Collector for reverse flotation, and preparation method therefor and use thereof

Abstract

A collector for reverse flotation, and a preparation method therefor and the use thereof. The collector for reverse flotation has a chemical structural formula as shown below: R1-NH-R2-NH2, wherein in the formula, R1 and / or R2 comprise(s) at least one of the following functional groups: a -CN3H4 functional group and a -SO3H functional group. The method comprises: S1, providing a diamine compound; and S2, introducing a -CN3 4 functional group and / or a -SO3H functional group into the diamine compound, so as to obtain a collector for reverse flotation. A diamine group and -CN3H4 in the collector for reverse flotation can enhance the interaction with a hydroxyl group, silicon, oxygen and other groups on the surface of an aluminosilicate mineral, thereby improving the selectivity of the collector for reverse flotation; -SO3H can reduce the interaction with metal ions in hard water, thereby improving the hard water resistance and enhancing the adaptability of the collector to hard water; moreover, a hydrocarbyl non-polar macromolecular chain in R1 and / or R2 enhances the hydrophobicity of the surface of mineral particles after the action of the collector, and therefore the collector for reverse flotation has an improved collecting capacity, and also has selectivity for and adaptability to minerals.

Description

A reverse flotation collector, its preparation method and application Cross-reference to related applications This application claims priority to Chinese patent application No. 202510002007.5, filed on January 2, 2025, the entire contents of which are incorporated herein by reference. Technical Field This disclosure relates to the field of bauxite reverse flotation desilication technology, and in particular to a reverse flotation collector and its preparation method and application. Background Technology Reverse flotation desilication technology for bauxite is a commonly used method in bauxite beneficiation. Its main purpose is to increase the grade of alumina and reduce the silicon content to meet the raw material requirements for alumina production. Compared with direct flotation desilication technology, reverse flotation desilication technology for bauxite has significant advantages, especially when processing bauxite in which there is a large difference in grindability between gibbsite and silicate minerals. It can effectively avoid the problem of mud formation caused by over-grinding, and can reduce mechanical entrainment and reagent dosage, which conforms to the flotation principle of "more suppression, less flotation". Bauxite reverse flotation collectors (hereinafter referred to as reverse flotation collectors or collectors) need to have a high selectivity for the valuable minerals and gangue minerals in bauxite. However, in practical applications, collectors often fail to achieve ideal selectivity, leading to the loss of valuable minerals or over-flotation of gangue minerals. Furthermore, some collectors have poor solubility and dispersibility in hard water and insufficient hard water tolerance, limiting their application under specific water quality conditions. Simultaneously, some collectors may cause environmental pollution during their preparation, failing to meet environmental protection requirements. Summary of the Invention This disclosure provides an anti-flotation collector, its preparation method, and its application through one or more embodiments, to improve the selectivity and adaptability of the anti-flotation collector to minerals. In a first aspect, some embodiments of this disclosure provide an anti-flotation collector having the chemical structural formula shown in formula (I): Equation (I) In formula (Ⅰ), R1 and / or R2 include at least one of the following functional groups: -CN3H4 functional group, -SO3H functional group. Secondly, some embodiments of this disclosure provide a method for preparing the anti-flotation collector as described in any embodiment of the first aspect, comprising: Provide diamine compounds; and Introducing the -CN3H4 functional group and / or the -SO3H functional group into the diamine compound yields an anti-flotation collector. Thirdly, some embodiments of this disclosure provide a method for desilication of bauxite by reverse flotation, including: pH adjustment of bauxite slurry; and An inhibitor and the reverse flotation collector described in any one of the embodiments of the first aspect are added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. Attached Figure Description The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort. Figure 1 shows a schematic flowchart of a method for preparing an anti-flotation collector according to some embodiments of the present disclosure. Figure 2 shows a schematic flowchart of a bauxite reverse flotation desilication method according to some embodiments of the present disclosure. Figure 3 shows a test flow chart of a bauxite reverse flotation desilication method according to some embodiments of the present disclosure, consisting of "one roughing, one cleaning and one scavenging". Figure 4 shows a test flow chart of a bauxite reverse flotation desilication method provided according to some embodiments of the present disclosure, consisting of "one roughing, two cleaning and one scavenging". Embodiments of the present invention To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Various embodiments of this disclosure may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this disclosure; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range. In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the orientation in the accompanying drawings. Furthermore, in the description of this disclosure, terms such as "comprising" and "including" mean "including but not limited to". In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0001] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this disclosure are available on the market or can be prepared by existing methods. In a first aspect, embodiments of this disclosure provide an anti-flotation collector having the chemical structural formula shown in formula (I): Equation (Ⅰ); In formula (Ⅰ), R1 and / or R2 include at least one of the following functional groups: -CN3H4 functional group, -SO3H functional group. In some embodiments of this disclosure, addressing the problems of poor selectivity and poor adaptability of existing bauxite reverse flotation collectors, a design concept for a reverse flotation collector is proposed by conducting mineral analysis on bauxite, examining its mineral composition, the charged properties of minerals in the slurry, and the characteristics of mineral cleavage surfaces. By introducing an amino group (-NH2) into a monoamine compound, a diamine compound is obtained; furthermore, guanidinium (-CN3H4) and / or sulfonic acid (-SO3H) functional groups are introduced into the diamine compound to obtain a novel diamine-based reverse flotation collector containing guanidinium and / or sulfonic acid groups. Compared to monoamine compounds, this novel diamine-based reverse flotation collector, due to the presence of two amino groups in its molecular structure, can provide more active sites to interact with the surface of silicate minerals in bauxite, thereby enhancing the collector's collecting ability. During flotation, the collector needs to form a stable adsorption layer on the surface of silicate minerals. This novel diamine-based reverse flotation collector has more active sites, and since the surface of silicate minerals also has corresponding active sites, the collector can interact more effectively with the surface of silicate minerals, thereby improving the collection efficiency. In addition, by introducing specific functional groups, such as -CN3H4 and / or -SO3H functional groups, this novel diamine-based reverse flotation collector can enhance the collector's collection ability, selectivity, and adaptability. The introduction of diamine groups and -CN3H4 functional groups in this novel diamine-based reverse flotation collector enhances the mutual adsorption between the collector and the hydroxyl, silicon, and oxygen groups on the surface of silicate minerals, which serve as corresponding active sites, thereby improving the selectivity of the reverse flotation collector for silicate minerals. The introduction of -SO3H functional groups reduces the interaction between the collector and metal ions in hard water, improving the collector's hard water resistance and adaptability. Simultaneously, after the novel diamine-based reverse flotation collector adsorbs onto the surface of silicate minerals, the nonpolar hydrocarbon macromolecular chains in R1 and / or R2 enhance the hydrophobicity of the silicate mineral surface, further improving the collector's ability to collect silicate minerals. Compared with conventional monoamines (such as aliphatic amines and alkylamines) and pyridine-based reverse flotation collectors, the novel diamine-based reverse flotation collector provided in this disclosure has the advantages of high selectivity, low collector dosage, and strong adaptability. Therefore, this disclosure improves the adaptability and synergistic effect of the collector through the design and optimization of functional groups. The novel diamine-based anti-flotation collector provided in this disclosure contains two amine groups, -NH- and -NH2, in its molecular structure. These two amine groups can interact with the surface of silicate minerals, thereby providing more active sites for the anti-flotation collector. These active sites act like "connection points," interacting with specific regions (corresponding active sites) on the surface of silicate minerals, increasing the chances of the anti-flotation collector contacting and reacting with the silicate minerals, thus improving the selectivity of the anti-flotation collector. -NH- and -NH2 can generate strong physical adsorption with the surface of silicate minerals based on intermolecular forces, especially electrostatic adsorption based on van der Waals forces and the lone pair electrons of the nitrogen atom in the amine group, which generates adsorption with specific regions (corresponding active sites) or partially positively charged regions on the surface of silicate minerals. The presence of these two amine groups further enhances the physical adsorption effect on the surface of silicate minerals. Furthermore, since the two amine groups can simultaneously interact with different corresponding active sites on the surface of silicate minerals, the adsorption between the flotation agent and the silicate minerals is more robust and covers a wider range. With enhanced physical adsorption, the surface properties of silicate minerals change, increasing their hydrophobicity. During reverse flotation, silicate minerals with good hydrophobicity are more likely to adhere to air bubbles, thus separating from the slurry by means of bubble buoyancy. This directly enhances the collecting capacity of the reverse flotation collector. The nitrogen atom in the -CN3H4 functional group has a higher electronegativity, making it more attractive to electrons in covalent bonds than carbon or hydrogen atoms. This results in a relatively high electron cloud density around the nitrogen atom, giving it partial electronegativity. Under specific acid-base conditions, the nitrogen atom in the guanidinium group (which contains a lone pair of electrons, making it easier to bind to protons H)... + Collectors can accept hydrogen ions through a protonation reaction, allowing the entire collector molecule to exist in cationic form. When silicate minerals (such as quartz and kaolinite) in bauxite come into contact with the slurry solution, the surface hydroxyl groups dissociate and become negatively charged. Therefore, according to the principle of electrostatic attraction between opposite charges, an electrostatic attraction exists between the positively charged reverse flotation collector (which exists in cationic form due to the interaction between the -CN3H4 functional group and the proton) and the negatively charged silicate mineral surface. This electrostatic attraction brings the collector and silicate mineral closer, making them more likely to interact and thus enhancing the interaction between the reverse flotation collector and silicate minerals. For example, in a slurry system, this attraction can guide the collector to preferentially move towards and attach to silicate minerals. Therefore, among many minerals, reverse flotation collectors have a stronger tendency to "capture" silicate minerals. The -SO3H functional group is acidic. When in contact with the surface of silicate minerals, it can form ionic bonds with some ions or corresponding active sites on the silicate mineral surface through chemical reactions such as proton loss. Ionic bonds are a strong chemical bond, and compared with physical adsorption, they can more firmly connect the collector to the silicate mineral surface, thus significantly enhancing the interaction between the reverse flotation collector and the silicate mineral surface. The -SO3H functional group maintains good solubility and dispersibility in water. Good solubility ensures that the collector is uniformly dispersed in the slurry solution, allowing it to fully contact the silicate minerals and avoiding situations where the local concentration is too high or too low, which would affect the collection effect. Good dispersibility also prevents the collector from agglomerating, ensuring that it exists in the form of single molecules or small molecular aggregates, allowing the collector to function better. At the same time, the -SO3H functional group can reduce the influence of calcium and magnesium ions on the performance of reverse flotation collectors. Under hard water conditions, the large amounts of calcium and magnesium ions in the water easily undergo adverse chemical reactions with traditional collectors, such as forming precipitates or interfering with the normal adsorption function of the collector. In some embodiments of this disclosure, because the -SO3H functional group in the collector is strongly acidic and easily dissociates into hydrophilic sulfonate (-SO3) groups... - Furthermore, sulfonate ions can form highly soluble salts with calcium and magnesium ions in water, making it difficult for stable precipitates to form. Therefore, the -SO3H functional group, by its own characteristics, can reduce the interference of hard water ions (e.g., calcium and magnesium ions), enhance the hard water adaptability of reverse flotation collectors, and enable the collectors to exist relatively stably and work effectively in slurry environments with different water qualities, thus broadening their application range. Therefore, the -CN3H4 and -SO3H functional groups, through the aforementioned mechanisms, enhance the collecting capacity, selectivity, and adaptability of the reverse flotation collector by strengthening its interaction with silicate mineral surfaces, improving adsorption capacity, enhancing selectivity, and improving adaptability to different water qualities. Ultimately, this achieves the important goal of improving the selectivity of the reverse flotation collector for silicate minerals, enabling it to more accurately separate target minerals (alumina minerals) from impurity minerals (silicate minerals) in the reverse flotation process. This is of great significance for improving the quality and efficiency of mineral processing. In some embodiments, R1 has 2 to 10 carbon atoms; and / or; R2 has 2 to 5 carbon atoms. In some embodiments of this disclosure, R1 can have 2 to 10 carbon atoms, and R2 can have 2 to 5 carbon atoms, enabling the reverse flotation collector to have good selectivity. Adjusting the carbon number of R1 and R2 essentially controls the length of the carbon chain in the collector's molecular structure. The length of the carbon chain has a significant impact on the hydrophobic and steric effects of the collector. An appropriate carbon chain length can enhance the interaction between the collector and the silicate mineral surface, improving the flotation efficiency of the reverse flotation collector. If the carbon number of R1 is higher than 10 and the carbon number of R2 is higher than 5, the solubility of the reverse flotation collector may decrease, requiring an increase in the amount of reverse flotation collector used. Furthermore, it may increase the interaction between collector molecules, reducing the collector's adsorption capacity on the silicate mineral surface, thereby weakening the flotation effect. If the carbon number of R1 is lower than 2 and the carbon number of R2 is lower than 2, the hydrophobic effect of the collector may be insufficient, reducing the collector's adsorption capacity on the silicate mineral surface, thereby reducing the flotation efficiency. For example, the number of carbon atoms in R1 can be 2, 4, 5, 6, 7, 8, 9, 10, etc.; the number of carbon atoms in R2 can be 2, 4, 5, etc. In some embodiments, the reverse flotation collector includes at least one of the following: N-decanesulfonic acid ethylenediamine, N-methylguanidinopentanediamine, N-butyl-2-sulfono-1,3-propanediamine, N-hexyl-3-guanidino-1,5-pentanediamine, N-(2-sulfono)propylpropanediamine, and N-ethylguanidino-2-sulfonopropanediamine.

[0002] In some embodiments of this disclosure, the reverse flotation collector may be N-decanesulfonic acid ethylenediamine (N-decanesulfonic acid ethylenediamine) ), N-methylguanidinopentanediamine ( ), N-butyl-2-sulfonyl-1,3-propanediamine ( ), N-hexyl-3-guanidino-1,5-pentanediamine ( ), N-(2-sulfonyl)propylpropanediamine ( ), N-ethylguanidino-2-sulfonic acid propanediamine ( One or more combinations of ) The use of the above-mentioned reverse flotation collector can achieve positive results in improving flotation desilication efficiency and selectivity, enhancing hard water adaptability, increasing the aluminum-silicon ratio of concentrate, reducing reagent dosage, and improving resource utilization. Secondly, embodiments of this disclosure provide a method for preparing an anti-flotation collector according to any one of the first aspects. Figure 1 is a schematic flowchart of a method for preparing an anti-flotation collector according to an embodiment of this disclosure. Referring to Figure 1, the method for preparing the anti-flotation collector includes: S1, providing a diamine compound; and S2. Introduce the -CN3H4 functional group and / or the -SO3H functional group into the diamine compound to obtain the reverse flotation collector. In some embodiments, the diamine compound includes at least one of the following: ethylenediamine, pentanediamine, and propylenediamine. In some embodiments, a diamine compound is provided, comprising: Introducing the -NH2 functional group into a monoamine compound yields a diamine compound. In some embodiments, the monoamine compound includes at least one of the following: ethanolamine, dimethylamine, n-propylamine, isopropylamine, n-pentylamine, and isopentylamine. In some embodiments of this disclosure, a diamine compound is synthesized from a monoamine compound, which can increase the collecting capacity of the reverse flotation collector. Furthermore, by introducing different functional groups—CN3H4 and / or SO3H—into the diamine compound, the selectivity and adaptability of the reverse flotation collector can be further improved. The diamine compound can be one or more combinations of ethylenediamine, pentanediamine, and propylenediamine; the monoamine compound can be one or more combinations of ethanolamine, dimethylamine, n-propylamine, isopropylamine, n-pentylamine, and isopentylamine. An exemplary method for preparing N-decanesulfonic acid ethylenediamine includes: first, dehydrogenating ethanolamine under the action of a catalyst to generate an aldehyde, and then reacting the aldehyde with ammonia to undergo a dehydration reaction to obtain ethylenediamine; and then reacting the ethylenediamine with 11-oxodecane-1-sulfonic acid to undergo an aldehyde condensation reaction to obtain N-decanesulfonic acid ethylenediamine. The preparation method of the reverse flotation collector is based on the above-mentioned reverse flotation collector. Therefore, the structure of the reverse flotation collector can be referred to the above embodiments. Since the preparation method of the reverse flotation collector has all the technical features of some of the above embodiments, it has at least all the beneficial effects brought about by some of the above embodiments, and will not be described in detail here. Thirdly, embodiments of this disclosure provide a method for desilication of bauxite via reverse flotation. Figure 2 shows a schematic flow diagram of a method for desilication of bauxite via reverse flotation according to some embodiments of this disclosure. Referring to Figure 2, the method for desilication of bauxite via reverse flotation includes: S1', Adjusting the pH of the bauxite slurry; and S2'. An inhibitor and a reverse flotation collector from any one of the embodiments of the first aspect are added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. In some implementations, the weight percentage of particles with a size <0.074 mm in the bauxite slurry is ≥75.0% based on the dry weight of the bauxite. In some embodiments of this disclosure, the aforementioned reverse flotation collector is applied in a method for desilication of bauxite via reverse flotation. The resulting desilication slurry can be separated to obtain flotation concentrate and flotation tailings. In bauxite slurry, the weight percentage of particles <0.074mm based on the dry weight of bauxite can be ≥75.0%. Since bauxite is typically an aggregate of multiple minerals, and these minerals are closely associated, grinding is necessary to liberate them. When the weight percentage of particles <0.074mm based on the dry weight of bauxite in the slurry is ≥75.0%, the silicate minerals (i.e., the silicate minerals mentioned above) in the bauxite can be better separated from aluminum-bearing minerals such as gibbsite. This allows for more complete liberation of individual minerals in the bauxite, enabling the reverse flotation collector to more accurately adsorb onto the surface of the silicate minerals. This facilitates the targeted action of the reverse flotation collector on the silicate minerals and their flotation, thereby improving the grade of the resulting flotation concentrate (aluminum concentrate). Meanwhile, when the proportion of fine particles <0.074mm in the bauxite slurry is high, the specific surface area of ​​the silica-containing minerals can be increased. This significantly increases the contact opportunities between the silica-containing minerals and the reverse flotation collector, and exposes more of the corresponding active sites of the silica-containing minerals. This promotes more effective adsorption between the silica-containing minerals and the active sites of the flotation agent, thereby enhancing the flotation effect. For example, in this bauxite slurry, based on the weight of the dry bauxite, the weight percentage of particles <0.074mm can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, etc. In some implementations, the endpoint pH for pH adjustment is 4–10; and / or, The amount of inhibitor added is 20 g / t dry ore to 100 g / t dry ore; and / or, The temperature for reverse flotation desilication is 15℃~50℃; and / or, The amount of reverse flotation collector added is 300.0 g / t slurry to 800.0 g / t slurry. In some embodiments of this disclosure, the endpoint pH for pH adjustment can be 4-10. In bauxite slurry, the electrical properties of aluminum-bearing minerals such as gibbsite and silicon-bearing minerals differ significantly. Silicon-bearing minerals typically carry a strong negative charge, while aluminum-bearing minerals such as gibbsite have a higher isoelectric point, resulting in weaker negative charge or near-neutral charge on their surfaces under flotation pH conditions. Since reverse flotation collectors are mostly cationic, they are more easily adsorbed onto the negatively charged surface of silicon-bearing minerals, facilitating selective flotation and thus separating the silicon-bearing minerals. Simultaneously, within this endpoint pH range, the reverse flotation collector exhibits good stability and activity, maintaining an appropriate degree of ionization and more readily interacting with the surface of silicon-bearing minerals. If the endpoint pH is higher than 10 or lower than 4, the reverse flotation collector may undergo hydrolysis, precipitation, or lose activity, thereby affecting the flotation effect. For example, the endpoint pH for pH adjustment can be 4, 5, 6, 7, 8, 9, 10, etc. In some embodiments, the amount of inhibitor added can be 20 g / t dry ore to 100 g / t dry ore. During bauxite reverse flotation desilication, the inhibitor's role is to cover or alter the properties of corresponding active sites on the surface of aluminum-bearing minerals, thereby reducing their interaction with the reverse flotation collector and preventing them from floating along with the silica-bearing minerals. If the amount of inhibitor added is less than 20 g / t dry ore, it may be difficult to completely inhibit the corresponding active sites on the surface of aluminum-bearing minerals, causing the aluminum-bearing minerals to mix into the froth product with the flotation agent, reducing the grade of the bauxite concentrate. If the amount of inhibitor added is greater than 100 g / t dry ore, over-inhibition may occur, not only inhibiting aluminum-bearing minerals that do not need to float but also potentially inhibiting silica-bearing minerals that do need to float, affecting the flotation effect. For example, the amount of the inhibitor added can be 20 g / t dry ore, 30 g / t dry ore, 40 g / t dry ore, 50 g / t dry ore, 60 g / t dry ore, 70 g / t dry ore, 80 g / t dry ore, 90 g / t dry ore, 100 g / t dry ore, etc. The inhibitor can be one or a combination of several of sodium hexametaphosphate, starch, dextrin, and cationic polyacrylamide. In some embodiments, the temperature for reverse flotation desilication can be between 15°C and 50°C. Within this temperature range, the solubility and selectivity of the collector are improved, while also exhibiting strong adaptability. If the reverse flotation desilication temperature is below 15°C, the solubility of the collector may decrease, requiring an increase in the amount of collector used; if the temperature is above 50°C, the stability and selectivity of the collector may be affected, leading to a decrease in flotation efficiency. For example, the reverse flotation desilication temperature can be 15°C, 18°C, 20°C, 23°C, 25°C, 28°C, 30°C, 33°C, 35°C, 38°C, 40°C, 43°C, 45°C, 48°C, or 50°C. In some embodiments, the amount of reverse flotation collector added can be 300.0 g / t pulp to 800.0 g / t pulp. That is, 300.0 g to 800 g of reverse flotation collector is added to each ton of bauxite pulp. At this amount, a high bauxite recovery rate can be obtained while ensuring a relatively good bauxite grade, effectively flotating gangue minerals in bauxite, and ensuring the grade and aluminum-silicon ratio of the final flotation concentrate (bauxite concentrate). For example, the amount of reverse flotation collector added can be 300.0 g / t pulp, 350 g / t pulp, 400 g / t pulp, 450 g / t pulp, 500 g / t pulp, 550 g / t pulp, 600 g / t pulp, 650 g / t pulp, 700 g / t pulp, 750 g / t pulp, 800 g / t pulp, etc. The method for desilication of bauxite by reverse flotation is based on the aforementioned reverse flotation collector. The specific structure of the reverse flotation collector can be referred to in the above embodiments. Since the method for desilication of bauxite by reverse flotation adopts some or all of the technical solutions in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments, which will not be elaborated here. The present disclosure is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the disclosure. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed. Example 1 In this embodiment, the flotation desilication collector is N-butyl-2-sulfono-1,3-propanediamine. The preparation method of N-butyl-2-sulfonic acid-1,3-propanediamine includes: reacting acrylonitrile with ammonia to prepare 3-aminopropionitrile; then catalytically hydrogenating the prepared 3-aminopropionitrile to obtain 1,3-propanediamine; under alkaline conditions, performing a ring-opening reaction between 1,3-propanediamine and butyl sulfonyl lactone to obtain an N-butylsulfonyl-protected 1,3-propanediamine intermediate; and then removing the protecting group of the 1,3-propanediamine intermediate by hydrolysis to obtain N-butyl-2-sulfonic acid-1,3-propanediamine. The bauxite reverse flotation desilication method of this embodiment includes: pH adjustment of bauxite slurry; and Inhibitors and reverse flotation collectors were added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. The above-mentioned method for desilication of bauxite by reverse flotation includes the following steps: grinding bauxite ore with an Al2O3 content of 50.34% and an aluminum-silicon ratio of 4.37 to obtain a bauxite slurry, wherein the test water is tap water, and the weight percentage of particles with a grinding fineness of -0.074 mm is 75.07%; then, under the condition of reverse flotation temperature of 30℃, adding Na2CO3 to the bauxite slurry to adjust the pH value of the bauxite slurry to 9.0; subsequently, adding... After H-adjustment, sodium hexametaphosphate (100 g / t dry ore) and N-butyl-2-sulfono-1,3-propanediamine (350 g / t slurry) were added sequentially to the bauxite slurry. The bauxite reverse flotation desilication method provided in this embodiment of the present disclosure was tested using the "one roughing, one cleaning and one scavenging" test process shown in Figure 3 to obtain a desilication slurry. The desilication slurry was then separated to obtain flotation concentrate (i.e., aluminum concentrate) and tailings. Example 2 In this embodiment, the flotation desilication collector is N-decanesulfonic acid ethylenediamine and N-methylguanidine pentanediamine, and the weight ratio of N-decanesulfonic acid ethylenediamine and N-methylguanidine pentanediamine is 1:1. The preparation method of N-decanesulfonic acid ethylenediamine includes: first, dehydrogenating ethanolamine under the action of a catalyst to generate aldehyde; then, dehydrating the generated aldehyde with ammonia to obtain ethylenediamine; and then reacting ethylenediamine with 11-oxodecane-1-sulfonic acid in an aldehyde condensation reaction to obtain N-decanesulfonic acid ethylenediamine. The preparation method of N-methylguanidinopentanediamine includes: coupling an appropriate amount of monopentanediamine and a catalyst (hydrochloric acid / sulfuric acid) to obtain pentamethylenediamine; mixing pentamethylenediamine with a guanidinizing agent (such as methylguanidine) and adding a catalyst to carry out a chemical reaction; after the reaction is completed, purifying the reaction product to obtain N-methylguanidinopentanediamine. The bauxite reverse flotation desilication method of this embodiment includes: pH adjustment of bauxite slurry; and Inhibitors and reverse flotation collectors were added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. The above-mentioned method for desilication of bauxite by reverse flotation includes the following steps: A certain bauxite ore with an Al2O3 content of 31.57% and an aluminum-silicon ratio of 3.26 is ground to obtain a bauxite slurry. The test water is tap water, and the weight percentage of particles with a grinding fineness of -0.074 mm is 62.13%. Then, under a reverse flotation temperature of 15℃, hydrochloric acid is added to the bauxite slurry to adjust its pH value to 9.0. Subsequently, the pH-adjusted bauxite slurry is further... The inhibitor cationic polyacrylamide (85 g / t dry ore) and the reverse flotation desilication collectors N-decanesulfonic acid ethylenediamine and N-methylguanidine pentanediamine (mass ratio 1:1, total addition amount 800 g / t slurry) were added sequentially. The test was conducted using the "one roughing, two cleaning and one scavenging" test flow of the bauxite reverse flotation desilication method provided in the embodiment of this disclosure, as shown in Figure 4, to obtain the desilication slurry. The desilication slurry was then separated to obtain the flotation concentrate (i.e., aluminum concentrate) and tailings. Example 3 In this embodiment, the flotation desilication collector is N-hexyl-3-guanidino-1,5-pentanediamine. The preparation method of N-hexyl-3-guanidino-1,5-pentanediamine includes: alkylating 1-aminopentane and a 1-chlorohexane hexylating agent (such as a hexyl halide) under alkaline conditions to obtain N-hexyl monoamine; converting the N-hexyl monoamine into N-hexyl-1,5-pentanediamine through a coupling reaction; reacting the N-hexyl-1,5-pentanediamine with cyanamide to generate an intermediate containing a guanidino group; and then modifying the intermediate containing the guanidino group as necessary, such as adjusting the substitution position, to obtain N-hexyl-3-guanidino-1,5-pentanediamine. The bauxite reverse flotation desilication method of this embodiment includes: pH adjustment of bauxite slurry; and Inhibitors and reverse flotation collectors were added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. The above-mentioned method for desilication of bauxite by reverse flotation includes the following steps: grinding bauxite ore with an Al2O3 content of 44.59% and an aluminum-silicon ratio of 4.58 to obtain a bauxite slurry, wherein the test water is tap water, and the weight percentage of particles with a grinding fineness of -0.074 mm is 95.83%; then, under a reverse flotation temperature of 50℃, adding hydrochloric acid to the bauxite slurry to adjust the pH value of the bauxite slurry to 4; subsequently, adding hydrochloric acid to the p... After H-adjustment, dextrin (65 g / t dry ore) and N-hexyl-3-guanidino-1,5-pentanediamine (500 g / t slurry) were added sequentially to the bauxite slurry. The bauxite reverse flotation desilication method provided in this embodiment of the present disclosure was tested using the "one roughing, two cleaning and one scavenging" test process shown in Figure 4 to obtain a desilication slurry. The desilication slurry was then separated to obtain flotation concentrate (i.e., aluminum concentrate) and tailings. Example 4 In this embodiment, the flotation desilication collector is N-hexyl-3-guanidino-1,5-pentanediamine and N-(2-sulfonyl)propylpropanediamine, and the weight ratio of N-hexyl-3-guanidino-1,5-pentanediamine to N-(2-sulfonyl)propylpropanediamine is 2:1. The preparation method of N-(2-sulfonyl)propylpropanediamine includes: subjecting N-methylpropylamine to a reductive amination reaction with formaldehyde or acetone to obtain N,N-dimethyl-1,3-propanediamine; subjecting N,N-dimethyl-1,3-propanediamine to a sulfonating reaction with a sulfonating agent (e.g., concentrated sulfuric acid, chlorosulfonic acid) to introduce a sulfonate group into a specific position in the N,N-dimethyl-1,3-propanediamine molecule to obtain N-(2-sulfonyl)propylpropanediamine. The bauxite reverse flotation desilication method of this embodiment includes: pH adjustment of bauxite slurry; and Inhibitors and reverse flotation collectors were added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. The above-mentioned method for desilication of bauxite by reverse flotation includes the following steps: Bauxite ore with an Al2O3 content of 37.92% and an aluminum-silicon ratio of 3.47 is ground to obtain a bauxite slurry. The test water is tap water, and the weight percentage of particles with a grinding fineness of -0.074 mm is 82.76%. Then, under a reverse flotation temperature of 45℃, NaOH is added to the bauxite slurry to adjust its pH to 7.5. Subsequently, the inhibitor hexametaphosphate is added sequentially to the pH-adjusted bauxite slurry. Sodium sulfate and starch (mass ratio 1:1, total addition amount 20g / t dry ore) were added to the reverse flotation desilication collectors N-hexyl-3-guanidino-1,5-pentanediamine and N-(2-sulfonyl)propylpropylenediamine (mass ratio 2:1, total addition amount 300g / t slurry). The experiment was conducted using the "one roughing, one cleaning and one scavenging" test flow of the bauxite reverse flotation desilication method provided in the embodiment of this disclosure, as shown in Figure 3, to obtain a desilication slurry. The desilication slurry was then separated to obtain flotation concentrate (i.e., aluminum concentrate) and tailings. Example 5 In this embodiment, the flotation desilication collector is N-ethylguanidino-2-sulfonic acid propanediamine. The preparation method of N-ethylguanidino-2-sulfonic acid propanediamine includes: reductive amination reaction of ethylamine with acrolein in the presence of a catalyst to obtain N-ethyl-1,3-propanediamine; sulfonation reaction of N-ethyl-1,3-propanediamine with chlorosulfonic acid to obtain N-ethyl-2-sulfonic acid propanediamine; chemical reaction of N-ethyl-2-sulfonic acid propanediamine with cyanamide to introduce a guanidino group at a specific position in the N-ethyl-2-sulfonic acid propanediamine molecule; and purification of the reaction product after the reaction to obtain N-ethylguanidino-2-sulfonic acid propanediamine. The bauxite reverse flotation desilication method of this embodiment includes: pH adjustment of bauxite slurry; and Inhibitors and reverse flotation collectors were added sequentially to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry. The above-mentioned method for desilication of bauxite by reverse flotation includes the following steps: Bauxite ore with an Al2O3 content of 53.35% and an aluminum-silicon ratio of 4.61 is ground to obtain a bauxite slurry. The test water is tap water, and the weight percentage of particles with a grinding fineness of -0.074 mm is 86.49%. Then, under a reverse flotation temperature of 20℃, Na2CO3 and NaOH (weight ratio 1:1) are added to the bauxite slurry to adjust the pH value of the slurry. Up to 10; then, the inhibitor starch (addition amount of 50g / t dry ore) and the reverse flotation desilication collector N-ethylguanidino-2-sulfonic acid propanediamine (addition amount of 650g / t slurry) are added sequentially to the bauxite slurry after pH adjustment, and the test is carried out using the "one roughing, one cleaning and one scavenging" test process of the bauxite reverse flotation desilication method provided in the embodiment of this disclosure shown in Figure 3 to obtain the desilication slurry; the desilication slurry is separated to obtain the flotation concentrate (i.e., aluminum concentrate) and tailings. Comparative Example 1 The bauxite reverse flotation desilication method of this embodiment includes: Bauxite ore with an Al2O3 content of 53.35% and an aluminum-silicon ratio of 4.61 was ground to obtain a bauxite slurry, using deionized water in the experiment. Reverse flotation desilication was then performed using a method for preparing a bauxite reverse flotation collector, as described in Chinese invention patent application CN102407189B, to obtain a flotation concentrate (i.e., aluminum concentrate) and tailings. The resulting flotation concentrate had an aluminum-silicon ratio of 7.21, corresponding to an alumina recovery rate of 80.54%, while the tailings had an aluminum-silicon ratio of 1.48. Comparative Example 2 The bauxite reverse flotation desilication method of this embodiment includes: Bauxite ore with an Al2O3 content of 53.35% and an aluminum-silicon ratio of 4.61 was ground to obtain a bauxite slurry, using deionized water in the experiment. Reverse flotation desilication was then performed using the reverse flotation collector and flotation method described in Chinese invention patent application CN107350084B (titled "A Triquaternary Ammonium Salt Compound for Mineral Flotation") to obtain a flotation concentrate (i.e., aluminum concentrate) and tailings. The resulting flotation concentrate had an aluminum-silicon ratio of 6.89, corresponding to an alumina recovery rate of 76.38%, while the tailings had an aluminum-silicon ratio of 1.54. The test results of the bauxite reverse flotation desilication method provided in Examples 1-5 and Comparative Examples 1-2 are shown in Table 1 below. Table 1. Experimental results of the reverse flotation desilication method for bauxite. As shown in Table 1, the collector and reverse flotation method provided in this disclosure can achieve an alumina recovery rate of ≥85% and an aluminum-silicon ratio of ≤1.30 in the tailings. A comparison of the data from Comparative Examples 1 and 2 and Examples 1-5 shows that the collector provided in this disclosure can achieve good flotation results at lower dosages, and the collector has strong adaptability to hard water. The technical solutions provided in this disclosure have the following advantages compared with the prior art: The reverse flotation collector provided in this embodiment has the chemical structural formula shown in formula (Ⅰ): Formula (I). The molecular structure of this reverse flotation collector contains two amine groups, which can provide more active sites to interact with the surface of silicate minerals. Both the -NH- and -NH2 amine groups can form strong physical adsorption with the surface of silicate minerals, and the two amine groups are more likely to form physical adsorption with the surface of silicate minerals and the adsorption effect is stronger. Due to the strong physical adsorption of amine groups with the surface of silicate minerals, the properties of the surface of silicate minerals are changed, and the hydrophobicity of silicate minerals increases. In the reverse flotation process, silicate minerals with good hydrophobicity are more likely to adhere to the bubbles, thereby separating from the pulp by means of bubble buoyancy, thus enhancing the collecting ability of the reverse flotation collector. R1 and / or R2 include at least one of the following functional groups: -CN3H4 functional group, -SO3H functional group. Due to the high electronegativity of the nitrogen atom in the -CN3H4 functional group, the attraction of electrons to the covalent bond is stronger than that of carbon and hydrogen atoms, resulting in a relatively high electron cloud density around the nitrogen atom, exhibiting partial electronegativity. Under specific acidic or alkaline conditions, the nitrogen atom in the guanidinium group can accept hydrogen ions through a protonation reaction, causing the entire collector molecule to exist in cationic form. When the silicate mineral surface in bauxite comes into contact with the slurry solution, the surface hydroxyl groups dissociate and become negatively charged. Therefore, according to the principle of attraction between opposite charges in electrostatics, there is an electrostatic attraction between the positively charged reverse flotation collector (which exists in cationic form due to the interaction between the -CN3H4 functional group and the proton) and the negatively charged silicate mineral surface. This electrostatic attraction can bring the collector and silicate mineral closer, making them more likely to approach and interact, thereby enhancing the interaction between the reverse flotation collector and the silicate mineral. The acidity of the -SO3H functional group allows it to form ionic bonds on the silicate mineral surface, enhancing the interaction between the reverse flotation collector and the silicate mineral surface, thus improving the adsorption capacity and selectivity of the reverse flotation collector. Meanwhile, the -SO3H functional group maintains good solubility and dispersibility in water, which can reduce the impact of calcium and magnesium ions on the performance of the reverse flotation collector and enhance its hard water adaptability. Therefore, the -CN3H4 and / or -SO3H functional groups can enhance the collecting capacity, selectivity, and adaptability of this reverse flotation collector. In summary, this improves the selectivity and adaptability of the reverse flotation collector to minerals. One or more technical solutions in the embodiments of this disclosure have at least the following technical effects or advantages. (1) The reverse flotation collector provided in this embodiment is obtained by introducing -NH into a monoamine compound to obtain a diamine compound, and then introducing -CN3H4 and -SO3H functional groups to obtain a novel guanidine (sulfonic acid) diamine reverse flotation collector. The introduction of the diamine group and -CN3H4 functional group in the reverse flotation collector provided in this embodiment enhances the interaction with hydroxyl, silicon, oxygen and other groups on the surface of silicate minerals, thereby improving the selectivity of the reverse flotation collector. The introduction of the -SO3H functional group reduces the interaction with metal ions in hard water, improves the hard water resistance, and enhances the adaptability of the collector in hard water. At the same time, after the collector is adsorbed on the surface of silicate minerals, the hydrocarbon nonpolar macromolecular chains in R1 and / or R2 can enhance the hydrophobicity of the silicate mineral surface and improve the collecting ability of the reverse flotation collector. (2) Compared with conventional monoamine (such as fatty amines, alkylamines) and pyridine anti-flotation collectors, the anti-flotation collectors provided in this embodiment have the advantages of high selectivity, low collector dosage and strong adaptability. (3) The reverse flotation collector provided in this embodiment, combined with the optimized reverse flotation desilication method, can achieve an alumina recovery rate of ≥85% and an aluminum-silicon ratio of ≤1.3 in the tailings.

[0003] The above are merely specific embodiments of this disclosure, enabling those skilled in the art to understand or implement this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A reverse flotation collector having the chemical structural formula shown in formula (Ⅰ): Equation (Ⅰ); In formula (Ⅰ), R1 and / or R2 include at least one of the following functional groups: -CN3H4 functional group, -SO3H functional group.

2. The reverse flotation collector according to claim 1, wherein, The number of carbon atoms in R1 is 2 to 10; and / or; The number of carbon atoms in R2 is 2 to 5.

3. The reverse flotation collector according to claim 1 or 2, wherein, The reverse flotation collector includes at least one of the following: N-decanesulfonic acid ethylenediamine, N-methylguanidinopentanediamine, N-butyl-2-sulfonic acid-1,3-propanediamine, N-hexyl-3-guanidino-1,5-pentanediamine, N-(2-sulfonic acid)propylpropanediamine, and N-ethylguanidino-2-sulfonic acid-propanediamine.

4. A method for preparing the reverse flotation collector according to any one of claims 1 to 3, comprising: Provides diamine compounds; and Introducing the -CN3H4 functional group and / or the -SO3H functional group into the diamine compound yields an anti-flotation collector.

5. The method according to claim 4, wherein, The diamine compound includes at least one of the following: ethylenediamine, pentanediamine, and propylenediamine.

6. The method according to claim 4 or 5, wherein, The provision of the diamine compound includes: Introducing the -NH2 functional group into a monoamine compound yields a diamine compound.

7. The method according to claim 6, wherein, The monoamine compound includes at least one of the following: ethanolamine, dimethylamine, n-propylamine, isopropylamine, n-pentylamine, and isopentylamine.

8. A method for desilication of bauxite by reverse flotation, comprising: pH adjustment of bauxite slurry; and An inhibitor and the reverse flotation collector according to any one of claims 1 to 3 are sequentially added to the pH-adjusted bauxite slurry to perform reverse flotation desilication and obtain a desilication slurry.

9. The method according to claim 8, wherein, In the bauxite slurry, based on the dry weight of bauxite, the weight percentage of particles with a particle size <0.074mm is ≥75.0%.

10. The method according to claim 8 or 9, wherein, The endpoint pH adjustment is 4-10; and / or, The amount of the inhibitor added is 20g / t dry ore to 100g / t dry ore; And / or, The temperature for the reverse flotation desilication is 15℃~50℃; and / or, The amount of the reverse flotation collector added is 300.0 g / t slurry to 800.0 g / t slurry.

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