Alkyl ether hydroxamic acid collecting agent and preparation method and application thereof

Abstract

The invention provides an alkyl ether hydroxamic acid collecting agent and a preparation method and application thereof, and belongs to the technical field of flotation beneficiation. The alkyl ether hydroxamic acid collecting agent is prepared through a hydroxylamine method, namely, alkyl ether acetic acid and methyl alcohol are subjected to an esterification reaction firstly, then hydroxylamine and alkali are subjected to a hydroximation reaction, and a final product is obtained. On the basis of a traditional hydroximic acid collecting agent, an alkyl ether functional group is introduced to enhance the selectivity, and the alkyl ether functional group and a hydroxime group in a molecular structure have a synergistic effect, so that the collecting performance and the selectivity are further improved. The alkyl ether hydroxamic acid collecting agent prepared through the method can be applied to the field of flotation of various minerals such as rare earth ore, tungsten ore, cassiterite, apatite, malachite and ilmenite. In addition, the collecting agent can reduce the use amount of flotation reagents, and has important significance in mineral flotation operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of flotation beneficiation, and particularly relates to an alkyl ether-based hydroxamic acid collector and its preparation method and application. Background Art

[0002] As the most critical and widely used technical link in the field of mineral processing, with the increasing poverty, fineness, and complexity of mineral resources, the properties of minerals are becoming increasingly complex, which puts higher requirements on the flotation process and the collecting performance and selectivity of collectors. However, traditional collectors have problems such as low collecting efficiency and poor selectivity, and it is difficult to meet the demand for the efficient utilization of mineral resources.

[0003] Hydroxamic acid collectors are easy to chelate with metal ions. Through two oxygen atoms in the hydroxamic group, they form a five-membered ring structure with metal cations, so they have good collecting performance for metal oxide ores. In industrial applications, benzohydroxamic acid, octyl hydroxamic acid, and salicylhydroxamic acid are common hydroxamic acid collectors. However, these traditional hydroxamic acid collectors also have some limitations: although benzohydroxamic acid and salicylhydroxamic acid perform well in terms of selectivity, the improvement effect on the floatability of minerals is limited; while octyl hydroxamic acid has strong collecting performance but poor selectivity.

[0004] Currently, the "hydroxylamine method" is generally used in industry to prepare hydroxamic acid collectors, that is, esters and hydroxylamine undergo a hydroxylation reaction under alkaline conditions to prepare hydroxamic acid. The hydroxylamine method has the advantages of simple process, low process technical requirements, and easy control of synthesis conditions. In the traditional synthesis process of hydroxamic acid, carboxylic acid lower alcohol esters and hydroxylamine are usually reacted in an alkaline solvent, and common solvents are water or methanol, etc.

[0005] Therefore, it is urgent to develop a new type of hydroxamic acid collector to improve its collecting performance and selectivity in flotation. Summary of the Invention

[0006] The present invention is to solve the above technical problems, and thus provides an alkyl ether-based hydroxamic acid collector and its preparation method and application. Aiming at the defects and deficiencies of traditional hydroxamic acid collectors, the present invention provides an alkyl ether-based hydroxamic acid collector with good collecting performance and selectivity, which can achieve the efficient collection of target minerals and the selective separation from gangue minerals.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The present invention first provides an alkyl ether-based hydroxamic acid collector, and the structural formula of the collector is shown as the following formula <Ⅰ>:

[0009]

[0010] In formula I, R1 and R2 are each independently selected from one of the following groups: an alkylene or methylene group having 1 to 20 carbon atoms; a cycloalkylene group having 3 to 8 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heterocyclic group having 3 to 10 carbon atoms; an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 3 to 20 carbon atoms;

[0011] R3 is selected from one of the following groups: H; a halogen atom; a nitro group; an alkyl group having 1 to 6 carbon atoms; a cycloalkyl group having 3 to 8 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heterocyclic group having 3 to 10 carbon atoms; an aryl group having 6 to 10 carbon atoms or a heteroaryl group having 3 to 10 carbon atoms.

[0012] As a preferred embodiment, R1 and R2 are each independently selected from an alkylene or methylene group having 1 to 6 carbon atoms; and R3 is selected from H or an alkyl group having 1 to 6 carbon atoms.

[0013] As a further preferred embodiment, R1 and R2 are each independently selected from one of methylene, ethyl or propyl; and R3 is selected from one of H, methyl or ethyl.

[0014] The above alkyl ether-based hydroxamic acid compound developed in the present invention significantly enhances the hydrophobicity and improves the collecting ability for minerals by introducing an alkyl ether group into the molecular structure. The ether bond and hydroxamic acid group in the molecular structure have a synergistic effect, enabling efficient selective collection of target minerals in complex mineral systems. In addition, the flotation performance of this compound is not affected by temperature, and it is prepared by an industrially simple and convenient hydroxylamine method. The alkyl ether-based hydroxamic acid collector prepared in the present invention has the characteristics of good water solubility, strong collecting ability and good selectivity, providing better flotation reagents for mineral flotation.

[0015] The second object of the present invention is to provide a preparation method of the above-mentioned alkyl ether-based hydroxamic acid collector, comprising the following steps:

[0016] (1) Esterification reaction: Mix the alkyl ether-based acetic acid having the structure shown in formula <Ⅱ> with a solvent, and carry out an esterification reaction under the catalysis of thionyl chloride to obtain methyl alkyl ether-based acetate having the structure shown in formula <Ⅲ>;

[0017] (2) Hydroxamic acid formation reaction: React methyl alkyl ether-based acetate having the structure shown in formula <Ⅲ> with a hydroxylamine compound and a base in a solvent to prepare the alkyl ether-based hydroxamic acid collector;

[0018]

[0019] Among them, R1 and R2 are each independently selected from one of the following groups: an alkylene or methylene group having C1-C 20 ; a cycloalkylene group having C3-C8; an alkenyl group having C2-C 20 ; an alkynyl group having C2-C 20 ; a heterocyclic group having C3-C 10 ; an aromatic group having C6-C 20 or a heteroaryl group having C3-C 20 .

[0020] R3 is selected from one of the following groups: H; a halogen atom; a nitro group; an alkyl group having C1-C6; a cycloalkyl group having C3-C8; an alkenyl group having C2-C 20 ; an alkynyl group having C2-C 20 ; a heterocyclic group having C3-C 10 ; an aromatic group having C6-C 10 or a heteroaryl group having C3-C 10 .

[0021] Furthermore, the solvent in step (1) is any one of water, methanol, ethanol, propanol or butanol.

[0022] Furthermore, the amount of the solvent used is 5 to 8 times the weight of alkyl ether acetic acid.

[0023] Furthermore, the molar ratio of thionyl chloride to alkyl ether acetic acid in step (1) is 1:1.0 to 1.2.

[0024] Furthermore, the reaction temperature of the esterification reaction in step (1) is 4 to 25 °C, and the reaction time is 2.5 to 3 h.

[0025] Furthermore, the reaction temperature of the oximation reaction in step (2) is 5 to 60 °C, and the reaction time is 2 to 5 h.

[0026] Furthermore, the hydroxylamine compound in step (2) is any one of hydroxylamine hydrochloride, hydroxylamine sulfate or hydroxylamine nitrate.

[0027] Furthermore, the base is any one of sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate or potassium carbonate.

[0028] Furthermore, the molar ratio of the hydroxylamine compound to the base in step (2) is 1:2.0 to 2.5.

[0029] Furthermore, the molar ratio of methyl alkyl ether acetate to the hydroxylamine compound is 1:1.2 to 1.5.

[0030] A third object of the present invention is to provide the application of the above-mentioned alkyl ether-based hydroxamic acid collector in mineral flotation.

[0031] Furthermore, the minerals include at least one of rare earth ores, tungsten ores, cassiterite, apatite, malachite, and ilmenite.

[0032] The beneficial effects of the present invention are as follows:

[0033] (1) The present invention uses the hydroxylamine method to prepare the alkyl ether-based hydroxamic acid collector, that is, first, alkyl ether-based acetic acid is esterified with methanol, and then hydroxylamine and a base are used for hydroxylation reaction to obtain the final product. Among them, in the esterification reaction, different from the traditional method of adding concentrated sulfuric acid, the present invention adds thionyl chloride as a catalyst and ensures that the reaction temperature is carried out at normal temperature or low temperature. In addition, the present invention introduces an alkyl ether-based functional group on the basis of the traditional hydroxamic acid collector to enhance selectivity, and has a synergistic effect with the hydroxamic group in the molecular structure, thereby further improving the collecting performance and selectivity.

[0034] (2) The alkyl ether-based hydroxamic acid collector prepared by the present invention can be applied to various mineral flotation fields, such as at least one of rare earth ores, tungsten ores, cassiterite, apatite, malachite, and ilmenite.

[0035] (3) The collector of the present invention has the function of efficient flotation and can reduce the dosage in mineral flotation. Description of the Drawings

[0036] Figure 1 1H NMR spectrum of the benzyloxyacetyl hydroxamic acid collector described in the embodiment of the present invention;

[0037] Figure 2 13C NMR spectrum of the benzyloxyacetyl hydroxamic acid collector described in the embodiment of the present invention;

[0038] Figure 3 Infrared spectrum of the benzyloxyacetyl hydroxamic acid collector described in the embodiment of the present invention;

[0039] Figure 4 Optimal configuration of the benzyloxyacetyl hydroxamic acid collector described in the embodiment of the present invention at the DFT / B3LYP(def-TZVP) level;

[0040] Figure 5 Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the benzyloxyacetyl hydroxamic acid collector described in the embodiment of the present invention at the DFT / B3LYP(def-TZVP) level;

[0041] Figure 6Molecular electrostatic potential of the benzoxyacetylhydroxamic acid collector described in the embodiments of the present invention at the DFT / B3LYP (def-TZVP) level;

[0042] Figure 7 Process flow chart of rare earth ore flotation described in the embodiments of the present invention;

[0043] Figure 8 Process flow chart of cassiterite flotation described in the embodiments of the present invention. Detailed implementation manners

[0044] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be specifically described below in conjunction with embodiments. It should be noted that the following embodiments are only used to explain and illustrate the present invention, and are not used to limit the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-mentioned invention content still fall within the protection scope of the present invention.

[0045] Embodiment 1

[0046] This embodiment is a preparation method of a benzoxyacetylhydroxamic acid collector (BOHA), including the following steps:

[0047] Step S1: Benzoxyacetic acid (17 g) is dissolved in a 500 mL three-necked round-bottom flask containing methanol (250 mL). Then, stir at a constant speed, and slowly drip SOCl2 solution through a dropping funnel. Stir for 30 min at a temperature below 8 °C. Then, stir the mixture at 350 r / min and room temperature (25 °C) for 2.5 h. After the reaction is completed, rotate and evaporate to remove the solvent to obtain Intermediate 1;

[0048] Step S2: Hydroxylamine hydrochloride (2.61 g) and sodium hydroxide (3 g) are stirred at a constant speed in a methanol solution in an ice bath for 1 h, and then solid sodium chloride is removed by suction filtration. Then, transfer the filtrate into a 100 mL three-necked round-bottom flask, slowly add methyl benzoxyacetate (4.5 g), react at 60 °C for 3 h, treat the crude mixture with 2 mol / L HCl until the pH = 6, and then rotate and distill under reduced pressure to remove the solvent. Place it in an oven at 40 °C and dry it in vacuum to obtain the final product 2.

[0049] The specific reaction equation is as follows:

[0050]

[0051] The benzoyloxyacetylhydroxamic acid collector prepared by the above preparation method of the present invention was subjected to nuclear magnetic resonance carbon-hydrogen spectrum and infrared tests, as shown in Table 1-3 specifically. Subsequently, it was applied to the field of rare earth ore flotation, having a high collecting performance for bastnaesite and being able to efficiently and selectively separate gangue minerals. The recovery rate of bastnaesite can be as high as over 90%, while the recovery rate of gangue minerals remains at 10% - 20%.

[0052] Table 1 Analysis results of 1 H NMR of benzoyloxyacetylhydroxamic acid

[0053]

[0054] Table 2 Analysis results of 13 C NMR of benzoyloxyacetylhydroxamic acid

[0055]

[0056] Table 3 Analysis results of FTIR of benzoyloxyacetylhydroxamic acid

[0057]

[0058]

[0059] Example 2

[0060] This example is a preparation method of a 2-(2-phenylethoxy)acetylhydroxamic acid collector (PAHA), including the following steps:

[0061] Step S1: 2-(2-Phenylethoxy)acetic acid (18 g) was dissolved in a 500 mL three-necked round-bottom flask containing methanol (300 mL). Then, it was stirred at a constant speed, and SOCl2 solution was slowly added dropwise through a dropping funnel, and stirred at a temperature below 8 °C for 30 min. After that, the mixture was stirred at 350 r / min at room temperature (25 °C) for 2.5 h. After the reaction ended, the solvent was removed by rotary evaporation to obtain intermediate 1;

[0062] Step S2: Hydroxylamine hydrochloride (2.71 g) and sodium hydroxide (3.12 g) were stirred at a constant speed for 1 h in an ice bath with a methanol solution, and then solid sodium chloride was removed by vacuum filtration. Then, the filtrate was transferred into a 100 mL three-necked round-bottom flask, and 2-(2-phenylethoxy)methyl acetate (5 g) was slowly added, and the reaction was carried out at 60 °C for 3 h. The crude mixture was treated with 2 mol / L HCl until pH = 6, and then the solvent was removed by rotary evaporation under reduced pressure and placed in an oven at 40 °C for vacuum drying to obtain the final product 2.

[0063] The specific reaction equation is as follows:

[0064]

[0065] The 2-(2-phenylethoxy)acetohydroxamic acid collector prepared by the above preparation method of the present invention was subjected to nuclear magnetic resonance carbon-hydrogen spectrum testing, as specifically shown in Table 4-5.

[0066] Table 4 Analysis results of 1 H NMR of 2-(2-phenylethoxy)acetohydroxamic acid

[0067]

[0068] Table 5 Analysis results of 13 C NMR of 2-(2-phenylethoxy)acetohydroxamic acid

[0069]

[0070] Example 3

[0071] This example is a preparation method of a 2-[(2-methylphenyl)methoxy]acetohydroxamic acid collector (MAHA), including the following steps:

[0072] Step S1: 2-[(2-Methylphenyl)methoxy]acetic acid (18 g) was dissolved in a 500 mL three-necked round-bottom flask containing methanol (300 mL). Then, it was stirred at a constant speed, and SOCl2 solution was slowly added dropwise through a dropping funnel, and stirred at a temperature below 8 °C for 30 min. After that, the mixture was stirred at 350 r / min and room temperature (25 °C) for 2.5 h. After the reaction ended, the solvent was removed by rotary evaporation to obtain Intermediate 1;

[0073] Step S2: Hydroxylamine hydrochloride (2.71 g) and sodium hydroxide (3.12 g) were stirred at a constant speed in a methanol solution for 1 h under ice bath conditions, and then solid sodium chloride was removed by vacuum filtration. Then, the filtrate was transferred into a 100 mL three-necked round-bottom flask, and 2-[(2-methylphenyl)methoxy]methyl acetate (5 g) was slowly added, and the reaction was carried out at 60 °C for 3 h. The crude mixture was treated with 2 mol / L HCl until the pH = 6, and then the solvent was removed by rotary evaporation under reduced pressure and placed in an oven at 40 °C for vacuum drying to obtain the final product 2.

[0074] The specific reaction equation is as follows:

[0075]

[0076] The 2-[(2-methylphenyl)methoxy]acetohydroxamic acid collector prepared by the above preparation method of the present invention was subjected to nuclear magnetic resonance carbon-hydrogen spectrum testing, as specifically shown in Tables 6-7.

[0077] Table 6 Analysis results of 1Analysis results of \(^1H\) NMR

[0078]

[0079] Table 7 Analysis results of 2-[(2-methylphenyl)methoxy]acetohydroxamic acid 13 Analysis results of \(^{13}C\) NMR

[0080]

[0081]

[0082] Example 4

[0083] An alkyl ether-based hydroxamic acid collector, whose structural formula is shown as the following formula <Ⅰ>:

[0084]

[0085] Referring to the synthesis methods of Examples 1-3, the cases where \(R_1\), \(R_2\) and \(R_3\) in formula <Ⅰ> are different substituents were examined. As shown in Table 1,

[0086] Table 1

[0087]

[0088] Both \(R_1\) and \(R_2\) are selected from one of the following groups: C1-C 20 alkylene or methylene; C3-C8 cycloalkylene; C2-C 20 alkenyl; C2-C 20 alkynyl; C3-C 10 heterocyclic group; C6-C 20 aryl or C3-C 20 heteroaryl;

[0089] \(R_3\) is selected from one of the following groups: H; halogen atom; nitro group; C1-C6 alkyl; C3-C8 cycloalkyl; C2-C 20 alkenyl; C2-C 20 alkynyl; C3-C 10 heterocyclic group; C6-C 10 aryl or C3-C 10 heteroaryl.

[0090] It was found that the yields of the above-mentioned synthesized final products were all about 85%, and they could all be applied to one of the minerals of rare earth ore, tungsten ore, cassiterite, apatite, malachite, ilmenite. For pure minerals, the flotation recovery rates could all reach over 80%, and the flotation separation from gangue minerals could be achieved. The conversion rate and flotation recovery rate of the final products were calculated by the following formulas <Ⅳ> and <Ⅴ> respectively.

[0091] Yield (%) = (Theoretical output / Actual output) × 100% Formula <Ⅳ>

[0092] Recovery rate (%) = (Weight of concentrate / Weight of concentrate + Weight of tailings) × 100% Formula <Ⅴ>

[0093] Example 5

[0094] Flotation of rare earth ores with benzyloxyacetylhydroxamic acid:

[0095] In this example, bastnasite from the continental trough in western Sichuan, calcite from Kunming, Yunnan, and barite from Tongliang, Chongqing were used as flotation targets. The flotation process flow chart is shown in Figure 7 as follows. The test conditions were as follows: when the concentrations of benzyloxyacetylhydroxamic acid, benzohydroxamic acid, and octylhydroxamic acid were 3×10 -4 mol / L, the pulp pH was 8.0, the concentration of the foaming agent (MIBC) was 0.5×10 -4 mol / L, the rotation speed was 1704 r / min, and the flotation time was 3 min. Test results: The flotation recovery rate of bastnasite with benzyloxyacetylhydroxamic acid as the collector was about 80%, and the flotation recovery rates for calcite and barite were both lower than 30%. When benzohydroxamic acid and octylhydroxamic acid were used as collectors, the flotation recovery rates for bastnasite were about 50% and 70% respectively; the flotation recovery rates of benzohydroxamic acid for calcite and barite were both lower than 20%, and the flotation recovery rates of octylhydroxamic acid for calcite and barite were 62% and 50% respectively. Compared with benzohydroxamic acid and octylhydroxamic acid, benzyloxyacetylhydroxamic acid showed excellent collecting property and selectivity.

[0096] Example 6

[0097] Flotation of cassiterite with benzyloxyacetylhydroxamic acid:

[0098] In this example, cassiterite provided by a Yunnan ore dressing plant was used as the research object to compare the Sn grade and flotation recovery rate of benzyloxyacetylhydroxamic acid and benzohydroxamic acid under the same conditions. The Sn grade in the original cassiterite ore was between 0.25% and 0.30%. The flotation process flow chart is shown in Figure 8 as follows, and the test results are shown in Table 2.

[0099] Table 2

[0100]

[0101] From the above results, it can be seen that when flotation of cassiterite with different collectors at the same dosage, the synthesized benzyloxyacetylhydroxamic acid of the present invention has excellent flotation indexes compared with the traditional collector benzohydroxamic acid.

Claims

1. An alkyl ether-based hydroxamic acid collector, characterized in that, The structural formula of the collector is as shown in the following formula <Ⅰ>: In Formula I, R1 and R2 are each independently selected from one of the following groups: C1-C 20 alkylene or methylene; C3-C8 cycloalkylene; C2-C 20 alkenyl; C2-C 20 alkynyl; C3-C 10 heterocyclic group; C6-C 20 aryl or C3-C 20 heteroaryl; R3 is selected from one of the following groups: H; a halogen atom; a nitro group; an alkyl group having 1 to 6 carbon atoms; a cycloalkyl group having 3 to 8 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heterocyclic group having 3 to 10 carbon atoms; an aromatic group having 6 to 10 carbon atoms or a heteroaryl group having 3 to 10 carbon atoms.

2. The alkyl ether hydroxamic acid collector according to claim 1, characterized in that, Each of the R1 and R2 is independently selected from C1-C6 alkylene or methylene; R3 is selected from H or C1-C6 alkyl; preferably, each of the R1 and R2 is independently selected from one of methylene, ethyl or propyl; R3 is selected from one of H, methyl or ethyl.

3. The preparation method of the alkyl ether hydroxamic acid collector according to claim 1 or 2, characterized in that, It includes the following steps: (1) Esterification reaction: Mix alkyl ether acetic acid having the structure shown in formula <Ⅱ> with a solvent, and carry out an esterification reaction under the catalysis of thionyl chloride to obtain methyl alkyl ether acetate having the structure shown in formula <Ⅲ>; (2) Hydroxamic acid reaction: Carry out a hydroxamic acid reaction on methyl alkyl ether acetate having the structure shown in formula <Ⅲ> with a hydroxylamine compound and a base in a solvent to prepare the alkyl ether hydroxamic acid collector; Among them, R1 and R2 are each independently selected from one of the following groups: C1-C 20 alkylene or methylene; C3-C8 cycloalkylene; C2-C 20 alkenyl; C2-C 20 alkynyl; C3-C 10 heterocyclic group; C6-C 20 aryl or C3-C 20 heteroaryl; R3 is selected from one of the following groups: H; a halogen atom; a nitro group; an alkyl group having 1 to 6 carbon atoms; a cycloalkyl group having 3 to 8 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heterocyclic group having 3 to 10 carbon atoms; an aromatic group having 6 to 10 carbon atoms or a heteroaryl group having 3 to 10 carbon atoms.

4. The preparation method according to claim 3, characterized in that, In step (1), the solvent is any one of water, methanol, ethanol, propanol or butanol; preferably, the amount of the solvent used is 5-8 times the weight of the alkyl ether acetic acid.

5. The preparation method according to claim 3, characterized in that, In step (1), the molar ratio of thionyl chloride to alkyl ether acetic acid is 1:1.0-1.

2.

6. The preparation method according to claim 3, characterized in that, In step (1), the reaction temperature of the esterification reaction is 4-25 °C, and the reaction time is 2.5-3 h; preferably, in step (2), the reaction temperature of the hydroxamic acid reaction is 5-60 °C, and the reaction time is 2-5 h.

7. The preparation method according to claim 3, characterized in that In step (2), the hydroxylamine compound is any one of hydroxylamine hydrochloride, hydroxylamine sulfate or hydroxylamine nitrate; preferably, the base is any one of sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate or potassium carbonate.

8. The preparation method according to claim 3 or 7, characterized in that, In step (2), the molar ratio of the hydroxylamine compound to the base is 1:2.0-2.5; preferably, the molar ratio of methyl alkyl ether acetate to the hydroxylamine compound is 1:1.2-1.

5.

9. Use of the alkyl ether hydroxamic acid collector according to claim 1 or 2 or the alkyl ether hydroxamic acid collector prepared by the method according to any one of claims 1-8 in mineral flotation.

10. The application according to claim 9, wherein, The minerals include at least one of rare earth ore, tungsten ore, cassiterite, apatite, malachite, ilmenite.

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