0022] Controlling the mass ratio within a certain range helps improve the collection capacity, where sulfonated oleic acid will dissociate into anions in the slurry, and these anions can be adsorbed on the positively charged surface of lepidolite through electrostatic action. This electrostatic adsorption can increase the negative charge density on the mineral surface and increase the electrostatic attraction between the mineral and the bubbles.

[0023] Preferably, in said S3, the content of modified salicylic hydroxamic acid in solution C is 40-80 mg / L.

[0024] Preferably, in S3, the heating temperature is 40-80° C. and the heating time is 10-60 min.

[0025] Heating can increase its solubility in the solution and make the reaction more complete. Controlling the heating temperature can make the reaction proceed at a more ideal rate. Too high a temperature may lead to an increase in side reactions, decomposition of reactants or deterioration of products; while too low a temperature may slow down the reaction rate and affect production efficiency. Controlling the reaction time can ensure that the reactants are fully converted into products. Too short a time may lead to incomplete reactions and reduce yields; while too long a time may waste energy and time, and may even lead to product decomposition or side reactions.

[0026] The present invention also provides a lepidolite flotation collector prepared by the above preparation method.

[0027] The present invention also proposes the use of the lepidolite flotation collector prepared by the above preparation method in the flotation of lepidolite ore, comprising the following steps:

[0028] S1, grinding the lepidolite ore, adding water to prepare the slurry, adding gangue mineral inhibitor and collector to perform primary roughing and tertiary concentrating to obtain lithium concentrate and middlings;

[0029] S2. After grinding the middling ore again and adding water to make a slurry, gangue mineral inhibitors and collectors are added to perform a roughing selection and a secondary scavenging selection to obtain lithium concentrate and gangue minerals.

[0030] The lepidolite flotation collector prepared by the present invention is applied in the flotation of lepidolite ore, and the lepidolite flotation collector is coordinated with the processes of grinding, slurry mixing, segmented grinding, and segmented flotation, so as to effectively realize the selective separation between lepidolite and gangue minerals such as feldspar and quartz. The segmented grinding process can effectively reduce the over-grinding phenomenon of lepidolite minerals.

[0031] Preferably, in S1, the ore is ground to a particle size of -0.074 mm and the content is 40% to 60%.

[0032] Controlling the particle size of the lepidolite ore after grinding within a certain range helps to achieve partial monomer dissociation of the mineral without over-grinding; this allows for better separation of the target mineral from the gangue mineral, improving the effectiveness of subsequent flotation and other mineral processing operations.

[0033] Preferably, in S1 and S2, the slurry is adjusted so that the solid content is 40% to 60%.

[0034] Solid content within a certain range helps to form a relatively stable flotation foam, so that the fluidity and stability of the slurry can achieve a better balance.

[0035] Preferably, in S1 and S2, the pH value is adjusted to 8-9 by using sodium hydroxide during the slurry adjustment process.

[0036] Preferably, in S1 and S2, the gangue mineral inhibitor is selected from one or more of sodium silicate, sodium humate and sodium hexametaphosphate.

[0037] Preferably, in the S1, the amount of gangue mineral inhibitor used is 500-700 g / t.

[0038] Controlling the dosage of gangue mineral inhibitors within a certain range is helpful to inhibit the floating of gangue minerals; for some gangue minerals that coexist with target minerals and are easily mixed into the concentrate during flotation, such as quartz and feldspar, the inhibitors can be selectively adsorbed on the surface of gangue minerals, making them hydrophilic and remaining in the slurry, thereby improving the selectivity of flotation and ensuring the grade of the concentrate.

[0039] Preferably, in S1, a roughing operation is: 500-700 g / t of gangue mineral inhibitor, 300-400 g / t of collector, stirring time 3-10 min, and flotation time 3-10 min.

[0040] Preferably, in S1, the three cleaning operations are: stirring time 1 to 5 minutes, and flotation time 1 to 5 minutes.

[0041] After a roughing process, most valuable minerals can be quickly separated from the gangue and the target minerals can be initially enriched. The concentrate obtained from the roughing process can be further purified and refined. Each time the concentration process can remove more impurities and associated minerals, the content of target minerals in the concentrate is continuously increased, thus significantly improving the grade of the minerals.

[0042] Preferably, in the S2, the ore is ground to a particle size of -0.074 mm, accounting for 70% to 80%.

[0043] The particle size of -0.074mm mesh accounts for 70% to 80%, which means that the mineral particles are very fine. At this particle size, the minerals can be more fully separated into monomers; this makes the separation of target minerals and gangue minerals more thorough, providing a good foundation for subsequent mineral processing operations and greatly improving the selectivity and recovery rate of flotation and other processes.

[0044] Preferably, in the S2, the amount of gangue mineral inhibitor used is 200-400 g / t.

[0045] At this stage, there may still be some gangue minerals that have not been completely separated in the slurry. Controlling the dosage of gangue mineral inhibitors within a certain range can more effectively inhibit the floating of gangue minerals, improve the separation effect of target minerals and gangue minerals, and thus improve the recovery rate of scavenging and the grade of concentrate.

[0046] Preferably, in said S2, a roughing operation is: 200-400 g / t of gangue mineral inhibitor, 200-400 g / t of collector, stirring time 1-5 min, and flotation time 1-5 min.

[0047] Preferably, in S2, the secondary scavenging operation is: the first scavenging is 100-200 g / t of gangue mineral inhibitor and 100-200 g / t of collector, the second scavenging is 50-100 g / t of gangue mineral inhibitor and 50-100 g / t of collector, the stirring time is 1-5 min, and the flotation time is 1-5 min.

[0048] Secondary scavenging can maximize the recovery of target minerals lost during roughing and concentrating. Scavenging can process tailings again and recycle the fine particles or target minerals with insufficient dissociation degree that have not been fully recovered back into the separation process.

[0049] The beneficial effects of the present invention are:

[0050] The present invention provides a lepidolite flotation collector, which adopts methanol and sulfuric acid as solution regulators, and cooperates with modified salicylic acid hydroxamic acid, sulfonated oleic acid and fatty alcohol polyoxyethylene ether to prepare the collector, thereby achieving selective collection of lepidolite. The process of pre-grinding with a ball mill, slurry mixing and dosing, segmented flotation, and re-grinding and re-selection of the intermediate ore can effectively realize the separation of lepidolite from gangue minerals such as feldspar and quartz, and improve the recovery rate of lepidolite. Sulfonated oleic acid and modified salicylic acid hydroxamic acid have a synergistic effect, and can be co-adsorbed on the surface of lepidolite to form a more stable adsorption layer, thereby enhancing the hydrophobicity and floatability of the mineral. At the same time, sulfonated oleic acid can also interact with fatty alcohol polyoxyethylene ether to further improve the performance of the collector. The amount of collector used in the flotation process is relatively small, which successfully solves the problem of poor solubility and unsatisfactory collection effect of traditional lepidolite collectors, and can effectively improve the grade of lepidolite in flotation concentrate.

[0051] Due to the characteristics of lepidolite, the collector of the present invention contains specific chemical substances or functional groups, which can better react with the surface of lepidolite. The collector specially designed for lepidolite can better adapt to the mineral characteristics of lepidolite and improve the flotation recovery rate and grade. Compared with traditional collectors, the dosage of reagents and energy consumption in the flotation process can be reduced. The composite application can further enhance the performance of the collector, improve the flotation efficiency of lepidolite, and reduce production costs. The collector of the present invention focuses on the selectivity of lepidolite in design, and can effectively separate lepidolite from other minerals to improve the purity of the product. The collector of the present invention has a stronger selectivity for lepidolite, reduces the mixing of impurities, and improves the efficiency and quality of subsequent processing.

[0052] The present invention provides a lepidolite flotation collector and a preparation method and application thereof, which provide a new technical means for the development and utilization of lepidolite resources. The present invention expands the application scope of the collector, which is not only applicable to specific lepidolite ores, but also can be adjusted and optimized according to different ore properties. The present invention brings new development opportunities to the lepidolite flotation industry and helps to improve my country's competitiveness in the field of lithium resource development. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is described in detail through specific embodiments.

[0054] Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial sources.

[0055] Sulfonated oleic acid: Shandong Guohua Chemical Co., Ltd.

[0056] Fatty alcohol polyoxyethylene ether: Liaoning Kelong Fine Chemical Co., Ltd., CAS No. 71060-57-6.

[0057] Lepidolite ore raw materials: The original ore containing lepidolite and gangue minerals in Yichun area, the grade of Li2O is 0.32%, which is the main mineral to be recovered, existing in the form of independent minerals in lepidolite, and other small amounts are in the form of isomorphous in biotite and muscovite, etc. SiO2 is the main gangue mineral, mainly in the form of quartz. The remaining gangue minerals are mainly plagioclase, potassium feldspar, etc.

[0058] Example 1

[0059] A method for preparing a lepidolite flotation collector comprises the following steps:

[0060] S1. Mix methanol and concentrated sulfuric acid in a mass ratio of 2:1 to obtain solution A;

[0061] S2, adding modified salicylic hydroxamic acid to solution A, mixing evenly to obtain solution B, wherein the concentration of modified salicylic hydroxamic acid in solution A is 40 g / L;

[0062] S3. Add water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether to solution B in a mass ratio of 2:1:1, mix well to obtain solution C, heat and stir solution C at 60° C. for 30 min to obtain a lepidolite flotation collector, wherein the content of modified salicylic hydroxamic acid in solution C is 40 mg / L.

[0063] Among them, the preparation method of modified salicylic hydroxamic acid includes the following steps: dissolving 100g salicylic hydroxamic acid in 200ml toluene, adding 50ml acetic anhydride and 5ml concentrated sulfuric acid, heating to 100°C, adjusting the stirring speed to 300r / min, heating and stirring for 8h, cooling to room temperature, adding 10% sodium hydroxide solution with a mass fraction to adjust the pH to 7, pouring the reaction mixture into a separatory funnel, washing with 100ml saturated brine and 100ml ethyl acetate in turn, repeating the washing 3 times, separating the organic phase, drying with 20g anhydrous sodium sulfate, removing residual moisture, and removing the solvent at 50°C by a rotary evaporator to obtain modified salicylic hydroxamic acid.

[0064] The application of lepidolite flotation collector in the flotation of lepidolite ore includes the following steps:

[0065] S1. Place the lithium mica ore in a ball mill for a grinding process until the particle size is -0.074mm and the content is 50%, add water to adjust the ore mass percentage concentration to 50%, use sodium hydroxide to adjust the slurry pH to 8.5, add 600g / t sodium silicate and 400g / t collector for a roughing process, stirring time 5min, flotation time 5min; three times of concentration operation stirring time 3min, flotation time 3min, to obtain lithium concentrate and middlings;

[0066] S2. Grind the medium ore again to make its particle size reach -0.074mm and its content account for 75%, add water to adjust the pulp to 50% of the mass percentage concentration of the ore, use sodium hydroxide to adjust the pH value of the pulp to 8.5, add 300g / t sodium silicate and 300g / t collector to carry out a rough selection with stirring time of 3min and flotation time of 3min; two scavenging operations include: the first scavenging of 150g / t sodium silicate and 150g / t collector, the second scavenging of 75g / t sodium silicate and 75g / t collector, stirring time of 3min and flotation time of 3min; obtain lithium concentrate and gangue minerals; adopt a closed-circuit process with step-by-step return of the medium ore.

[0067] After testing, the grade of the obtained lithium concentrate was 1.83% and the recovery rate was 69.12%.

[0068] Example 2

[0069] A method for preparing a lepidolite flotation collector comprises the following steps:

[0070] S1. Mix methanol and concentrated sulfuric acid in a mass ratio of 2:1 to obtain solution A;

[0071] S2, adding modified salicylic hydroxamic acid to solution A, mixing evenly to obtain solution B, wherein the concentration of modified salicylic hydroxamic acid in solution A is 60 g / L;

[0072] S3. Add water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether to solution B in a mass ratio of 2:1:1, mix well to obtain solution C, heat and stir solution C at 60° C. for 30 min to obtain a lepidolite flotation collector, wherein the content of modified salicylic hydroxamic acid in solution C is 60 mg / L.

[0073] The preparation method of modified salicylic hydroxamic acid is the same as that in Example 1.

[0074] The lepidolite flotation collector is used in the flotation of lepidolite ore, and the difference from Example 1 is only that the collector is different, and the other parts are the same as Example 1.

[0075] After testing, the grade of the obtained lithium concentrate was 2.03% and the recovery rate was 72.31%.

[0076] Example 3

[0077] A method for preparing a lepidolite flotation collector comprises the following steps:

[0078] S1. Mix methanol and concentrated sulfuric acid in a mass ratio of 2:1 to obtain solution A;

[0079] S2, adding modified salicylic hydroxamic acid to solution A, mixing evenly to obtain solution B, wherein the concentration of modified salicylic hydroxamic acid in solution A is 80 g / L;

[0080] S3. Add water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether to solution B in a mass ratio of 2:1:1, mix well to obtain solution C, heat and stir solution C at 60° C. for 30 min to obtain a lepidolite flotation collector, wherein the content of modified salicylic hydroxamic acid in solution C is 80 mg / L.

[0081] The preparation method of modified salicylic hydroxamic acid is the same as that in Example 1.

[0082] The lepidolite flotation collector is used in the flotation of lepidolite ore, and the difference from Example 1 is only that the collector is different, and the other parts are the same as Example 1.

[0083] After testing, the grade of the obtained lithium concentrate was 1.91% and the recovery rate was 70.22%.

[0084] Comparative Example 1

[0085] The application of lepidolite flotation collector in the flotation of lepidolite ore includes the following steps:

[0086] S1. Place the lithium mica ore in a ball mill for a grinding process until the particle size is -0.074mm and the content is 50%, add water to adjust the slurry to 50% by mass concentration of the ore, add 600g / t of sodium silicate, a gangue mineral inhibitor, and 400g / t of traditional lithium mica collector 8-1 (Jinjuyuan), and perform a concentration with a stirring time of 5min and a flotation time of 5min; perform a three-time concentration operation with a stirring time of 3min and a flotation time of 3min to obtain lithium concentrate and middlings;

[0087] S2. Grind the middling ore again to make its particle size reach -0.074mm and its content account for 75%, add water to adjust the slurry to 50% of the mass percentage concentration of the ore, add 300g / t sodium silicate and 300g / t traditional lithium mica collector 8-1 (Jinjuyuan), and carry out a roughing operation with stirring time of 3min and flotation time of 3min; two scavenging operations include: the first scavenging operation includes 150g / t sodium silicate and 150g / t collector, and the second scavenging operation includes 75g / t sodium silicate and 75g / t collector, stirring time of 3min and flotation time of 3min to obtain lithium concentrate and gangue minerals; adopt a closed-circuit process with step-by-step return of middling ore.

[0088] After testing, the grade of the obtained lithium concentrate was 1.89% and the recovery rate was 70.13%.

[0089] In summary, the lepidolite flotation collector provided by the present invention realizes the effective flotation of lepidolite and improves the recovery rate of lepidolite.

[0090] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a lepidolite flotation collector, characterized in that: The following steps are involved: S1, mixing methanol and concentrated sulfuric acid uniformly to obtain solution A; S2, adding modified salicylic hydroxamic acid to solution A, and mixing evenly to obtain solution B; S3, adding water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether to solution B, mixing evenly to obtain solution C, heating and stirring solution C to obtain a lepidolite flotation collector.

2. The preparation method according to claim 1, characterized in that: In the S1, the mass ratio of methanol to concentrated sulfuric acid is (2-4):

1.

3. The preparation method according to claim 1, characterized in that: In S2, the preparation method of modified salicylic hydroxamic acid comprises the following steps: dissolving salicylic hydroxamic acid in a solvent, adding acetic anhydride and concentrated sulfuric acid, heating and stirring evenly, cooling to room temperature, adding pH buffer solution to adjust the pH to neutral, washing, separating the organic phase, drying and evaporating to obtain modified salicylic hydroxamic acid.

4. The preparation method according to claim 3, characterized in that: The mass volume ratio of salicylic hydroxamic acid to solvent, acetic anhydride and concentrated sulfuric acid is (80-120):(100-300):50:(1-10); the heating temperature is 80-150° C. and the heating time is 6-10 hours.

5. The preparation method according to claim 1, characterized in that: In the S2, the content of modified salicylic hydroxamic acid in solution B is 40-80 g / L.

6. The preparation method according to claim 1, characterized in that: In the S3, the mass ratio of water, sulfonated oleic acid and fatty alcohol polyoxyethylene ether is (1-3):1:1; the heating temperature is 40-80° C. and the heating time is 10-60 min.

7. Use of the lepidolite flotation collector obtained by the preparation method according to any one of claims 1 to 6 in the flotation of lepidolite ore, characterized in that: The following steps are involved: S1, grinding the lepidolite ore, adding water to prepare the slurry, adding gangue mineral inhibitor and collector to perform primary roughing and tertiary concentrating to obtain lithium concentrate and middlings; S2. After grinding the middling ore again and adding water to make a slurry, gangue mineral inhibitors and collectors are added to perform a roughing selection and a secondary scavenging selection to obtain lithium concentrate and gangue minerals.

8. The use according to claim 7, characterized in that: In the S1, the ore is ground to a particle size of -0.074 mm and the content is 40% to 60%; the amount of gangue mineral inhibitor is 500 to 700 g / t; the primary roughing operation is: 500 to 700 g / t gangue mineral inhibitor, 300 to 400 g / t collector, stirring time 3 to 10 minutes, and flotation time 3 to 10 minutes.

9. The use according to claim 7, characterized in that: In the S2, the ore is ground to a particle size of -0.074 mm and the content is 70% to 80%; the dosage of the gangue mineral inhibitor is 200 to 400 g / t; the primary roughing operation is: 200 to 400 g / t gangue mineral inhibitor, 200 to 400 g / t collector, stirring time 1 to 5 min, and flotation time 1 to 5 min; the secondary scavenging operation is: the first scavenging is 100 to 200 g / t gangue mineral inhibitor, 100 to 200 g / t collector, the second scavenging is 50 to 100 g / t gangue mineral inhibitor, 50 to 100 g / t collector, stirring time 1 to 5 min, and flotation time 1 to 5 min.

10. The use according to claim 7, characterized in that: The gangue mineral inhibitor is selected from one or more of sodium silicate, sodium humate and sodium hexametaphosphate.