Steel plate enamel low temperature acid resistant translucent glaze without fluorinated salt and nitrate and its preparation method and application

Abstract

The application discloses a steel plate enamel low-temperature acid-resistant translucent glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The translucent glaze is composed of quartz, zero-water borax, titanium white, trisodium phosphate, potassium carbonate, lithium carbonate, aluminum oxide, zinc oxide and soda ash in a specific mass ratio. The preparation comprises the steps of raw material mixing, high-temperature smelting under pure oxygen condition, wire drawing detection and rapid cooling. The translucent glaze is completely free of fluorinated salt and nitrate, avoids fluorine emission and environmental protection equipment blockage problems from the source, the fluorine content of the product is not detected through detection, meets the requirements of the EU REACH regulation, has good porcelain surface, gloss and low-temperature firing adaptability, is suitable for a steel plate substrate, has a firing temperature of 760-800 DEG C, and can be used for the production of green and environmentally-friendly enamel products.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of enamel, and particularly relates to a steel plate enamel low-temperature acid-resistant translucent glaze without fluorinated salt and nitrate, and a preparation method and application thereof. BACKGROUND

[0002] The steel plate enamel low-temperature acid-resistant translucent glaze needs to meet the requirements of acid resistance (≥ A level), low-temperature firing (760-800 DEG C), and no defects in appearance, smooth porcelain surface and gloss ≥ 80. The traditional formula relies on fluorinated salt (fluorite / fluorosilicate accounts for 1-12%) to achieve fluxing, increase gloss and improve transparency. Fluorinated salt is not an "optional" additive in traditional enamel base glaze, but a "indispensable" skeleton component. Due to the multiple synergies of fluorinated salt, such as reducing the melting temperature, improving the gloss and increasing the stability of the crystal, simply removing fluorinated salt will not result in "performance decline", but "collapse" of the entire enamel system. Any attempt to remove fluorinated salt must be based on finding or inventing a new material or new process system that can completely simulate or replace the above multiple functions, and this is still a major technical challenge in the field of enamel technology. Therefore, the importance of fluorinated salt in the traditional process cannot be overemphasized. However, research has shown that:

[0003] 1. Hydrogen fluoride (HF) and silicon tetrafluoride (SiF4) gases released during high-temperature melting process cause harm to health and environment.

[0004] 2. The European Union REACH regulation lists fluorides as a high-concern substance (SVHC), and fluorinated salt products cannot meet the EU REACH regulation requirements for fluorine, with a fluorine (F) limit of 20 mg / kg.

[0005] 3. End environmental management equipment is blocked due to fluorinated salt crystallization, which seriously restricts normal production of enterprises.

[0006] At the same time, nitrate, as a traditional oxidizing agent and close-together promoting component, is prone to produce nitrogen oxides (NO x ) during high-temperature decomposition, which also faces environmental pressure. Currently, the removal of nitrate from enamel glaze has solved the problem of nitrogen oxide emission (such as CN114368912B, CN114315150B, CN114315151B, etc.), and further implementation of fluorine-free and nitrate-free system is not only a necessary choice to respond to regulations, but also a forward-looking technical layout for the future.

[0007] The replacement of fluorinated salt is a major technical bottleneck at present, mainly reflected in:

[0008] (1) Fluorinated salt dependence is strong, and environmental risk is prominent: CN119710693A (high-temperature-resistant enamel enamel) uses cryolite (Na3AlF6) as a fluxing agent, although it improves the temperature resistance, but does not solve the problem of fluorine emission; CN112342544A (low-temperature acid and alkali-resistant steel plate enamel) contains sodium fluoride (5-7 parts) in the semi-transparent enamel formula.

[0009] (2) Non-fluorine substitution scheme has functional defects: CN105800935A (enamel enamel material) attempts to use lanthanide oxides to enhance adhesion, but it still needs to add 8% fluoride to assist melting, and the high cost of rare earth makes it difficult to promote. CN116854374A (black enamel composite glaze) uses a cobalt-nickel base glaze system, but the anti-explosive agent used contains 8-10% of fluorite powder.

[0010] (3) The field of ceramics involves fluorine-free schemes, but it is difficult to migrate applications: CN110885189A relates to zirconium-free enamel and the positioning crystal flower ceramic tile made by using the same, CN115626774A relates to a soft light skin ceramic rock plate and a preparation method thereof, CN112979271A relates to a preparation method of a light-weight high-strength pure-color glaze tile, and CN118754723A relates to a hydrophilic self-cleaning antique tile based on phase separation and a preparation method thereof. The above prior art does not involve the use of fluorinated salt, but its technical essence belongs to the field of building ceramic glaze, which is different from the field of enamel glaze for metal substrate. There are essential differences between ceramic glaze and enamel glaze for metal substrate in terms of thermal expansion coefficient (the difference in expansion coefficient is one order of magnitude), firing temperature (the firing temperature of ceramic glaze is higher than that of enamel glaze by more than 200℃), and bonding mechanism (the base of ceramic glaze is porcelain clay, while the base of enamel glaze for metal substrate is metal), which cannot be directly applied to the field of enamel for metal substrate.

[0011] In summary, on the basis of denitrification, the problem of defluorination is solved, and the quality of enamel products is improved, which has very important practical significance for promoting the green, low-carbon and high-quality development of the enamel industry. SUMMARY

[0012] In view of the excessive emission of fluorides in the production process of existing enamel glaze, which causes damage to health and environment, the fluorinated salt-containing products cannot meet the requirements of EU REACH regulations on fluorine, and the emitted fluorinated salt blocks environmental management facilities, which seriously restricts the normal production of enterprises, the present application provides a steel plate enamel low-temperature acid-resistant semi-transparent glaze without fluorinated salt and nitrate, as well as a preparation method and application thereof.

[0013] The enamel low-temperature acid-resistant translucent glaze of the steel plate without fluorinated salt and nitrate of the application is prepared by the following steps: (1) weighing the raw materials according to the above-mentioned mass fraction; (2) stirring and mixing the raw materials uniformly; (3) putting the mixed materials into a melting furnace and melting under the condition of pure oxygen, with the melting temperature controlled at 1300±10℃; (4) after the materials are completely melted, borosilicate glass is obtained, the borosilicate glass is drawn into a glass filament of 1.2-1.5 meters for detection, and the detection requirement is that the glass filament is continuously melted for 10-15 minutes without joints within 1 meter of the glass filament; and (5) rapidly cooling the melted borosilicate glass to obtain the product.

[0014] Further, the mass fraction of SiO2 in quartz is ≥99%, the mass fraction of TiO2 in titanium white powder is ≥99%, and the mass purity of zinc oxide prepared by distillation of metallic zinc and then oxidation is ≥99.7%.

[0015] Further, the mass fraction of SiO2 in quartz is ≥99%, the mass fraction of TiO2 in titanium white powder is ≥99%, and the mass purity of zinc oxide prepared by distillation of metallic zinc and then oxidation is ≥99.7%.

[0016] The preparation method of the enamel low-temperature acid-resistant translucent glaze of the steel plate without fluorinated salt and nitrate, comprising the following steps:

[0017] (1) weighing the raw materials according to the above-mentioned mass fraction;

[0018] (2) stirring and mixing the raw materials uniformly;

[0019] (3) putting the mixed materials into a melting furnace and melting under the condition of pure oxygen, with the melting temperature controlled at 1300±10℃;

[0020] (4) after the materials are completely melted, borosilicate glass is obtained, the borosilicate glass is drawn into a glass filament of 1.2-1.5 meters for detection, and the detection requirement is that the glass filament is continuously melted for 10-15 minutes without joints within 1 meter of the glass filament;

[0021] (5) rapidly cooling the melted borosilicate glass to obtain the product.

[0022] Further, in step (5), the rapid cooling is achieved by water quenching or tabletting process.

[0023] The enamel low-temperature acid-resistant translucent glaze of the steel plate without fluorinated salt and nitrate is applied to blanks with steel plate as the base body, and the firing temperature of the finished product is 760-800℃.

[0024] The application introduces zinc oxide into the formula of the low-temperature acid-resistant translucent enamel of steel plate enamel, cooperates with titanium dioxide in titanium white powder, reduces the liquid phase viscosity of ZnO / TiO2, accelerates ion and bubble diffusion, increases phosphate, forms a eutectic complex fluxing system of'multinary carbonate + phosphate + borate' to strengthen fluxing, and the components cooperate to promote the improvement of the performance of the low-temperature acid-resistant transparent enamel of steel plate enamel, such as enamel surface, gloss, acid resistance, transparency, sintering performance and the like.

[0025] The application has the following beneficial effects:

[0026] (1) The fluoride is discharged at an ultra-low standard;

[0027] (2) The product is detected by SGS, and the fluoride detection result shows that no fluoride is detected, which meets the limit requirement of the SVHC (substance of very high concern) of the EU REACH regulation.

[0028] (3) The end environmental protection equipment blockage problem is solved: the application completely removes fluoride (fluorite, sodium fluorosilicate, etc.), eliminates the fluoride salt crystallization source from the source, and solves the end environmental protection equipment blockage problem. According to the actual measurement of the production line, the continuous operation period of the equipment is prolonged from the original 10-15 days to more than 180 days, and the maintenance cost is significantly reduced.

[0029] (4) Good low-temperature sintering adaptability: the eutectic complex fluxing system (multinary carbonate + phosphate + borate) interacts with other components, so that the sintering temperature is stably controlled at 760-800 DEG C, and the enamel surface has good flowability.

[0030] (5) The zinc oxide is added, cooperates with TiO2 in titanium white powder, reduces the liquid phase viscosity of ZnO / TiO2, accelerates ion diffusion, and cooperates with other components to promote the improvement of the performance of the low-temperature acid-resistant translucent enamel, such as enamel surface, gloss, acid resistance, transparency, sintering performance and the like. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The photo of the enamel plate made of the product obtained in example 1 of the application. DETAILED DESCRIPTION

[0032] The application will be further described in detail in combination with specific embodiments, but the application is not limited thereto.

[0033] The equipment used in the example of the application is as follows:

[0034] Batching: a full-automatic batching and mixing system is used. The system is fully automatic computer controlled, has the characteristics of accurate weighing, uniform mixing and high batching efficiency.

[0035] Melting: an automatic feeding system, an automatic pure oxygen combustion control system and an automatic discharging system are used.

[0036] Packaging: An automated packaging system is used.

[0037] The purity of the raw materials used in the embodiments of this invention meets the requirements of industrial grade.

[0038] Example 1

[0039] (1) Weigh the raw materials according to the following mass parts of each component:

[0040] Quartz 38 parts, anhydrous borax 30 parts, titanium dioxide 7 parts, trisodium phosphate 3 parts, potassium carbonate 6 parts, lithium carbonate 2 parts, soda ash 9 parts, alumina 2 parts, zinc oxide 2 parts.

[0041] The mass percentage of SiO2 in quartz is ≥99%, the mass percentage of TiO2 in titanium dioxide is ≥99%, and zinc oxide is obtained by oxidation after distillation of metallic zinc, with a mass purity of ≥99.7%.

[0042] (2) Mix the above raw materials evenly.

[0043] (3) Add the mixed material into the melting furnace and melt it under pure oxygen conditions. The melting temperature is controlled at 1300±10℃.

[0044] (4) After the above materials are completely melted, a borosilicate glass body is obtained. The molten borosilicate glass body is drilled and quickly drawn into a glass wire of 1.2 to 1.5 meters for testing. The testing requirement is: the glass wire is melted without knots for 10 minutes to complete the melting.

[0045] (5) The molten borosilicate glass body is rapidly cooled (water quenched) to obtain the product.

[0046] A photograph of the product obtained in Example 1 of this invention applied to a ceramic enamel printing plate made of steel plate is shown below. Figure 1 As shown, the steel plate enamel low-temperature acid-resistant semi-transparent glaze, which is free of fluoride salts and nitrates, has a smooth and delicate surface, no obvious defects in appearance, excellent gloss and color development performance, and acid resistance of A or above. The product quality meets the enterprise's standard requirements.

[0047] Example 2

[0048] The preparation process in this embodiment is basically the same as that in Example 1, except that:

[0049] The mass fractions of each component in step (1) are: 39 parts quartz, 28 parts anhydrous borax, 6 parts titanium dioxide, 4 parts trisodium phosphate, 5 parts potassium carbonate, 3 parts lithium carbonate, 8 parts soda ash, 3 parts zinc oxide, and 4 parts aluminum oxide.

[0050] In step (5), the molten borosilicate glass body is rapidly cooled by pressing.

[0051] Example 3

[0052] The preparation process of this example is basically the same as that of Example 1, except that:

[0053] The mass parts of each component in step (1) are: quartz 40 parts, zero-water borax 29 parts, titanium white 5 parts, trisodium phosphate 5 parts, potassium carbonate 4 parts, lithium carbonate 4 parts, aluminum oxide 2.5 parts, zinc oxide 3.5 parts, and soda ash 7 parts.

[0054] Example 4

[0055] The preparation process of this example is basically the same as that of Example 1, except that:

[0056] The mass parts of each component in step (1) are: quartz 42 parts, zero-water borax 27 parts, titanium white 6.5 parts, trisodium phosphate 4 parts, potassium carbonate 5.5 parts, lithium carbonate 2.5 parts, aluminum oxide 3.5 parts, zinc oxide 5 parts, and soda ash 8 parts.

[0057] The product prepared by the present application is applied to a blank with a steel plate as a base body, and the firing temperature of the finished product is 760-800℃.

[0058] Comparative Example 1

[0059] The rest is the same as Example 1, except that the mass parts of each component in step (1) are: quartz 39.5 parts, zero-water borax 28.5 parts, soda ash 2.2 parts, sodium fluorosilicate 5.8 parts, potassium carbonate 5.0 parts, titanium white 6.0 parts, lithium carbonate 4.0 parts, and aluminum oxide 1.9 parts.

[0060] The test results of the products obtained in the above examples and comparative examples are shown in Table 1 below.

[0061] Table 1 Test results of products obtained in each example and comparative example

[0062]

[0063] The above examples and test results prove that the steel plate enamel low-temperature acid-resistant translucent glaze produced by the method of the present application does not contain fluorinated salt and nitrate, no fluorinated compound is generated in the preparation process, and each performance (appearance, porcelain surface, acid resistance, transparency, gloss, firing temperature) of the obtained product meets the requirements of steel plate enamel acid-resistant translucent glaze, the fluorinated compound test result of the product shows no detection, which meets the limit requirements of SVHC (high concern substance) of the EU REACH regulation, and fundamentally solves the technical problems of environmental pollution caused by fluorinated compound gas emission and fluorinated salt emission during the production process of the existing steel plate enamel low-temperature acid-resistant translucent glaze.

Claims

1. A low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates, characterized in that, Its formula consists of the following components by weight: quartz 38-42 parts, anhydrous borax 27-30 parts, titanium dioxide 5-7 parts, trisodium phosphate 3-5 parts, potassium carbonate 4-6 parts, lithium carbonate 2-4 parts, alumina 2-4 parts, zinc oxide 2-5 parts, and soda ash 7-9 parts.

2. The low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1, characterized in that, Quartz 40-42 parts, anhydrous borax 27-29 parts, titanium dioxide 5-6.5 parts, trisodium phosphate 4-5 parts, potassium carbonate 4-5.5 parts, lithium carbonate 2.5-4 parts, alumina 2.5-3.5 parts, zinc oxide 3.5-5 parts, soda ash 7-8 parts.

3. The low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1 or 2, characterized in that, The mass percentage of SiO2 in quartz is ≥99%.

4. The low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1 or 2, characterized in that, In titanium dioxide, TiO2 accounts for ≥99% by mass.

5. The low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1 or 2, characterized in that, Zinc oxide is obtained by oxidizing metallic zinc after distillation, and its purity is ≥99.7%.

6. The method for preparing a low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates, as described in any one of claims 1 to 5, is characterized in that... Includes the following steps: (1) Weigh the raw materials of each component; (2) Stir and mix the raw materials described in step (1) until they are evenly mixed; (3) Add the mixed material into the melting furnace and melt it under pure oxygen conditions. The melting temperature is controlled at 1300±10℃. (4) After the material described in step (3) is completely melted, a borosilicate glass body is obtained. The molten borosilicate glass body is drilled and quickly drawn into a glass wire of 1.2 to 1.5 meters for testing. The testing requirement is: the glass wire is melted without knots within 1 meter for 10 to 15 minutes to complete the melting process. (5) The molten borosilicate glass body is rapidly cooled to obtain the product.

7. The preparation method according to claim 6, characterized in that, In step (5), the rapid cooling is achieved by water quenching or tableting.

8. The application of the low-temperature acid-resistant translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in any one of claims 1 to 5, characterized in that, It is applied to blanks with steel plates as the base material, and the firing temperature of the finished product is 760-800℃.

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