Fly ash pretreatment method, and preparation method and application of anti-corrosion and wear-resistant coating

Abstract

The invention discloses a fly ash pretreatment method and a preparation method and application of an anti-corrosion and wear-resistant coating, and relates to the technical field of fly ash treatment, and the method comprises the following steps: s1, dispersing inferior fly ash in water, and then uniformly stirring to form ore pulp; s2, an emulsifying agent is dissolved in water, a collecting agent is added under stirring, and then an O / W type emulsifying collecting agent is obtained; s3, the prepared O / W type emulsifying collecting agent and foaming agent are added into the ore pulp, first-stage flotation solid removal treatment is conducted after sufficient stirring, and first-stage solid-removed fly ash is obtained; s4, drying the obtained first-stage solid-removed fly ash, and then carrying out second-stage electric separation solid-removed treatment to obtain second-stage solid-removed fly ash; and s5, adding a modifier and water into the obtained secondary solid-removed fly ash, carrying out wet grinding, taking out the fly ash after the modifier fully reacts with the fly ash, taking out the fly ash, drying the fly ash, and carrying out dry grinding to obtain the fly ash subjected to chambering modification. Therefore, the problem of incapability of direct resource utilization due to excessive impurity content of fly ash in the power plant in the prior art is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of fly ash treatment, specifically to a method for pretreating fly ash, a method for preparing an anti-corrosion and wear-resistant coating, and applications thereof. Background Art

[0002] As a major coal-producing and coal-using country in the world, a large amount of coal in China is used for thermal power generation. Fly ash is the main solid waste generated by the combustion of pulverized coal in coal-fired power plants. Its large discharge and complex components pose a huge threat to the ecological environment and human health. At present, fly ash in China is mainly used for preparing fly ash cement, fly ash concrete, and producing fly ash bricks, etc., with a utilization rate of only 30%. Achieving the deep resource utilization of fly ash is an important trend for future development.

[0003] Most of the utilization of fly ash is mainly low-carbon ash. However, affected by boiler operating conditions and coal types, coal combustion is usually not sufficient, resulting in large differences in the composition of fly ash, and there are residual carbon particles and impurity mineral particles to varying degrees. These unburned carbon particles and mineral impurities have high water absorption, low strength, are easy to weather, and are difficult to remove because they are similar in size to fly ash, which is not conducive to the wide application of fly ash resources.

[0004] The existing invention patent CN202110984192.4, a method for modifying fly ash and the obtained modified fly ash, and the invention patent CN202210550230.X, a modified fly ash and its preparation method and application, respectively use modified fly ash for the reinforcement of concrete and the treatment of sewage. They do not fully utilize the characteristics that fly ash can enhance the anti-corrosion, wear-resistant, temperature-resistant, and mechanical properties of the coating as a functional filler, which is not conducive to the further wide application of fly ash resources. Summary of the Invention

[0005] The present invention aims to provide a method for pretreating fly ash, a method for preparing an anti-corrosion and wear-resistant coating, and applications thereof, so as to solve the problems in the prior art that the impurity content of fly ash in power plants exceeds the standard and cannot be directly used for resource utilization, and the utilization range is relatively low.

[0006] To solve the above technical problems, the specific solutions adopted by the present invention are as follows: A method for pretreating fly ash, comprising the following steps:

[0007] s1. Disperse low-quality fly ash in water, and then stir evenly to form a pulp;

[0008] s2. Dissolve an emulsifier in water, and add a collector under stirring to obtain an O / W type emulsified collector;

[0009] s3. Add the prepared O / W type emulsified collector and a foaming agent to the pulp, and perform primary flotation desolidification treatment after sufficient stirring to obtain primary desolidified fly ash;

[0010] s4. Dry the obtained first-stage de-solidified fly ash, and then perform a second-stage electrostatic separation de-solidification treatment to obtain second-stage de-solidified fly ash;

[0011] s5. Add a modifier and water to the obtained second-stage de-solidified fly ash for wet grinding. After the modifier fully reacts with the fly ash, take it out, dry it after taking it out, and then perform dry grinding to obtain fly ash with pore-expanded modification.

[0012] As a further optimization of the fly ash pretreatment method of the present invention, the process of adding the collector under stirring in s2 is carried out in an ultrasonic emulsifier, and the O / W type emulsified collector is composed of an emulsifier, water, and a collector in a ratio of 0.1 - 3:0.15 - 40:0.4 - 10.

[0013] As a further optimization of the fly ash pretreatment method of the present invention, the first-stage flotation de-solidification treatment in s3 is carried out in a flotation machine, and the flotation conditions for the first-stage flotation de-solidification treatment are as follows: flotation time 3 - 6 min, agent-slurry interaction time 1 - 3 min, slurry concentration 25% - 35%, O / W type emulsified collector concentration 600 - 700 g / t, frother concentration 500 - 600 g / t, air inflow 0.25 - 0.35 m 3 / (m 2 ·min).

[0014] As a further optimization of the fly ash pretreatment method of the present invention, the drying condition of the first-stage de-solidified fly ash in s4 is to dry at 90 - 110 °C for 3 - 5 h. The equipment used for the second-stage electrostatic separation de-solidification treatment is a drum-type high-voltage electrostatic separator, and the electrostatic separation conditions for the second-stage electrostatic separation de-solidification treatment are as follows: voltage 27 - 35 kv, drum rotation speed 300 - 350 r / min, drum wall temperature 60 - 80 °C.

[0015] As a further optimization of the fly ash pretreatment method of the present invention, the equipment used for both wet grinding and dry grinding in s5 is a ball mill, and the duration of dry grinding using the ball mill is 30 min. The dosage of the modifier is 10% - 35% of the mass of the fly ash, the dosage of water is 29% - 31% of the mass of the fly ash, and the full reaction time is 0.8 - 1.2 h.

[0016] As a further optimization of the fly ash pretreatment method of the present invention, the emulsifier in s2 is one or a mixture of more than one of alkyl benzene sulfonate, sodium stearate, sodium dodecyl sulfate, dodecyl benzene, and calcium sulfonate.

[0017] As a further optimization of the fly ash pretreatment method of the present invention, the collector in s2 is one or a mixture of more than one of kerosene, light diesel oil, and tar.

[0018] As a further optimization of the fly ash pretreatment method of the present invention, the foaming agent in S3 is one or a mixture of more than one of No. 2 oil, sec-octanol, fusel oil, and turpentine.

[0019] As a further optimization of the fly ash pretreatment method of the present invention, the modifier in S5 is one or a mixture of more than one of sodium hydroxide, calcium oxide, and calcium hydroxide.

[0020] The anti-corrosion and wear-resistant coating comprises the following raw materials: 5-40 parts of pretreated fly ash, 0.5-5 parts of two-dimensional flaky micro-nano fillers, 1-10 parts of surfactant, 20-50 parts of organic solvent, and 50-90 parts of resin. The pretreated fly ash is prepared by any one of the fly ash pretreatment methods described in claims 1-9.

[0021] As a further optimization of the anti-corrosion and wear-resistant coating of the present invention, the particle size of the pretreated fly ash is one or a mixture of more than one of fly ash particles with a mesh size of 600 mesh, 800 mesh, 1000 mesh, and 1200 mesh.

[0022] The preparation method of the anti-corrosion and wear-resistant coating comprises the following steps:

[0023] S1. Filler activation treatment: Mix the pretreated fly ash with two-dimensional flaky micro-nano fillers, then add a surfactant and carry out a hydrothermal reaction.

[0024] S2. Coating preparation: The fly ash and two-dimensional fillers activated by the hydrothermal reaction are added to an organic solvent after filtration, washing, and drying, and then ultrasonic treatment is carried out until the fly ash and two-dimensional fillers are uniformly dispersed in the solvent. Subsequently, the organic solvent containing the fillers is mixed with the resin and stirred thoroughly until evenly dispersed to obtain the prepared composite coating, namely the anti-corrosion and wear-resistant coating.

[0025] As a further optimization of the preparation method of the anti-corrosion and wear-resistant coating of the present invention, the reaction temperature of the hydrothermal reaction in S1 is 60-100 °C, and the reaction time of the hydrothermal reaction is 6-8 h.

[0026] As a further optimization of the preparation method of the anti-corrosion and wear-resistant coating of the present invention, the ultrasonic treatment in S2 is carried out in an ultrasonic device.

[0027] Application of the anti-corrosion and wear-resistant coating: The prepared anti-corrosion and wear-resistant coating is evenly coated on the surface of the substrate by brushing, dipping, or spraying. After the coating is completely cured, a substrate with an anti-corrosion and wear-resistant coating on its surface is obtained.

[0028] The beneficial effects of the present invention compared with the prior art are as follows: The present invention pre-treats the power plant fly ash with excessive impurity content that cannot be directly recycled through the fly ash pretreatment method, that is, through primary flotation de-solidification, secondary electrostatic separation de-solidification, pore expansion modification, and screening treatment. Among them, through the treatment of two-stage de-solidification units, unburned carbon particles and mineral particles in the fly ash are efficiently removed, and then the obtained fly ash is subjected to pore expansion modification by ball milling to expand the pore size distribution of the material, so as to reduce its diffusion resistance, improve mass transfer, and increase the effective utilization rate of active sites. Furthermore, high-quality fly ash is obtained to realize the resource utilization of fly ash, which has good environmental and economic benefits.

[0029] By using the high-quality fly ash prepared by the fly ash pretreatment method of the present invention as the raw material for composing the anti-corrosion and wear-resistant coating, an anti-corrosion and wear-resistant coating with low cost can be obtained, which can effectively enhance the corrosion resistance and wear resistance of the organic coating, and at the same time improve the mechanical properties such as the anti-permeability, heat resistance, and tensile strength of the organic coating.

[0030] By setting the preparation method and application of the anti-corrosion and wear-resistant coating to prepare and apply the anti-corrosion and wear-resistant coating, a high-quality anti-corrosion and wear-resistant coating can be obtained under the condition of low cost, and it can be applied to the surface of the substrate to form an anti-corrosion and wear-resistant coating for protecting the surface of the substrate. Brief Description of the Drawings

[0031] Figure 1 It is a schematic flow chart of the fly ash pretreatment method and the preparation method of the anti-corrosion and wear-resistant coating of the present invention;

[0032] Figure 2 It is the EIS test result of the untreated fly ash coating sample of the present invention immersed in 3.5 wt.% NaCl solution for 30 days and the schematic diagram of the equivalent circuit of the coating;

[0033] Figure 3 It is the EIS test result of the composite filler anti-corrosion and wear-resistant coating sample of the present invention immersed in 3.5 wt.% NaCl solution for 30 days and the schematic diagram of the equivalent circuit of the coating. Detailed Embodiments

[0034] In order to further describe the fly ash treatment method, the preparation method and application of the anti-corrosion and wear-resistant coating, and the composition of the anti-corrosion and wear-resistant coating of the present invention, the following examples and performance tests will be described in detail.

[0035] Example 1 of the present invention:

[0036] First, the inferior fly ash obtained from a coal-fired power plant is treated by the fly ash pretreatment method, and the steps are as follows: S1. The inferior fly ash is dispersed in water and stirred evenly to form a slurry;

[0037] s2. Select alkylbenzene sulfonate as the emulsifier, dissolve it in water, add kerosene as the collector under the intense stirring of an ultrasonic emulsifier, and then obtain an O / W type emulsified collector. The O / W type emulsified collector is a mixed solution of alkylbenzene sulfonate, water, and kerosene with a ratio of 2:30:8.

[0038] s3. Add the prepared O / W type emulsified collector and No. 2 oil foaming agent to the pulp, stir well in a stirring tank, and then send it to a flotation machine for primary flotation solid removal treatment to obtain primary solid-removed fly ash. The flotation conditions are as follows: flotation time 4 min, agent-pulp interaction time 2 min, pulp concentration 30%, emulsified collector concentration 650 g / t, foaming agent concentration 550 g / t, and air inflow rate 0.30 m 3 / (m 2 ·min);

[0039] s4. Dry the primary solid-removed fly ash obtained by flotation at 105 °C for 4 h, and then send it to a drum-type high-voltage electrostatic separator for secondary electrostatic solid removal treatment to obtain secondary solid-removed fly ash. The electrostatic separation conditions are as follows: voltage 30 kv, drum rotation speed 330 r / min, and drum wall temperature 70 °C;

[0040] s5. Send the secondary solid-removed fly ash after electrostatic separation to a ball mill, add sodium hydroxide modifier and water for wet grinding to make the modifier fully react with the fly ash. The dosage of sodium hydroxide is 15% of the mass of the fly ash, and the water dosage is 30% of the mass of the fly ash. After 1 h, take out the abrasive, dry it, and then put it back into the ball mill for dry grinding for 30 min to obtain the fly ash with enlarged pores and modified.

[0041] Next, prepare the following raw materials in parts by weight: 25 parts of fly ash prepared by the above fly ash pretreatment method, 5 parts of two-dimensional graphene filler, 5 parts of silane coupling agent, 25 parts of ethyl acetate, and 80 parts of epoxy resin.

[0042] Subsequently, prepare an anti-corrosion and wear-resistant coating through the preparation method of the anti-corrosion and wear-resistant coating. The steps are as follows:

[0043] s1. Filler activation treatment: Screen the fly ash obtained after pretreatment by the fly ash pretreatment method, then mix the fly ash with a particle size of 800 mesh obtained with the prepared two-dimensional flaky graphene filler, and at the same time add the selected surfactant, namely silane coupling agent. Then carry out a hydrothermal reaction in a reflux device. The reaction temperature is 80 °C, and the reaction time is 7 h. The ratio of fly ash, graphene, and silane coupling agent is 5:1:1;

[0044] S2. Coating preparation: The activated fly ash and graphene fillers are filtered, washed and dried, and then added into ethyl acetate, an organic solvent, and placed in an ultrasonic device for ultrasonic treatment until the fly ash and graphene fillers are uniformly dispersed in the ethyl acetate. Subsequently, the ethyl acetate containing the fillers is mixed with epoxy resin and stirred thoroughly until uniformly dispersed, thus obtaining the prepared composite coating, i.e., the anti-corrosion and wear-resistant coating.

[0045] Finally, the anti-corrosion and wear-resistant coating is applied. The specific steps are as follows: The obtained coating above is uniformly coated on the surface of the substrate by spraying. After the coating is completely cured, a substrate with an anti-corrosion and wear-resistant coating on its surface is obtained.

[0046] Example two of the present invention:

[0047] First, the inferior fly ash obtained from a coal-fired power plant is processed by the fly ash pretreatment method. The steps are as follows: S1. The inferior fly ash is dispersed in water and stirred evenly to form a slurry.

[0048] S2. Sodium stearate is selected as an emulsifier and dissolved in water. Under the stirring of an ultrasonic emulsifier, light diesel is added as a collector to obtain an O / W type emulsified collector, where the O / W type emulsified collector is a mixed solution of sodium stearate, water and light diesel with a ratio of 2:35:9.

[0049] S3. The prepared O / W type emulsified collector and sec-octanol foaming agent are added into the slurry, stirred thoroughly in a stirring tank, and then sent into a flotation machine for primary flotation desolidification treatment to obtain primary desolidified fly ash. The flotation conditions are as follows: flotation time 6 min, reagent and slurry interaction time 3 min, slurry concentration 35%, emulsified collector concentration 700 g / t, foaming agent concentration 600 g / t, air inflow 0.35 m 3 / (m 2 ·min);

[0050] S4. The primary desolidified fly ash obtained by flotation is dried at 110 °C for 3 h, and then sent into a drum-type high-voltage electrostatic separator for secondary electrostatic desolidification treatment to obtain secondary desolidified fly ash. The electrostatic separation conditions are as follows: voltage 35 kv, drum rotation speed 350 r / min, drum wall temperature 80 °C.

[0051] S5. The secondary desolidified fly ash after electrostatic separation is sent into a ball mill, and an appropriate amount of calcium oxide modifier and water are added for wet grinding to make the modifier react fully with the fly ash. The dosage of calcium oxide is 35% of the mass of the fly ash, and the water dosage is 31% of the mass of the fly ash. After 1.2 h, the abrasive is taken out, dried and then put back into the ball mill for dry grinding for 28 min to obtain the fly ash with enlarged pores and modified.

[0052] Next, prepare the following raw materials in parts by weight: 40 parts of fly ash prepared by the above fly ash pretreatment method, 5 parts of flaky molybdenum disulfide filler, 10 parts of dodecyl dimethyl ammonium, 50 parts of dimethylformamide, and 90 parts of polyurethane resin.

[0053] Subsequently, prepare the anti-corrosion and wear-resistant coating by the preparation method of the anti-corrosion and wear-resistant coating. The steps are as follows:

[0054] S1. Filler activation treatment: Screen the fly ash obtained after pretreatment by the fly ash pretreatment method. Then mix the obtained fly ash particles with a particle size of 1200 mesh with the flaky molybdenum disulfide filler, and then add them to the dodecyl dimethyl ammonium. Subsequently, carry out a hydrothermal reaction in a reflux device, where the temperature of the hydrothermal reaction is 100 °C and the reaction time is 6 h;

[0055] S2. Coating preparation: After filtering, washing, and drying the activated fly ash and molybdenum disulfide filler, add them to the organic solvent dimethylformamide, and at the same time place them in an ultrasonic device for ultrasonic treatment until the fly ash and graphene filler are uniformly dispersed in the organic solvent dimethylformamide. Subsequently, mix the organic solvent dimethylformamide containing the filler with the polyurethane resin and stir well until evenly dispersed to obtain the prepared composite coating, that is, the anti-corrosion and wear-resistant coating.

[0056] Finally, apply the anti-corrosion and wear-resistant coating through the application of the anti-corrosion and wear-resistant coating. The specific steps are as follows: Uniformly coat the above anti-corrosion and wear-resistant coating on the surface of the substrate by dip coating. After the coating is completely cured, obtain the substrate with the anti-corrosion and wear-resistant coating protection on the surface.

[0057] Example three of the present invention:

[0058] Pretreat the inferior fly ash directly obtained from the electrostatic precipitator by the fly ash pretreatment method, including the following steps: S1. Disperse the inferior fly ash in water and stir evenly to form a slurry with a certain concentration;

[0059] S2. Select sodium dodecyl sulfate as the emulsifier, dissolve it in water, and add kerosene as the collector under the intense stirring of an ultrasonic emulsifier to obtain an O / W type emulsified collector. The O / W type emulsified collector is a mixed solution of sodium dodecyl sulfate, water, and kerosene with a ratio of 3:40:10;

[0060] S3. Add the prepared O / W type emulsified collector and fusel oil foaming agent to the slurry, stir well in a stirring tank, and then send it into a flotation machine for primary flotation desolidification treatment to obtain primary desolidified fly ash. The flotation conditions are as follows: flotation time 3 min, agent-slurry interaction time 1 min, slurry concentration 25%, emulsified collector concentration 600 g / t, foaming agent concentration 500 g / t, air inflow 0.25 m3 / (m 2 ·min);

[0061] S4. Dry the first-stage de-solidified fly ash obtained by flotation at 90 °C for 5 h, and then send it to a drum-type high-voltage electrostatic separator for secondary electrostatic separation de-solidification treatment to obtain secondary de-solidified fly ash. The electrostatic separation conditions are as follows: voltage 27 kV, barrel rotation speed 300 r / min, barrel wall temperature 60 °C;

[0062] S5. Send the secondary de-solidified fly ash after electrostatic separation to a ball mill, add calcium hydroxide modifier and water for wet grinding to make the modifier fully react with the fly ash. The dosage of calcium hydroxide is 10% of the mass of the fly ash, and the dosage of water is 29% of the mass of the fly ash. Take out the abrasive after 0.8 h, dry it and then put it back into the ball mill for dry grinding for 32 min to obtain the fly ash modified by pore expansion.

[0063] Next, prepare the following raw materials in parts by weight: 5 parts of fly ash prepared by the above fly ash pretreatment method, 0.5 part of flaky boron nitride filler, 1 part of organosilane, 20 parts of xylene, and 50 parts of acrylic resin.

[0064] Subsequently, prepare an anti-corrosion and wear-resistant coating through the preparation method of the anti-corrosion and wear-resistant coating. The steps are as follows:

[0065] S1. Filler activation treatment: Screen the fly ash obtained after pretreatment by the fly ash pretreatment method, and then mix the obtained mixed fly ash particles with particle sizes of 800 mesh, 1000 mesh, and 1200 mesh with the flaky boron nitride filler, and add them to the organosilane. Carry out hydrothermal reaction in a reflux device. The hydrothermal reaction temperature is 60 °C, and the reaction time is 8 h;

[0066] S2. Coating preparation: After the activated fly ash and boron nitride filler are filtered, washed, and dried, add them to the organic solvent xylene, and put them into an ultrasonic device for ultrasonic treatment until the fly ash and boron nitride filler are uniformly dispersed in the organic solvent xylene. Then mix the xylene containing the filler with the acrylic resin and stir well until evenly dispersed to obtain the prepared composite coating.

[0067] Finally, apply the anti-corrosion and wear-resistant coating through the application of the anti-corrosion and wear-resistant coating. The specific steps are as follows: Uniformly coat the above anti-corrosion and wear-resistant coating on the surface of the substrate by brushing. After the coating is completely cured, obtain a substrate with an anti-corrosion and wear-resistant coating on the surface.

[0068] Performance test: Take Example 1 as an example. Prepare an untreated fly ash coating and a composite filler anti-corrosion and wear-resistant coating. Both coatings are composed of the following raw materials in parts by weight: 25 parts of fly ash, 5 parts of two-dimensional graphene filler, 5 parts of silane coupling agent, 25 parts of ethyl acetate, and 80 parts of epoxy resin.

[0069] The main differences between the two are as follows: The fly ash used in the untreated fly ash coating is low-quality fly ash directly obtained from power plants, while the fly ash used in the composite filler anti-corrosion and wear-resistant coating is pretreated fly ash obtained through fly ash pretreatment methods.

[0070] The test of anti-corrosion performance is as follows: Take the untreated fly ash coating and the composite filler anti-corrosion and wear-resistant coating as specimens, place the above two specimens in an environment containing 3.5% NaCl solution, adopt a three-electrode system, select a saturated calomel electrode as the reference electrode, a platinum electrode as the auxiliary electrode, and use the two specimens as the working electrodes. Use an electrochemical workstation to perform electrochemical impedance spectroscopy analysis with a 5 mV sinusoidal perturbation on the specimens with different immersion times in the frequency range of 100 kHz to 0.01 Hz.

[0071] The results are as Figure 2 、 Figure 3 shown. Compared with the untreated fly ash coating specimen, the impedance modulus of the composite filler anti-corrosion and wear-resistant coating specimen increased from 10 6 to 10 7 or so. The time required for the composite filler anti-corrosion and wear-resistant coating specimen to enter the middle stage of soaking was extended from 10 days to more than 30 days. The obtained electrochemical measurement data was analyzed by fitting with Zview software. The fitting data of the untreated fly ash coating specimen was close to the RQR(QR) fitting circuit, while the fitting data of the composite filler anti-corrosion and wear-resistant coating specimen was closer to the RQR fitting circuit.

[0072] The conclusion is as follows: The above results indicate that the anti-corrosion performance of the composite filler anti-corrosion and wear-resistant coating has been greatly improved.

[0073] The test of wear resistance is as follows: Take the composite filler anti-corrosion and wear-resistant coating and the untreated fly ash coating as specimens, let them stand at room temperature for 25 days, and after they are completely cured, test their wear resistance on a Taber wear tester.

[0074] The test conditions are as follows: The sandpaper is 1000 mesh, the grinding wheel speed is 1000 r / h, the duration of the friction test is 30 min, the normal load is 10 N. Use a coating thickness gauge to measure the composite filler anti-corrosion and wear-resistant coating specimen and the untreated fly ash coating specimen, and use the thickness difference before and after the test and the weight loss of both to reflect the wear amount of the coating.

[0075] The results are shown in Table 1. The wear degree of the untreated fly ash coating specimen is more serious. The thickness of the coating in the test area is greatly reduced, and the weight loss reaches more than 150 mg. In contrast, for the composite filler anti-corrosion and wear-resistant coating specimen, the wear thickness difference before and after is reduced from 91 μm to 48 μm, and the weight loss degree is reduced from 156 mg to 65 g. The following conclusions are obtained.

[0076] The conclusions are as follows: The anti-corrosion and wear-resistant coating formed by the application of the anti-corrosion and wear-resistant coating has good wear resistance.

[0077] As can be seen from the above examples and test data, by pretreating fly ash through the fly ash pretreatment method, one of the main components of the anti-corrosion and wear-resistant coating can be obtained. At the same time, through the preparation method and application of the anti-corrosion and wear-resistant coating, the anti-corrosion and wear-resistant coating is prepared and applied, thereby effectively solving the problems of expanding the utilization rate of low-quality fly ash, providing a low-cost anti-corrosion and wear-resistant coating, the preparation method and application of the anti-corrosion and wear-resistant coating. Coated specimen Unprocessed fly ash coated specimen Composite filler anti-corrosion and wear-resistant coating specimen Thickness difference / μm 91 48 Weight loss / mg 156 65 Table 1 Test results of the wear resistance of the coating

Claims

1. A method for pretreating fly ash, characterized in that: It includes the following steps: S1. Disperse inferior fly ash in water, and then stir evenly to form a pulp; S2. Dissolve an emulsifier in water, and add a collector under stirring to obtain an O / W type emulsified collector; S3. Add the prepared O / W type emulsified collector and a foaming agent into the pulp, carry out primary flotation desolidification treatment after sufficient stirring to obtain primary desolidified fly ash; S4. Dry the obtained primary desolidified fly ash, and then carry out secondary electrostatic separation desolidification treatment to obtain secondary desolidified fly ash; S5. Add a modifier and water to the obtained secondary desolidified fly ash for wet grinding, take it out after the modifier fully reacts with the fly ash, dry it after taking it out, and then carry out dry grinding to obtain fly ash with pore-expanded modification; 2. The fly ash pretreatment method according to claim 1, characterized in that: In step S2, the process of adding the collector under stirring is carried out in an ultrasonic emulsifier, and the O / W type emulsified collector is composed of an emulsifier, water and a collector in a ratio of 2-3:30-40:8-10; 3. The fly ash pretreatment method according to claim 1, wherein: The primary flotation for solid removal in S3 is carried out in a flotation machine, and the flotation conditions for the primary flotation for solid removal are as follows: flotation time is 3 - 6 min, the action time of the reagent and the pulp is 1 - 3 min, the pulp concentration is 25% - 35%, the concentration of the O / W type emulsified collector is 600 - 700 g / t, the concentration of the foaming agent is 500 - 600 g / t, and the gas charging volume is 0.25 - 0.35 m 3 / (m 2 ·min).

4. The fly ash pretreatment method according to claim 1, characterized in that: In step S4, the drying condition of the primary desolidified fly ash is drying at 90-110 °C for 3-5 h, the equipment used for the secondary electrostatic separation desolidification treatment is a drum-type high-voltage electrostatic separator, and the electrostatic separation conditions for the secondary electrostatic separation desolidification treatment are as follows: voltage 27-35 kv, barrel rotation speed 300-350 r / min, barrel wall temperature 60-80 °C; 5. The fly ash pretreatment method according to claim 1, characterized in that: In step S5, the equipment used for both wet grinding and dry grinding is a ball mill, the duration of dry grinding using the ball mill is 28-32 min, the dosage of the modifier is 10%-35% of the mass of the fly ash, the dosage of water is 29%-31% of the mass of the fly ash, and the time for sufficient reaction is 0.8-1.2 h; 6. The fly ash pretreatment method according to claim 1, wherein: The emulsifier in step S2 is one or a mixture of more than one of alkyl benzene sulfonate, sodium stearate, sodium dodecyl sulfate, dodecyl benzene and calcium sulfonate; 7. The fly ash pretreatment method according to claim 1, characterized in that: The collector in step S2 is one or a mixture of more than one of kerosene, light diesel oil and tar; 8. The fly ash pretreatment method according to claim 1, characterized in that: The foaming agent in step S3 is one or a mixture of more than one of No. 2 oil, sec-octanol, fusel oil and turpentine; 9. The fly ash pretreatment method according to claim 1, characterized in that: The modifier in step S5 is one or a mixture of more than one of sodium hydroxide, calcium oxide and calcium hydroxide; 10. Anticorrosive and wear-resistant coating, characterized in that: It includes the following raw materials: 5-40 parts of pretreated fly ash, 0.5-5 parts of two-dimensional flaky micro-nano filler, 1-10 parts of surfactant, 20-50 parts of organic solvent, 50-90 parts of resin, and the pretreated fly ash is prepared by any one of the fly ash pretreatment methods described in claims 1-9; 11. The anti-corrosion and wear-resistant coating according to claim 10, wherein: The particle size of the pretreated fly ash is one or a mixture of fly ash particles of 600 mesh, 800 mesh, 1000 mesh and 1200 mesh; 12. The preparation method of the anti-corrosion and wear-resistant coating according to claim 10, characterized in that: It includes the following steps: S1. Filler activation treatment: Mix the pretreated fly ash with the two-dimensional flaky micro-nano filler, and then add a surfactant and carry out a hydrothermal reaction; S2. Coating preparation: The fly ash and two-dimensional fillers activated by hydrothermal reaction are added to an organic solvent after filtration, washing, and drying. Subsequently, ultrasonic treatment is carried out until the fly ash and two-dimensional fillers are uniformly dispersed in the solvent. Then, the organic solvent containing the fillers is mixed with the resin and stirred thoroughly until uniformly dispersed, obtaining the prepared composite coating, i.e., the anti-corrosion and wear-resistant coating.

13. The preparation method of the anti-corrosion and wear-resistant coating according to claim 12, wherein: In S1, the reaction temperature of the hydrothermal reaction is 60 - 100 °C, and the reaction time of the hydrothermal reaction is 6 - 8 h.

14. The preparation method of the anti-corrosion and wear-resistant coating according to claim 12, characterized in that: The ultrasonic treatment in S2 is carried out in an ultrasonic device.

15. The application of the anti-corrosion and wear-resistant coating according to claim 10, wherein: The prepared anti-corrosion and wear-resistant coating is uniformly coated on the surface of the substrate by brushing, dipping, or spraying. After the coating is completely cured, a substrate with an anti-corrosion and wear-resistant coating on its surface is obtained.

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