A nano-coating material for rapid defoaming in flotation, and its preparation method and application

Abstract

The present invention belongs to the field of nano-coating technology, and specifically relates to a nano-coating material for rapid defoaming in flotation, and its preparation method and application. The nano-coating material is arranged on a substrate, including an adhesion layer in contact with the substrate and needle-shaped synapses arranged on the adhesion layer in a jungle-like distribution. First, a polymer or a mixture of a polymer and a silane coupling agent is dissolved in isopropyl alcohol to form a precursor solution. Then, using a liquid flame spraying method, the precursor solution is loaded into a spray gun, atomized by a nozzle, and enters a high-temperature and high-speed flame flow to disperse into nanoparticles and deposit on the surface of the substrate to form a nano-coating material. After the spraying is completed, the desired nano-coating material is obtained. The present invention creatively proposes to use nano-coating materials to regulate the defoaming of mineral flotation. The application of the coating of the present invention can achieve rapid defoaming without relying on the addition of external chemical defoaming agents, thereby improving flotation efficiency and reducing operating costs.

Description

Technical Field

[0001] The invention belongs to the technical field of nano coatings, and in particular relates to a nano coating material for rapid flotation defoaming, a preparation method and an application thereof. Background Art

[0002] Flotation is a method of separating solid particles by utilizing differences in the surface properties of minerals. During the flotation process, the generation and control of foam is one of the key factors affecting separation efficiency and product quality. Therefore, adjusting the generation and stability of foam is an important part of flotation. However, if the foam is too stable during the flotation process, it will lead to reduced processing efficiency, increased energy consumption, and may cause problems such as equipment overload. Therefore, active defoaming is required to control the foam during the flotation process. The current method of controlling foam during flotation mainly relies on the addition of chemical defoamers, which destroy the foam structure by changing the surface tension of the foam. Although this method is effective to a certain extent, the use of chemical defoamers is often accompanied by problems such as increased costs, possible adverse effects on the environment, and negative impacts on the recovery rate and quality of minerals.

[0003] Therefore, seeking a new method to achieve rapid defoaming in flotation without relying on the addition of chemical defoaming agents is a technical problem to be solved in flotation. Summary of the Invention

[0004] In order to solve the above technical problems, one of the objectives of the present invention is to provide a method for preparing a nano-coating material for flotation rapid defoaming.

[0005] The technical solution adopted in the present invention is as follows:

[0006] A method for preparing a nano-coating material for rapid flotation defoaming, wherein the nano-coating material is disposed on a substrate and comprises an adhesion layer contacting the substrate and needle-shaped synapses disposed on the adhesion layer and distributed in a jungle-like manner. The preparation method comprises the following steps:

[0007] S1. Preparing a precursor solution: The precursor solution is a mixture of a polymer and a silane coupling agent dissolved in isopropyl alcohol, wherein the polymer is polydimethylsiloxane or polytetrafluoroethylene, and the dissolved concentration is 0.15 to 2.0 mol / L, and the silane coupling agent is tetraethoxysilane or silicon tetrachloride, and the dissolved amount is 1 to 5% by weight of the polymer;

[0008] S2. Spraying: Using a liquid flame spraying method, the precursor liquid is loaded into a spray gun, atomized by the nozzle, and then enters a high-temperature, high-velocity flame flow, dispersing into nanoparticles that are deposited on the substrate surface, forming an adhesion layer and needle-like synapses. The nanoparticle size is 40-60 nm, the distance between the spray gun and the substrate is 20-50 cm, the spray flow rate is 1 mL / min-5 mL / min, and the spraying time is 5-10 minutes.

[0009] After spraying, the desired nano coating material is obtained.

[0010] Preferably, the liquid flame spraying method uses oxygen as a dispersion carrier and combustion aid, with a flow rate set to 2 L / min, and methane as a fuel, with a flow rate set to 1 L / min.

[0011] Preferably, the substrate is any one of a metal element, an alloy material, and a heat-resistant glass, and the softening point of the heat-resistant glass is higher than 500°C.

[0012] Preferably, the method further comprises post-processing the nano-coating material, depositing a silicon dioxide shell layer on the surface of the prepared nano-coating material by vapor deposition technology, and then performing surface fluorination treatment on the silicon dioxide shell layer to obtain a nano-coating material containing a protective layer.

[0013] Preferably, the vapor deposition technique comprises the following steps:

[0014] A. Clean the surface of the nano-coating material with ethanol, vacuum dry it, and set aside;

[0015] B. The nano-coating material is placed in a sealed container, and vaporized tetraethoxysilane, vaporized hydrated ammonia solution and oxygen are introduced into the sealed container. The reaction is carried out at 500°C for 2 to 5 hours under N2 or Ar atmosphere. The flow rate of the tetraethoxysilane gas is 1 to 10 cm 3 / min, the gas flow rate of the hydrated ammonia solution is 1-5cm 3 / min, the oxygen flow rate is 10-100cm 3 / min, the N2 or Ar gas flow rate is 100~500cm 3 / min;

[0016] C. After the deposition is completed, the nano-coating material is taken out and sintered at 500° C. for 3 h in an air environment to obtain a nano-coating material with a silicon dioxide shell layer deposited on the surface.

[0017] Preferably, the fluorination treatment method is: using a dipping, spraying or brushing method to evenly apply a 1H,1H,2H,2H-perfluorooctyltrichlorosilane solution with a mass concentration of 0.5-2.0% on the surface of the silica shell layer, and curing it at 60-80°C for 2 hours, and removing excess 1H,1H,2H,2H-perfluorooctyltrichlorosilane residues with ethanol to obtain a nano-coating material containing a protective layer.

[0018] A second object of the present invention is to provide an application of the above-mentioned preparation method in the preparation of a flotation device or a flotation defoaming product.

[0019] A third object of the present invention is to provide a nano-coating material prepared by the above-mentioned preparation method or a product containing the nano-coating material.

[0020] Preferably, the product is a flotation device.

[0021] Preferably, the thickness of the nano-coating material is 20 to 80 μm, and the nano-coating material includes an adhesion layer in contact with the substrate and needle-like synapses arranged on the adhesion layer in a jungle-like distribution. The thickness of the adhesion layer is 5 to 10 μm, and the height of the needle-like synapses is 10 to 70 μm. The material of the adhesion layer and the needle-like synapses is the same, which is polydimethylsiloxane or polytetrafluoroethylene.

[0022] Preferably, the bottom width of the needle-shaped synapse is 100-250 nm, the top width of the needle-shaped synapse is 50-100 nm, and the distribution density of the needle-shaped synapse is 10 7 ~10 9 pieces / cm 2 .

[0023] Preferably, it further comprises a silica shell layer arranged on the surface of the nano-coating material, and a fluorinated coating layer arranged on the surface of the silica shell layer; the thickness of the silica shell layer is 10 to 20 nm, and the thickness of the fluorinated coating layer is 10 to 20 nm.

[0024] The beneficial effects of the present invention are:

[0025] 1) In recent years, nanocoating materials have seen increasing application in mineral processing due to their exceptional chemical stability and ability to control surface properties, particularly in improving the corrosion resistance of related equipment and reducing energy consumption. Considering the advantages of nanocoating materials in controlling surface properties, the present invention innovatively proposes utilizing nanocoating materials to control defoaming in mineral flotation. The coating of the present invention achieves rapid defoaming without the need for external chemical defoamers, thereby improving flotation efficiency and reducing operating costs.

[0026] 2) The nanocoating material of the present invention is mainly prepared from a precursor solution by liquid flame spraying technology. The nanoparticles generated by the liquid flame spraying technology are deposited on the substrate to form a coating. Combined with the specific parameters in the spraying process provided by this method, the prepared coating can present a two-layer structure, the upper layer is an adhesion layer evenly distributed on the surface of the substrate, serving as the adhesion basis of the synapse layer. The upper layer is the synapse layer, presenting a needle-shaped accumulation structure, wherein the head size of the needle-shaped synapse tip is between 50 and 100 nm, which is much smaller than the flotation bubble size, and can "puncture" the bubbles during flotation, achieving high-speed defoaming capability.

[0027] 3) A silica shell layer can be provided on the surface of the prepared nano-coating material to enhance the mechanical stability of the particle coating, and a fluorinated coating can be provided to reduce the surface energy of the coating and stabilize the chemical structure of the coating.

[0028] 4) The coating prepared by the present invention has excellent super-hydrophobic properties and efficient defoaming ability. When used in a flotation device, it can reduce production costs, improve the defoaming efficiency of flotation, reduce foam accumulation, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the spraying method of the present invention.

[0030] Figure 2 The nanocoating structures under different preparation conditions are shown in FIG. 4 . The results ad in FIG. 4 correspond to the experimental conditions ad in Table 1 in Example 1.

[0031] Figure 3 The sharpness of the nano-coating material at different spraying distances. The results ad in the figure correspond to the experimental conditions 5-8 in Table 2 in Example 1.

[0032] Figure 4 Schematic diagram of the multi-angle structure of the nanocoating.

[0033] Figure 5 Schematic diagram of the single bubble burst test system in Example 2.

[0034] Figure 6 Schematic diagram of the bubble bursting when it contacts the nanocoating material.

[0035] Figure 7 Schematic diagram of the defoaming test in Example 3. DETAILED DESCRIPTION

[0036] Unless otherwise specified, the terms used herein have the meanings commonly understood by those skilled in the art.

[0037] The technical solution of the present invention is described in more detail below with reference to the embodiments:

[0038] Example 1

[0039] A nanocoating material for rapid flotation defoaming comprises an adhesive layer contacting a substrate and a forest of needle-shaped synapses arranged on the adhesive layer. The adhesive layer and the synapses are made of the same material: polydimethylsiloxane or polytetrafluoroethylene. The adhesive layer is adsorbed onto the surface of the substrate material, serving as the adhesion base for the synapse layer. The tips of the needle-shaped synapses are 50 to 100 nm in size, much smaller than the size of flotation bubbles, and are primarily used to "puncture" flotation bubbles (typically 100 to 1000 times the size of the tips).

[0040] refer to Figure 1 The nano coating material is prepared from a precursor solution by liquid flame spraying technology, the method is as follows:

[0041] S1. Prepare a precursor solution: a polymer and a silane coupling agent dissolved in isopropyl alcohol to form a precursor solution, wherein the polymer is polydimethylsiloxane, and the dissolved concentration is 0.15 mol / L; the silane coupling agent is tetraethoxysilane, and the dissolved amount is 1-5% of the weight of the polymer.

[0042] S2. Spraying: Using liquid flame spraying, the precursor solution is loaded into a spray gun, atomized by the nozzle, and then dispersed into a high-temperature, high-velocity flame, forming nanoparticles that are deposited on the substrate surface to form a nanocoating material. Oxygen is used as a dispersion carrier and combustion aid at a flow rate of 2 L / min, and methane is used as a fuel at a flow rate of 1 L / min. The distance between the spray gun and the substrate is 20-50 cm, the spray flow rate is 1 mL / min-5 mL / min, the nanoparticle size is 40-60 nm, and the spraying time is 5-10 minutes.

[0043] By adjusting the distance between the liquid flame spraying unit and the substrate and the spraying time, the microstructure and morphology of the coating can be precisely controlled to promote the formation of a defoaming coating with a needle-like synaptic structure. After the spraying is completed, the desired nano-coating material is obtained.

[0044] In the present invention, the thickness of the prepared nano-coating material is 20 to 80 μm, the thickness of the adhesion layer is about 5 to 10 μm, the height of the needle-shaped synapses is between 10 and 70 μm, and the substrate can be selected from any one of metal elements, alloys, and heat-resistant glass (softening point higher than 500°C, such as quartz glass, silicate glass, etc.).

[0045] On the basis of the above, a silica shell layer can be added to the surface of the nano-coating material through chemical vapor deposition technology to enhance the mechanical stability of the coating. Through surface fluorination coating post-treatment, the surface energy of the coating can be reduced to form a super-hydrophobic nano-coating and stabilize the chemical structure of the coating.

[0046] The post-processing method is:

[0047] 1) Depositing a silica shell layer on the surface of the nanocoating material by vapor deposition technology:

[0048] A. Use ethanol to clean the surface of the nano-spraying material to remove organic matter and impurities, then dry the surface of the nano-material in a vacuum to remove ethanol residue and set aside;

[0049] B. Place the nano-coating material in a reactor and introduce: ① vaporized tetraethoxysilane into the reactor, with a flow rate range of 1 to 10 cm 3 / min; ②Oxygen, flow range: 10~100cm3 / min; ③Carrier gas (N2 or Ar): used to dilute the reaction gas, flow range: 100~500cm 3 / min; ④ Gasified hydrated ammonia solution: acts as an alkaline catalyst to promote the hydrolysis and condensation reactions of tetraethoxysilane, flow rate range: 1-5cm 3 / min; deposited at 500℃ for 2-5h;

[0050] C. After the deposition is completed, the nano-coating material is taken out and sintered at 500° C. for 3 h in an air environment to obtain a nano-coating material with a silicon dioxide shell layer deposited on the surface.

[0051] 2) Fluorination treatment method is:

[0052] A. Prepare 1H,1H,2H,2H-perfluorooctyltrichlorosilane (FOTS) solution: prepare a FOTS solution with a mass concentration of 0.5-2%;

[0053] B. Coating treatment: immerse the pretreated silica shell coating in FOTS solution, or evenly apply the FOTS solution to the entire coating surface by spraying, brushing, etc.;

[0054] C. Curing process: The FOTS-treated coating is kept at 60-80°C for 2h;

[0055] D. Post-treatment: After the cured coating, ethanol is used to remove excess FOTS residue to obtain a nano-coating material containing a protective layer.

[0056] The spraying time, spraying speed and precursor solution concentration were adjusted to conduct multiple spraying tests. The results are shown in Table 1. The results of tests ad are shown in Figure 2 It can be seen that under the set conditions, the higher the precursor concentration, the lower the spraying speed and the longer the spraying time, the easier it is for the nanoparticles to form synaptic structures during the accumulation process, and the size of the formed synaptic structures is more "sharp".

[0057] Table 1 Setting of spraying conditions

[0058]

[0059] The results show that the coating synapses under test a are the sharpest, while the synapses under the other conditions are needle-shaped but relatively blunt. Taking test a in Table 1 as the optimal condition, the spraying distances were adjusted to 2cm, 5cm, 8cm, 10cm, 20cm, 30cm, 40cm and 50cm respectively and the results are shown in Table 2. The results of tests 5-8 are shown in Table 2. Figure 3 .

[0060] Table 2 Setting of spraying distance conditions

[0061]

[0062] The results show that when the spraying distance is 20 cm, the sharp structure formed is the most obvious, that is, the synaptic structure formed is "sharper".

[0063] The nano coating structure prepared in this application is shown in Figure 4 According to the measurement, the bottom width of the needle-like synapse is 100-250nm, the top width of the needle-like synapse is 50-100nm, the gap between the tops of adjacent needle-like synapses is 100-150nm, and the distribution density is about 10 7 ~10 9 pieces / cm 2 .

[0064] Example 2

[0065] Conventional ferroalloy plates, nano-coated ferroalloy plates, and chemical defoamers (ethylene glycol and isoamyl alcohol) were used to compare the single bubble burst time to verify the defoaming effect of the nano-coating.

[0066] like Figure 5 As shown in the figure, a homemade experimental setup was used in which bubbles generated by a bubble microinjector collided with a ferroalloy plate. A high-speed dynamic camera, the bubbles, and a light-emitting diode (LED) were always kept at the same level, with the camera focused on the bubbles. The microinjector was used to slowly eject the bubbles, which rose in the solution and collided with the ferroalloy plate. The addition of a chemical defoamer was 1%. The bubble collapse process was observed with a high-speed dynamic camera and recorded by a data acquisition system. The results are shown in Table 3.

[0067] Table 3 Single bubble burst results

[0068]

[0069] See the schematic diagram of the bubble bursting when it contacts the nanocoating material. Figure 6 It can be seen that the use of nano-coating and chemical defoaming agent can significantly reduce the bubble bursting time. When using chemical defoaming agent, the time required for bubble bursting is 10-20ms, and when using nano-coated ferroalloy plate, the time required for bubble bursting is within 10ms. The defoaming time of nano-coated ferroalloy plate is shorter, and because nano-coating is environmentally friendly and reusable, it has more advantages than chemical defoaming agent.

[0070] Example 3

[0071] Two types of iron alloy plate foam funnels, standard type and nano-coating type, were designed and compared with the addition of chemical defoamers to compare the defoaming effects under three conditions, such as Figure 7 As shown, the test steps are as follows:

[0072] The experimental materials used were low-rank coal and molybdenite. The flotation test was conducted using a 1.0L XFD hanging trough flotation cell with a spindle speed of 1700 rpm. A 50g ore sample was weighed and poured into the flotation cell. A frother (1500g / t) of octanol was added. After stirring for 30 seconds, air (at a flow rate of 0.1L / min) was introduced for 3 minutes to allow flotation to proceed. The froth was then removed by placing it in a funnel for defoaming.

[0073] The nanocoating thickness of the funnel ranged from 20 to 80 μm. The coating was sprayed onto the entire interior sidewall of the funnel, with the tip of the coated synapse measuring 50 to 100 nm. The chemical defoamers (ethylene glycol and isoamyl alcohol) were added at a 1% level. The foam residence time and foam layer thickness within the funnel were measured, and the test results are shown in Table 4.

[0074] Table 4 Flotation results

[0075]

[0076] The results showed that for the flotation of low-rank coal, the foam residence time was 26 seconds and the foam layer thickness was 2.5 cm when using a standard funnel. When ethylene glycol was added, the foam residence time decreased to 11 seconds and the foam layer thickness decreased to 1.1 cm. When using a nanocoated funnel, the foam residence time decreased to 9 seconds and the foam layer thickness decreased to 0.8 cm. For the flotation of molybdenite, the foam residence time was 24 seconds and the foam layer thickness was 2.3 cm when using a standard funnel. When isoamyl alcohol was added, the foam residence time decreased to 10 seconds and the foam layer thickness decreased to 1.2 cm. When using a nanocoated funnel, the foam residence time decreased to 8 seconds and the foam layer thickness decreased to 0.9 cm. This shows that the nanocoating prepared by the present invention exhibits excellent effects in reducing both foam residence time and foam layer thickness, indicating that the nanocoating has excellent defoaming properties for flotation foam and has the potential to replace, partially replace, or assist the use of chemical defoamers in practice.

[0077] The above are merely preferred practical examples of the present invention and are not intended to limit the invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a nano-coating material for flotation rapid defoaming, characterized in that: The nano-coating material is disposed on a substrate and includes an adhesion layer contacting the substrate and needle-shaped synapses disposed on the adhesion layer and distributed in a jungle-like manner. The preparation method includes the following steps: S1. Preparing a precursor solution: The precursor solution is a mixture of a polymer and a silane coupling agent dissolved in isopropyl alcohol, wherein the polymer is polydimethylsiloxane or polytetrafluoroethylene, and the dissolved concentration is 0.15 to 2.0 mol / L, and the silane coupling agent is tetraethoxysilane or silicon tetrachloride, and the dissolved amount is 1 to 5% by weight of the polymer; S2. Spraying: Using a liquid flame spraying method, the precursor solution is loaded into a spray gun, atomized by the nozzle, and then dispersed into a high-temperature, high-velocity flame. The resulting nanoparticles are then deposited on the substrate surface, forming an adhesion layer and needle-like synapses. The nanoparticle size is 40 to 60 nm, the distance between the spray gun and the substrate is 20 to 50 cm, the spray flow rate is 1 mL / min to 5 mL / min, and the spraying time is 5 to 10 minutes. After spraying, the nano coating material is obtained.

2. The method for preparing a nano-coating material for flotation rapid defoaming according to claim 1, characterized in that: The liquid flame spraying method uses oxygen as a dispersion carrier and combustion aid, with a flow rate set at 2 L / min, and methane as a fuel, with a flow rate set at 1 L / min.

3. The method for preparing a nano coating material for flotation rapid defoaming according to claim 1, characterized in that: The substrate is any one of a metal element, an alloy material, and a heat-resistant glass, and the softening point of the heat-resistant glass is higher than 500°C.

4. The method for preparing a nano coating material for flotation rapid defoaming according to claim 1, characterized in that: The dissolved concentration of the polymer was 2.0 mol / L, the distance between the spray gun and the substrate was 20 cm, the spray flow rate was 1 mL / min, and the spray time was 10 min.

5. The method for preparing a nano coating material for flotation rapid defoaming according to claim 1, characterized in that: The method also includes post-processing of the nano-coating material, depositing a silicon dioxide shell layer on the surface of the prepared nano-coating material by vapor deposition technology, and then performing surface fluorination treatment on the silicon dioxide shell layer to obtain a nano-coating material containing a protective layer.

6. The method for preparing a nano-coating material for flotation rapid defoaming according to claim 5, characterized in that: The vapor deposition technique comprises the following steps: A. Clean the surface of the nano-coating material with ethanol, vacuum dry it, and set aside; B. The nano-coating material is placed in a sealed container, and vaporized tetraethoxysilane, vaporized hydrated ammonia solution and oxygen are introduced into the sealed container. The reaction is carried out at 500°C for 2 to 5 hours under N2 or Ar atmosphere. The gas flow rate of the tetraethoxysilane is 1 to 10 cm 3 / min, the gas flow rate of the hydrated ammonia solution is 1 ~ 5 cm 3 / min, the oxygen flow rate is 10 ~ 100cm 3 / min, the gas flow rate of N2 or Ar is 100 ~ 500 cm 3 / min; C. After the deposition is completed, the nano-coating material is taken out and sintered at 500°C for 3 h in an air environment to obtain a nano-coating material with a silica shell layer deposited on the surface.

7. The method for preparing a nano-coating material for flotation rapid defoaming according to claim 5, characterized in that: The fluorination treatment method comprises: using a dipping, spraying or brushing method to uniformly apply a 1H,1H,2H,2H-perfluorooctyltrichlorosilane solution with a mass concentration of 0.5-2.0% on the surface of the silica shell layer, and curing the solution at 60-80°C for 2 hours, and removing excess 1H,1H,2H,2H-perfluorooctyltrichlorosilane residues with ethanol to obtain a nano-coating material containing a protective layer.

8. A nano coating material prepared by the preparation method according to any one of claims 1 to 4, or a product comprising the nano coating material.

9. The nano coating material or a product comprising the nano coating material according to claim 8, characterized in that: The thickness of the nano-coating material is 20 to 80 μm. The nano-coating material includes an adhesion layer that contacts the substrate and needle-shaped synapses arranged on the adhesion layer in a jungle-like distribution. The thickness of the adhesion layer is 5 to 10 μm, and the height of the synapses is 10 to 70 μm. The material of the adhesion layer and the needle-shaped synapses is the same, namely polydimethylsiloxane or polytetrafluoroethylene.

10. The nano coating material or a product comprising the nano coating material according to claim 9, characterized in that: The bottom width of the needle-like synapse is 100-250 nm, the top width of the needle-like synapse is 50-100 nm, and the distribution density is 1 ~ 1 pieces / cm 2 .

11. The nano coating material or a product comprising the nano coating material according to claim 9, characterized in that: It also includes a silica shell layer arranged on the surface of the nano-coating material, and a fluorinated coating arranged on the surface of the silica shell layer; the thickness of the silica shell layer is 10 to 20 nm, and the thickness of the fluorinated coating is 10 to 20 nm.

12. The nano coating material or a product comprising the nano coating material according to claim 8, characterized in that: The product described is a flotation device.

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