Combined collecting agent applied to flotation of spodumene in low-alkali environment and application of combined collecting agent

Abstract

The invention discloses a combined collecting agent applied to flotation of spodumene in a low-alkali environment and application of the combined collecting agent. The combined collecting agent comprises a polymer of unsaturated fatty acid, at least one of N, N-dimethyl dodecylamine or N-dodecyl-1, 3-propane diamine, polypropylene sulfonate, methyl isobutyl carbinol and a terpene oil collecting agent. The combined collecting agent is suitable for being used in a low-alkali solution environment with the pH being 8-9, carboxyl, hydroxyl, amino and ether group functional groups contained in the combined collecting agent selectively act on aluminum, lithium and other atomic sites on the surface of spodumene, physical and chemical adsorption is generated, hydrogen bonds and ligand compounds are formed on the surface of minerals, and therefore the surface of the spodumene is protected. And the selective collection of spodumene is effectively enhanced in a low-alkali environment, so that the problems of spodumene minerals in a high-alkali flotation process are avoided.

Description

Technical Field

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

[0002] Lithium is the lightest metal in nature, with excellent physical properties and chemical activity. It is widely used in various industries such as glass, ceramics, grease, aluminum alloy, 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 growing, and the corresponding consumption continues to rise. Spodumene is an important lithium extraction mineral, which often coexists with silicate minerals such as albite, beryl, quartz and mica in pegmatite lithium deposits. The similar surface properties of these minerals make separation more difficult. The main beneficiation methods used are hand selection, flotation, magnetic separation, heavy liquid and suspension method and thermal cracking, among which flotation is used more in actual production and has the best effect.

[0003] In the flotation process of spodumene, two positive flotation processes are generally used, namely, desludging-flotation and high-alkali non-desludging flotation. The latter has been widely promoted due to the simplification of the process, and a single collector is difficult to achieve effective separation due to its poor selectivity. Combination reagents are often used to play a synergistic role in improving flotation efficiency and concentrate grade. At the same time, although strong alkali plays a role in scrubbing the surface of spodumene and reducing mudification, due to the poor selectivity of anionic collectors, high-valent metal cation activators are often used in combination under strong alkaline conditions. There are problems such as high investment cost, unstable production operation, and difficulty in using backwater due to the large amount of drugs used, and even potential ecological risks to the surrounding environment. Therefore, in order to overcome the disadvantages of high alkaline environment and poor selectivity of collectors in traditional mineral processing technology, a spodumene combination collector for use in a low-alkali environment 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-alkali environment, which overcomes the disadvantages of the high-alkali environment and poor selectivity of the collector in the traditional mineral processing process.

[0005] The 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, wherein the total mass of active components is 100 parts, and each component comprises, by weight, 25 to 40 parts of a polymer of unsaturated fatty acids, 15 to 25 parts of at least one of N,N-dimethyldodecylamine and N-dodecyl-1,3-propylenediamine, 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.

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

[0008] The preparation method of the N,N-dimethyldodecylamine is specifically as follows: dodecylamine and a methylating agent are mixed in a solvent 1 accounting for 30% to 50% of the total volume of the reaction mixture at a molar ratio of 1:2, 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; 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 solvent 2 accounting for 30% to 50% of the total volume of the reaction mixture at a molar ratio of 1:1, 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; the basic catalyst 2 includes sodium hydroxide, ammonia water and sodium carbonate;

[0010] The preparation method of the polypropylene sulfonate is specifically as follows: acrylic acid and propylene sulfonic acid or other monomers containing sulfonic acid groups 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 volume of the reaction liquid is added to the mixture, and then ammonium persulfate or a peroxide initiator is added in an amount of 0.05% of the total mass of the monomers, and a polymerization reaction is carried out at 70 to 80° C. for 10 to 12 hours to obtain the polypropylene sulfonate.

[0011] The terpene oil collector is at least one of turpentine 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 spodumene beneficiation process, comprising the following steps:

[0014] S1. crushing and grinding the spodumene ore to obtain a grinding product;

[0015] S2. slurrying the grinding product, adding a conditioning agent, and obtaining a slurrying product;

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

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

[0018] Furthermore, in step S1, the spodumene ore is crushed to a particle size of -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 slurry 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 inhibiting role, and 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 to clean the surface of the spodumene mineral. The hydroxide ions are mainly used to interact with the lithium, aluminum, and silicon atomic sites on the surface of the 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 activation of metal cations and the adsorption of the combined collector.

[0021] Further, 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, so that the overall positive charge of the surface is increased, the difference in surface properties of spodumene and other gangue minerals is changed, and their selective flotation is promoted.

[0023] Further, in step S4, the aeration flotation includes one roughing selection, at least three cleaning selections and at least two scavenging selections;

[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 roughing 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 roughing 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 by the weight of spodumene ore, the amount of combined collector used in the roughing process is 500-800 g / t, the amount of combined collector used in the first scavenging process is 100-300 g / t, the amount of combined collector used in the second 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 uses the polymer of unsaturated fatty acid as the main component. In a low-alkali environment, hydroxylation occurs in some areas of the spodumene surface, mainly combining with 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 mainly physically and chemically adsorbs with the exposed Al and Li atomic sites by means of carboxyl (-COO-) and hydroxyl (-OH). On the one hand, it is adsorbed on the outer layer of the compact layer on the mineral surface by means of electrostatic force and van der Waals force (association between hydrophobic hydrocarbon chains). On the other hand, it relies on the interaction of modified soap anions with metal cations on the mineral surface. The chemical bond is adsorbed on the compact layer on the surface of the mineral, with strong capture ability but poor selectivity. Then, at least one of N,N-dimethyldodecylamine or N-dodecyl-1,3-propylenediamine is introduced to improve the selectivity for spodumene in a low-alkali environment. Its amino (-NH2) functional group selectively acts on the active sites of Al and Li atoms on the surface of spodumene, and plays a synergistic role with the modified soap collector. Through charge compensation and splicing mechanism, it associates with the Al and Li principle sites of hydroxyl adsorption on the surface of spodumene to form a stable network structure adsorption complex, while changing the surface tension of the mineral, making it easy to interact with the foam and 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. It can further improve the adsorption selectivity by adjusting the charge characteristics of the spodumene surface and forming ligands with the Al and Li active sites on its surface. It can also form hydrogen bonds with the mineral surface to enhance the adsorption capacity of the combined collector and enhance 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 co-adsorption, mainly acting on the metal Al and Li atomic active sites exposed by alkaline dissolution on the spodumene surface by physical adsorption or molecular adsorption, enhancing the adsorption of the combined collector to strengthen the 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 application thereof. The combined collector has economical dosage and 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 the mineral processing process of the present invention are further explained in detail below in conjunction with specific examples. In the present invention, all the reagents used are purchased through commercial channels.

[0033] The raw ore used in the embodiment is a pegmatite-type lithium polymetallic ore from a foreign mine. The lithium in the raw ore mainly exists in the form of spodumene, and there are also a small amount of minerals such as pyroxenite and lithium mica. The lithium grade is 1.47%, and the content of associated valuable elements such as beryllium, tin, niobium and tantalum is low, and the comprehensive recycling value is not high. The gangue minerals mainly include feldspar and quartz, most of which are adjacent to spodumene and contain fine-grained tantalum-niobite.

[0034] The components of the combined collector used in the embodiment include: based on the total mass of 100 parts of active components, the components are measured in parts by weight: 35 parts of 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 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 10% of the total mass of the monomers is added to water to form a reaction mixture, which is then heated to 80°C for reaction 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 by sodium carbonate and sodium hydroxide; the metal cation activating agent before addition is a 2% aqueous solution.

[0038] Example 1

[0039] The spodumene ore was ground to a fineness of -0.074mm and a content of 65%. Then 300g / t of sodium carbonate was added, and after stirring for 5min, 400g / t of sodium hydroxide was added, and the stirring time was 15min. Then 50g / t of calcium chloride was added, and after stirring for 5min, 500g / t of combined collector was added, and after stirring for 3min, 20g / t of pine oil was added, and after stirring for 2min, rough selection was performed. Then 200g / t of combined collector was added to the tailings for a first scavenging selection, followed by 100g / t for a second scavenging selection, 100g / t of sodium carbonate was added for a first concentrating selection, 50g / t of sodium carbonate was added for a second concentrating selection, and no reagent was added for a third concentrating selection. The obtained flotation indexes are shown in Table 1.

[0040] Table 1 Flotation index of product of Example 1

[0041] Product Name Yield / % <![CDATA[Li2O grade / %]]> <![CDATA[Li2O recovery rate / %]]> Spodumene concentrate 24.34 5.01 82.95 Tailings 75.66 0.33 17.05 Ore 100.00 1.47 100.0

[0042] From the flotation indexes 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 collection ability of the combined collector for spodumene.

[0043] Example 2

[0044] The spodumene ore was ground to a fineness of -0.074mm and a content of 70%, and then 400g / t of sodium carbonate was added, and after stirring for 5min, 500g / t of sodium hydroxide was added, and the stirring time was 15min. Then 60g / t of calcium chloride was added, and after stirring for 5min, 600g / t of combined collector was added, and after stirring for 3min, 20g / t of pine oil was added, and after stirring for 2min, rough selection was performed. Then 300g / t of combined collector was added to the tailings for a first scavenging selection, followed by 200g / t for a second scavenging selection, 150g / t of sodium carbonate was added for a first concentrating selection, 100g / t of sodium carbonate was added for a second concentrating selection, and no reagent was added for a third concentrating selection. The obtained flotation indexes are shown in Table 2.

[0045] Table 2 Flotation index of product of Example 2

[0046] Product Name Yield / % <![CDATA[Li2O grade / %]]> <![CDATA[Li2O recovery rate / %]]> Spodumene concentrate 27.36 4.65 86.55 Tailings 72.64 0.27 13.45 Ore 100.00 1.47 100.0

[0047] 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 reflects that the appropriate and slightly increased dosage of the combined collector can improve the collection effect, and the grade loss is small, and the mineral processing process under the application of the combined collector in a low-alkali environment achieves a good selective collection effect on the flotation of spodumene ore.

[0048] By comparing the test results of Example 1 and Example 2, it can be seen that the method of the present invention achieves a good separation effect for spodumene in a low-alkali environment, is environmentally friendly and economical, has low reagent cost, has a high Li2O grade in the obtained spodumene concentrate, a high Li2O recovery rate, a stable process effect, and is easy to handle with backwater, effectively avoiding a series of problems such as unstable production effects in a high-alkali environment. In summary, the present invention provides an economical and environmentally friendly combined collector and a corresponding simple and easy-to-implement mineral processing process for the efficient recycling of spodumene.

Claims

1. A combined collector for flotation of spodumene in a low-alkali environment, characterized in that: The combined collector is based on 100 parts of the total mass of active components, and each component includes, by weight, 25 to 40 parts of a polymer of unsaturated fatty acids, 15 to 25 parts of at least one of N,N-dimethyldodecylamine and N-dodecyl-1,3-propylenediamine, 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.

2. The combined collector according to claim 1, characterized in that The unsaturated fatty acid polymer is a chain structure or polymer using docosahexaenoic acid or decenoic acid as an unsaturated fatty acid monomer.

3. The combined collector according to claim 1, characterized in that The preparation method of the N,N-dimethyldodecylamine is specifically as follows: dodecylamine and a methylating agent are mixed in a solvent 1 accounting for 30% to 50% of the total volume of the reaction mixture at a molar ratio of 1:2, 3.0 to 5.0 wt % of an alkaline 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 alkaline catalyst 1 includes sodium hydroxide or aqueous ammonia.

4. The combined collector according to claim 1, characterized in that The preparation method of N-dodecyl-1,3-propylenediamine is specifically as follows: dodecyl chloride and 1,3-propylenediamine are mixed in a solvent 2 accounting for 30% to 50% of the total volume of the reaction mixture at a molar ratio of 1:1, 1.0 to 5.0 wt % of an alkaline 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 alkaline catalyst 2 includes sodium hydroxide, aqueous ammonia and sodium carbonate.

5. The combined collector according to claim 1, characterized in that: The preparation method of the polypropylene sulfonate is specifically as follows: acrylic acid and propylene sulfonic acid or other monomers containing sulfonic acid groups 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 volume of the reaction liquid is added to the mixture, and then ammonium persulfate or a peroxide initiator is added in an amount of 0.05% of the total mass of the monomers, and a polymerization reaction is carried out at 70 to 80° C. for 10 to 12 hours to obtain the polypropylene sulfonate.

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

7. Use of the combined collector according to any one of claims 1 to 6 in spodumene flotation, characterized in that: The application is specifically a flotation spodumene beneficiation process, comprising the following steps: S1. crushing and grinding the spodumene ore to obtain a grinding product; S2. slurrying the grinding product, adding a conditioning agent, and obtaining a slurrying product; S3. Adding a metal cation activator to the slurry product to obtain an activated slurry product; S4. Add the combined collector to the activated slurry product for aeration flotation to obtain spodumene concentrate and tailings.

8. The use according to claim 7, characterized in that: In step S1, the particle size of the crushed spodumene ore is -2.5mm, the grinding fineness is -0.074mm, 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 pulp concentration is 35-55%.

9. The use according to claim 7, 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 selection, at least three cleaning selections and at least two scavenging selections; based on the weight of the spodumene ore, the dosage of the combined collector in the roughing selection process is 500-800 g / t, the dosage of the combined collector in the one cleaning selection process is 100-300 g / t, the dosage of the combined collector in the two cleaning selection processes is 50-100 g / t, and no combined collector is added in the cleaning process.

10. The use according to claim 7, characterized in that: When the number of cleaning times in the aeration flotation is three and the number of scavenging times is two, the specific process of the aeration flotation is as follows: the rougher concentrate obtained by the 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 the spodumene concentrate; the rougher tailings obtained by the 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 is 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 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 is returned to the first scavenging process.

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