Amphoteric collecting agent and application thereof in spodumene flotation separation

Abstract

The invention discloses an amphoteric collecting agent and application thereof in spodumene flotation separation, and belongs to the technical field of spodumene flotation separation. The amphoteric collecting agent is alpha-di-n-hexylamino-lauric acid, the alpha-di-n-hexylamino-lauric acid serving as the amphoteric collecting agent has the advantages of being high in selectivity, good in foaming performance, good in low-temperature resistance and the like when used for spodumene flotation, and good flotation indexes can be obtained in the low-temperature environment of 10 DEG C. The amphoteric collecting agent can form chemical action with spodumene, can stably form single-layer adsorption on the surface of the spodumene, effectively improves the hydrophobicity of the surface of the spodumene, and can form multi-layer reverse adsorption with gangue minerals such as feldspar and quartz, so that the surfaces of the gangue minerals still have high hydrophilicity, and the purpose of separation is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of spodumene flotation separation, and particularly relates to an amphoteric collector and its application in spodumene flotation separation. Background Art

[0002] As the new energy industry has become the focus of future social sustainable development, lithium, as an indispensable key element in new energy batteries, has been massively put into production and application in the past decade. Natural lithium resources can be divided into three categories: brine type, hard rock type, and clay type. Spodumene is one of the main sources of lithium resources and has great mining and development value. However, the currently mined spodumene has a low grade and complex dissemination characteristics, and is mostly symbiotic with gangue minerals such as feldspar and quartz. In addition, the collectors for spodumene ore mainly rely on fatty acid collectors at present, but traditional fatty acid collectors have problems such as poor low-temperature resistance, low selectivity, and large dosage. Due to the similar surface characteristics and active sites between spodumene and gangue minerals, it is difficult to achieve flotation separation, and the sorting performance of flotation reagents deteriorates in a low-temperature environment, resulting in a low degree of development and utilization of spodumene. Therefore, it is of great significance to develop high-selectivity low-temperature flotation reagents. Summary of the Invention

[0003] The purpose of the present invention is to provide an amphoteric collector and its application in spodumene flotation separation. The amphoteric collector provided by the present invention has high selectivity, good foam performance, and good low-temperature resistance, and can obtain good flotation indexes in a low-temperature environment of 10°C. This amphoteric collector can form a chemical interaction with spodumene, stably form a monolayer adsorption on the surface of spodumene, effectively improve the hydrophobicity of the spodumene surface, and form a multi-layer reverse adsorption with gangue minerals such as feldspar and quartz, so that the surface of the gangue minerals still has strong hydrophilicity, achieving the purpose of separation.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] One of the technical solutions of the present invention: Provide an α-di-n-hexylamino-dodecanoic acid, and the structural formula of the α-di-n-hexylamino-dodecanoic acid is as follows:

[0006]

[0007] Another technical solution of the present invention: Provide a preparation method of the above α-di-n-hexylamino-dodecanoic acid, including the following steps:

[0008] Mix 2-bromododecanoic acid and di-n-hexylamine, and heat and react to obtain the α-di-n-hexylamino-dodecanoic acid.

[0009] During the heating reaction process, the Br atom of 2-bromododecanoic acid is replaced by di-n-hexylamine to form the target product α-di-n-hexylamino-dodecanoic acid. One H atom of di-n-hexylamine is removed to react with Br to generate HBr and escape.

[0010] Preferably, the molar ratio of the 2-bromododecanoic acid to the di-n-hexylamine is 1:1.

[0011] Preferably, the temperature of the heating reaction is 90 °C and the time is 3 h.

[0012] The third technical solution of the present invention: provides an application of the above-mentioned α-di-n-hexylamino-dodecanoic acid in the flotation separation of spodumene, and the α-di-n-hexylamino-dodecanoic acid is used as an amphoteric collector.

[0013] The N of α-di-n-hexylamino-dodecanoic acid is located at the α position, which can affect the activity of the carboxyl group through the electron cloud density of the carboxyl group, reduce the electrostatic repulsion between spodumene and the carboxyl group of the reagent, and promote the interaction between the reagent and the mineral surface. The main sites of the interaction between spodumene and the reagent are Al and Si. However, since the most common cleavage plane of spodumene is the spodumene (110) plane, the interaction between spodumene and the collector mainly occurs between the Al site and the functional group of α-di-n-hexylamino-dodecanoic acid. The COOH in the reagent - adsorbs on the Al site on the surface of spodumene, and α-di-n-hexylamino-dodecanoic acid acts on the surface of spodumene through chemical adsorption. Since there is no Al site in quartz, there are fewer sites on the surface of quartz that can interact with α-di-n-hexylamino-dodecanoic acid, while in feldspar, the Al-O bond in the AlO 4 tetrahedron is more difficult to break than the Al-O bond in the AlO 6 in the hexahedron of spodumene, and there are also fewer Al sites in feldspar that can interact with α-di-n-hexylamino-dodecanoic acid. Therefore, the reagent is prone to form reverse multi-layer adsorption on the surfaces of feldspar and quartz, resulting in the hydrophilicity of the surfaces of albite and quartz. In addition, since N can promote the low-temperature solubility of the reagent through hydrogen bond interaction. This reagent not only has good selectivity but also can exhibit good collecting performance in a low-temperature environment of 10 °C. The reagent developed by the present invention is of great significance for the efficient development and utilization of spodumene.

[0014] The fourth technical solution of the present invention: provides a method for flotation separation of spodumene concentrate from spodumene ore, including the following steps:

[0015] First, grind the spodumene ore, add water to the ground ore powder to prepare a pulp, adjust the pH value of the pulp to 4-5, then add the solution of the above-mentioned α-di-n-hexylamino-dodecanoic acid, and then inflate and float and scrape the foam to obtain spodumene concentrate.

[0016] Preferably, the particle size of the ore powder is such that, by mass, particles with a particle size less than 0.074 mm account for 75 to 85%.

[0017] Preferably, the mass fraction of the pulp is 20 to 30%.

[0018] Preferably, the temperature during the flotation process is 10 to 25 °C.

[0019] Preferably, 500 to 1000 g of the amphoteric collector is used for each ton of the ore powder during flotation.

[0020] Preferably, the mass fraction of the solution of α-di-n-hexylamino-dodecanoic acid is 0.2 to 0.5%.

[0021] Preferably, the specific process of aeration and flotation skimming is one roughing, two scavengings and three cleanings. Among them, 30 to 50 g / t (30 to 50 g per ton of ore powder) of the amphoteric collector is added during scavenging I, and 30 to 50 g / t (30 to 50 g per ton of ore powder) of the amphoteric collector is added during scavenging II.

[0022] The beneficial technical effects of the present invention are as follows:

[0023] (1) Compared with the existing collectors, the amphoteric collector provided by the present invention has the advantages of not requiring the use of an activator, being easy to synthesize, having good low-temperature resistance, strong selectivity, and good foam properties.

[0024] (2) The amphoteric collector of the present invention can be directly used for raw ore, has a simple process, a wide application range and low operating costs, and can improve the economic benefits of the concentrator. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a process flow chart of low-temperature flotation of spodumene according to the present invention.

[0026] Figure 2 is a mass spectrum of α-di-n-hexylamino-dodecanoic acid prepared in Example 1 of the present invention.

[0027] Figure 3 is a nuclear magnetic resonance hydrogen spectrum of α-di-n-hexylamino-dodecanoic acid prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0029] It should be noted that the parts not described in detail in the present invention are all conventional operating means in the art and are not the focus of the present invention.

[0030] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between 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 from the range.

[0031] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0032] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0033] The process flow chart of the low-temperature flotation of spodumene in the present invention is shown in Figure 1 .

[0034] Example 1

[0035] Preparation of α-di-n-hexylamino-dodecanoic acid:

[0036] Mix 2-bromododecanoic acid and di-n-hexylamine in a molar ratio of 1:1 and heat react at 90 °C for 3 h to obtain α-di-n-hexylamino-dodecanoic acid.

[0037] Since the two raw materials used in Example 1 are added according to the stoichiometric ratio and there is no side reaction, the product purity is extremely high and can be regarded as pure α-di-n-hexylamino-dodecanoic acid.

[0038] The relative molecular weight of the α-di-n-hexylamino-dodecanoic acid prepared in Example 1 was detected by mass spectrometry and compared with the theoretical relative molecular weight. The measured value of its mass spectrometry is shown in Figure 2 .

[0039] The above mass spectrometry detection results show that the measured relative amount of the synthesized collector α-di-n-hexylamino-dodecanoic acid is 384.38, which is basically consistent with the theoretical relative molecular weight of 383.64, indicating that the relative molecular weight of the synthesized agent is consistent with the molecular weight of the target product.

[0040] The nuclear magnetic resonance hydrogen spectrum of α-di-n-hexylamino-dodecanoic acid is shown in Figure 3 .

[0041] The types of H in the structure of the α-di-n-hexylamino-dodecanoic acid are determined by information such as chemical shift and peak splitting, and the theoretical number of protons is determined by integration. The attribution of each peak is as shown in Figure 2As shown, the types and amounts of H in the structure of the synthesized collector in Example 1 can correspond to the types and amounts of H in the structure of the target product. Combining with the mass spectrometry results, it shows that the synthesized reagent is the target reagent.

[0042] The α - di - n - hexylamino - dodecanoic acid used in Examples 2 - 3 was prepared in Example 1.

[0043] Example 2

[0044] In this example, the chemical composition of the spodumene ore is: Li 2 O content is 1.7%, Al 2 O 3 content is 15.76%, SiO 2 content is 70.44%, Na 2 O content is 3.98%, K 2 O content is 2.55%. The flotation steps are as follows:

[0045] (1) Crushing and grinding: First, the spodumene is crushed by a jaw crusher to less than 2 mm, and then the crushed ore is ground by a three - head grinder to a particle size less than 0.074 mm accounting for 80% by mass.

[0046] (2) Pulp conditioning and flotation: The ore powder obtained from grinding in step (1) is formulated into a pulp with a mass percentage concentration of 25%, and then a HCl solution with a mass percentage concentration of 3% is added to the pulp to adjust the pH value of the pulp to 5. The pulp conditioning time is 3 min. Then, a collector (a solution of α - di - n - hexylamino - dodecanoic acid with a mass percentage concentration of 0.3%, added in an amount of 800 g of α - di - n - hexylamino - dodecanoic acid per ton of ore powder) is added to the pulp, and the action time is 4 min. Through a flotation process of one roughing, two scavengings, and three cleanings, flotation foam products and in - trough products are obtained. 50 g / t of α - di - n - hexylamino - dodecanoic acid is supplemented in scavenging I, and 30 g / t of α - di - n - hexylamino - dodecanoic acid is supplemented in scavenging II; the flotation temperature is 10°C.

[0047] (3) Post - treatment of flotation foam products: The flotation foam products obtained in step (2) are dried to obtain spodumene concentrate with a Li 2 O grade of 6.3% and a recovery rate of 68%.

[0048] Example 3

[0049] In this example, the chemical composition of the spodumene ore is: Li 2 O content is 1.12%, Al 2 O 3 content is 14.22%, SiO 2 content is 74.44%, Na 2 O content is 3.21%, K 2The O content is 2.11%. The flotation steps are as follows:

[0050] (1) Crushing and grinding: First, the spodumene ore is crushed by a jaw crusher to less than 2 mm, and then the crushed ore is ground by a ceramic ball mill to a particle size of less than 0.074 mm accounting for 80% by mass.

[0051] (2) Slurry adjustment and flotation: The ore powder obtained from the grinding in step (1) is formulated into a slurry with a mass percentage concentration of 20%, and then a HCl solution with a mass percentage concentration of 2% is added to the slurry to adjust the pH value of the slurry to 5. The slurry adjustment time is 3 min. Then, a collector (a solution of α - di - n - hexylamino - dodecanoic acid with a mass percentage concentration of 0.3%, added in an amount of 1000 g of α - di - n - hexylamino - dodecanoic acid per ton of ore powder) is added to the slurry, and the action time is 5 min. Through a flotation process of one roughing, two scavengings, and three cleanings, a flotation foam product and an in - cell product are obtained. 50 g / t of α - di - n - hexylamino - dodecanoic acid is supplemented in scavenging I, and 50 g / t of α - di - n - hexylamino - dodecanoic acid is supplemented in scavenging II; the flotation temperature is 15°C.

[0052] Post - treatment of the flotation foam product: The flotation foam product obtained in step (2) is dried to obtain spodumene concentrate with an Li 2 O grade of 5.56% and a recovery rate of 80%.

[0053] The above - described embodiments are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An α-di-n-hexylamino-dodecanoic acid, characterized in that: The structural formula of the α-di-n-hexylamino-dodecanoic acid is as follows:

2. A method for preparing α-di-n-hexylamino-dodecanoic acid according to claim 1, characterized in that: The following steps are involved: 2-bromododecanoic acid and di-n-hexylamine are mixed and heated for reaction to obtain the α-di-n-hexylamino-dodecanoic acid.

3. The method for preparing α-di-n-hexylamino-dodecanoic acid according to claim 2, characterized in that: The molar ratio of the 2-bromododecanoic acid to the di-n-hexylamine is 1:

1.

4. The method for preparing α-di-n-hexylamino-dodecanoic acid according to claim 2, characterized in that: The heating reaction was carried out at a temperature of 90° C. and for a period of 3 hours.

5. An application of α-di-n-hexylamino-dodecanoic acid according to claim 1 in the flotation separation of spodumene, characterized in that: The α-di-n-hexylamino-dodecanoic acid is used as an amphoteric collector.

6. A method for flotation separation of spodumene concentrate from spodumene ore, characterized in that: The following steps are involved: Firstly, the spodumene ore is ground, and the ore powder obtained by grinding is added with water to form a slurry, and the pH value of the slurry is adjusted to 4-5, and then the solution of α-di-n-hexylamino-dodecanoic acid described in claim 1 is added, and then aeration, flotation and foam scraping are carried out to obtain the spodumene concentrate.

7. The method for flotation separation of spodumene concentrate from spodumene ore according to claim 6, characterized in that: The particle size of the ore powder is as follows: by mass, particles with a particle size less than 0.074 mm account for 75-85%; and / or the mass fraction of the ore pulp is 20-30%.

8. The method for flotation separation of spodumene concentrate from spodumene ore according to claim 6, characterized in that: The flotation temperature is 10-25°C.

9. The method for flotation separation of spodumene concentrate from spodumene ore according to claim 6, characterized in that: 500-1000g of the amphoteric collector is used for flotation per ton of the ore powder.

10. The method for flotation separation of spodumene concentrate from spodumene ore according to claim 6, characterized in that: The mass fraction of the α-di-n-hexylamino-dodecanoic acid solution is 0.2-0.5%.

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