Dicarboxylic acid nano collecting agent and synthesis method thereof

Abstract

The invention discloses a dicarboxylic acid nano collecting agent and a synthesis method thereof, belongs to the technical field of mineral flotation, and aims to solve the problems that a stable adsorption layer is difficult to form on the surfaces of mineral particles due to less adsorption sites of a collecting agent and the flotation effect is poor due to poor hydrophobicity in the prior art. The dicarboxylic acid nano collecting agent comprises a substrate, a silane coupling layer arranged on the surface of the substrate and a dicarboxylic acid grafting layer arranged on the surface of the silane coupling layer. The synthesis method comprises the following steps: mixing a nano-particle dispersion liquid with a coupling agent, hydrolyzing, stirring, heating, and forming a silane coupling layer on the surface of a substrate; mixing the substrate with the silane coupling layer formed on the surface with a butenedioic acid solution, carrying out polymerization reaction in a closed container under the action of a free radical initiator, and forming a dicarboxylic acid grafting layer on the surface of the silane coupling layer. The method can be used for micro-fine particle oxidized mineral flotation.

Description

Technical Field

[0001] The present invention belongs to the technical field of mineral flotation, and particularly relates to a dicarboxylic acid nano collector applicable to the flotation of fine-grained oxidized minerals and a synthesis method thereof. Background Art

[0002] In the technical field of mineral flotation, traditional collectors, such as sodium oleate and hydroxamic acid, etc., usually have only one functional group in the collector molecule, providing limited adsorption sites during the adsorption process with mineral particles, and it is difficult to form a stable adsorption layer on the surface of mineral particles, thus unable to significantly improve the hydrophobicity of mineral particles.

[0003] Especially for fine-grained oxidized minerals with a particle size less than 20 μm (such as ilmenite, tungsten ore, cassiterite, etc.), due to their small size, strong fluidity in water, insufficient hydrophobicity of their own, and difficulty in effectively contacting and adhering with flotation reagents, the flotation effect is poor. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a dicarboxylic acid nano collector and a synthesis method thereof to solve the problems in the prior art that the adsorption sites of the collector are few, it is difficult to form a stable adsorption layer on the surface of mineral particles, and the poor hydrophobicity leads to a poor flotation effect.

[0005] The object of the present invention is mainly achieved through the following technical solutions.

[0006] In a first aspect, the present invention provides a dicarboxylic acid nano collector, including a substrate, a silane coupling layer provided on the surface of the substrate, and a dicarboxylic acid grafting layer provided on the surface of the silane coupling layer.

[0007] Further, the substrate is TiO 2 metal oxide nanoparticles and / or Fe 2 O 3 metal oxide nanoparticles.

[0008] Further, the silane coupling layer is formed by 5-hexenyltrimethoxysilane and / or 7-octenyltrimethoxysilane on the surface of the substrate through a silane coupling reaction.

[0009] Further, the dicarboxylic acid grafting layer is formed by maleic acid grafted onto the silane coupling layer through free radical polymerization.

[0010] Further, the maleic acid is maleic acid and / or fumaric acid.

[0011] Further, the particle size of the substrate is 100 - 500 nm.

[0012] Second aspect, the present invention also provides a method for synthesizing a dicarboxylic acid nano collector for synthesizing the above-mentioned dicarboxylic acid nano collector. The synthesis method includes the following steps:

[0013] Step 1: Disperse metal oxide nanoparticles in a solution to form a uniform nanoparticle dispersion liquid, with the nanoparticles as the substrate.

[0014] Step 2: Mix the nanoparticle dispersion liquid with a coupling agent, hydrolyze and stir, and then heat to enable the coupling agent to form a chemical bond graft on the surface of the nanoparticles, forming a silane coupling layer on the surface of the substrate.

[0015] Step 3: Mix the substrate with a surface formed with a silane coupling layer with a maleic acid solution, and carry out a polymerization reaction in a closed container under the action of a radical initiator, so that maleic acid is grafted onto the surface of the silane coupling layer, forming a dicarboxylic acid graft layer on the surface of the silane coupling layer.

[0016] Further, in step 3, the radical initiator is ammonium persulfate, potassium persulfate, hydrogen peroxide or azobisisobutyronitrile.

[0017] Further, in step 2, the concentration of the coupling agent is 0.1M - 0.25M.

[0018] Further, in step 3, the concentration of the maleic acid solution is 0.01M - 0.02M.

[0019] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0020] A) The dicarboxylic acid nano collector provided by the present invention adopts a multi-layer composite structure, which greatly increases the particle size of the dicarboxylic acid nano collector, can increase the collision probability between the dicarboxylic acid nano collector and fine-grained oxidized mineral particles, and the surface graft layer of the dicarboxylic acid nano collector is formed by dicarboxylic acid (-COOH), and the number of surface functional groups is greatly increased. During the flotation process, it can provide highly selective adsorption sites on the surface of fine-grained oxidized minerals, enhance the interaction between the reagent and the mineral particles, and the dicarboxylic acid nano collector can form a stable adsorption layer on the surface of the mineral particles.

[0021] B) The binary carboxylic acid nano - collector provided by the present invention. The alkyl chain (C6 or C8) of the silane coupling layer endows the collector with good hydrophobicity, fundamentally improving the hydrophobicity of the mineral particle surface, enabling effective collision and adsorption between the binary carboxylic acid nano - collector and fine - grained oxidized mineral particles, thereby effectively improving the flotation efficiency and selectivity of fine - grained oxidized minerals. In practical applications, the above - mentioned binary carboxylic acid nano - collector is applicable to the flotation of fine - grained oxidized minerals with a particle size of 5μm - 200μm, can significantly reduce the lower limit of the flotation of fine - grained oxidized minerals, has characteristics such as strong adaptability and good flotation performance, and the concentrate recovery rate can reach more than 85%.

[0022] C) For the binary carboxylic acid nano - collector provided by the present invention, the core metal oxide nanoparticles (i.e., the substrate) of the above - mentioned binary carboxylic acid nano - collector are connected to the binary carboxylic acid grafting layer through the Si - O - M bond (M is Ti or Fe) of the silane coupling agent, which can significantly improve the chemical stability of the binary carboxylic acid nano - collector in an aqueous environment.

[0023] In the present invention, the above - mentioned technical solutions can also be combined with each other to achieve more preferred combined solutions. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the examples in the specification and the content specifically pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation of the present invention. Throughout the drawings, the same reference signs represent the same components.

[0025] Figure 1 It is a schematic structural diagram of the binary carboxylic acid nano - collector provided by the present invention;

[0026] Figure 2 It is an infrared spectrum diagram of the binary carboxylic acid nano - collector synthesized in Example 1 of the present invention.

[0027] Reference Signs:

[0028] 1 - Substrate; 2 - Silane coupling layer; 3 - Binary carboxylic acid grafting layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Next, the preferred embodiments of the present invention will be specifically described with reference to the drawings. The drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention, not for limiting the scope of the present invention.

[0030] First, the present invention provides a binary carboxylic acid nano - collector. See Figure 1, including a substrate 1, a silane coupling layer 2 provided on the surface of the substrate 1, and a dicarboxylic acid grafting layer 3 provided on the surface of the silane coupling layer 2. Among them, the substrate 1 is TiO 2 metal oxide nanoparticles and / or Fe 2 O 3 metal oxide nanoparticles. The silane coupling layer 2 is formed by 5-hexenyltrimethoxysilane and / or 7-octenyltrimethoxysilane on the surface of the substrate 1 through a silane coupling reaction. The dicarboxylic acid grafting layer 3 is formed by grafting maleic acid onto the silane coupling layer 2 through free radical polymerization. Exemplarily, the maleic acid is maleic acid (cis-butenedioic acid) and / or fumaric acid (trans-butenedioic acid).

[0031] The structural general formula of the dicarboxylic acid nano-collector is as follows:

[0032]

[0033] In the formula, n = 4 or 6, and m < 50.

[0034] Compared with the prior art, the dicarboxylic acid nano-collector provided by the present invention, on the one hand, adopts a multi-layer composite structure, which greatly increases the particle size of the dicarboxylic acid nano-collector, can increase the collision probability between the dicarboxylic acid nano-collector and the fine-grained oxidized mineral particles. And the surface grafting layer of the dicarboxylic acid nano-collector is formed by dicarboxylic acid (-COOH), and the number of surface functional groups is greatly increased. During the flotation process, it can provide highly selective adsorption sites on the surface of the fine-grained oxidized minerals, enhancing the interaction between the reagent and the mineral particles, and enabling the dicarboxylic acid nano-collector to form a stable adsorption layer on the surface of the mineral particles.

[0035] On the other hand, the alkyl chain (C6 or C8) of the silane coupling layer 2 endows the collector with good hydrophobicity, fundamentally improving the hydrophobicity of the mineral particle surface, enabling effective collision and adsorption between the dicarboxylic acid nano-collector and the fine-grained oxidized mineral particles, thereby effectively improving the flotation efficiency and selectivity of the fine-grained oxidized minerals. In practical applications, the above-mentioned dicarboxylic acid nano-collector is suitable for the flotation of fine-grained oxidized minerals with a particle size of 5μm to 200μm, can significantly reduce the lower limit of the flotation of fine-grained oxidized minerals, has characteristics such as strong adaptability and good flotation performance, and the concentrate recovery rate can reach more than 85%.

[0036] On the other hand, the core metal oxide nanoparticles (i.e., the substrate 1) of the above-mentioned dicarboxylic acid nano-collector are connected to the dicarboxylic acid grafting layer 3 through the Si-O-M bond (M is Ti or Fe) of the silane coupling agent, which can significantly improve the chemical stability of the dicarboxylic acid nano-collector in an aqueous environment.

[0037] In order to ensure the overall structural dimensions of the above-mentioned dicarboxylic acid nano-collector, exemplarily, the particle size of the substrate 1 is 100-500 nm.

[0038] In a second aspect, the present invention provides a method for synthesizing a dicarboxylic acid nano-collector, which is used for synthesizing the dicarboxylic acid nano-collector provided in the first aspect. The synthesis method includes the following steps:

[0039] Step 1: Disperse metal oxide nanoparticles in a solution to form a uniform nanoparticle dispersion liquid, and the nanoparticles are substrate 1;

[0040] Step 2: Mix the nanoparticle dispersion liquid with a coupling agent (for example, 7-octenyltrimethoxysilane or 5-hexenyltrimethoxysilane), hydrolyze and stir, and then heat to form a chemical bond graft between the coupling agent and the surface of the nanoparticles, and form a silane coupling layer 2 on the surface of substrate 1;

[0041] Step 3: Mix the substrate 1 with a surface formed with a silane coupling layer 2 with a maleic acid solution, and carry out a polymerization reaction in a closed container under the action of a radical initiator (for example, ammonium persulfate, potassium persulfate, hydrogen peroxide or azobisisobutyronitrile), so that maleic acid is grafted onto the surface of the silane coupling layer 2, and a dicarboxylic acid grafted layer 3 is formed on the surface of the silane coupling layer 2;

[0042] Step 4: Cool the reactant in Step 3 to 25°C - 30°C, then centrifuge and separate, wash the solid phase with ethanol 3 - 4 times, and vacuum dry at 60°C or below for 2h - 5h to obtain the dicarboxylic acid nano-collector.

[0043] Compared with the prior art, the beneficial effects of the method for synthesizing the dicarboxylic acid nano-collector provided by the present invention are basically the same as those of the dicarboxylic acid nano-collector provided in the first aspect, and will not be elaborated here one by one.

[0044] Exemplarily, in order to improve the dispersion uniformity of the nanoparticles in the nanoparticle dispersion liquid, in the above Step 1, the solution is a mixed solution of an organic solvent and deionized water. In the mixed solution, the volume ratio of the organic solvent to deionized water is 9 - 10:1.

[0045] Exemplarily, the organic solvent is one or more of ethanol, isopropanol, methanol, and acetone mixed in any proportion.

[0046] In order to further improve the dispersion uniformity of the nanoparticles in the nanoparticle dispersion liquid, in the above Step 1, the dispersion is carried out by ultrasonic dispersion, and the ultrasonic dispersion time is 15 min - 25 min.

[0047] It should be noted that the coverage rate of the coupling agent on the surface of the substrate 1 will directly affect the sufficiency of the subsequent grafting reaction. Exemplarily, the concentration of 7-octenyltrimethoxysilane or 5-hexenyltrimethoxysilane is 0.1M to 0.25M. In this way, 7-octenyltrimethoxysilane or 5-hexenyltrimethoxysilane with sufficient concentration can uniformly cover the surface of the substrate 1, ensuring the sufficiency of the subsequent grafting reaction.

[0048] In the above step 2, after the nanoparticle dispersion liquid is mixed with the coupling agent, acetic acid is used to adjust the pH to 4 to 6.

[0049] In order to ensure the sufficient hydrolysis and grafting reaction of the nanoparticle dispersion liquid and the coupling agent, the above hydrolysis stirring time is 30 min to 60 min, the heating temperature is 70 °C to 90 °C, and the grafting reaction time is 1 h to 2 h.

[0050] Correspondingly, the coverage rate of maleic acid on the surface of the silane coupling layer 2 will directly affect the sufficiency of the subsequent grafting reaction. Exemplarily, in the above step 3, the concentration of the maleic acid solution is 0.01M to 0.02M. In this way, the maleic acid solution with sufficient concentration can uniformly cover the surface of the silane coupling layer 2, ensuring the sufficiency of the subsequent grafting reaction.

[0051] In order to ensure the grafting reaction efficiency of maleic acid and the silane coupling layer 2, exemplarily, in the above step 3, the concentration of the radical initiator is 0.1 mM to 0.5 mM, the reaction temperature is 60 °C to 80 °C, and the reaction time is 1 h to 2 h.

[0052] It should be noted that by adjusting the concentration of the maleic acid solution, the dosage of the initiator, and the polymerization time, the grafting amount of maleic acid is 5% to 20%.

[0053] In summary, the synthesis method of the dicarboxylic acid nano collector provided by the present invention can synthesize the dicarboxylic acid nano collector under mild reaction conditions and at low cost by precisely controlling and optimizing the dispersion of nanoparticles, the grafting of the silane coupling layer 2, and the grafting of the dicarboxylic acid, and adjusting the grafting amount of the dicarboxylic acid by controlling conditions such as the amount of butadienoic acid and the polymerization time.

[0054] In the third aspect, the present invention provides a synthesis method of a dicarboxylic acid nano collector for synthesizing the dicarboxylic acid nano collector provided in the first aspect. This synthesis method is basically the same as the synthesis method of the dicarboxylic acid nano collector provided in the second aspect, except that:

[0055] The silane coupling layer 2 is 5-hexenyltrimethoxysilane and 7-octenyltrimethoxysilane.

[0056] Correspondingly, in the synthesis method of the dicarboxylic acid nano collector provided in the second aspect, step 2 includes the following steps:

[0057] Step 21: Mix the nanoparticle dispersion with 7-octenyltrimethoxysilane, hydrolyze and stir for the first time and then heat for the first time, so that 7-octenyltrimethoxysilane forms a chemical bond graft with the surface of the nanoparticles, and a 7-octenyltrimethoxysilane layer is formed on the surface of the substrate 1 to obtain a first composite structure. The 7-octenyltrimethoxysilane layer is a continuous structure. However, the continuous structure has voids, and part of the surface of the substrate 1 is exposed by these voids;

[0058] Step 22: Wash and dry the first composite structure to remove the 7-octenyltrimethoxysilane layer that has not formed a chemical bond with the substrate 1;

[0059] Step 23: Mix the first composite structure with 5-hexenyltrimethoxysilane, hydrolyze and stir for the second time and then heat for the second time, so that 5-hexenyltrimethoxysilane forms a chemical bond graft with the exposed surface of the substrate 1, and 5-hexenyltrimethoxysilane fills the voids of the 7-octenyltrimethoxysilane layer to form a 5-hexenyltrimethoxysilane layer. The 7-octenyltrimethoxysilane layer and the 5-hexenyltrimethoxysilane layer constitute the silane coupling layer 2.

[0060] Compared with the prior art, in the synthesis method of the binary carboxylic acid nano collector provided by the present invention, the silane coupling layer 2 also adopts a composite structure (including a continuous 7-octenyltrimethoxysilane layer and a discontinuous 5-hexenyltrimethoxysilane layer). In practical applications, during the process of forming a chemical bond graft between 7-octenyltrimethoxysilane and the substrate 1, it is inevitable that there will be an incomplete grafting situation, resulting in the exposure of part of the surface of the substrate 1 and a reduction in the number of attachment sites. The present invention uses 5-hexenyltrimethoxysilane to secondarily cover the exposed surface of the substrate 1. Since the carbon chain of 5-hexenyltrimethoxysilane is shorter and the molecular volume is smaller, it can better enter the voids of the 7-octenyltrimethoxysilane layer to form a chemical bond graft, thus ensuring the complete coverage of the substrate 1 by the silane coupling layer 2.

[0061] In addition, due to the different molecular sizes of 5-hexenyltrimethoxysilane and the 7-octenyltrimethoxysilane layer, the surface of the formed silane coupling layer 2 has a certain roughness, which can improve the binding stability between the silane coupling layer 2 and the binary carboxylic acid grafting layer 3.

[0062] It should be noted that the molar concentration of 5-hexenyltrimethoxysilane is less than the molar concentration of 7-octenyltrimethoxysilane.

[0063] Exemplarily, the concentration of 5-hexenyltrimethoxysilane is 0.1M - 0.14M, and the concentration of 7-octenyltrimethoxysilane is 0.16M - 0.2M.

[0064] Example 1

[0065] This example provides a dicarboxylic acid nano - collector and a corresponding synthesis method, which are as follows:

[0066] Materials: Fe 2 O 3 nanoparticles (particle size: 200 nm), 5 - hexenyltrimethoxysilane, maleic acid, ammonium persulfate (APS) initiator.

[0067] Steps: Add 50 g of Fe 2 O 3 nanoparticles into a mixed solution of 950 ml of ethanol and deionized water (volume ratio 9:1), and ultrasonically disperse for 20 min to obtain a homogeneous dispersion; add 0.2 M of 5 - hexenyltrimethoxysilane to the dispersion, adjust the pH to 5.5 with acetic acid, hydrolyze and stir for 1 h, then heat to 85 °C and react for 1.5 h; after the reaction, separate the product by centrifugation, wash it 4 times with ethanol, and vacuum - dry it at 60 °C or below for 2 h to obtain silane - functionalized Fe 2 O 3 nanoparticles; disperse the above - mentioned silane - functionalized Fe 2 O 3 nanoparticles in 100 ml of 0.015 M maleic acid solution, add 0.3 mM of ammonium persulfate (APS) as an initiator; after ultrasonically dispersing for 15 min, carry out a polymerization reaction in a sealed container at 70 °C for 1 h; after the reaction, cool to room temperature, separate the product by centrifugation, and wash it 4 times with deionized water, and finally vacuum - dry it at 60 °C or below for 4 h to obtain the dicarboxylic acid nano - collector.

[0068] The dicarboxylic acid nano - collector synthesized in this example was tested by infrared spectroscopy. The infrared spectrum is shown in Figure 2 , Figure 2 . Among them, 3287 cm -1 represents the stretching vibration of O - H or N - H, 2954 cm -1 and 2924 cm -1 are the stretching vibrations of C - H, 1684 cm -1 is the C = O stretching vibration of carboxylic acid, 1401 cm -1 is the bending vibration of C - O, 1180 cm -1 and 1049 cm -1 are the stretching vibrations of C - O, 722 cm -1 is the bending vibration of C - H, 615 cm -1 and 536 cm -1 are the bending vibrations of C - H or some metal - oxygen and C - O vibrations.

[0069] The obtained collector was used to treat a certain ilmenite in Chengde. The raw material had a TiO 2 grade of 9.39%. The main titanium mineral was ilmenite, and the gangue minerals were olivine, pyroxene, garnet, etc. The lower limit of the ore particle size was 10 μm, and the proportion below 20 μm was 22%. The specific method included:

[0070] Based on the dosage of the reagent relative to the original ore, 200 g / t of water glass was taken as the depressant, 220 g / t of the obtained collector was used as the flotation collector, and 30 g / t of pine oil was used as the foaming agent. They were fully mixed with the ilmenite, and then a flotation process flow of one roughing, two cleanings, and two scavengings was carried out to collect the concentrate and tailings. The flotation test results of the ilmenite are shown in Table 1 below:

[0071] Table 1 Flotation test results of a certain ilmenite in Chengde

[0072] Product Yield / % <![CDATA[TiO 2 Grade / %]]> <![CDATA[TiO 2 Recovery rate / %]]> Concentrate 26.34 31.61 88.70 Tailings 73.66 1.44 11.30 Raw ore 100.00 9.39 100.00

[0073] The test obtained a concentrate with a TiO 2 grade of 31.61%, and the operation recovery rate of TiO 2 was 88.70%. It can be seen that the collector has a very strong selective collection ability for fine-grained ilmenite, greatly improving the concentrate grade and flotation operation recovery rate.

[0074] Example 2

[0075] This example provides a binary carboxylic acid nano-collector and the corresponding synthesis method, which are as follows:

[0076] Materials: Fe 2 O 3 nano-particles (particle size: 300 nm), 7-octenyltrimethoxysilane, fumaric acid, potassium persulfate initiator.

[0077] Steps: Add 60 g of Fe 2 O 3 nano-particles into a mixed solution of 1100 ml of ethanol and deionized water (volume ratio 10:1), and ultrasonically disperse for 25 min to obtain a uniform dispersion; add 0.15 M of 7-octenyltrimethoxysilane to the dispersion, adjust the pH to 4.8 with hydrochloric acid, hydrolyze and stir for 45 min, and then heat to 75 °C and react for 2 h; after the reaction, centrifuge to separate the product, wash it 3 times with ethanol, and vacuum dry it at 60 °C or below for 3 h to obtain silane-functionalized Fe 2 O 3 nano-particles; the above-mentioned silane-functionalized Fe 2 O 3The nanoparticles were dispersed in 120 ml of 0.02 M fumaric acid solution, and 0.4 mM of potassium persulfate was added as an initiator; after ultrasonic dispersion for 20 min, the polymerization reaction was carried out in a sealed container at 65 °C for 1.5 h; after the reaction was completed, it was cooled to room temperature, and the product was separated by centrifugation and washed 3 times with deionized water, and finally vacuum dried at 60 °C or below for 5 h to obtain a dicarboxylic acid nano collector.

[0078] Using the prepared collector to treat a tungsten ore in Ninghua, Fujian, the raw material WO 3 The grade is 0.15%, the main tungsten minerals are scheelite and wolframite, the gangue minerals are calcite and quartz, etc., the lower limit of the ore particle size is 5 μm, and the proportion below 20 μm is 29%. The specific steps include:

[0079] Calculated according to the dosage of the reagent relative to the original ore, 400 g / t of soda ash was taken as the pH adjuster, 100 g / t of water glass as the inhibitor, 160 g / t of the obtained collector as the flotation collector, and 30 g / t of pine oil as the foaming agent. After fully conditioning with the tungsten ore, through a technological process of one roughing, two scavenging and two cleaning, the concentrate and tailings were collected. The flotation test results are shown in Table 2 below:

[0080] Table 2 Flotation test results of a tungsten ore in Ninghua, Fujian

[0081] Product Yield / % <![CDATA[WO 3 Grade / %]]> <![CDATA[WO 3 Recovery rate / %]]> Concentrate 0.41 30.77 86.36 Tailings 99.59 0.02 13.64 Raw ore 100.00 0.15 100.00

[0082] The test obtained a concentrate with a WO 3 grade of 30.77%, and the WO 3 operation recovery rate was 86.36%. It can be seen that the collector has a strong selective collection ability for fine-grained tungsten ore, and greatly improves the concentrate grade and flotation operation recovery rate.

[0083] Example 3

[0084] This example provides a dicarboxylic acid nano collector and a corresponding synthesis method, which are as follows:

[0085] Materials: TiO 2 nanoparticles (particle size: 100 nm), 5-hexenyltrimethoxysilane, maleic acid, hydrogen peroxide initiator.

[0086] Steps: 40 g of TiO 2The nanoparticles were added to a mixed solution of 800 ml of ethanol and deionized water (volume ratio 9:1), and ultrasonically dispersed for 15 min to obtain a homogeneous dispersion; 0.25 M of 5-hexenyltrimethoxysilane was added to the dispersion, and the pH was adjusted to 6.0 with sodium hydroxide. After hydrolysis and stirring for 30 min, the mixture was heated to 80 °C and reacted for 1 h; after the reaction, the product was separated by centrifugation, washed 4 times with ethanol, and vacuum dried at 60 °C or below for 1.5 h to obtain silane-functionalized TiO 2 nanoparticles; the above-mentioned silane-functionalized TiO 2 nanoparticles were dispersed in 150 ml of 0.01 M maleic acid solution, and 0.5 mM of hydrogen peroxide was added as an initiator; after ultrasonic dispersion for 10 min, the polymerization reaction was carried out in a sealed container at 75 °C for 2 h; after the reaction, it was cooled to room temperature, the product was separated by centrifugation, and washed 4 times with deionized water, and finally vacuum dried at 60 °C or below for 4 h to obtain a dicarboxylic acid nano-collector.

[0087] A certain cassiterite in Chenzhou, Hunan was treated with the prepared collector. The raw material SnO 2 grade was 0.75%, the main gangue minerals were calcite, quartz, etc., the lower limit of the ore particle size was 5 μm, and the proportion below 20 μm was 36%. The specific steps were as follows:

[0088] Calculated according to the dosage of the reagent relative to the original ore, 200 g / t of sodium carbonate was taken to adjust the pH value to 9.5, 300 g / t of water glass as an inhibitor, 260 g / t of the obtained collector as a flotation collector, and 30 g / t of pine oil as a foaming agent. The cassiterite was fully slurried, and through a technological process of one roughing, three cleanings and two scavengings, the concentrate and tailings were collected. The flotation test results are shown in Table 3 below:

[0089] Table 3 Flotation test results of a certain cassiterite in Chenzhou, Hunan

[0090] Product Yield / % <![CDATA[SnO 2 Grade / %]]> <![CDATA[SnO 2 Recovery rate / %]]> Concentrate 1.80 35.56 85.56 Tailings 98.20 0.11 14.44 Raw ore 100.00 0.75 100.00

[0091] The test obtained a concentrate with a SnO 2 grade of 35.56%, and the SnO 2 operating recovery rate was 85.56%. It can be seen that the collector has a strong selective collection ability for fine-grained cassiterite, and greatly improves the concentrate grade and flotation operating recovery rate.

[0092] Example 4

[0093] This example provides a dicarboxylic acid nano-collector and a corresponding synthesis method, which are as follows:

[0094] Materials: Fe 2 O 3Nanoparticles (particle size: 200 nm), 5 - hexenyltrimethoxysilane, maleic acid, ammonium persulfate (APS) initiator.

[0095] Steps: Add 50 g of Fe 2 O 3 nanoparticles into a mixed solution of 950 ml of ethanol and deionized water (volume ratio 9:1), and ultrasonically disperse for 20 min to obtain a homogeneous dispersion; add 0.2 M of 7 - octenyltrimethoxysilane to the dispersion, adjust the pH to 5.5 with acetic acid, hydrolyze and stir for 1 h, then heat to 85 °C and react for 1.5 h; after the reaction, separate the product by centrifugation, wash it 4 times with ethanol, and dry it under vacuum at 60 °C or below for 2 h. Add the dried product into a mixed solution of 950 ml of ethanol and deionized water (volume ratio 9:1), ultrasonically disperse for 20 min, add 0.1 M of 5 - hexenyltrimethoxysilane, adjust the pH to 5.5 with acetic acid, hydrolyze and stir for 1 h, then heat to 85 °C and react for 1.5 h. After the reaction, separate the product by centrifugation, wash it 4 times with ethanol, and dry it under vacuum at 60 °C or below for 2 h to obtain silane - functionalized Fe 2 O 3 nanoparticles; Disperse the above - mentioned silane - functionalized Fe 2 O 3 nanoparticles in 100 ml of 0.015 M maleic acid solution, add 0.3 mM of ammonium persulfate (APS) as an initiator; after ultrasonically dispersing for 15 min, carry out a polymerization reaction in a sealed container at 70 °C for 1 h; after the reaction, cool to room temperature, separate the product by centrifugation, and wash it 4 times with deionized water, and finally dry it under vacuum at 60 °C or below for 4 h to obtain a dicarboxylic acid nano - collector.

[0096] Use the prepared collector to treat a certain ilmenite in Chengde. The raw material TiO 2 grade is 9.39%, the main titanium mineral is ilmenite, the gangue minerals are olivine, pyroxene, garnet, etc., the lower limit of the ore particle size is 10 μm, and the proportion below 20 μm is 22%. The specific method includes:

[0097] Based on the dosage of the reagent relative to the original ore, take 200 g / t of water glass as an inhibitor, 220 g / t of the obtained collector as a flotation collector, and 30 g / t of pine oil as a foaming agent, fully slurry with the ilmenite, and then carry out a flotation process of one roughing, two scavenging, and two cleaning, collect the concentrate and tailings. The flotation test results of the ilmenite are shown in Table 4 below:

[0098] Table 4 Flotation test results of a certain ilmenite in Chengde

[0099] Product Yield / % <![CDATA[TiO 2 Grade / %]]> <![CDATA[TiO 2 Recovery rate / %]]> Concentrate 24.12 35.23 90.61 Tailings 75.88 1.16 9.39 Raw ore 100.00 9.38 100.00

[0100] The test obtained TiO 2Concentrate with a grade of 35.23%, TiO 2 The operation recovery rate is 90.61%. It can be seen that the collector has extremely strong selective collection ability for fine-grained ilmenite, greatly improving the concentrate grade and the flotation operation recovery rate.

[0101] As mentioned above, it is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A dicarboxylic acid nano collector, characterized in that: The invention comprises a substrate, a silane coupling layer arranged on the surface of the substrate and a dicarboxylic acid grafting layer arranged on the surface of the silane coupling layer.

2. The dicarboxylic acid nano collector according to claim 1, characterized in that: The substrate is TiO2 metal oxide nanoparticles and / or Fe2O3 metal oxide nanoparticles.

3. The dicarboxylic acid nano collector according to claim 1, characterized in that: The silane coupling layer is formed by silane coupling reaction of 5-hexenyltrimethoxysilane and / or 7-octenyltrimethoxysilane on the surface of the substrate.

4. The dicarboxylic acid nano collector according to claim 1, characterized in that: The dicarboxylic acid graft layer is formed by grafting maleic acid onto the silane coupling layer through free radical polymerization.

5. The dicarboxylic acid nano collector according to claim 4, characterized in that: The butenedioic acid is maleic acid and / or fumaric acid.

6. The dicarboxylic acid nano collector according to any one of claims 1 to 5, characterized in that: The particle size of the substrate is 100-500 nm.

7. A method for synthesizing a dicarboxylic acid nano collector, characterized in that: Used for the synthesis of the dicarboxylic acid nano collector according to any one of claims 1 to 6, the synthesis method comprising the following steps: Step 1: dispersing metal oxide nanoparticles in a solution to form a uniform nanoparticle dispersion, with the nanoparticles serving as a substrate; Step 2: Mix the nanoparticle dispersion with the coupling agent, hydrolyze and stir, and then heat to allow the coupling agent to form a chemical bond graft with the surface of the nanoparticles to form a silane coupling layer on the surface of the substrate; Step 3: Mix the substrate with a silane coupling layer on the surface with a butenedioic acid solution, and cause a polymerization reaction in a closed container under the action of a free radical initiator, so that the butenedioic acid is grafted on the surface of the silane coupling layer to form a dicarboxylic acid grafted layer on the surface of the silane coupling layer.

8. The method for synthesizing the dicarboxylic acid nano collector according to claim 7, characterized in that: In the step 3, the free radical initiator is ammonium persulfate, potassium persulfate, hydrogen peroxide or azobisisobutyronitrile.

9. The method for synthesizing a dicarboxylic acid nano collector according to claim 7, characterized in that: In the step 2, the concentration of the coupling agent is 0.1M to 0.25M.

10. The method for synthesizing a dicarboxylic acid nano collector according to claim 7, characterized in that: In the step 3, the concentration of the maleic acid solution is 0.01M to 0.02M.

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