Preparation method for composite quaternary ammonium salt cationic collector and use of preparation method

Abstract

The present disclosure relates to a preparation method for a composite quaternary ammonium salt cationic collector and a use of the preparation method. The method comprises: adding halogenated alkyl into alkyl tertiary amine containing amide groups for a quaternization reaction to obtain an intermediate; and adding a catalyst into the intermediate for a catalytic reaction to obtain a first mixture, adding alkyl benzylamine into the first mixture for an amidation reaction to obtain a second mixture, and carrying out desalination treatment on the second mixture to obtain a composite quaternary ammonium salt cationic collector, wherein a molar ratio of the alkyl tertiary amine to the halogenated alkyl to the alkyl benzylamine is (1-1.4):(0.8-1.2):(1-1.4).

Description

Preparation method and application of composite quaternary ammonium salt cationic collector

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310730899.1 filed on June 19, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of mineral processing reagent preparation, and in particular to a preparation method and application of a composite quaternary ammonium salt cationic collector. Background Art

[0004] At present, domestic bauxite is mainly kaolinite and illite bauxite, and among the bauxite reverse flotation desiliconization collectors, most commonly used are amine cationic collectors. Commonly used amine cationic collectors mainly include dodecylamine, dodecyltrimethylammonium salt and dodecyldimethylbenzyl quaternary ammonium salt and other compounds. Among them, quaternary ammonium salt collectors are more studied, and quaternary ammonium salt compounds are mainly alkyl quaternary ammonium salts. Among the alkyl quaternary ammonium salts, dodecyltrimethylammonium chloride has a better effect on bauxite reverse flotation desiliconization than dodecylammonium. Studies have shown that the effect of dodecyltrimethylammonium chloride on aluminosilicate minerals is mainly electrostatic effect.

[0005] At present, the application of cationic collectors in the flotation of potash ores and lepidolite or in the reverse flotation desiliconization and impurity removal of iron ores and bauxite has its own characteristics, but there are still certain shortcomings, mainly manifested in the poor biodegradability of the collectors, which easily pollutes the environment; they are sensitive to ore slime and have poor selectivity; and the reverse flotation desiliconization efficiency is much lower than the direct flotation desiliconization efficiency. In the related art, cationic collectors are mainly based on dodecylamine or other long-chain fatty amines. Although polyamines, polyetheramines, tertiary amines, quaternary ammonium salts and alkylguanidines have been developed after years of research, which has greatly promoted the development of cationic collectors, their development in the reverse flotation desiliconization process is still relatively slow. In addition, the collectors of the related art have disadvantages such as inconvenient reagent configuration, high foam viscosity, and poor selectivity in the reverse flotation desiliconization process.

[0006] At present, research on cationic collectors mainly focuses on etheramines and quaternary ammonium salts. However, these directions still have disadvantages such as difficult synthesis and high cost, which seriously hinder the promotion and application of bauxite reverse flotation desiliconization process. Therefore, how to provide a simple and efficient synthesis method of cationic collectors to improve the cationic reverse flotation desiliconization process is a technical problem that needs to be solved urgently.

[0007] Summary of the Invention

[0008] By utilizing one or more embodiments of the present disclosure, the technical problem of difficult and high cost synthesis of cationic collectors for reverse flotation desiliconization in the related art is solved.

[0009] According to a first aspect of the present disclosure, a method for preparing a composite quaternary ammonium salt cationic collector is provided, the method comprising: adding a halide alkyl to an amide-containing alkyl tertiary amine to carry out a quaternization reaction to obtain an intermediate; adding a catalyst to the intermediate to carry out a catalytic reaction to obtain a first mixture; adding an alkylbenzylamine to the first mixture to carry out an amidation reaction to obtain a second mixture; and desalting the second mixture to obtain a composite quaternary ammonium salt cationic collector; wherein the molar ratio of the alkyl tertiary amine, the halide alkyl and the alkylbenzylamine is (1 to 1.4):(0.8 to 1.2):(1 to 1.4).

[0010] In the second aspect, an application of a preparation method of a composite quaternary ammonium salt cationic collector is provided, wherein the application comprises using the composite quaternary ammonium salt cationic collector obtained by the preparation method described in the first aspect in reverse flotation desiliconization of bauxite. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0013] FIG1 shows a schematic flow diagram of a method for preparing a composite quaternary ammonium salt cationic collector according to some embodiments of the present disclosure;

[0014] FIG2 shows a detailed schematic flow diagram of a method for preparing a composite quaternary ammonium salt cationic collector according to some embodiments of the present disclosure;

[0015] FIG3 shows a schematic diagram of the principle of a method for preparing a composite quaternary ammonium salt cationic collector according to some embodiments of the present disclosure;

[0016] FIG4 shows a schematic diagram of a process for using a composite quaternary ammonium salt cationic collector in reverse flotation desiliconization of pure minerals according to some embodiments of the present disclosure;

[0017] FIG5 shows an open circuit process diagram of a composite quaternary ammonium salt cationic collector used in reverse flotation desiliconization of bauxite according to some embodiments of the present disclosure;

[0018] FIG6 shows a schematic diagram of a closed-circuit process for using a composite quaternary ammonium salt cationic collector in reverse flotation desiliconization of bauxite according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0020] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present disclosure can be purchased from the market or prepared by existing methods.

[0021] At present, the main application directions of cationic collectors are:

[0022] (1) Patent CN102259062A discloses a method for preparing organosilicon quaternary ammonium salt compounds and their application in the flotation separation of potassium chloride and sodium chloride and the reverse flotation desiliconization and impurity removal of iron ore and bauxite.

[0023] (2) Patent CN101337204 discloses the use of diquaternary ammonium salt compounds as flotation collectors in the reverse flotation desiliconization of bauxite and iron ore.

[0024] (3) Patent CN107442287A discloses the application of a Gemini surfactant in the reverse flotation desiliconization and impurity removal of potash ore, lepidolite ore or iron ore, and bauxite.

[0025] (4) Patent CN1507954A discloses a collector for reverse flotation desiliconization and its preparation method. The collector is a composite quaternary ammonium salt cationic surfactant containing a quaternary ammonium group and / or a benzyl group-containing quaternary ammonium salt compound, and is suitable for reverse flotation separation of silicate minerals from iron ores such as magnetite, hematite and ilmenite, and ores containing silicate minerals such as bauxite.

[0026] (5) Patent CN106238215A discloses a quaternary ammonium salt cationic collector and its synthesis method. A diquaternary ammonium salt is synthesized by a two-step method and is mainly used for the reverse flotation desiliconization of collophosphate.

[0027] (6) Patent CN112657681A discloses a cationic collector and its preparation method and application, which is used for desiliconization of iron ore, desiliconization of magnesite, desiliconization of phosphate rock, feldspar flotation, adaptive flotation or silicate flotation.

[0028] (7) Patent CN112474061A discloses the preparation and application of a quaternary ammonium salt cationic collector containing an ester group for reverse flotation of phosphate rock. The collector contains an ester group, which makes the collector have a good degradation effect. It contains a long carbon chain and a quaternary ammonium group. However, the amount of the quaternary ammonium salt cationic collector containing an ester group in reverse flotation of phosphate rock is too large and the cost is high. In addition, the raw material N,N-dimethylethanolamine is a controlled product and is flammable and toxic.

[0029] (8) Patent CN107716116A discloses a preparation method and application of an iron ore reverse flotation collector.

[0030] (9) Patent CN110605183A discloses a desiliconized aluminum collector for reverse flotation of phosphate rock, its preparation method, and use. The collector comprises a mixed amine, a mixed alcohol, and methyl cocoate. Patent CN110038728A discloses a method for reverse flotation of hematite using a highly degradable amine collector. The collector used is lauramide propyl dimethylamine oxide. CN109847944A discloses a method for preparing N-(2-hydroxy-1,1-dimethylethyl)alkylamine, which is suitable for the field of reverse flotation of iron ore.

[0031] (10) CN103769307B discloses a water-soluble collector containing a tertiary amine with two hydroxypropyl groups for use in iron ore flotation. This collector has good water solubility but weak collecting ability and is not easy to form foams.

[0032] (11) CN107350084A discloses a triquaternary ammonium salt compound for mineral flotation, which has three mineralophilic groups and is used for the flotation of minerals such as phosphate ore and iron ore.

[0033] (12) CN113751207A discloses a collector, its preparation method and application. The prepared hydrophobic nanoparticle collector is used for desulfurization and collection of fine-grained high-sulfur bauxite by reverse flotation, and belongs to a desulfurization collector.

[0034] (13) CN113769896A discloses a collector, its preparation method and application. The prepared collector mainly captures aluminum minerals in bauxite and is a positive flotation desiliconization collector, which is different from the reverse flotation desiliconization collector of the present invention.

[0035] The collectors of the above-mentioned related technologies have their own characteristics in the flotation of potash ores and lepidolite or in the reverse flotation desiliconization and impurity removal of iron ores and bauxite, but there are still certain shortcomings, mainly manifested in the poor biodegradability of the collectors, which easily pollute the environment; they are sensitive to ore slime and have poor selectivity; and the reverse flotation desiliconization efficiency is much lower than the direct flotation desiliconization. Moreover, the cationic collectors of the related technologies are mainly based on dodecylamine or other long-chain fatty amines. Although polyamines, polyetheramines, tertiary amines, quaternary ammonium salts and alkylguanidines have been developed after years of research, which has greatly promoted the development of cationic collectors, their development in the reverse flotation desiliconization process is still relatively slow. In addition, the collectors of the related technologies have disadvantages such as inconvenient reagent configuration, high foam viscosity, and poor selectivity in the reverse flotation desiliconization process.

[0036] At present, research on cationic collectors mainly focuses on etheramines and quaternary ammonium salts. However, these directions still have disadvantages such as difficult synthesis and high cost, which seriously hinder the promotion and application of bauxite reverse flotation desiliconization process. Therefore, how to provide a simple and efficient synthesis method of cationic collectors to improve the cationic reverse flotation desiliconization process is a technical problem that needs to be solved urgently.

[0037] As shown in FIG1 , a method for preparing a composite quaternary ammonium salt cationic collector according to some embodiments of the present disclosure comprises the following steps:

[0038] S1. A quaternization reaction is performed by adding an alkyl halide to an alkyl tertiary amine containing an amide group to obtain an intermediate containing an amide group;

[0039] S2. A catalyst is added to the intermediate to carry out a catalytic reaction to obtain a first mixture, an alkylbenzylamine is added to the first mixture to carry out an amidation reaction to obtain a second mixture, and the second mixture is desalted to obtain a composite quaternary ammonium salt cationic collector;

[0040] The molar ratio of the alkyl tertiary amine, the alkyl halide and the alkyl benzylamine is (1-1.4):(0.8-1.2):(1-1.4).

[0041] In some optional embodiments of the present disclosure, the molar ratio of alkyl tertiary amine, alkyl halide and alkyl benzylamine is controlled to be (1-1.4):(0.8-1.2):(1-1.4), which can make the quaternization reaction sufficient, so that the intermediate contains quaternary ammonium group and carboxylic acid group, and at the same time, it can also form amide group in the subsequent amidation reaction, thereby obtaining a composite quaternary ammonium salt cationic scavenger containing quaternary ammonium group, amide group, linear alkane group and benzyl group.

[0042] The principles of some optional preparation methods of the composite quaternary ammonium salt cationic collector disclosed in the present invention are shown in FIG3 , wherein the R1 group represents a straight-chain alkane with a hydrocarbon chain length of 11 to 17, and X is Cl or Br.

[0043] In some optional embodiments of the present disclosure, the alkyl tertiary amine is an alkyl tertiary amine with a carbon chain length of 12 to 18.

[0044] In some optional embodiments of the present disclosure, the carbon chain length of the alkyl tertiary amine is controlled to be 12 to 18, so that a long-chain alkane group can be present in the composite quaternary ammonium salt cationic collector. Since the long-chain alkane group is hydrophobic, the hydrophobicity of the composite quaternary ammonium salt cationic collector can be improved, thereby facilitating the smooth progress of the capture process.

[0045] In some optional embodiments of the present disclosure, the alkyl tertiary amine includes lauryl amide propyl dimethyl tertiary amine and / or stearyl amide propyl dimethyl tertiary amine; and / or,

[0046] The haloalkyl group includes sodium chloroacetate and / or sodium bromoacetate; and / or,

[0047] The alkylbenzylamine includes benzyloxylamine hydrochloride.

[0048] In some optional embodiments of the present disclosure, the alkyl tertiary amine is controlled to include lauryl amide propyl dimethyl tertiary amine and / or stearyl amide propyl dimethyl tertiary amine; and / or the alkyl halide includes sodium chloroacetate and / or sodium bromoacetate; and / or the alkyl benzylamine includes benzyloxyamine hydrochloride, thereby making it possible to simply synthesize a composite quaternary ammonium salt cationic collector containing a quaternary ammonium group, an amide group, a linear alkane group and a benzyl group.

[0049] In some optional embodiments of the present disclosure, the temperature of the quaternization reaction is 30° C. to 55° C., and the time of the quaternization reaction is 18 h to 24 h.

[0050] In some optional embodiments of the present disclosure, the temperature of the quaternization reaction is controlled to be 30° C. to 55° C., and the time of the quaternization reaction is 18 h to 24 h, so that the alkyl tertiary amine and the haloalkyl group can fully react to obtain an intermediate containing a quaternary ammonium group and a carboxylic acid group.

[0051] In some optional embodiments of the present disclosure, the temperature of the amidation reaction is 3° C. to 10° C., and the time of the amidation reaction is 22 h to 26 h.

[0052] In some optional embodiments of the present disclosure, the temperature of the amidation reaction is controlled to be 3°C to 10°C, and the time of the amidation reaction is 22h to 26h, so that the amidation reaction between the intermediate after the catalytic reaction and the alkylbenzylamine can be fully carried out to form an amide group, thereby obtaining a composite quaternary ammonium salt cationic scavenger containing a quaternary ammonium group, an amide group, a straight-chain alkane group and a benzyl group.

[0053] In some optional embodiments of the present disclosure, the step of adding a haloalkyl group to an amide-containing alkyl tertiary amine to carry out a quaternization reaction to obtain an intermediate comprises the following sub-steps:

[0054] S101. After adding a solvent to an alkyl tertiary amine containing an amide group, a first stirring is performed to obtain an alkyl tertiary amine solution, and an alkyl halide is added dropwise to the alkyl tertiary amine solution while a second stirring is performed to quaternize the alkyl tertiary amine containing an amide group with the alkyl halide to obtain an intermediate precursor;

[0055] S102. Adjusting the pH of the intermediate precursor, condensing and extracting the intermediate precursor after adjusting the pH, and then evaporating and drying with a desiccant and purifying by vacuum distillation to obtain an intermediate containing a quaternary ammonium group and a carboxylic acid group.

[0056] In some optional embodiments of the present disclosure, an alkyl tertiary amine solution can be formed by first stirring and mixing the alkyl tertiary amine with a solvent, and then a haloalkyl group is added to the alkyl tertiary amine solution while performing a second stirring, so that a sufficient quaternization reaction occurs between the haloalkyl group and the alkyl tertiary amine containing an amide group, thereby obtaining an intermediate precursor containing a quaternary ammonium group and a carboxylic acid group. The intermediate precursor is then subjected to subsequent pH adjustment, condensation, and extraction, and then evaporation drying and vacuum distillation purification can be used to obtain an intermediate containing a quaternary ammonium group and a carboxylic acid group, thereby further improving the purity of the intermediate.

[0057] In some optional embodiments of the present disclosure, the solvent may be anhydrous ethanol.

[0058] In some optional embodiments of the present disclosure, the desiccant may be sodium sulfate.

[0059] In some optional embodiments of the present disclosure, the reagent used for the extraction may be acetone.

[0060] In some optional embodiments of the present disclosure, the first stirring time is 10 min to 20 min; and / or the second stirring temperature is 35° C. to 45° C., and the second stirring time is 19 h to 22 h.

[0061] In some optional embodiments of the present disclosure, the first stirring time is controlled to be 10 minutes to 20 minutes, so that the alkyl tertiary amine can be fully dispersed in the solvent through the first stirring; the second stirring temperature is controlled to be 35°C to 45°C and the second stirring time is controlled to be 19 hours to 22 hours, so that the quaternization reaction can occur between the haloalkyl and the alkyl tertiary amine and the quaternization reaction can be completed through the second stirring, thereby obtaining sufficient intermediates.

[0062] In some optional embodiments of the present disclosure, the step of adding a catalyst to the intermediate to carry out a catalytic reaction to obtain a first mixture, adding alkylbenzylamine to the first mixture to carry out an amidation reaction to obtain a second mixture, and desalting the second mixture to obtain a composite quaternary ammonium salt cationic collector comprises the following sub-steps:

[0063] S201. To a solution containing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) hydrochloride and N-hydroxysulfosuccinimide (sulfo-NHS), the intermediate is added for a catalytic reaction to obtain a first mixture, the pH of the first mixture is adjusted to a preset pH using a 2-(N-morpholino)ethanesulfonic acid (MES) solution, and an alkylbenzylamine is added for an amidation reaction to obtain a second mixture, and the second mixture is desalted to obtain a composite quaternary ammonium salt cationic collector;

[0064] Wherein, the preset pH is 5.0-5.5.

[0065] In some optional embodiments of the present disclosure, semi-stable NHS or sulfo-NHS ester can be formed by a catalytic reaction between EDC hydrochloride, sulfo-NHS and the intermediate, and then the pH of the catalytic reaction solution of EDC hydrochloride, sulfo-NHS and the intermediate is controlled to a preset pH of 5.0 to 5.5 by MES solution, so that the semi-stable NHS or sulfo-NHS ester in the first mixture can undergo an amidation reaction with the subsequent alkylbenzylamine, and an amide group can be formed on the intermediate containing a quaternary ammonium group and a carboxylic acid group, and a benzyl group can be introduced at the same time, thereby obtaining a composite quaternary ammonium salt cationic collector containing a quaternary ammonium group, an amide group, a linear alkane group and a benzyl group on the basis of the intermediate containing a quaternary ammonium group and a carboxylic acid group.

[0066] In some optional embodiments, the structural formula of the composite quaternary ammonium salt cationic collector is as shown in Formula 1:

[0067] wherein the R1 group includes a straight chain alkane group; X includes Cl or Br;

[0068] The carbon chain length of the linear alkane group is 11 to 17.

[0069] In some optional embodiments of the present disclosure, the structural formula of the composite quaternary ammonium salt cationic collector is controlled to be as shown in Formula 1, so that the position and distribution of the quaternary ammonium group, amide group, linear alkane group and benzyl group contained in the composite quaternary ammonium salt cationic collector can be clearly defined, thereby ensuring that the composite quaternary ammonium salt cationic collector has good water solubility, and also has the characteristics of high reverse flotation desiliconization efficiency and environmental friendliness. At the same time, by introducing halide ions as anions into the composite quaternary ammonium salt cationic collector, the hydrophobic benzyl group in the composite quaternary ammonium salt cationic collector can be better matched, thereby improving the foaming performance of the composite quaternary ammonium salt cationic collector, making the foam easy to dissipate after reverse flotation desiliconization, and having good foam fluidity.

[0070] By controlling the length of the straight-chain alkane group in the composite quaternary ammonium salt cationic collector to be 11 to 17, the R1 group can be a longer straight-chain alkane group, thereby improving the hydrophobicity of the composite quaternary ammonium salt cationic collector and improving the reverse flotation desiliconization effect of the composite quaternary ammonium salt cationic collector on silicate minerals.

[0071] Based on a general inventive concept, the application of the preparation method of the composite quaternary ammonium salt cationic collector according to some embodiments of the present disclosure includes using the composite quaternary ammonium salt cationic collector obtained by the preparation method in bauxite reverse flotation desiliconization.

[0072] In some optional embodiments of the present disclosure, it is found that the reverse flotation desiliconization pH value of the composite quaternary ammonium salt cationic collector is 5-6 in the application of bauxite reverse flotation desiliconization. The aluminum-silicon ratio of the selected bauxite is 3.55, the grade of SiO2 is 14.29%, the aluminum concentrate obtained after reverse flotation desiliconization has an aluminum-silicon ratio of 4.76, the grade of SiO2 is reduced to 11.03, the grade of SiO2 in the tailings is 23.12%, and the recovery rate of SiO2 reaches more than 48.31%; the aluminum-silicon ratio of the selected bauxite is 5.69, the grade of SiO2 is 10.92%, and the aluminum concentrate with a yield of 77.41% is obtained after reverse flotation desiliconization, the aluminum concentrate has an aluminum-silicon ratio of 7.23, the grade of SiO2 is reduced to 8.97%, and the Al2O3 recovery rate / % reaches 80.19%.

[0073] This application is realized based on the above-mentioned preparation method. The steps of the preparation method can refer to the above-mentioned embodiment. Since this application adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0074] Based on a general inventive concept, a composite quaternary ammonium salt cationic collector is prepared according to some embodiments of the present disclosure and a preparation method of the composite quaternary ammonium salt cationic collector.

[0075] The composite quaternary ammonium salt cationic collector is realized based on the preparation method of the above-mentioned composite quaternary ammonium salt cationic collector. The steps of the preparation method of the composite quaternary ammonium salt cationic collector can refer to the above-mentioned embodiment. Since the composite quaternary ammonium salt cationic collector adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0076] Based on a general inventive concept, according to some embodiments of the present disclosure, a composite quaternary ammonium salt cationic collector is used in a bauxite reverse flotation desiliconization process.

[0077] The application of the composite quaternary ammonium salt cationic collector in the bauxite reverse flotation desiliconization process is based on the above-mentioned composite quaternary ammonium salt cationic collector. The steps of the preparation method of the composite quaternary ammonium salt cationic collector can refer to the above-mentioned embodiment. Since the application of the composite quaternary ammonium salt cationic collector in the bauxite reverse flotation desiliconization process adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0078] The following examples further illustrate the present disclosure. It should be understood that these examples are intended to illustrate the present disclosure only and are not intended to limit the scope of the present disclosure. Experimental methods in the following examples where conditions are not specified are generally measured in accordance with national standards. If there are no corresponding national standards, the methods were performed in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0079] Example 1

[0080] As shown in FIG2 , a method for preparing a composite quaternary ammonium salt cationic collector comprises:

[0081] (1) The molar ratio of each raw material is controlled to be n (alkyl tertiary amine): n (haloalkyl): n (benzyloxyamine hydrochloride) = 1.2:1:1.2.

[0082] (2) Lauramide propyl dimethyl tertiary amine was added to the reactor, anhydrous ethanol was added and stirred for 10 to 20 minutes, and then sodium chloroacetate was added dropwise for 1 hour, and then stirred at 40°C for 20 hours. After the reaction, 1 mol / L HCl was added to acidify to pH 5, vacuum condensed and extracted with acetone (2×20 mL), the organic layers were combined, washed with brine (3×20 mL), dried with sodium sulfate and evaporated, and the residue was purified by vacuum distillation to obtain the first product.

[0083] (3) The first product was added to a solution containing EDC and sulfo-NHS, and the pH value was adjusted to 5.5 with MES as a buffer, and then a benzyloxyamine hydrochloride solution was added dropwise. After the addition was completed, the mixture was reacted at 4°C for 24 hours. After desalting, a composite quaternary ammonium salt cationic collector was obtained, which was recorded as collector A.

[0084] Example 2

[0085] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is:

[0086] A method for preparing a composite quaternary ammonium salt cationic collector comprises:

[0087] (1) The molar ratio of each raw material is controlled to be n (alkyl tertiary amine): n (haloalkyl): n (benzyloxyamine hydrochloride) = 1:1.2:1.

[0088] (2) Lauramide propyl dimethyl tertiary amine was added to the reactor, anhydrous ethanol was added and stirred for 10 to 20 minutes, and then sodium chloroacetate was added dropwise for 1 hour, and then stirred at 35°C for 19 hours. After the reaction, 1 mol / L HCl was added to acidify to pH 5, vacuum condensed and extracted with acetone (2×20 mL), the organic layers were combined, washed with brine (3×20 mL), dried with sodium sulfate and evaporated, and the residue was purified by vacuum distillation to obtain the first product.

[0089] (3) The first product was added to a solution containing EDC and sulfo-NHS, and the pH value was adjusted to 5.5 with MES as a buffer, and then a benzyloxyamine hydrochloride solution was added dropwise. After the addition was completed, the mixture was reacted at 4°C for 23 hours. After desalting, a composite quaternary ammonium salt cationic collector was obtained, which was recorded as collector B.

[0090] Example 3

[0091] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is:

[0092] A method for preparing a composite quaternary ammonium salt cationic collector comprises:

[0093] (1) The molar ratio of the raw materials is controlled to be n(alkyl tertiary amine):n(halogenated alkyl):n(benzyloxyamine hydrochloride) = 1.2:0.8:1.4.

[0094] (2) Lauramide propyl dimethyl tertiary amine was added to the reactor, anhydrous ethanol was added and stirred for 10 to 20 minutes, and then sodium chloroacetate was added dropwise for 1 hour, and then stirred at 45°C for 19 hours. After the reaction, 1 mol / L HCl was added to acidify to pH 5, vacuum condensed and extracted with acetone (2×20 mL), the organic layers were combined, washed with brine (3×20 mL), dried with sodium sulfate and evaporated, and the residue was purified by vacuum distillation to obtain the first product.

[0095] (3) The first product was added to a solution containing EDC and sulfo-NHS, and the pH value was adjusted to 5.5 with MES as a buffer, and then a benzyloxyamine hydrochloride solution was added dropwise. After the addition was completed, the mixture was reacted at 4°C for 25 hours. After desalting, a composite quaternary ammonium salt cationic collector was obtained, which was recorded as collector C.

[0096] Related experiments and effect data:

[0097] 1. Collectors A, B, C and conventional reverse flotation desiliconization collectors (such as dodecyltrimethylammonium chloride, lauryl amide) are used in the reverse flotation desiliconization process of pure kaolinite ore.

[0098] Reverse flotation desiliconization tests were conducted on an XFG hanging trough flotation machine at a spindle speed of 1650 rpm. Three grams of mineral was weighed and placed in a 40 mL flotation cell. A defined amount (25 mL to 30 mL) of distilled water was added and stirred for 1 minute. A conditioning agent was then added for 3 minutes, followed by a collector and 3 minutes of stirring. Reverse flotation desiliconization was then performed for 5 minutes. During the reverse flotation desiliconization process, the foam product was collected, dried, and weighed separately from the product in the cell, and the recovery rate was calculated. The experimental flow chart is shown in Figure 4, and the test results are shown in Table 1.

[0099] Table 1 Comparative test results of collector reverse flotation for desiliconized kaolinite

[0100] It can be seen from Table 1 that among the prepared collectors, Collector A has a stronger ability to capture kaolinite and surpasses the conventional reverse flotation desiliconization collector in the related art.

[0101] 2. Collectors A, B, C and conventional reverse flotation desiliconization collectors in related technologies are used for reverse flotation desiliconization of pure illite minerals.

[0102] The test steps are the same as above, and the test results are shown in Table 2.

[0103] Table 2 Comparative test results of collector reverse flotation desiliconized illite

[0104] It can be seen from Table 2 that among the three prepared reagents, collector A has a stronger ability to capture illite and surpasses the conventional reverse flotation desiliconization collector in the related art.

[0105] 3. Collectors A, B, C and conventional reverse flotation desiliconization collectors in related technologies are used for reverse flotation desiliconization of pure pyrophyllite ore.

[0106] The test steps are the same as above, and the test results are shown in Table 3.

[0107] Table 3 Collector reverse flotation desiliconized pyrophyllite comparative test results

[0108] The test results in Table 3 show that Collector A has a strong ability to capture pyrophyllite and surpasses the conventional reverse flotation desiliconization collector in the related art.

[0109] 4. Collectors A, B, and C, along with conventional reverse flotation desiliconization collectors in related art, were used for reverse flotation desiliconization of bauxite. The bauxite used was Henan bauxite, and its component analysis is shown in Tables 4 and 5. 1227 refers to dodecyldimethylbenzyl ammonium chloride, and 1221 refers to dodecyltrimethylammonium chloride.

[0110] The chemical composition analysis results of the experimental bauxite are shown in Table 4 and Table 5:

[0111] Table 4 Chemical composition analysis results of bauxite minerals (%)

[0112] Table 5 Analysis results of bauxite mineral phase composition (%)

[0113] Experimental steps:

[0114] Step 1: Slurry preparation:

[0115] 250 g of ore sample was put into the flotation cell of a 1.5 L XFG hanging trough flotation machine, tap water was added, and the slurry was prepared for 3 minutes at a flotation machine speed of 2100 r / min.

[0116] Step 2: Add the adjuster:

[0117] After step 1 above, hydrochloric acid and an inhibitor were added to adjust the pH to between 5 and 6, and the slurry was further stirred for 2 minutes.

[0118] Step 3: Add collector:

[0119] In the above step 2, a collector is added to perform reverse flotation desiliconization for 5 minutes, and then the air valve is opened to perform flotation scraping.

[0120] Step 4: Reverse flotation desiliconization product processing:

[0121] After the reverse flotation desiliconization process is completed, the samples of the flotation foam product mixed with the middlings (tailings) and the product in the tank (concentrate) are dried, weighed, tested, and the product indicators are calculated. The test process is shown in Figure 5, where the test process includes one roughing, one cleaning, and one scavenging process. The flotation foam and middlings are mixed as tailings, and the bottom of the tank is used as concentrate. The results are shown in Table 6.

[0122] Table 6 Reagent reverse flotation desiliconization test results

[0123] Table 6 shows that among the three prepared collectors (Collector A, Collector B, and Collector C), Collector A requires a lower dosage, while also achieving a higher concentrate yield, aluminum-silicon ratio, and aluminum recovery rate. Compared to conventional collectors in related art, Collector A requires a lower dosage. Furthermore, observing the increases in the concentrate yield and aluminum-silicon ratio indicates that Collector A provides superior reverse flotation desiliconization effectiveness.

[0124] 5. Collector A and conventional collectors in related technologies were used in reverse flotation desiliconization of Chongqing mine.

[0125] The chemical composition analysis results of Chongqing ore are shown in Tables 7 and 8. The experimental steps are the same as those of Experiment 4, and the experimental results are shown in Table 9.

[0126] Table 7 Chemical composition analysis results of bauxite minerals (%)

[0127] Table 8 Bauxite mineral phase composition analysis results (%)

[0128] Table 9 Reverse flotation desiliconization test results at the optimal dosage of each collector

[0129] As shown in Table 9, the optimal dosage of different collectors for reverse flotation desiliconization is different, and the dosage of collector A is relatively small. By observing and comparing the aluminum-silicon ratio and yield of each concentrate, the concentrate yield obtained after reverse flotation with collector A reached 76.61%, the aluminum-silicon ratio was relatively high, reaching 5.5, and the aluminum recovery rate in the concentrate was relatively high, reaching 81.7%.

[0130] 6. An example of the application of Collector A in open circuit test for reverse flotation desiliconization in Shanxi bauxite.

[0131] The chemical composition analysis results of Shanxi ore are shown in Tables 10 and 11. The experimental steps are the same as those of Experiment 4, and the experimental results are shown in Table 12.

[0132] Table 10 Chemical composition analysis results of bauxite minerals (%)

[0133] Table 11 Analysis results of bauxite mineral phase composition (%)

[0134] The test steps were the same as in Example 4, and the test results are shown in Table 12.

[0135] Table 12 Comparative test results of collector reverse flotation desiliconized bauxite

[0136] According to Table 12, a comprehensive comparison of the concentrate yield, the aluminum-silicon ratio, and the silicon recovery rate in the tailings shows that compared with conventional collectors in the related art, the collectors of some embodiments of the present disclosure have better selectivity and stronger collection ability.

[0137] 7. Example of application of Collector A in closed-circuit test of reverse flotation desiliconization in bauxite:

[0138] The test steps are the same as those in Experiment 4. The test process is shown in Figure 6, and the test results are shown in Table 13:

[0139] Table 13 Comparative test results of collector reverse flotation desiliconized bauxite

[0140] Table 13 shows that in the closed circuit test, the collectors according to some embodiments of the present disclosure achieved better reverse flotation desiliconization effects.

[0141] One or more technical solutions in the embodiments of the present disclosure may also have at least the following technical effects or advantages:

[0142] (1) According to the preparation method of the composite quaternary ammonium salt cationic collector of some embodiments of the present disclosure, the prepared composite quaternary ammonium salt compound is easier to degrade and more hydrophilic due to the presence of an amide group in the molecule, and is therefore more friendly to the environment and humans in terminal applications; and its molecule has a hydrophobic benzyl group and a quaternary ammonium group that is affinity with the mineral surface group, thereby enhancing the reverse flotation separation of oxide ores and salt minerals, and has the characteristic of high reverse flotation desiliconization efficiency.

[0143] (2) According to a method for preparing a composite quaternary ammonium salt cationic collector in some embodiments of the present disclosure, the prepared composite quaternary ammonium salt cationic collector has good water solubility and is green and safe.

[0144] (3 According to the application of a method for preparing a composite quaternary ammonium salt cationic collector in some embodiments of the present disclosure, the obtained composite quaternary ammonium salt cationic collector has a strong capture ability for silicate minerals such as kaolinite and illite, is suitable for bauxite reverse flotation desiliconization, has good selectivity, and requires a small amount of water.

[0145] (4) According to the application of the preparation method of the composite quaternary ammonium salt cationic collector in some embodiments of the present disclosure, the obtained composite quaternary ammonium salt cationic collector is floated under acidic pulp, which is beneficial to the utilization of recycled water; and compared with conventional reverse flotation desiliconization collectors, the collector provided by the embodiments of the present disclosure has a small dosage, a high aluminum-silicon ratio of the concentrate, and a high reverse flotation desiliconization efficiency.

[0146] (5) According to the application of a method for preparing a composite quaternary ammonium salt cationic collector in some embodiments of the present disclosure, the foam is easy to disappear after flotation and the foam fluidity is good.

[0147] The above technical solution provided by the embodiments of the present disclosure has the following advantages compared with the related art:

[0148] The present invention provides a preparation method of a composite quaternary ammonium salt cationic collector, which comprises the following steps: using an alkyl tertiary amine and a haloalkyl to carry out a quaternary ammonium reaction to generate an intermediate having a quaternary ammonium group and a carboxylic acid group; then using a catalyst to carry out a catalytic reaction on the intermediate; and then adding alkylbenzylamine to carry out an amidation reaction, so that the carboxylic acid group can react with the alkylbenzylamine under the condition of the catalyst to generate an amide group and simultaneously obtain a benzyl group, thereby obtaining a composite quaternary ammonium salt cationic collector containing a quaternary ammonium group, an amide group, a straight-chain alkane group and a benzyl group. The straight-chain alkane group makes the cationic collector have good hydrophobicity, and the quaternary ammonium group can generate static electricity by reacting with the surface of siliceous mineral particles. The quaternary ammonium group can be adsorbed on the surface of mineral particles to float out the siliceous mineral particles, and the quaternary ammonium group can be used for reverse flotation and desiliconization of silicate minerals under acidic pulp. At the same time, the presence of the amide group makes it easier to degrade and more hydrophilic, so it is more friendly to the environment and people in terminal applications. At the same time, the molecule has a hydrophobic benzyl group, which can enhance the flotation separation of oxide ores and salt minerals, improve their foaming performance and increase the desiliconization selectivity. It has the characteristics of high reverse flotation desiliconization efficiency and environmental friendliness. Since the overall synthesis process only requires three steps of reaction and the reaction conditions are mild, the cationic collector can be synthesized more simply and at a low cost. The various embodiments of the present disclosure can be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a hard limit to the scope of the present disclosure; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, description of a range from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5, etc., as well as individual numbers within that range, such as 1, 2, 3, 4, and 5, regardless of the range. Additionally, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.

[0149] In the present disclosure, unless otherwise specified, the directional words used, such as "upper" and "lower", specifically refer to the directions of the drawings in the accompanying drawings. In addition, in the description of the present disclosure, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" refers to one or more, and "plurality" refers to 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 mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0150] The foregoing description is intended only to provide specific embodiments of the present disclosure, which will enable those skilled in the art to understand and implement the present 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 the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein, but rather to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a composite quaternary ammonium salt cationic collector, comprising: Adding a haloalkyl group to an alkyl tertiary amine containing an amide group to carry out a quaternization reaction to obtain an intermediate; Adding a catalyst to the intermediate to carry out a catalytic reaction to obtain a first mixture, adding alkylbenzylamine to the first mixture to carry out an amidation reaction to obtain a second mixture, and desalting the second mixture to obtain a composite quaternary ammonium salt cationic collector; Wherein, the molar ratio of the alkyl tertiary amine, the alkyl halide and the alkyl benzylamine is (1-1.4):(0.8-1.2):(1-1.4).

2. The preparation method according to claim 1, wherein The alkyl tertiary amine is an alkyl tertiary amine with a carbon chain length of 12 to 18.

3. The preparation method according to claim 2, wherein The alkyl tertiary amine includes lauryl amide propyl dimethyl tertiary amine and / or stearyl amide propyl dimethyl tertiary amine; and / or, The haloalkyl group includes sodium chloroacetate and / or sodium bromoacetate; and / or, The alkylbenzylamine includes benzyloxylamine hydrochloride.

4. The preparation method according to claim 1, wherein The temperature of the quaternization reaction is 30° C. to 55° C., and the time of the quaternization reaction is 18 h to 24 h.

5. The preparation method according to claim 1, wherein The temperature of the amidation reaction is 3° C. to 10° C., and the time of the amidation reaction is 22 h to 26 h.

6. The preparation method according to claim 1, wherein The method of adding a haloalkyl group to an amide-containing alkyl tertiary amine to carry out a quaternization reaction to obtain an intermediate comprises the steps of: Adding a solvent to the alkyl tertiary amine containing an amide group and performing a first stirring to obtain an alkyl tertiary amine solution, adding a haloalkyl to the alkyl tertiary amine solution by dropwise addition and performing a second stirring to allow the alkyl tertiary amine containing an amide group to undergo a quaternization reaction with the haloalkyl to obtain an intermediate precursor; The pH value of the intermediate precursor is adjusted, and the intermediate precursor after the adjustment of pH value is condensed and extracted, and then evaporated and dried by a desiccant and purified by vacuum distillation to obtain an intermediate containing a quaternary ammonium group and a carboxylic acid group.

7. The preparation method according to claim 6, wherein: The first stirring time is 10 min to 20 min; and / or, The temperature of the second stirring is 35° C. to 45° C., and the time of the second stirring is 19 h to 22 h.

8. The preparation method according to claim 1, wherein The method comprises the steps of adding a catalyst to the intermediate to carry out a catalytic reaction to obtain a first mixture, adding alkylbenzylamine to the first mixture to carry out an amidation reaction to obtain a second mixture, and desalting the second mixture to obtain a composite quaternary ammonium salt cationic collector. The intermediate is added to a solution containing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysulfosuccinimide for catalytic reaction to obtain a first mixture, the pH of the first mixture is adjusted to a preset pH using a 2-(N-morpholine)ethanesulfonic acid solution, and then an alkylbenzylamine is added for amidation reaction to obtain a second mixture, and the second mixture is desalted to obtain a composite quaternary ammonium salt cationic collector; Wherein, the preset pH is 5.0-5.

5.

9. The preparation method according to claim 1, wherein The structural formula of the composite quaternary ammonium salt cationic collector is shown in Formula 1: wherein the R1 group includes a straight chain alkane group; X includes Cl or Br; The carbon chain length of the straight chain alkane group is 11 to 17.

10. An application of a preparation method of a composite quaternary ammonium salt cationic collector, the application comprising using the composite quaternary ammonium salt cationic collector obtained by the preparation method according to any one of claims 1 to 9 in reverse flotation desiliconization of bauxite.

11. A composite quaternary ammonium salt cationic collector, prepared by the preparation method of the composite quaternary ammonium salt cationic collector according to any one of claims 1 to 9.

12. Use of the composite quaternary ammonium salt cationic collector as claimed in claim 11, wherein the composite quaternary ammonium salt cationic collector is used in a bauxite reverse flotation desiliconization process.

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