Hydroximic acid derivative as well as preparation method and application thereof
By simplifying the preparation method to synthesize hydroxamic acid derivatives as collectors, the problem of collector instability in existing rare earth mineral flotation is solved, achieving efficient rare earth mineral recovery and stable flotation effect.
Patent Information
- Application Number
- CN202510937214.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-10-31
AI Technical Summary
Existing rare earth mineral flotation collectors are cumbersome to synthesize and have unstable properties, affecting flotation efficiency and recovery rate, especially when processing fine-grained minerals.
Hydroxyxamic acid derivatives were synthesized using a simple preparation method as collectors. Highly efficient collectors were obtained by reacting under specific pH conditions and then post-processing them for use in multiple selection processes to improve the recovery rate of rare earth minerals.
It improves the flotation grade and recovery rate of rare earth minerals, forms a stable foam layer, simplifies the preparation process, and reduces costs.
Smart Images
Figure CN120865023A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a hydroxamic acid derivative, its preparation method, and its uses. Background Technology
[0002] In the flotation and beneficiation of rare earth minerals, collectors are widely used for the enrichment and separation of these minerals. Currently, commonly used rare earth flotation collectors on the market, such as compound P8, are typically composed of multiple chemical components, commonly including hydroxamic acids, fatty acids, and other organic compounds. Although compound collectors can effectively improve the flotation recovery rate of rare earth minerals to a certain extent, their complex component ratios lead to certain process fluctuations and stability issues in practical applications. In particular, the synthesis process of these compound reagents is relatively complicated, and their properties are easily affected by changes in raw material composition, ratios, and process parameters, making it difficult to consistently achieve ideal flotation grades and recovery rates.
[0003] Salicylic acid collectors are chelating agents containing a benzene ring, primarily using chemisorption with secondary physisorption. Salicylic acid is suitable not only for the flotation of rare earth ores but also widely used in the beneficiation of oxidized copper ores, oxidized lead-zinc ores, gold ores, kaolin, and other minerals. In the flotation of rare earth and other metallic ores, salicylic acid maintains good performance even at high temperatures, making it suitable for various industrial environments. It exhibits strong collecting ability during flotation, especially when processing fine-grained minerals. Given the numerous challenges faced by existing compound collectors in practical industrial applications, there is an urgent need to develop a rare earth flotation collector that is simpler to synthesize, more stable, and less expensive, in order to improve flotation efficiency, reduce costs, and enhance overall beneficiation performance. Summary of the Invention
[0004] In view of this, one object of the present invention is to provide a hydroxamic acid derivative that can improve the grade and recovery rate of rare earth mineral flotation.
[0005] Another object of the present invention is to provide a method for preparing the above-mentioned hydroxamic acid derivative.
[0006] Another object of the present invention is to provide a use of a hydroxamic acid derivative.
[0007] The present invention adopts the following technical solution to achieve the above-mentioned technical objectives.
[0008] On one hand, the present invention provides a hydroxamic acid derivative, which is shown in formula (I):
[0009]
[0010] Wherein, R is selected from halogen, C 1-6 Alkyl, C 1-6Alkoxy, C 1-6 Haloalkyl, C 2-6 alkenyl or C 2-6 Alkyne group.
[0011] In this invention, C 1-6 Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, neopentyl, or n-hexyl.
[0012] C 1-6 Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, and n-hexoxy.
[0013] C 1-6 Examples of alkyl halogens include, but are not limited to, monofluoromethyl, difluoromethyl, trifluoromethyl, monochloromethyl, dichloromethyl, trichloromethyl, monobromomethyl, dibromomethyl, tribromomethyl, monofluoroethyl, difluoroethyl, trifluoroethyl, monochloroethyl, dichloroethyl, trichloroethyl, monobromoethyl, dibromoethyl, tribromoethyl, propyl halogen, isopropyl halogen, butyl halogen, isobutyl halogen, etc.
[0014] C 2-6 Examples of alkenyl groups include, but are not limited to, vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, etc.
[0015] C 2-6 Examples of alkynyl groups include, but are not limited to, ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, etc.
[0016] According to the present invention, the hydroxamic acid derivative is preferably selected from formula (I-1), formula (I-2), or formula (I-3):
[0017]
[0018] Wherein, R is selected from halogen, C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Haloalkyl, C 2-6 alkenyl or C 2-6 Alkyne group.
[0019] According to the hydroxamic acid derivative of the present invention, preferably, R is selected from F, Cl, C.1-3 Alkyl, C 1-3 Alkoxy, C 1-3 Haloalkyl, C 2-4 alkenyl or C 2-4 Alkyne group.
[0020] According to the hydroxamic acid derivative of the present invention, preferably, R is selected from C. 1-3 Alkyl group. More preferably, R is selected from methoxy, ethoxy, n-propoxy, and isopropoxy; even more preferably, R is selected from methoxy.
[0021] According to the present invention, the hydroxamic acid derivative, preferably, is the compound represented by formula (I):
[0022]
[0023] According to the present invention, the hydroxamic acid derivative, preferably, is the compound represented by formula (I):
[0024]
[0025] On the other hand, the present invention also provides a method for preparing the above-mentioned hydroxamic acid derivative, comprising the following steps:
[0026] Under conditions of pH 9.0–13.5, the compound shown in formula (II) was reacted with hydroxylamine at 25–70 °C for 2–12 hours to obtain the reaction product; the pH of the reaction product was adjusted to 5.0–8.0 to obtain a hydroxamic acid derivative.
[0027]
[0028] In equation (II),
[0029] The definition of R is as described above;
[0030] R' is selected from C 1-6 Alkyl; preferably, R' is selected from C 1-3 Alkyl; in some technical solutions, R' is selected from methyl, ethyl, n-propyl or isopropyl.
[0031] Preferably, the pH of the reaction product is adjusted to 5.5-7.5; more preferably, the pH of the reaction product is adjusted to 6-7; even more preferably, the pH of the reaction product is adjusted to 6.2-6.8.
[0032] According to the preparation method of the present invention, preferably, the molar ratio of the compound shown in formula (II) to hydroxylamine is 1:(0.3-6); the compound shown in formula (II) is reacted with hydroxylamine in the presence of a solvent, the solvent being selected from one or more of water, methanol, ethanol, n-propanol, isopropanol or acetone.
[0033] In some technical solutions, the molar ratio of the compound represented by formula (II) to hydroxylamine is 1:(0.5-4); preferably 1:(1-3); and more preferably 1:(1.5-2.5).
[0034] In some technical solutions, the pH value is 9.5–13.5; preferably 11–13. The pH value can be adjusted by a pH adjuster. The pH adjuster can be selected from one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, or ammonia water; preferably, the pH adjuster is selected from sodium hydroxide, potassium hydroxide, or ammonia water.
[0035] In some technical solutions, the reaction temperature is 35–80°C, preferably 40–70°C, and more preferably 45–60°C. The reaction time is 3–10 hours, preferably 4–8 hours.
[0036] In some technical solutions, after the reaction is completed, the resulting reaction product is cooled to room temperature, then the pH of the reaction system is adjusted to 5.0–8.0, and after post-treatment, a hydroxamic acid derivative is obtained. The post-treatment includes extraction, vacuum distillation, concentration, washing, filtration, and / or drying.
[0037] This preparation method is simple to operate and has mild reaction conditions, enabling the efficient acquisition of high-quality collectors at low temperatures and in a mild environment.
[0038] In another aspect, the present invention also provides the use of the aforementioned hydroxamic acid derivative as a collector in the flotation of rare earth minerals.
[0039] According to the intended use of the invention, preferably, the method includes the following steps:
[0040] (1) Saponify the hydroxamic acid derivative to obtain the saponified collector;
[0041] (2) Rare earth minerals are formed into a slurry. The slurry, water glass and saponified collector are reacted to obtain a roughing intermediate product. The pH of the roughing intermediate product is adjusted to 8-11 and then reacted with pine oil to obtain a roughing reaction product. Aeration is introduced into the roughing reaction product to obtain a roughing concentrate and a roughing tailings.
[0042] (3) The rough concentrate is formed into a rough concentrate slurry; the rough concentrate slurry, water glass and saponified collector are reacted to obtain the first cleaning intermediate product; the pH of the first cleaning intermediate product is adjusted to 8-11, and then reacted with pine oil to obtain the first cleaning reaction product; the first cleaning reaction product is aerated to obtain the first cleaning concentrate and the first cleaning tailings.
[0043] (4) The first-selected concentrate is used to form a first-selected concentrate slurry; the first-selected concentrate slurry, water glass and saponified collector are reacted to obtain a second-selected intermediate product; the pH of the second-selected intermediate product is adjusted to 8-11, and then reacted with pine oil to obtain a second-selected reaction product; air is introduced into the second-selected reaction product to obtain a second-selected concentrate and a second-selected tailings.
[0044] (5) The second-selected concentrate is used to form a second-selected concentrate slurry; the second-selected concentrate slurry, water glass and saponified collector are reacted to obtain a third-selected intermediate product; the pH of the second-selected intermediate product is adjusted to 8-11, and then reacted with pine oil to obtain a third-selected reaction product; air is introduced into the third-selected reaction product to obtain the concentrate final product and the tailings final product.
[0045] In this invention, the rare earth mineral is iron ore tailings; preferably, it is Bayan Obo iron ore tailings. The REO grade of the rare earth mineral is 7–13 wt%, preferably 8–11 wt%; the CaO content is 20–33 wt%, preferably 24–30 wt%; the SiO2 content is 13–22 wt%, preferably 25–20 wt%; and the F content is 8–17 wt%, preferably 10–15 wt%. The proportion of mineral particles with a diameter of 200 mesh or less in the rare earth mineral is 70–90%, preferably 75–85%.
[0046] In this invention, the water glass used has a concentration of 4 to 13 wt%; preferably 7 to 10 wt%.
[0047] In step (2), the amount of water glass used per ton of rare earth minerals can be 1 to 5 kg, preferably 2.5 to 3.5 kg. The amount of the collector used after saponification per ton of rare earth minerals can be 0.08 to 1.5 kg, preferably 0.1 to 1.2 kg, and preferably 0.5 to 1 kg.
[0048] The pH value of the roughing intermediate can be adjusted to 8-11, preferably 8.5-10, and more preferably 9.1 or 9.2.
[0049] In step (3), the amount of water glass used can be 1 / 4 to 1 / 6 of the amount of water glass used in step (2). The amount of the collector after saponification can be 1 / 4 to 1 / 6 of the amount of the collector after saponification in step (2). The pH value of the intermediate product of the first selection can be adjusted to 8 to 11, preferably 8.5 to 10, and more preferably 9.1 or 9.2.
[0050] In step (4), the amount of water glass used can be 1 / 2 to 2 / 3 of the amount of water glass used in step (3). The amount of the collector after saponification can be 1 / 2 to 1 of the amount of the collector after saponification used in step (3). The pH value of the intermediate product of the second selection can be adjusted to 8 to 11, preferably 8.5 to 10, and more preferably 9.1 or 9.2.
[0051] In step (5), the amount of water glass used can be 1 / 2 to 2 / 3 of the amount of water glass used in step (4). The amount of the saponified collector can be 1 / 2 to 1 of the amount of the saponified collector used in step (4). The pH value of the intermediate product of the third selection can be adjusted to 8 to 11, preferably 8.5 to 10, and more preferably 9.1 or 9.2.
[0052] In steps (2), (3), (4) or (5) of the present invention, the amount of pine oil used is 50-250g per ton of rare earth minerals, preferably 100-180g.
[0053] The hydroxamic acid derivatives in this invention can be used as collectors in the flotation of rare earth minerals. Their preparation process is simple and the raw materials are readily available.
[0054] During the flotation process, hydroxamic acid derivatives, as flotation agents, exhibit high selectivity for rare earth elements and can form a stable and uniform foam layer, thereby improving the grade and recovery rate of rare earth elements after flotation. Attached Figure Description
[0055] Figure 1 The infrared spectrum of 4-methoxysalicylic acid, the product of Example 1.
[0056] Figure 2 The image shows the 1H NMR spectrum of 4-methoxysalicylic acid, the product of Example 1. Detailed Implementation
[0057] Unless otherwise specified, all raw materials, reagents, instruments, and equipment involved in this invention can be obtained through market channels or prepared according to existing technologies. The content provided in this embodiment is merely illustrative and not restrictive. Any equivalent alternatives or technical implementations that conform to the basic principles of this invention should be considered within the scope of protection of the claims of this invention.
[0058] Example 1 Synthesis of 4-methoxysalicylic acid
[0059] 8.0 g of methyl 4-methoxysalicylate (98% purity), 6.7 g of hydroxylamine hydrochloride, and 120 mL of anhydrous methanol were added to a reactor and stirred until fully dissolved to obtain a reaction solution. The pH of the reaction solution was adjusted to 12.5 using a 2.5 mol / L NaOH aqueous solution. The pH-adjusted reaction solution was then heated to 50 °C and maintained at this temperature for 6 hours to obtain the reaction product.
[0060] The reaction product was cooled to room temperature, and the pH was adjusted to 6.3 with 15 wt% hydrochloric acid. It was then extracted three times with ethyl acetate, and the supernatant was retained. The supernatant was distilled under reduced pressure until the solvent was completely evaporated, yielding a residue. Water at 10°C was added to the residue to allow it to solidify, and then the residue was filtered to obtain a filter cake. The filter cake was dried in a 45°C oven for 12 hours to obtain 4-methoxysalicylic acid (yellow powder), with a yield of 70%. The structural formula of 4-methoxysalicylic acid is as follows:
[0061]
[0062] The infrared spectrum and nuclear magnetic resonance spectrum of the obtained product are shown in the figure below. Figure 1 and Figure 2 .
[0063] Example 2 Synthesis of 4-methoxysalicylic acid
[0064] 4.00 g of methyl 4-methoxysalicylate (98% purity), 2.5 g of hydroxylamine hydrochloride, and 140 mL of ultrapure water were added to a reactor, stirred, and heated to 50 °C until fully dissolved to obtain a reaction solution. The pH of the reaction solution was adjusted to 12.5 using a 2.5 mol / L NaOH aqueous solution. The pH-adjusted reaction solution was then reacted at 50 °C for 6 hours to obtain the reaction product.
[0065] The reaction product was cooled to room temperature, and the pH was adjusted to 6.7 with 15 wt% hydrochloric acid. It was then extracted three times with ethyl acetate, and the supernatant was retained. The supernatant was distilled under reduced pressure (water bath temperature 45°C) to obtain the residue. Water at 10°C was added to the residue to allow it to solidify, and then the residue was filtered to obtain a filter cake. The filter cake was dried in a 45°C oven for 12 hours to obtain 4-methoxysalicylic acid (yellow powder) in 65% yield.
[0066] Example 3 and Comparative Example 1
[0067] The REO grade of the Bayan Obo iron tailings is 9.08 wt%, the CaO content is 27.00 wt%, the SiO2 content is 17.12 wt%, and the F content is 12.77 wt%. Mineral particles with a diameter of less than 200 mesh account for 81.68% of the raw ore.
[0068] The collector was saponified using NaOH solution to obtain the saponified collector.
[0069] Roughing: A 500mL single-cell flotation machine was used in this step; the rotation speed of the single-cell flotation machine was set to 1980 r / min. 400g of Bayan Obo iron tailings and 300mL of tap water were mixed and heated to 60℃ for 4 minutes to obtain a slurry. 9wt% water glass was added to the slurry and reacted for 3 minutes; then, a saponified collector was added and reacted for 1 minute to obtain the roughing intermediate product. The amount of water glass used per ton of Bayan Obo iron tailings was 3000g, and the amount of saponified collector was 800g. The pH of the roughing intermediate product was adjusted to 9.1 with a 12wt% Na2CO3 solution, and the reaction continued for 3 minutes; then, pine oil was added and reacted for 3 minutes to obtain the roughing reaction product. The amount of pine oil used per ton of Bayan Obo iron tailings was 140g. Aeration was introduced into the roughing reaction product to obtain the roughing concentrate and roughing tailings. The ventilation rate was 0.1 L / min.
[0070] First Refinement: In this step, a 500mL single-cell flotation machine was used for flotation experiments; the rotation speed of the single-cell flotation machine was set to 1980 r / min. Water was added to the rougher concentrate to a volume of 500mL, and the mixture was heated to 60℃ and held at that temperature for 4 minutes. 9wt% water glass was added to the rougher concentrate pulp and reacted for 3 minutes; then, a saponified collector was added and reacted for 1 minute to obtain the first refinement intermediate product. The amount of water glass used per ton of Bayan Obo iron tailings was 530g, and the amount of saponified collector was 160g. The pH of the first refinement intermediate product was adjusted to 9.1 with a 12wt% Na₂CO₃ solution and reacted for 3 minutes; then, pine oil was added and reacted for 3 minutes to obtain the first refinement reaction product. The amount of pine oil used per ton of Bayan Obo iron tailings was 140g. Aeration was then applied to the first refinement reaction product for flotation to obtain the first refined concentrate and the first refined tailings. The ventilation rate was 0.1 L / min.
[0071] Secondary Refinement: In this step, a 500mL single-cell flotation machine was used for flotation experiments; the rotation speed of the single-cell flotation machine was set to 1980 r / min. The concentrate from the first refinement was mixed with water to a volume of 500mL, heated to 60℃, and held at that temperature for 4 minutes. 9wt% water glass was added to the first refinement concentrate slurry and reacted for 3 minutes, followed by the addition of a saponified collector and a reaction for 1 minute, yielding the intermediate product of the second refinement. The amount of water glass used per ton of Bayan Obo iron tailings was 265g, and the amount of saponified collector was 134g. The pH of the intermediate product of the second refinement was adjusted to 9.1 with a 12wt% Na₂CO₃ solution and reacted for 3 minutes; then pine oil was added and reacted for 3 minutes, yielding the reaction product of the second refinement. The amount of pine oil used per ton of Bayan Obo iron tailings was 140g. Aeration was then applied to the reaction product of the second refinement for flotation, yielding the second refined concentrate and the second refined tailings. The ventilation rate was 0.1 L / min.
[0072] Third Refinement: In this step, a 500mL single-cell flotation machine was used for flotation experiments; the rotation speed of the single-cell flotation machine was set to 1980 r / min. The second-refinement concentrate was mixed with water to a volume of 500mL, heated to 60℃, and held at that temperature for 4 minutes. 9wt% water glass was added to the second-refinement concentrate slurry and reacted for 3 minutes, followed by the addition of a saponified collector and a reaction for 1 minute, yielding the third-refinement intermediate product. The amount of water glass used per ton of Bayan Obo iron tailings was 265g, and the amount of saponified collector was 80g. The pH of the third-refinement intermediate product was adjusted to 9.1 with a 12wt% Na₂CO₃ solution and reacted for 3 minutes, followed by the addition of pine oil and a reaction for 3 minutes, yielding the third-refinement reaction product. The amount of pine oil used per ton of Bayan Obo iron tailings was 140g. Aeration was then applied to the second-refinement reaction product for flotation, yielding the final concentrate product and the final tailings product. The ventilation rate was 0.1 L / min.
[0073] The grade and recovery rate of the rare earth ore flotation are shown in Table 1.
[0074] Table 1. Grade and recovery rate of rare earth ore flotation
[0075]
[0076] As shown in Table 1, compared with salicylic acid, 4-methoxysalicylic acid can effectively improve the grade and recovery rate of rare earth minerals as a collector, and has excellent collecting effect.
[0077] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.
Claims
1. A hydroxamic acid derivative, characterized in that, The hydroxamic acid derivative is shown in formula (I): Wherein, R is selected from halogen, C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Haloalkyl, C 2-6 alkenyl or C 2-6 Alkyne group.
2. The hydroxamic acid derivative according to claim 1, characterized in that, The hydroxamic acid derivative is selected from formula (I-1), formula (I-2), or formula (I-3): Wherein, R is selected from halogen, C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Haloalkyl, C 2-6 alkenyl or C 2-6 Alkyne group.
3. The hydroxamic acid derivative according to claim 1, characterized in that, R is selected from F, Cl, C 1-3 Alkyl, C 1-3 Alkoxy, C 1-3 Haloalkyl, C 2-4 alkenyl or C 2-4 Alkyne group.
4. The hydroxamic acid derivative according to claim 1, characterized in that, R is selected from C 1-3 Alkyl group.
5. The hydroxamic acid derivative according to claim 1, characterized in that, The compound shown in formula (I) is:
6. The hydroxamic acid derivative according to claim 1, characterized in that, The compound shown in formula (I) is:
7. A method for preparing a hydroxamic acid derivative according to any one of claims 1 to 6, characterized in that, Includes the following steps: Under conditions of pH 9.0–13.5, the compound shown in formula (II) was reacted with hydroxylamine at 25–70 °C for 2–12 hours to obtain the reaction product; the pH of the reaction product was adjusted to 5.0–8.0 to obtain a hydroxamic acid derivative. In equation (II), R is defined as described in any one of claims 1-6; R' is selected from C. 1-6 alkyl.
8. The preparation method according to claim 7, characterized in that, The molar ratio of the compound shown in formula (II) to hydroxylamine is 1:(0.3-6); the compound shown in formula (II) is reacted with hydroxylamine in the presence of a solvent, which is selected from one or more of water, methanol, ethanol, n-propanol, isopropanol or acetone.
9. Use of a hydroxamic acid derivative according to any one of claims 1 to 6 as a collector in the flotation of rare earth minerals.
10. The use according to claim 9, characterized in that, Includes the following steps: (1) Saponify the hydroxamic acid derivative to obtain the saponified collector; (2) Rare earth minerals are formed into a slurry. The slurry, water glass and saponified collector are reacted to obtain a roughing intermediate product. The pH of the roughing intermediate product is adjusted to 8-11 and then reacted with pine oil to obtain a roughing reaction product. Aeration is introduced into the roughing reaction product to obtain a roughing concentrate and a roughing tailings. (3) The rough concentrate is formed into a rough concentrate slurry; the rough concentrate slurry, water glass and saponified collector are reacted to obtain the first cleaning intermediate product; the pH of the first cleaning intermediate product is adjusted to 8-11, and then reacted with pine oil to obtain the first cleaning reaction product; the first cleaning reaction product is aerated to obtain the first cleaning concentrate and the first cleaning tailings. (4) The first-selected concentrate is used to form a first-selected concentrate slurry; the first-selected concentrate slurry, water glass and saponified collector are reacted to obtain the second-selected intermediate product; The pH of the intermediate product from the second refining process was adjusted to 8-11, and then reacted with pine oil to obtain the product from the second refining process. Aeration was then introduced into the product from the second refining process to obtain the concentrate and tailings from the second refining process. (5) The second-selected concentrate is used to form a second-selected concentrate slurry; the second-selected concentrate slurry, water glass and saponified collector are reacted to obtain a third-selected intermediate product; the pH of the second-selected intermediate product is adjusted to 8-11, and then reacted with pine oil to obtain a third-selected reaction product; air is introduced into the third-selected reaction product to obtain the concentrate final product and the tailings final product.