A hydroxamic acid-quaternary ammonium salt ionic liquid collector, a preparation method and application thereof

Abstract

The application discloses a hydroxamic acid-quaternary ammonium salt ionic liquid collector and a preparation method and application thereof. The structural formula of the hydroxamic acid-quaternary ammonium salt ionic liquid collector is shown as formula (I): (I). The hydroxamic acid-quaternary ammonium salt ionic liquid collector has good collecting property and selectivity to rare earth ores compared with traditional salicylhydroxamic acid collectors, and can still achieve good collecting effect without adding a foaming agent, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing reagents technology, and particularly relates to a hydroxamic acid-quaternary ammonium salt ionic liquid collector, its preparation method and application. Background Technology

[0002] Rare earth elements, hailed as "industrial vitamins," are strategic elements for developing high-tech industries and are widely used in electronics, petrochemicals, metallurgy, machinery, energy, light industry, environmental protection, agriculture, and defense. Baustenite is currently the most important mineral source for extracting rare earth elements, and flotation is the primary method for enriching and recovering basteneite industrially. Common collectors used for flotation of rare earth minerals include carboxylates (fatty acids), isohydroxyoxime esters, and some organophosphates. However, because basteneite has similar surface properties and floatability to calcium-containing minerals such as fluorite, rare earth ore flotation separation faces challenges such as low selectivity and sensitivity to impurity ions.

[0003] Ionic liquids are liquid molten salt systems composed entirely of organic positive ions and organic or inorganic anions at room temperature or near room temperature. They are known as green solvents due to their low melting point, high boiling point, good solubility, high thermal and chemical stability, near non-volatility, and low toxicity.

[0004] Due to their characteristics such as high design capability, low vapor pressure, non-flammability, and near-non-volatility, ionic liquids can be synthesized to meet specific needs. Ionic liquids have a wide range of applications, rapidly expanding from their initial use in green chemistry and chemical engineering to functional materials and energy fields; however, their application in flotation is currently limited. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a hydroxamic acid-quaternary ammonium salt ionic liquid collector, its preparation method, and its application, thereby solving the technical problems of low collection and selectivity of traditional flotation reagents for rare earth ore flotation separation.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a hydroxamic acid-quaternary ammonium salt ionic liquid collector, the structural formula of which is shown in formula (I):

[0008] (I).

[0009] This invention also provides a method for preparing a hydroxamic acid-quaternary ammonium salt ionic liquid collector, comprising the following steps:

[0010] S1. Salicylic acid hydroxamic acid salt and tetrabutylammonium halide are mixed in a solvent to obtain a first mixture;

[0011] S2. The first mixture is mechanically mixed at 20-30°C to obtain the second mixture;

[0012] S3. Perform solid-liquid separation on the second mixture to obtain a product solution;

[0013] S4. Remove the solvent from the product solution to obtain the hydroxamic acid-quaternary ammonium salt ionic liquid collector.

[0014] Preferably, in step S1, the molar ratio of salicylhydroxyoxime salt to tetrabutylammonium halide is (2:3) to (3:2).

[0015] Preferably, in step S1, salicylhydroxamic acid salt is one or more of sodium salicylhydroxamic acid and potassium salicylhydroxamic acid; tetrabutylammonium halide is one or more of tetrabutylammonium chloride, tetrabutylammonium bromide and tetrabutylammonium iodide.

[0016] Preferably, in step S1, the solvent is one or more of methanol, ethanol, and propanol.

[0017] Preferably, in step S2, the mechanical mixing method is magnetic stirring, and the magnetic stirring time is 18~24h.

[0018] Preferably, in step S3, after solid-liquid separation, the precipitate is washed with a solvent, and then the filtrate and washing liquid are mixed to obtain a product solution.

[0019] Preferably, after step S4, the method further includes: S5. Vacuum drying the product obtained in step S4 to obtain a hydroxamic acid-quaternary ammonium salt ionic liquid collector; the vacuum drying temperature is 30~50℃.

[0020] The present invention also provides an application of the hydroxamic acid-quaternary ammonium salt ionic liquid collector as described above in mineral flotation.

[0021] Preferably, the above-mentioned minerals are rare earth minerals, including the useful mineral bastnaesite and the gangue mineral fluorite.

[0022] The beneficial effects of this invention are:

[0023] The hydroxamic acid-quaternary ammonium salt ionic liquid collector provided by this invention has good collection and selectivity for rare earth minerals, and can still achieve good collection effect without adding foaming agent, and the preparation process is simple and easy to operate.

[0024] The hydroxamic acid-quaternary ammonium salt ionic liquid collector provided by this invention is neutral, while salicylic acid is acidic. In comparison, the flotation process of this reagent may produce fewer harmful byproducts, which is more beneficial to subsequent wastewater treatment and environmental protection. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0026] Figure 1 This is the infrared spectrum of the tetrabutylsalicylic acid ammonium ionic liquid from Example 1. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] In a 100 mL beaker, 50 mL of deionized water was added as the reaction solvent, along with 1.54 g (0.01 mol) of salicylic acid and 1.06 g (0.01 mol) of sodium carbonate. The mixture was stirred at room temperature until completely dissolved. The water was then heated to dryness to obtain 1.706 g (0.00974 mol) of sodium salicylic acid, with a yield of 97.4%. Take another 100mL beaker, add 30mL (0.50mol) of anhydrous ethanol as the reaction solvent, and add 0.175g (0.001mol) of sodium salicylic acid hydroxamic acid and 0.278g (0.001mol) of tetrabutylammonium chloride. Place the beaker in a magnetic stirrer and stir at a constant temperature (25℃) for 20 hours. The resulting reaction solution is filtered and washed with anhydrous ethanol to remove the sodium chloride generated in the reaction. After washing, the product solution is allowed to stand for 10 hours. Finally, the ethanol solvent is evaporated by heating in a water bath at 100℃. The brown liquid obtained is the target product. Then, the target product is vacuum dried in a vacuum drying oven at 50℃ to obtain tetrabutylammonium salicylic acid hydroxamic acid (TS).

[0030] The obtained product was characterized by infrared spectroscopy, such as... Figure 1 As shown. The infrared spectrum of the collector shows: 3396 cm⁻¹ -1 The peaks at 1773, 1383, and 1030 cm⁻¹ represent the stretching vibration peaks of the -OH group on the benzene ring. -1 The peaks at 1462 and 1486 cm⁻¹ represent the stretching vibrations of C=O, CN, and NO in the isohydroxamic acid group, respectively; -1 The characteristic absorption peaks of the quaternary ammonium salt of the collector are at 2962, 2875, and 1631 cm⁻¹. -1 The stretching vibration peaks of CH in -CH3 and -CH2- reflect the structural characteristics of methyl-type cationic surfactants; therefore, infrared spectroscopy confirms that the synthesized product is the target product, tetrabutylsalicylic acid ammonium ionic liquid.

[0031] The hydroxamic acid-quaternary ammonium salt ionic liquid collector prepared in Example 1 was used for the flotation of fluorocarbon cerium ore and fluorite ore, respectively. The fluorocarbon cerium ore came from the Yakuping rare earth mine in Sichuan Province, and the fluorite ore came from Hubei Province. Their chemical composition analyses are shown in Tables 1 and 2, respectively.

[0032] The salicylic acid-quaternary ammonium salt ionic liquid prepared in Example 1 was formulated with deionized water to a concentration of 25 × 10⁻⁶. -3 A solution of mol / L was prepared, and the reagent was added to a 50mL flotation cell of an XFGCⅡ5-35g laboratory aerated flotation machine according to a certain ratio, so that the reagent concentration in the flotation cell was 0.1×10 mol / L. -3 mol / L, 0.2×10 -3 mol / L, 0.3×10 -3 mol / L, 0.4×10 - 3 mol / L, 0.5×10 -3 mol / L, 0.6×10 -3 mol / L; that is, different concentrations of collector solutions were prepared in the flotation cell. 3.0 g of fluorocarbon cerium pure ore was weighed and placed in the flotation cells with different collector concentrations, maintaining a pulp concentration of 6%. The stirring speed was set to 1800 rpm for 3 minutes at room temperature (25℃). The pH was adjusted to 9 using NaOH or HCl, and the pulp was conditioned for 3 minutes at 1800 rpm. Then, frother MIBC was added, maintaining its concentration in the flotation cell at 20 mg / L. After stirring for 1 minute, flotation was performed for 4 minutes. The frothing product and the product in the cell were dried, weighed, and the recovery rate was calculated. The effect of collector concentration on the recovery rate of fluorite pure ore was obtained using the same method as above. The results are shown in Table 3. It can be seen that the mineral recovery rate increases with increasing reagent concentration. The collector concentration is 0.3 × 10⁻⁶ mol / L. -3 At a concentration of mol / L, the recovery rate of the valuable mineral bastnaesite reached over 90%. At this point, the recovery rate of bastnaesite differed from that of the gangue mineral fluorite by 36.38%. Furthermore, increasing the collector concentration did not significantly improve the recovery rate. Considering factors such as reagent economics and environmental impact, the optimal collector concentration was determined to be 0.3 × 10⁻⁶ mol / L. -3 mol / L. Subsequently, pH conditions were tested under optimal concentration conditions, with pH values ​​set at 3.5, 4.5, 6, 7.5, 9, 10.5, and 12. The recovery rates are shown in Table 4. It was found that at a concentration of 0.3 × 10⁻⁶ mol / L... -3 At a concentration of mol / L and pH = 9, the recovery rate of bastnaesite can reach 90.18%, while the recovery rate of fluorite is 53.80%. Under these conditions, flotation separation of bastnaesite and fluorite can be achieved.

[0033] Table 1. Chemical composition analysis results of fluorocarbon cerium ore (%)

[0034]

[0035] Table 2. Chemical composition analysis results of fluorite ore (%)

[0036]

[0037] Table 3. Effect of collector concentration on the recovery rate of pure minerals (mol / L)

[0038]

[0039] Table 4. Effect of pH value on the recovery rate of pure minerals (mol / L)

[0040]

[0041] The hydroxamic acid-quaternary ammonium salt ionic liquid and salicylic acid prepared in Example 1 were used for flotation of a mixed ore of bastnaesite and fluorite, respectively. Specifically:

[0042] Weigh 3.0 g of an artificial binary mineral mixture, wherein the mass ratio of bastnaesite to fluorite is 1:1. At a reagent concentration of 0.3 × 10⁻⁶... -3 At pH 9, frother MIBC was added and its concentration in the flotation cell was maintained at 20 mg / L for flotation. The grade (based on rare earth oxides REO) and recovery rate of bastnaesite were obtained, as shown in Table 5. Table 5 shows that using the collector provided by this invention to float the mixed ore resulted in a bastnaesite grade of 61.01% in the concentrate, higher than the 45.26% obtained using salicylic acid. Furthermore, the recovery rate of bastnaesite was 90.27%, also higher than the 77.03% obtained using salicylic acid. Without the use of inhibitors, the separation performance of salicylic acid was significantly inferior to that of the synthetic reagent of this invention.

[0043] Table 5 Flotation Indicators for Artificially Mixed Minerals

[0044]

[0045] Example 2

[0046] In a 100 mL beaker, 60 mL (1.00 mol) of anhydrous ethanol was used as the reaction solvent. 0.350 g (0.002 mol) of sodium salicylic acid hydroxamic acid and 0.556 g (0.002 mol) of tetrabutylammonium chloride were added. The beaker was placed in a magnetic stirrer and stirred at a constant temperature (25 °C) for 24 hours. The resulting reaction solution was filtered and washed with anhydrous ethanol to remove the sodium chloride generated in the reaction. After washing, the product solution was allowed to stand for 9 hours. Finally, the ethanol solvent was evaporated by heating in a water bath at 100 °C, and the brown liquid obtained was the target product. The target product was then vacuum dried in a vacuum drying oven at 50 °C to obtain tetrabutylammonium salicylic acid hydroxamic acid (TS).

[0047] Following the same method as in Example 1, the hydroxamic acid-quaternary ammonium salt ionic liquid collector prepared in Example 2 was used for the flotation of fluorocarbon cerium ore and fluorite ore, respectively, and the results are shown in Tables 6 and 7. As can be seen from Tables 6 and 7, the collector prepared in Example 2, with a collector concentration of 0.3 × 10⁻⁶, was suitable for mineral flotation. -3 At a concentration of mol / L, the recovery rate of the valuable mineral bastnaesite is relatively high, and the recovery rate of the valuable mineral bastnaesite differs significantly from that of the gangue mineral fluorite, at 34.92%. The optimal flotation conditions are consistent with those obtained in Example 1, with an optimal concentration of 0.3 × 10⁻⁶ mol / L. -3 mol / L, pH=9.

[0048] Table 6. Effect of collector concentration on the recovery rate of pure minerals (mol / L)

[0049]

[0050] Table 7. Effect of pH value on the recovery rate of pure minerals (mol / L)

[0051]

[0052] Meanwhile, following the same mineral processing method as in Example 1, the hydroxamic acid-quaternary ammonium salt ionic liquid collector prepared in Example 2, and salicylic acid, were used for flotation of mixed bastnaesite and fluorite ore. The flotation results are shown in Table 8. Table 8 shows that using the collector provided by this invention to flotate the mixed rare earth ore resulted in a bastnaesite grade of 59.67% in the concentrate, higher than the 46.54% obtained using salicylic acid. Furthermore, the bastnaesite recovery rate of 92.04% was also higher than the 71.55% obtained using salicylic acid. Without the use of inhibitors, the separation performance of salicylic acid was significantly inferior to that of the synthetic reagent of this invention.

[0053] Table 8 Flotation Indicators for Artificially Mixed Minerals

[0054]

[0055] Comparative Example 1

[0056] In a 100 mL beaker, 30 mL (0.50 mol) of anhydrous ethanol was used as the reaction solvent. 0.159 g (0.001 mol) of sodium benzoate and 0.278 g (0.001 mol) of tetrabutylammonium chloride were added. The beaker was placed in a magnetic stirrer and stirred at a constant temperature (25 °C) for 20 hours. The resulting reaction solution was filtered and washed with anhydrous ethanol to remove the sodium chloride generated in the reaction. After washing, the product solution was allowed to stand for 10 hours. Finally, the ethanol solvent was evaporated by heating in a water bath at 100 °C. The target product was then vacuum dried in a vacuum drying oven at 50 °C to obtain the benzoate-quaternary ammonium salt ionic liquid.

[0057] Following the same method as in Example 1, the benzyl hydroxamic acid-quaternary ammonium salt ionic liquid prepared in Comparative Example 1 was used for the flotation of bastnaesite and fluorite, respectively, and the results are shown in Tables 9 and 10. As can be seen from Tables 9 and 10, the recovery rate of fluorite by the benzyl hydroxamic acid-quaternary ammonium salt ionic liquid prepared in Comparative Example 1 was higher than that of bastnaesite at all concentrations, with a concentration of 0.6 × 10⁻⁶. -3 At a concentration of mol / L, the recovery rate of the useful mineral bastnaesite was only 73.07%. The benzoxoxime acid-quaternary ammonium salt ionic liquid prepared in Comparative Example 1 was not as effective as the salicylxoxime acid-quaternary ammonium salt ionic liquid in Example 1 in collecting bastnaesite. Since this invention explores reagents with better collecting effects on rare earth minerals (such as bastnaesite), there is no need to conduct mixed mineral flotation experiments.

[0058] Table 9. Effect of collector concentration on the recovery rate of pure minerals (mol / L)

[0059]

[0060] Table 10 Effect of pH on the recovery rate of pure minerals (mol / L)

[0061]

[0062] Example 3

[0063] Following the same mineral processing method as in Example 1, the hydroxamic acid-quaternary ammonium salt ionic liquid collector prepared in Example 1 and salicylic acid were used to float pure bastnaesite (pH=9). The difference was that whether or not a frother was added was used as the experimental variable, and the comparison results shown in Table 11 were obtained.

[0064] Table 11 Effect of collector type on the recovery rate of pure bastnaesite.

[0065]

[0066] As shown in Table 11, when only salicylic acid is added as a collector without using a frother, salicylic acid has virtually no collecting effect on bastnaesite, and the recovery rate of bastnaesite is significantly lower than when a frother is used. However, when using the ionic liquid collector of this invention, the recovery rate of bastnaesite is similar to that without using a frother, still showing a good collecting effect. This indicates that the collector provided by this invention can simplify the flotation reagent system and reduce costs.

[0067] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0068] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. The application of a hydroxamic acid-quaternary ammonium salt ionic liquid collector in mineral flotation, characterized in that, The structural formula of the hydroxamic acid-quaternary ammonium salt ionic liquid collector is shown in formula (Ⅰ): （Ⅰ）； The preparation method of the hydroxamic acid-quaternary ammonium salt ionic liquid collector includes: S1. Mixing salicylhydroxamic acid salt with tetrabutylammonium halide in a solvent to obtain a first mixture; S2. The first mixture is mechanically mixed at 20-30°C to obtain a second mixture; S3. Perform solid-liquid separation on the second mixture to obtain a product solution; S4. Remove the solvent from the product solution to obtain the hydroxamic acid-quaternary ammonium salt ionic liquid collector.

2. The application according to claim 1, characterized in that, The mineral in question is a rare earth mineral.

3. A method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector as described in claim 1, characterized in that, Includes the following steps: S1. Salicylic acid hydroxamic acid salt and tetrabutylammonium halide are mixed in a solvent to obtain a first mixture; S2. The first mixture is mechanically mixed at 20-30°C to obtain a second mixture; S3. Perform solid-liquid separation on the second mixture to obtain a product solution; S4. Remove the solvent from the product solution to obtain the hydroxamic acid-quaternary ammonium salt ionic liquid collector.

4. The method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector according to claim 3, characterized in that, In step S1, the molar ratio of the salicylhydroxyoxime salt to the tetrabutylammonium halide is (2:3) to (3:2).

5. The method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector according to claim 3, characterized in that, In step S1, the salicylhydroxamic acid salt is one or more of sodium salicylhydroxamic acid and potassium salicylhydroxamic acid; the tetrabutylammonium halide is one or more of tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium iodide.

6. The method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector according to claim 3, characterized in that, In step S1, the solvent is one or more of methanol, ethanol, and propanol.

7. The method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector according to claim 3, characterized in that, In step S2, the mechanical mixing method is magnetic stirring, and the magnetic stirring time is 18~24h.

8. The method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector according to claim 3, characterized in that, In step S3, after the solid-liquid separation, the precipitate is washed with a solvent, and then the filtrate and the washing liquid are mixed to obtain the product solution.

9. The method for preparing the hydroxamic acid-quaternary ammonium salt ionic liquid collector according to claim 3, characterized in that, After step S4, the method further includes: S5. Vacuum drying the product obtained in step S4 to obtain a hydroxamic acid-quaternary ammonium salt ionic liquid collector; the vacuum drying temperature is 30~50℃.

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