A combined collector for flotation of spodumene in a low-alkali environment and its application

Abstract

The present invention discloses a combination collector for flotation of spodumene in a low-alkali environment and its application. The combination collector includes a polymer of unsaturated fatty acids, at least one of N,N-dimethyldodecylamine or N-dodecyl-1,3-propylenediamine, polypropylene sulfonate, methyl isobutyl carbinol and a terpene oil collector. The combination collector provided by the present invention is suitable for use in a low-alkali solution environment with a pH of 8 to 9. The carboxyl, hydroxyl, amino and ether-based energy groups contained in the combination collector selectively act on atomic sites such as aluminum and lithium on the surface of spodumene, producing physical and chemical adsorption, and forming hydrogen bonds and ligand compounds with the mineral surface, effectively strengthening the selective capture of spodumene in a low-alkali environment, thereby avoiding the problem of spodumene minerals in a high-alkali flotation process.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral flotation, and in particular to a combined collector for flotating spodumene in a low-alkali environment and application thereof. Background Art

[0002] Lithium is the lightest metal in nature, possessing excellent physical properties and chemical activity. It is widely used in various industries, including glass, ceramics, lubricating greases, aluminum alloys, batteries, and new energy. With the rapid development of strategic emerging industries such as new energy vehicles and electronic information, the demand for lithium resources is increasing, and corresponding consumption is also rising. Spodumene is an important lithium-extraction mineral, often coexisting with silicate minerals such as albite, beryl, quartz, and mica in pegmatite-type lithium deposits. The similar surface properties of these minerals make separation more difficult. The main beneficiation methods used include hand sorting, flotation, magnetic separation, heavy liquid and suspension methods, and thermal cracking. Among them, flotation is the most commonly used method in actual production and has the best results.

[0003] In the flotation process of spodumene, two direct flotation processes are generally used: desliming-flotation and high-alkali non-desliming flotation. The latter has been widely adopted due to its simplified process. However, due to the poor selectivity of a single collector, effective separation is difficult to achieve. Therefore, a combination of reagents is often used to achieve synergistic effects to improve flotation efficiency and concentrate grade. At the same time, while strong alkali can scrub the spodumene surface and reduce mudification, due to the poor selectivity of anionic collectors, high-valent metal cation activators are often used in combination with strong alkaline conditions. This leads to high investment costs due to the large dosage, unstable production operations, difficulty in recycling return water, and even potential ecological risks to the surrounding environment. Therefore, to overcome the drawbacks of traditional mineral processing processes such as high alkalinity and poor collector selectivity, a spodumene combination collector for use in low-alkalinity environments is urgently needed. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a combined collector for flotation of spodumene in a low-alkaline environment, which overcomes the disadvantages of the high alkaline environment and poor selectivity of the collector in the traditional mineral processing process.

[0005] A second object of the present invention is to provide an application of the combined collector.

[0006] The invention provides a combined collector for flotation of spodumene in a low-alkali environment. The combined collector comprises, based on 100 parts by total weight of active components, 25 to 40 parts by weight of an unsaturated fatty acid polymer, 15 to 25 parts by weight of at least one of N,N-dimethyldodecylamine and N-dodecyl-1,3-propylenediamine, 5 to 20 parts by weight of polypropylene sulfonate, 4 to 16 parts by weight of methyl isobutyl carbinol, and 3 to 12 parts by weight of a terpene oil collector.

[0007] The unsaturated fatty acid polymer is a chain structure or polymer with docosahexaenoic acid or decenoic acid as the unsaturated fatty acid monomer.

[0008] The preparation method of N, N-dimethyldodecylamine is specifically as follows: dodecylamine and a methylating agent are mixed in a molar ratio of 1:2 in a solvent 1 accounting for 30% to 50% of the total volume of the reaction mixture, 3.0 to 5.0 wt% of a basic catalyst 1 is added, and the mixture is reacted at 50 to 80° C. for 2 to 5 hours to obtain the N, N-dimethyldodecylamine; the solvent 1 is ethanol or dichloromethane; and the basic catalyst 1 includes sodium hydroxide or aqueous ammonia.

[0009] The preparation method of N-dodecyl-1,3-propylenediamine is specifically as follows: dodecyl chloride and 1,3-propylenediamine are mixed in a molar ratio of 1:1 in a solvent 2 accounting for 30% to 50% of the total volume of the reaction mixture, 1.0 to 5.0 wt% of a basic catalyst 2 is added, and the mixture is reacted at 70 to 120° C. for 3 to 5 hours to obtain the N-dodecyl-1,3-propylenediamine; the solvent 2 is ethanol or dichloromethane; and the basic catalyst 2 includes sodium hydroxide, aqueous ammonia, and sodium carbonate.

[0010] The preparation method of the polypropylene sulfonate is specifically as follows: acrylic acid and propylene sulfonic acid or other sulfonic acid group-containing monomers are mixed in a mass ratio of 1.0:5.3 to 1.0:5.9, water or an organic solvent accounting for 10% of the reaction liquid volume is added to the mixture, and ammonium persulfate or a peroxide initiator is added in an amount of 0.05% of the total weight of the monomers, and a polymerization reaction is carried out at 70-80°C for 10-12 hours to obtain the polypropylene sulfonate.

[0011] The terpene oil collector is at least one of pine oil, menthone, thyme oil and lemon oil.

[0012] The present invention also provides an application of the combined collector in spodumene flotation.

[0013] The application is specifically a flotation beneficiation process for spodumene, comprising the following steps:

[0014] S1. The spodumene ore is crushed and ground to obtain a grinding product;

[0015] S2. The grinding product is slurried and an adjusting agent is added to obtain a slurry product;

[0016] S3. Adding a metal cation activator to the slurry product to obtain an activated slurry product;

[0017] S4. Adding the combined collector to the activated slurry product to perform aeration flotation to obtain spodumene concentrate and tailings.

[0018] Furthermore, in step S1, the particle size of the spodumene ore is crushed to -2.5 mm, the grinding fineness is -0.074 mm, and the content is 65-75%.

[0019] Furthermore, in step S2, the adjusting agent is sodium carbonate and sodium hydroxide in a mass ratio of 1:1, the solution pH value is 8-9, and the pulp concentration is 35-55%.

[0020] The purpose of adding the adjusting agent is, on the one hand, to reduce the influence of the ore slime and play a dispersing and inhibitory role; on the other hand, to adjust the pH of the ore pulp so that it is placed in a low-alkali environment for surface alkaline dissolution treatment and clean the surface of the spodumene mineral. It mainly uses the interaction between hydroxide ions and the lithium, aluminum, and silicon atom sites on the surface of spodumene to increase its originally slight dissolution effect, promote the breaking of the surface lithium oxygen bonds, aluminum oxygen bonds, and silicon oxygen bonds, and then achieve surface selective alkaline dissolution, which has an important impact on the subsequent metal cation activation and adsorption of the combined collector.

[0021] Furthermore, in step S3, the metal cation activator includes calcium chloride and magnesium chloride in an amount of 50 to 100 g / t based on the weight of the spodumene ore;

[0022] The main purpose of adding the metal cation activator is that under the surface alkaline dissolution of spodumene, the added metal cation activator will exist on the mineral surface in the form of ions and hydroxyl complexes, and adsorb lithium, aluminum and silicon atomic sites on the surface of spodumene in a low-alkali environment, thereby increasing the overall positive charge of the surface, changing the difference in surface properties between spodumene and other gangue minerals, and promoting their selective flotation.

[0023] Furthermore, in step S4, the aeration flotation includes one roughing, at least three cleanings, and at least two scavengings;

[0024] Preferably, when the number of cleaning times is three times and the number of scavenging times is two, the aerated flotation process is specifically as follows: the rougher concentrate obtained by roughing is subjected to the first cleaning; the concentrated concentrate 1 obtained by the first cleaning is subjected to the second cleaning; the concentrated concentrate 2 obtained by the second cleaning is subjected to the third cleaning; the concentrated concentrate 3 obtained by the third cleaning is used as spodumene concentrate; the rougher tailings obtained by roughing are subjected to the first scavenging; the scavenged tailings 1 obtained by the first scavenging is subjected to the second scavenging; the scavenged tailings 2 obtained by the second scavenging are used as the final tailings; the tailings obtained by the first cleaning and the concentrate obtained by the first scavenging are returned to the roughing process; the tailings obtained by the second cleaning are returned to the first cleaning process; the tailings obtained by the third cleaning are returned to the second cleaning process; and the concentrate obtained by the second scavenging is returned to the first scavenging process.

[0025] Calculated based on the weight of the spodumene ore, the amount of the combined collector used in the roughing process is 500-800 g / t, the amount of the combined collector used in the primary scavenging process is 100-300 g / t, the amount of the combined collector used in the secondary scavenging process is 50-100 g / t, and no combined collector is added in the concentrating process.

[0026] Principle of the present invention:

[0027] The collector of the present invention is mainly composed of a polymer of unsaturated fatty acids. In a low-alkali environment, hydroxylation occurs in some areas of the spodumene surface, mainly binding to the active sites of Li, Al and Si atoms on the surface, and exposing some Al, Li and unsaturated O atomic sites through selective alkali dissolution. The modified soap collector used relies on carboxyl (-COO-) and hydroxyl (-OH) groups to undergo physical and chemical adsorption mainly with the exposed Al and Li atomic sites. On the one hand, it is adsorbed on the outer layer of the compact layer on the mineral surface by electrostatic force and van der Waals force (association between hydrophobic hydrocarbon chains). On the other hand, it relies on the chemical bond between the modified soap anions and the metal cations on the mineral surface to adsorb on the compact layer on the mineral surface. It has strong collecting ability but poor selectivity. Then, N, N-dimethyldodecylamine or N-dodecyl-1, At least one of the 3-propylenediamines improves the selectivity for spodumene in a low-alkali environment, selectively acts on the active sites of Al and Li atoms on the surface of spodumene with its amino (-NH2) functional group, and exerts a synergistic effect with the modified soap collector, associates with the Al and Li principle sites of the hydroxyl groups adsorbed on the surface of spodumene through charge compensation and splicing mechanisms, forms a stable network structure adsorption complex, and at the same time changes the surface tension of the mineral, making it easy to interact with the foam, thereby improving the flotation efficiency.

[0028] Polypropylene sulfonate has multiple sulfonic acid groups (-SO3H), which makes the combined collector have good water solubility and surface activity. By adjusting the charge characteristics of the spodumene surface and forming ligands with the Al and Li active sites on its surface, the adsorption selectivity is further improved. It can also form hydrogen bonds with the mineral surface, enhancing the adsorption capacity of the combined collector and the stability of the foam, making the foam formed during the flotation process more durable, thereby improving the recovery rate of the mineral. The added terpene oil can associate with other component collectors for joint adsorption, mainly acting on the metal Al and Li atomic active sites exposed by alkaline dissolution on the spodumene surface through physical adsorption or molecular adsorption, enhancing the adsorption of the combined collector to strengthen coarse particle flotation, increasing the upper limit of the particle size of the combined collector, and reducing the dosage of the combined collector, improving its selectivity and stabilizing the foam structure.

[0029] Beneficial effects of the present invention:

[0030] The invention discloses a combined collector for flotation of spodumene in a low-alkali environment and an application thereof. The combined collector is economical in dosage and has a high collecting capacity, can ensure the grade and recovery rate of spodumene, and effectively solves the problems caused by the high-alkali process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the process of aeration flotation in the application of the present invention. DETAILED DESCRIPTION

[0032] The combined collector and its mineral processing process of the present invention are further explained in detail below with reference to specific examples. In the present invention, all the reagents used are purchased through commercial channels.

[0033] The raw ore used in the examples is a pegmatite-type lithium polymetallic ore from a foreign mine. The lithium in the ore primarily exists as spodumene, with smaller amounts of other minerals, such as lepidolite and lepidolite. The lithium grade is 1.47%, and the contents of associated valuable elements, such as beryllium, tin, niobium, and tantalum, are low, making their comprehensive recycling value low. The gangue minerals primarily consist of feldspar and quartz, most of which coexist adjacent to the spodumene and contain fine-grained tantalite.

[0034] The components of the combined collector used in the examples include: based on the total mass of the active ingredients being 100 parts, the components thereof are calculated in parts by weight: 35 parts of an unsaturated fatty acid polymer, 25 parts of N, N-dimethyldodecylamine, 15 parts of polypropylene sulfonate, 15 parts of methyl isobutyl carbinol, and 10 parts of a terpene oil collector are mixed to prepare a solution with a mass concentration of 5%.

[0035] The unsaturated fatty acid monomer of the unsaturated fatty acid polymer is docosahexaenoic acid; the polypropylene sulfonate is a mixture of acrylic acid and propylene sulfonic acid in a mass ratio of 1.0:5.4, and ammonium persulfate accounting for 0.05% of the total mass of the monomers is added to water to form a reaction mixture, which is then heated to 80°C for 10 hours. After the polymerization reaction is completed, it is precipitated and filtered, and then dried in a vacuum drying oven for separation and purification.

[0036] The terpene oil collector in the embodiment is pine oil.

[0037] In the embodiment, the adjusting agent before addition is a 5% aqueous solution prepared from sodium carbonate and sodium hydroxide; the metal cation activator before addition is a 2% aqueous solution.

[0038] Example 1: The spodumene ore was ground to a fineness of -0.074 mm and a content of 65%. Then, 300 g / t of sodium carbonate was added, and after stirring for 5 minutes, 400 g / t of sodium hydroxide was added, and the stirring time was 15 minutes. Then, 50 g / t of calcium chloride was added, and after stirring for 5 minutes, 500 g / t of a combined collector was added. After stirring for 3 minutes, 20 g / t of pine oil was added, and after stirring for 2 minutes, roughing was carried out. Then, 200 g / t of a combined collector was added to the tailings for a primary scavenging, followed by adding 100 g / t for a secondary scavenging, 100 g / t of sodium carbonate was added for a primary concentrating, 50 g / t of sodium carbonate was added for a secondary concentrating, and no reagent was added for a tertiary concentrating. The obtained flotation indexes are shown in Table 1.

[0039] Table 1 Flotation index of product in Example 1

[0040]

[0041] From the flotation indicators in Table 1, it can be found that after the spodumene ore is flotated in a low-alkali environment, the Li2O grade of the flotation spodumene concentrate reaches 5.01%, and the Li2O recovery rate reaches 82.89%, which reflects the good selective capture ability of the combined collector for spodumene.

[0042] Example 2: The spodumene ore was ground to a fineness of -0.074 mm and a content of 70%. Then, 400 g / t of sodium carbonate was added, and after stirring for 5 minutes, 500 g / t of sodium hydroxide was added, and the stirring time was 15 minutes. Then, 60 g / t of calcium chloride was added, and after stirring for 5 minutes, 600 g / t of combined collector was added, and after stirring for 3 minutes, 20 g / t of pine oil was added, and after stirring for 2 minutes, roughing was carried out. Then, 300 g / t of combined collector was added to the tailings for a primary scavenging, followed by 200 g / t for a secondary scavenging, 150 g / t of sodium carbonate was added for a primary concentrating, 100 g / t of sodium carbonate was added for a secondary concentrating, and no reagent was added for a tertiary concentrating. The obtained flotation indexes are shown in Table 2.

[0043] Table 2 Flotation index of product in Example 2

[0044]

[0045] From the flotation indicators in Table 2, it can be found that after the spodumene ore is flotated in a low-alkali environment, the Li2O grade of the flotation spodumene concentrate reaches 4.65%, and the Li2O recovery rate reaches 86.39%, which shows that a slight increase in the dosage of the combined collector can improve the collection effect and cause less grade loss, thereby achieving a good selective collection effect on the flotation of spodumene ore in the mineral processing process under the application of the combined collector in a low-alkali environment.

[0046] By comparing the test results of Example 1 and Example 2, it can be seen that the method of the present invention achieves good separation effect for spodumene in a low-alkali environment, is environmentally friendly and economical, has low reagent cost, and the obtained spodumene concentrate has a high Li2O grade, a high Li2O recovery rate, a stable process flow, and is easy to handle with backwater, effectively avoiding a series of problems such as unstable production effects caused by a high-alkali environment. In summary, the present invention provides an economical and environmentally friendly combined collector and a corresponding mineral processing process with simple and easy implementation for the efficient recovery and utilization of spodumene.

Claims

1. A combined collector for flotation of spodumene in a low-alkali environment, characterized in that: The combined collector comprises 100 parts by weight of the total mass of the active components, and the components include, by weight, 25 to 40 parts of an unsaturated fatty acid polymer having a structural formula of at least one of N,N-dimethyldodecylamine or N-dodecyl-1,3-propylenediamine, 15 to 25 parts, 5 to 20 parts of polypropylene sulfonate, 4 to 16 parts of methyl isobutyl carbinol, and 3 to 12 parts of a terpene oil collector; the unsaturated fatty acid polymer is a chain structure or polymer with docosahexaenoic acid or decenoic acid as the unsaturated fatty acid monomer.

2. The combined collector according to claim 1, wherein The preparation method of N, N-dimethyldodecylamine is specifically as follows: dodecylamine and a methylating agent are mixed in a molar ratio of 1:2 in a solvent 1 accounting for 30% to 50% of the total volume of the reaction mixture, 3.0 to 5.0 wt% of a basic catalyst 1 is added, and the mixture is reacted at 50 to 80° C. for 2 to 5 hours to obtain the N, N-dimethyldodecylamine; the solvent 1 is ethanol or dichloromethane; and the basic catalyst 1 includes sodium hydroxide or aqueous ammonia.

3. The combined collector according to claim 1, wherein The preparation method of N-dodecyl-1,3-propylenediamine specifically comprises: mixing dodecyl chloride and 1,3-propylenediamine at a molar ratio of 1:1 in a solvent 2 accounting for 30% to 50% of the total volume of the reaction mixture, adding 1.0 to 5.0 wt% of a basic catalyst 2, and reacting at 70 to 120° C. for 3 to 5 hours to obtain the N-dodecyl-1,3-propylenediamine; the solvent 2 is ethanol or dichloromethane; and the basic catalyst 2 includes sodium hydroxide, aqueous ammonia, and sodium carbonate.

4. The combined collector according to claim 1, wherein The preparation method of the polypropylene sulfonate is specifically as follows: acrylic acid and propylene sulfonic acid are mixed in a mass ratio of 1.0:5.3 to 1.0:5.9, water or an organic solvent accounting for 10% of the reaction liquid volume is added to the mixture, and then ammonium persulfate or a peroxide initiator is added in an amount of 0.05% of the total weight of the monomers, and a polymerization reaction is carried out at 70-80°C for 10-12 hours to obtain the polypropylene sulfonate.

5. The combined collector according to claim 1, characterized in that The terpene oil collector is at least one of pine oil, menthone, thyme oil and lemon oil.

6. An application of the combined collector according to any one of claims 1 to 5 in spodumene flotation, characterized in that: The application is specifically a flotation beneficiation process for spodumene, comprising the following steps: S1. The spodumene ore is crushed and ground to obtain a grinding product; S2. The grinding product is slurried and an adjusting agent is added to obtain a slurry product; S3. Adding a metal cation activator to the slurry product to obtain an activated slurry product; S4. Adding the combined collector to the activated slurry product to perform aeration flotation to obtain spodumene concentrate and tailings.

7. The use according to claim 6, characterized in that In step S1, the particle size of the crushed spodumene ore is -2.5 mm, the grinding fineness is -0.074 mm, and the content is 65-75%; in step S2, the adjusting agent is sodium carbonate and sodium hydroxide in a mass ratio of 1:1, the solution pH value is 8-9, and the slurry concentration is 35-55%.

8. The use according to claim 6, characterized in that In step S3, based on the weight of the spodumene ore, the metal cation activator includes calcium chloride and magnesium chloride, and the dosage is 50-100 g / t; in step S4, the aerated flotation includes one roughing, at least three cleaning and at least two scavenging; based on the weight of the spodumene ore, the dosage of the combined collector in the roughing process is 500-800 g / t, the dosage of the combined collector in the one scavenging process is 100-300 g / t, the dosage of the combined collector in the two scavenging processes is 50-100 g / t, and no combined collector is added in the cleaning process.

9. The use according to claim 6, characterized in that When the number of cleaning times in aeration flotation is three and the number of scavenging times is two, the aeration flotation process is specifically as follows: the rougher concentrate obtained from the roughing is subjected to the first cleaning; the concentrated concentrate 1 obtained from the first cleaning is subjected to the second cleaning; the concentrated concentrate 2 obtained from the second cleaning is subjected to the third cleaning; the concentrated concentrate 3 obtained from the third cleaning is used as spodumene concentrate; the rougher tailings obtained from the roughing are subjected to the first scavenging; the scavenged tailings 1 obtained from the first scavenging is subjected to the second scavenging; the scavenged tailings 2 obtained from the second scavenging is used as the final tailings; the tailings obtained from the first cleaning and the concentrate obtained from the first scavenging are returned to the roughing process; The tailings obtained from the second concentration are returned to the first concentration process; The tailings obtained from the third concentration are returned to the second concentration process; The concentrate obtained from the second scavenging process is returned to the first scavenging process.

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