阅读说明：本技术 耐候结构钢表面的抗酸腐蚀搪瓷涂层及其制备方法 (Acid corrosion resistant enamel coating on surface of weather-resistant structural steel and preparation method thereof ) 是由 尤宝乾 孙叙军 刘广阳 于 2020-07-03 设计创作，主要内容包括：本发明公开了一种耐候结构钢表面的抗酸腐蚀搪瓷涂层及其制备方法。本发明的耐候结构钢表面的抗酸腐蚀搪瓷涂层的制备方法包括：a)熔制搪瓷釉料,b)制备搪瓷釉粉,c)耐候结构钢碱性脱脂处理,d)搪瓷涂层的喷涂与高温烧成,其中,所述搪瓷釉料有两种,分别为搪瓷瓷釉A和搪瓷瓷釉B。采用本发明的制备方法获得耐候结构钢表面的抗酸腐蚀搪瓷涂层,具有优异的抗酸腐蚀性能特别是耐硫酸抗腐蚀性,结合强度高,使用寿命长等优点。另外,本发明制备方法简单,采用两种釉料分开熔制、耐候结构钢表面碱性脱脂处理,提高生产效率,节约了能源消耗,降低了搪瓷涂层的生产成本,适于大规模推广应用。(The invention discloses an acid corrosion resistant enamel coating on the surface of weather-resistant structural steel and a preparation method thereof. The preparation method of the acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel comprises the following steps: a) melting enamel glaze materials, B) preparing enamel glaze powder, c) alkaline degreasing treatment of weather-resistant structural steel, d) spraying and high-temperature sintering of an enamel coating, wherein the number of the enamel glaze materials is two, namely enamel glaze A and enamel glaze B. The acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel obtained by the preparation method has the advantages of excellent acid corrosion resistance, particularly sulfuric acid corrosion resistance, high bonding strength, long service life and the like. In addition, the preparation method is simple, two kinds of glaze materials are separately melted, and the surface of the weather-resistant structural steel is subjected to alkaline degreasing treatment, so that the production efficiency is improved, the energy consumption is saved, the production cost of the enamel coating is reduced, and the method is suitable for large-scale popularization and application.)

1. A preparation method of an acid corrosion resistant enamel coating on the surface of weather-resistant structural steel comprises the following steps: a) melting an enamel glaze, b) preparing enamel glaze powder, c) alkaline degreasing treatment of weather-resistant structural steel, and d) spraying and high-temperature sintering of an enamel coating;

the two kinds of enamel glaze materials are respectively enamel glaze A and enamel glaze B.

2. The method for preparing the acid corrosion resistant enamel coating on the surface of the weathering structure steel as claimed in claim 1, characterized in that:

the a) preparation of the enamel glaze A: uniformly mixing 50 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 12 parts of borax pentahydrate, 8.5 parts of sodium carbonate, 4 parts of lithium carbonate, 5 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 4 parts of calcium carbonate, 2 parts of cobalt oxide and 1.5 parts of nickel oxide according to mass fraction to obtain a batch mixture, melting the batch mixture in a high-temperature electric furnace at the temperature of 1300 ℃ for 2.5 hours, and performing water quenching to obtain an enamel glaze A;

Preparing enamel glaze B: according to the mass fraction, 47 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 10 parts of borax pentahydrate, 12.5 parts of sodium carbonate, 4 parts of lithium carbonate, 6 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 3 parts of calcium carbonate, 2.5 parts of cobalt oxide and 2 parts of manganese dioxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a high-temperature electric furnace at the temperature of 1280 ℃ for 2.0 hours, and the enamel glaze B is prepared through water quenching.

3. The method for preparing the acid corrosion resistant enamel coating on the surface of the weathering structure steel as claimed in claim 1, characterized in that:

the b) enamel glaze powder is prepared by the following steps: according to the mass fraction, 40.4 percent of enamel glaze A, 40.4 percent of enamel glaze B, 5.6 percent of kaolin, 0.3 percent of borax decahydrate, 0.3 percent of boric acid, 0.15 percent of sodium carbonate, 0.15 percent of sodium nitrite, 0.15 percent of magnesium carbonate, 0.4 percent of cobaltosic oxide and 12.15 percent of calcined quartz powder are put into a high-speed ball mill for grinding. Pure water with the relative mass fraction of 60% is used as a solvent, grinding is carried out for 15 minutes, and the prepared enamel glaze pulp is screened by a standard sieve with 60 meshes.

4. The method for preparing the acid corrosion resistant enamel coating on the surface of the weathering structure steel as claimed in claim 1, characterized in that:

The c) alkali degreasing treatment process of the weather-resistant structural steel comprises the following steps: the industrial alkaline cleaning agent is prepared into alkaline degreasing solution according to the mass percentage of 3 percent, the sodium hydroxide is prepared into alkaline degreasing solution according to the mass percentage of 2 percent and the water, and the alkaline leaching solution is prepared into alkaline leaching solution according to the mass percentage of 0.6 percent of sodium carbonate, 0.2 percent of sodium nitrite and the water. The weathering structural steel is soaked in an alkaline degreasing solution at 95 ℃ for 10 minutes, taken out, soaked in a clear water solution at 50 ℃ for 2 minutes, then soaked in an alkaline leaching solution at 50 ℃ for 3 minutes, and then dried at 150 ℃ for 10 minutes.

5. The method for preparing the acid corrosion resistant enamel coating on the surface of the weathering structure steel as claimed in claim 1, characterized in that:

the d) spraying and high-temperature sintering of the enamel coating comprises the following specific steps: the enamel slurry of the enamel porcelain is uniformly coated on the surface of the weather-resistant structural steel subjected to alkaline degreasing treatment, and is dried for 15-20 minutes at the temperature of 200-220 ℃. And (3) placing the dried sample coated with the enamel glaze slurry coating in a high-temperature furnace at the temperature of 860-880 ℃ for sintering for 6-8 minutes to obtain the acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel.

6. The method for preparing the acid corrosion resistant enamel coating on the surface of the weathering structure steel according to claim 4 or 5, characterized in that:

The weather-resistant structural steel is cold-rolled weather-resistant structural steel.

7. An acid corrosion resistant enamel coating on a surface of a weathering structure steel, characterized by comprising the acid corrosion resistant enamel coating on a surface of a weathering structure steel prepared by the method of any of claims 1 to 6.

Technical Field

The invention belongs to the field of inorganic protective coatings, and particularly relates to an acid corrosion resistant enamel coating on the surface of weather-resistant structural steel and a preparation method thereof.

Background

The weathering structural steel is formed by adding a small amount of alloy elements such as Cu, P, Cr, Ni and rare earth elements into steel to form a protective layer on the surface of a metal matrix, thereby improving the weathering resistance of the steel plate. However, when the weathering structural steel is applied to a corrosive environment, such as a heat exchange element in a desulfurization and denitrification heat exchanger, the weathering structural steel is easily corroded when the local temperature reaches the dew point of sulfuric acid, particularly in the desulfurization and denitrification heat exchanger, due to the poor sulfuric acid corrosion resistance of the weathering structural steel, so that the service life of the heat exchange element is short.

The enamel can resist organic acid and inorganic acid with various concentrations except hydrofluoric acid, and the comprehensive corrosion resistance of the enamel is incomparable with other materials. The containers used for containing strong corrosive media in chemical production are mostly enamel products. In addition, because of its excellent high temperature resistance and strength, enamel is often coated on the surface of metal material to protect the metal substrate.

Enamel coating is a widely used protective coating technique. The enamel coating can react with the alloy matrix in the sintering preparation process to form chemical combination of an interface, the interface peeling resistance of the coating under the thermal cycle condition is superior to that of the traditional ceramic coating, and the high-temperature oxidation resistance of the enamel coating is superior to that of the traditional metal coating due to the excellent oxygen diffusion resistance of the enamel coating.

The enamel coating mainly consists of a silicon-oxygen tetrahedron structure, and a glass network structure is formed by adding other tetravalent, trivalent, divalent or even monovalent ions into gaps of the silicon-oxygen tetrahedron. However, because the conventional enamel coating contains excessive low-melting-point components (such as zinc oxide, sodium oxide and the like) as cosolvent, the low-melting-point components are easy to react with Cr in the alloy matrix in the high-temperature service process, and finally, a large amount of chromate spinel corrosion products such as ZnCr2O4 are further oxidized on the coating surface, so that the oxidation resistance of the enamel coating is greatly reduced, and the addition of a large amount of low-melting-point components breaks silicon-oxygen bonds in silicon-oxygen tetrahedrons, so that alloy ions in a corrosion medium can more easily permeate into the enamel coating, the softening point of the enamel coating is further reduced, sulfur and chloride ions can more easily permeate through the enamel coating to the alloy matrix, and the corrosion resistance of the enamel coating is seriously influenced.

At present, a great number of reports are made on the enamel coating sprayed on the surface of common steel, such as CN201010529933.1, CN201410653315.6 and the like. However, the weathering structural steel contains a small amount of alloy elements, and a protective layer is already formed on the surface of the weathering structural steel, so that a special process is required for spraying the enamel coating on the surface of the weathering structural steel.

Disclosure of Invention

Aiming at the defects in the prior art, the invention mainly aims to provide an acid corrosion resistant enamel coating on the surface of weather-resistant structural steel, which has the advantages of excellent acid corrosion resistance, particularly sulfuric acid corrosion resistance, high bonding strength, long service life and the like.

The invention also aims to provide a preparation method of the acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel, which has simple preparation process requirement and convenient operation and is suitable for industrial production.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the method for preparing the acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel, which is provided in some embodiments of the invention, comprises the following steps: a) melting enamel glaze, b) preparing enamel glaze powder, c) alkaline degreasing treatment of the surface of the weather-resistant structural steel, and d) spraying and high-temperature sintering of an enamel coating.

The two kinds of enamel glaze materials are respectively enamel glaze A and enamel glaze B.

Preparing enamel glaze A: according to the mass fraction, 50 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 12 parts of borax pentahydrate, 8.5 parts of sodium carbonate, 4 parts of lithium carbonate, 5 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 4 parts of calcium carbonate, 2 parts of cobalt oxide and 1.5 parts of nickel oxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a high-temperature electric furnace at the temperature of 1300 ℃ for 2.5 hours, and the enamel glaze A is prepared through water quenching.

Preparing enamel glaze B: according to the mass fraction, 47 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 10 parts of borax pentahydrate, 12.5 parts of sodium carbonate, 4 parts of lithium carbonate, 6 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 3 parts of calcium carbonate, 2.5 parts of cobalt oxide and 2 parts of manganese dioxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a high-temperature electric furnace at the temperature of 1280 ℃ for 2.0 hours, and the enamel glaze B is prepared through water quenching.

The b) enamel glaze powder is prepared by the following steps: according to the mass fraction, 40.4 percent of enamel glaze A, 40.4 percent of enamel glaze B, 5.6 percent of kaolin, 0.3 percent of borax decahydrate, 0.3 percent of boric acid, 0.15 percent of sodium carbonate, 0.15 percent of sodium nitrite, 0.15 percent of magnesium carbonate, 0.4 percent of cobaltosic oxide and 12.15 percent of calcined quartz powder are put into a high-speed ball mill for grinding. Pure water with the relative mass fraction of 60% is used as a solvent, grinding is carried out for 15 minutes, and the prepared enamel glaze pulp is screened by a standard sieve with 60 meshes.

The c) alkaline degreasing treatment process of the surface of the weather-resistant structural steel comprises the following steps: the industrial alkaline cleaning agent is prepared into alkaline degreasing solution according to the mass percentage of 3 percent, the sodium hydroxide is prepared into alkaline degreasing solution according to the mass percentage of 2 percent and the water, and the alkaline leaching solution is prepared into alkaline leaching solution according to the mass percentage of 0.6 percent of sodium carbonate, 0.2 percent of sodium nitrite and the water. The weathering structural steel is soaked in an alkaline degreasing solution at 95 ℃ for 10 minutes, taken out, soaked in a clear water solution at 50 ℃ for 2 minutes, then soaked in an alkaline leaching solution at 50 ℃ for 3 minutes, and then dried at 150 ℃ for 10 minutes.

The d) spraying and high-temperature sintering of the enamel coating comprises the following specific steps: the enamel slurry of the enamel porcelain is uniformly coated on the surface of the weather-resistant structural steel subjected to alkaline degreasing treatment, and is dried for 15-20 minutes at the temperature of 200-220 ℃. And (3) placing the dried sample coated with the enamel glaze slurry coating in a high-temperature furnace at the temperature of 860-880 ℃ for sintering for 6-8 minutes to obtain the acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel.

Also provided in some embodiments of the present invention are acid corrosion resistant enamel coatings for weathering structural steel surfaces prepared by the above-described methods.

Compared with the prior art, the invention has the advantages that:

(1) the preparation method adopted by the invention is characterized in that the melting enamel glaze is divided into an enamel glaze A and an enamel glaze B, and the melting enamel glaze A and the enamel glaze B are melted at different temperatures for different time according to different component proportions, so that the energy is saved, the energy consumption is reduced, and the melting uniformity can be fully ensured;

(2) the preparation method adopted by the invention is characterized in that the enamel glaze powder contains kaolin, borax decahydrate, boric acid, calcined quartz powder and the like, wherein the kaolin has the function of introducing Al2O3 in the ceramic, which is beneficial to the generation of mullite, improves the chemical stability and the sintering strength of the mullite, and the kaolin is decomposed to generate the mullite during sintering to form a main frame of blank strength, thereby preventing the deformation of products, widening the sintering temperature and enabling the blank to have certain whiteness, and in addition, the Al2O3 enables the viscosity of the enamel glaze to be increased at the sintering temperature, the crystal nucleus to be formed smoothly, the crystal growth to be blocked, a large number of microcrystal structures to be formed and the hardness of an enamel layer to be improved; the borax is weathered in the air, can be dehydrated into anhydrous sodium tetraborate when heated to 400-500 ℃, is melted into a glass at 878 ℃, and meanwhile, the B2O3 has smaller surface tension and low elastic modulus, so that the fluidity of a melt is promoted, the glossiness, the fineness and the elasticity of enamel are improved, the melting point is low, and the function of a cosolvent is played; the calcined quartz powder is colloidal and is difficult to react with strong alkali, while the non-calcined quartz powder is crystalline and can react with alkali, and carbonate which can be decomposed at high temperature is removed by the pre-calcination purpose and effect of the quartz;

(3) The preparation method adopted by the invention comprises the step of alkaline degreasing treatment on the surface of the weather-resistant structural steel, and aims to improve the adhesion between the enamel coating and the weather-resistant structural steel.

(4) The enamel coating obtained by the invention has excellent bonding performance with weather-resistant structural steel, and has the advantages of excellent sulfuric acid resistance and corrosion resistance, long service life and the like.

(5) The preparation method is simple, mild in condition and suitable for large-scale popularization and application.

Detailed Description

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other systems for carrying out the same purposes of the present invention. It should also be realized that such equivalent constructions do not depart from the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

In a more specific embodiment of the present invention, a method for preparing an acid corrosion resistant enamel coating on a surface of weathering structural steel comprises: a) melting enamel glaze, b) preparing enamel glaze powder, c) alkaline degreasing treatment of the surface of the weather-resistant structural steel, and d) spraying and high-temperature sintering of an enamel coating.

The two kinds of enamel glaze materials are respectively enamel glaze A and enamel glaze B.

In a preferred embodiment of the present invention, a method for preparing an acid corrosion resistant enamel coating on a surface of weathering structural steel comprises the steps of:

a) preparing enamel glaze A: according to the mass fraction, 50 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 12 parts of borax pentahydrate, 8.5 parts of sodium carbonate, 4 parts of lithium carbonate, 5 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 4 parts of calcium carbonate, 2 parts of cobalt oxide and 1.5 parts of nickel oxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a high-temperature electric furnace at the temperature of 1300 ℃ for 2.5 hours, and the enamel glaze A is prepared through water quenching.

Preparing enamel glaze B: according to the mass fraction, 47 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 10 parts of borax pentahydrate, 12.5 parts of sodium carbonate, 4 parts of lithium carbonate, 6 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 3 parts of calcium carbonate, 2.5 parts of cobalt oxide and 2 parts of manganese dioxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a high-temperature electric furnace at the temperature of 1280 ℃ for 2.0 hours, and the enamel glaze B is prepared through water quenching.

b) The enamel glaze powder is prepared by the following steps: according to the mass fraction, 40.4 percent of enamel glaze A, 40.4 percent of enamel glaze B, 5.6 percent of kaolin, 0.3 percent of borax decahydrate, 0.3 percent of boric acid, 0.15 percent of sodium carbonate, 0.15 percent of sodium nitrite, 0.15 percent of magnesium carbonate, 0.4 percent of cobaltosic oxide and 12.15 percent of calcined quartz powder are put into a high-speed ball mill for grinding. Pure water with the relative mass fraction of 60% is used as a solvent, grinding is carried out for 15 minutes, and the prepared enamel glaze pulp is screened by a standard sieve with 60 meshes.

c) The process of the alkaline degreasing treatment of the surface of the weathering structural steel comprises the following steps: the industrial alkaline cleaning agent is prepared into alkaline degreasing solution according to the mass percentage of 3 percent, the sodium hydroxide is prepared into alkaline degreasing solution according to the mass percentage of 2 percent and the water, and the alkaline leaching solution is prepared into alkaline leaching solution according to the mass percentage of 0.6 percent of sodium carbonate, 0.2 percent of sodium nitrite and the water. The weathering structural steel is soaked in an alkaline degreasing solution at 95 ℃ for 10 minutes, taken out, soaked in a clear water solution at 50 ℃ for 2 minutes, then soaked in an alkaline leaching solution at 50 ℃ for 3 minutes, and then dried at 150 ℃ for 10 minutes.

d) The spraying and high-temperature sintering of the enamel coating comprises the following specific steps: the enamel slurry of the enamel porcelain is uniformly coated on the surface of the weather-resistant structural steel subjected to alkaline degreasing treatment, and is dried for 15-20 minutes at the temperature of 200-220 ℃. And (3) placing the dried sample coated with the enamel glaze slurry coating in a high-temperature furnace at the temperature of 860-880 ℃ for sintering for 6-8 minutes to obtain the acid corrosion resistant enamel coating on the surface of the weather-resistant structural steel.

Preferably, the weathering structural steel is cold-rolled weathering structural steel.

The invention is further illustrated below with reference to several examples. These examples are intended to illustrate the invention only and are not intended to limit the scope of the invention.

Example 1

The method comprises the following steps of: according to the mass fraction, 50 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 12 parts of borax pentahydrate, 8.5 parts of sodium carbonate, 4 parts of lithium carbonate, 5 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 4 parts of calcium carbonate, 2 parts of cobalt oxide and 1.5 parts of nickel oxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a silicon-molybdenum rod high-temperature electric furnace at the temperature of 1300 ℃ for 2.5 hours, and the enamel glaze A is prepared by water quenching.

Enamel glaze B: according to the mass fraction, 47 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 10 parts of borax pentahydrate, 12.5 parts of sodium carbonate, 4 parts of lithium carbonate, 6 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 3 parts of calcium carbonate, 2.5 parts of cobalt oxide and 2 parts of manganese oxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a silicon-molybdenum rod high-temperature electric furnace at the temperature of 1280 ℃ for 2.0 hours, and the enamel glaze B is prepared by water quenching.

The method comprises the following steps of filling 40.4% of enamel glaze A, 40.4% of enamel glaze B, 5.6% of kaolin, 0.3% of borax decahydrate, 0.3% of boric acid, 0.15% of sodium carbonate, 0.15% of sodium nitrite, 0.15% of magnesium carbonate, 0.4% of cobaltosic oxide and 12.15% of calcined quartz powder into a high-speed ball mill for grinding. Pure water with the relative mass fraction of 60% is used as a solvent, grinding is carried out for 15 minutes, and the prepared enamel glaze pulp is screened by a standard sieve with 60 meshes.

Preparing an alkaline degreasing solution from 3% of industrial alkaline cleaning agent, 2% of sodium hydroxide and water by mass percent; 0.6 percent of sodium carbonate, 0.2 percent of sodium nitrite and water are prepared into alkaline leaching solution according to the mass percentage. The weathering structural steel sample is soaked in an alkaline degreasing solution at 95 ℃ for 10 minutes, taken out, soaked in a clear water solution at 50 ℃ for 2 minutes, then soaked in an alkaline leaching solution at 50 ℃ for 3 minutes, and then dried at 150 ℃ for 10 minutes.

And fourthly, uniformly coating the enamel glaze slip on the surface of the weather-resistant structural steel sample subjected to alkaline degreasing treatment, and drying at the temperature of 200 ℃ for 20 minutes. And (3) placing the dried sample coated with the enamel glaze slurry coating into a box-type high-temperature furnace at the temperature of 860 ℃ for sintering for 8 minutes. Namely, the enamel coating which is resistant to sulfuric acid and corrosion is prepared on the surface of the weathering structural steel.

The vitriol-resistant and corrosion-resistant enamel coating prepared by the invention is boiled in 30% vitriol solution for 18 hours, the single-side erosion amount is 1.67 g/m 2, and the enamel coating conforms to GB/T31567-2015 < enamel heat exchange element for air-smoke and smoke-smoke Regenerative heat exchanger > and DIN EN ISO 28763-2011 < vitamins and pore amines-Regenerative, and the enamel and packed minerals for air-gas and gas-gas heat exchangers-specifications > standard, namely, the single-side erosion amount is not more than 2.0 g/m 2 after being boiled in 30% vitriol solution for 18 hours.

Example 2

The method comprises the following steps of: according to the mass fraction, 50 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 12 parts of borax pentahydrate, 8.5 parts of sodium carbonate, 4 parts of lithium carbonate, 5 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 4 parts of calcium carbonate, 2 parts of cobalt oxide and 1.5 parts of nickel oxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a silicon-molybdenum rod high-temperature electric furnace at the temperature of 1300 ℃ for 2.5 hours, and the enamel glaze A is prepared by water quenching.

Enamel glaze B: according to the mass fraction, 47 parts of quartz powder, 3 parts of fluorite, 5 parts of sodium nitrate, 10 parts of borax pentahydrate, 12.5 parts of sodium carbonate, 4 parts of lithium carbonate, 6 parts of strontium carbonate, 3 parts of titanium oxide, 2 parts of barium carbonate, 3 parts of calcium carbonate, 2.5 parts of cobalt oxide and 2 parts of manganese oxide are uniformly mixed to obtain a batch mixture, then the obtained batch mixture is melted in a silicon-molybdenum rod high-temperature electric furnace at the temperature of 1280 ℃ for 2.0 hours, and the enamel glaze B is prepared by water quenching.

The method comprises the following steps of filling 40.4% of enamel glaze A, 40.4% of enamel glaze B, 5.6% of kaolin, 0.3% of borax decahydrate, 0.3% of boric acid, 0.15% of sodium carbonate, 0.15% of sodium nitrite, 0.15% of magnesium carbonate, 0.4% of cobaltosic oxide and 12.15% of calcined quartz powder into a high-speed ball mill for grinding. Pure water with the relative mass fraction of 60% is used as a solvent, grinding is carried out for 15 minutes, and the prepared enamel glaze pulp is screened by a standard sieve with 60 meshes.

Preparing an alkaline degreasing solution from 3% of industrial alkaline cleaning agent, 2% of sodium hydroxide and water by mass percent; 0.6 percent of sodium carbonate, 0.2 percent of sodium nitrite and water are prepared into alkaline leaching solution according to the mass percentage. The weathering structural steel sample is soaked in an alkaline degreasing solution at 95 ℃ for 10 minutes, taken out, soaked in a clear water solution at 50 ℃ for 2 minutes, then soaked in an alkaline leaching solution at 50 ℃ for 3 minutes, and then dried at 150 ℃ for 10 minutes.

And fourthly, uniformly coating the enamel glaze slip on the surface of the weather-resistant structural steel sample subjected to alkaline degreasing treatment, and drying at the temperature of 220 ℃ for 15 minutes. And (3) placing the dried sample coated with the enamel glaze slurry coating into a box-type high-temperature furnace at the temperature of 880 ℃ for sintering for 6 minutes. Namely, the enamel coating which is resistant to sulfuric acid and corrosion is prepared on the surface of the weathering structural steel.

The vitriol-resistant and corrosion-resistant enamel coating prepared by the invention is boiled in 30% vitriol solution for 18 hours, the single-side erosion amount is 1.56 g/m 2, and the enamel coating conforms to GB/T31567-2015 < enamel heat exchange element for air-smoke and smoke-smoke Regenerative heat exchanger > and DIN EN ISO 28763-2011 < vitamins and pore amines-Regenerative, and the enamel and packed minerals for air-gas and gas-gas heat exchangers-specifications > standard, namely, the single-side erosion amount is not more than 2.0 g/m 2 after being boiled in 30% vitriol solution for 18 hours.

The embodiments described above are intended to illustrate the technical solutions of the present invention in detail, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modification, supplement or similar substitution made within the scope of the principles of the present invention should be included in the protection scope of the present invention.