Lepidolite positive flotation combined collector and application thereof

Abstract

This invention discloses a combined collector for lepidolite direct flotation and its application. The combined collector is composed of sodium hexadecyl sulfonate and dodecylamine in a molar ratio of 1:3 to 3:1. A lepidolite sample to be desilicate is mixed with water and stirred until a flotation slurry is obtained. After adjusting the pH of the slurry to the desired value, the combined collector is added, and direct flotation desilication is performed to obtain lepidolite concentrate. The above-mentioned combined collector exhibits good selectivity and excellent separation performance in the field of lepidolite direct flotation desilication, and has advantages such as easy availability of reagents, simple preparation process, and low reagent dosage.

Description

Technical Field

[0001] This invention belongs to the field of mineral flotation and separation technology, and relates to the separation and upgrading of lepidolite ore, specifically to a lepidolite positive flotation combined collector and its application. Background Technology

[0002] In recent years, with the rapid development of the lithium battery industry, the global demand for lithium resources has been rising continuously, and competition among countries for lithium resources has become increasingly fierce. Although my country is not lacking in lithium resources, due to the limitations of traditional beneficiation processes, its resource advantages have been difficult to realize, resulting in significant supply risks. Consequently, China imports large quantities of lithium, with an external dependence rate exceeding 60%. Therefore, the efficient development of lithium resources is of great strategic importance.

[0003] Lepidolite is a lithium-bearing clay mineral and an important component of lithium resources. Currently, flotation is a crucial method for separating and upgrading lepidolite ore. However, due to the similar surface physicochemical properties and floatability of lepidolite and its associated siliceous gangue minerals (such as feldspar), mineral flotation separation is challenging. Industrially, cationic collectors such as aliphatic amines are commonly used for lepidolite flotation; however, the poor selectivity and sensitivity to slime of amine collectors result in unsatisfactory separation. Therefore, there is an urgent need to develop highly selective collectors to achieve efficient flotation separation of lepidolite and siliceous gangue minerals. Summary of the Invention

[0004] To address the issues of poor selectivity and low separation efficiency when using a single amine collector in the flotation of lepidolite, this invention provides a combined collector for positive flotation of lepidolite and its application. Through the synergistic effect of the two collectors, the separation effect is improved, and the flotation process is simple, achieving the goal of efficient positive flotation desilication of lepidolite.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, this invention provides a combined collector for positive flotation of lepidolite, composed of sodium hexadecyl sulfonate and dodecylamine in a molar ratio of 1:3 to 3:1. Dodecylamine and sodium hexadecyl sulfonate in the combined collector are cationic and anionic collectors, respectively. These two collectors are electrically complementary and have a synergistic effect. Specifically, collectors with opposite charges can generate a charge compensation effect, easily undergoing molecular association. The combined collector is co-adsorbed onto the surface of the target mineral lepidolite, exhibiting good selectivity and enabling selective collection of lepidolite minerals, thus achieving efficient flotation separation of lepidolite from the siliceous gangue mineral feldspar.

[0007] Secondly, the present invention provides the application of the above-mentioned combined collector in the positive flotation desilication of lepidolite.

[0008] Specifically, it includes the following steps:

[0009] Step 1: Grinding

[0010] The raw lepidolite ore or a mixture of lepidolite and feldspar mineral samples were crushed and ground, and then screened to obtain mineral samples with a particle size of less than 0.105 mm.

[0011] Step 2: Prepare the paste

[0012] Mix the ore sample after screening in step 1 with water, add it to the flotation equipment, and stir evenly to obtain a slurry with a mass concentration of 5-30%.

[0013] Step 3: Flotation

[0014] At room temperature, adjust the pH of the slurry to 3–11.5 and stir until homogeneous; add sodium hexadecyl sulfonate collector to the slurry with pH 3–11.5 and stir for 2 min; then add dodecylamine collector, stir for 2 min, and then perform flotation separation.

[0015] In step 2, the flotation equipment is preferably a stirred flotation machine with a rotation speed of 1500-2000 r / min and a flotation time of 3-5 min.

[0016] In step 3, the stirring rate is 1500-2000 r / min and the stirring time is 2-3 min.

[0017] In step 3, the pH value is preferably 5.

[0018] In step 3, the preferred total amount of the combined collectors sodium hexadecyl sulfonate and dodecylamine is 3 × 10⁻⁶. - 4 mol / L~5×10 -4 mol / L.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention develops a combined collector of dodecylamine and sodium hexadecyl sulfonate for the positive flotation desilication of lepidolite. Sodium hexadecyl sulfonate and dodecylamine are added sequentially during the flotation process. Through the synergistic effect of the combined collector, lepidolite is selectively collected, achieving efficient flotation separation of lepidolite and siliceous gangue mineral feldspar. Finally, a lepidolite concentrate with a lepidolite recovery rate of greater than 95% and a Li2O grade of higher than 4.0% can be obtained.

[0021] 2. The dodecylamine and sodium hexadecyl sulfonate combined collector of the present invention is miscible with water, non-toxic and non-polluting, chemically stable, and has the advantages of simple preparation method, low dosage, good selectivity and high sorting efficiency. Attached Figure Description

[0022] Figure 1This is a schematic diagram of a process flow for the positive flotation desiliconization of lithium mica according to an embodiment of the present invention. Detailed Implementation

[0023] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0024] Unless otherwise specified, the reagents and materials described in the following examples are commercially available.

[0025] The mineral samples in the following examples are artificial mixed mineral samples prepared by mixing lepidolite and feldspar in a mass ratio of 1:1. Both lepidolite and feldspar are taken from lepidolite mining areas in Jiangxi Province. The particle size of the samples prepared after sieving is 0.038-0.105 mm.

[0026] The XFGII type hanging flotation machine used in the following embodiments was purchased from Jilin Prospecting Machinery Factory.

[0027] In the following examples, the collector dodecylamine was dissolved in water with hydrochloric acid at a molar ratio of 1:1 before use to prepare a solution of 0.01 to 0.05 mol / L; the collector sodium hexadecyl sulfonate was dissolved directly in water before use to prepare a solution of 0.01 to 0.05 mol / L.

[0028] In Examples 1-5 below, the pH value of the slurry was adjusted using a pH adjuster. The acidic adjuster was hydrochloric acid with a concentration of 0.01-0.1 mol / L; the alkaline adjuster was sodium hydroxide with a concentration of 0.01-0.1 mol / L.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] Step 1: Grinding

[0032] The lepidolite and feldspar were crushed and ground, and then screened to obtain mineral samples with a particle size of 0.038-0.105 mm.

[0033] Step 2: Prepare the paste

[0034] Add the mixed lepidolite and feldspar ore with deionized water to the flotation equipment, mix and stir at 1500 r / min for 1 min, and adjust the slurry concentration to 5%.

[0035] Step 3: Flotation Separation

[0036] At room temperature, hydrochloric acid solution was added to the slurry to adjust the pH of the slurry to 5.0, and the mixture was stirred at 1500 r / min for 1 min to obtain a slurry with a pH of 5.0.

[0037] Sodium hexadecyl sulfonate collector was added to the slurry with a pH of 5.0 and stirred for 2 minutes at a flotation machine speed of 1500 rpm. Then, dodecylamine collector was added and mixed and stirred at 1500 rpm for 2 minutes. The molar ratio of sodium hexadecyl sulfonate to dodecylamine in the combined collector was 1:3, and the total amount of the combined collector was 4 × 10⁻⁶. -4 mol / L. Then flotation was carried out, with the bubbles scraped every 10 seconds for 3 minutes. After flotation, the froth product (concentrate) and the product in the tank (tailings) were dried, weighed, and samples were taken to test the Li2O grade and calculate the recovery rate. The recovery rate of lepidolite in the flotation concentrate was 58.44%, and the Li2O grade was 3.05%.

[0038] Example 2

[0039] Steps 1 and 2 are the same as steps 1 and 2 in Example 1.

[0040] Step 3: Flotation Separation

[0041] At room temperature, sodium hydroxide solution was added to the slurry to adjust the pH of the slurry to 9.60, and the mixture was stirred at 1500 r / min for 1 min to obtain a slurry with a pH of 9.60.

[0042] Sodium hexadecyl sulfonate collector was added to the slurry with a pH of 9.6 and stirred for 2 minutes at a flotation machine speed of 1500 rpm. Then, dodecylamine collector was added and mixed and stirred at 1500 rpm for 2 minutes. The molar ratio of sodium hexadecyl sulfonate to dodecylamine in the combined collector was 1:3, and the total amount of the combined collector was 4 × 10⁻⁶. -4 mol / L. Then, flotation separation was performed, with bubbles scraped every 10 seconds for 3 minutes. After flotation, the froth product (concentrate) and the product in the tank (tailings) were dried, weighed, and samples were taken to test the Li2O grade and calculate the recovery rate. The recovery rate of lepidolite in the flotation concentrate was 60.51%, and the Li2O grade was 2.73%.

[0043] Example 3

[0044] Steps 1 and 2 are the same as steps 1 and 2 in Example 1.

[0045] Step 3: Flotation Separation

[0046] At room temperature, hydrochloric acid solution was added to the slurry to adjust the pH of the slurry to 5.0, and the mixture was stirred at 1500 r / min for 1 min to obtain a slurry with a pH of 5.0.

[0047] Sodium hexadecyl sulfonate collector was added to the slurry with a pH of 5.0 and stirred for 2 minutes at a flotation machine speed of 1500 rpm. Then, dodecylamine collector was added and mixed and stirred at 1500 rpm for 2 minutes. The molar ratio of sodium hexadecyl sulfonate to dodecylamine in the combined collector was 1:1, and the total amount of the combined collector was 4 × 10⁻⁶. -4 mol / L. Then, flotation separation was performed, with bubbles scraped every 10 seconds for 3 minutes. After flotation, the froth product (concentrate) and the product in the tank (tailings) were dried, weighed, and samples were taken to test the Li2O grade and calculate the recovery rate. The recovery rate of lepidolite in the flotation concentrate was 69.89%, and the Li2O grade was 3.62%.

[0048] Example 4

[0049] Steps 1 and 2 are the same as steps 1 and 2 in Example 1.

[0050] Step 3: Flotation Separation

[0051] At room temperature, hydrochloric acid solution was added to the slurry to adjust the pH of the slurry to 5.0, and the mixture was stirred at 1500 r / min for 1 min to obtain a slurry with a pH of 5.0.

[0052] Sodium hexadecyl sulfonate collector was added to the slurry with a pH of 5.0 and stirred for 2 minutes at a flotation machine speed of 1500 rpm. Then, dodecylamine collector was added and mixed and stirred at 1500 rpm for 2 minutes. The molar ratio of sodium hexadecyl sulfonate to dodecylamine in the combined collector was 3:1, and the total amount of the combined collector was 4 × 10⁻⁶. -4 mol / L. Then, flotation separation was performed, with bubbles scraped every 10 seconds for 3 minutes. After flotation, the froth product (concentrate) and the product in the tank (tailings) were dried, weighed, and samples were taken to test the Li2O grade and calculate the recovery rate. The recovery rate of lepidolite in the flotation concentrate was 98.12%, and the Li2O grade was 4.20%.

[0053] Example 5

[0054] Steps 1 and 2 are the same as steps 1 and 2 in Example 1.

[0055] Step 3: Flotation Separation

[0056] At room temperature, sodium hydroxide solution was added to the slurry to adjust the pH of the slurry to 9.6, and the mixture was stirred at 1500 r / min for 1 min to obtain a slurry with a pH of 9.6.

[0057] Sodium hexadecyl sulfonate collector was added to the slurry with a pH of 9.6 and stirred for 2 minutes at a flotation machine speed of 1500 rpm. Then, dodecylamine collector was added and mixed and stirred at 1500 rpm for 2 minutes. The molar ratio of sodium hexadecyl sulfonate to dodecylamine in the combined collector was 1:1, and the total amount of the combined collector was 4 × 10⁻⁶. -4 mol / L. Then, flotation separation was performed, with bubbles scraped every 10 seconds for 3 minutes. After flotation, the froth product (concentrate) and the product in the tank (tailings) were dried, weighed, and samples were taken to test the Li2O grade and calculate the recovery rate. The recovery rate of lepidolite in the flotation concentrate was 48.99%, and the Li2O grade was 2.54%.

[0058] Comparative Example 1

[0059] The only difference between Comparative Example 1 and Example 4 is that only sodium hexadecyl sulfonate, a collector, was added, and the total amount of collector used was 4 × 10⁻⁶. -4 mol / L.

[0060] The slurry was floated using the method of Comparative Example 1, and the recovery rate of lithium mica in the flotation concentrate was 77.61%, while the Li2O grade was only 2.87%.

[0061] Comparative Example 2

[0062] The only difference between Comparative Example 2 and Example 4 is that only dodecylamine, the collector, was added, and the total amount of collector used was 4 × 10⁻⁶. - 4 mol / L.

[0063] The slurry was floated using the method of Comparative Example 2, and the recovery rate of lithium mica in the flotation concentrate was 98.59%, while the Li2O grade was only 2.57%.

[0064] Compared to the use of sodium hexadecyl sulfonate or dodecylamine alone, the use of a combination of dodecylamine and sodium hexadecyl sulfonate as collectors can achieve a higher lepidolite recovery rate (greater than 95%) and significantly improve the Li2O grade of the flotation concentrate (greater than 4.20%).

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. The application of a combined collector in the positive flotation desilication of lepidolite, characterized in that, The combined collector is composed of sodium hexadecyl sulfonate and dodecylamine in a molar ratio of 1:3 to 3:1; the total dosage of the combined collector is 3 × 10⁻⁶. - 4 mol / L~5×10 -4 mol / L; Specifically, the following steps are included: Step 1: Grinding The raw lepidolite ore or a mixture of lepidolite and feldspar mineral samples were crushed and ground, and then screened to obtain mineral samples with a particle size of less than 0.105 mm. Step 2: Prepare the paste Mix the ore sample after screening in step 1 with water, add it to the flotation equipment, and stir evenly to obtain a slurry with a mass concentration of 5-30%. Step 3: Flotation At room temperature, adjust the pH of the slurry to 5 and stir until homogeneous; add sodium hexadecyl sulfonate collector to the slurry at pH=5 and stir for 2 minutes; then add dodecylamine collector, stir for 2 minutes, and then perform flotation separation.

2. The application according to claim 1, characterized in that, In step 2, the flotation equipment is a stirred flotation machine with a rotation speed of 1500-2000 r / min and a flotation time of 3-5 min.

3. The application according to claim 1, characterized in that, In step 3, the stirring rate is 1500-2000 r / min and the stirring time is 2-3 min.

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