Non-fluoride and non-nitrate steel plate enamel for medium temperature acid-resistant transparent glaze, its preparation method and application

Abstract

The application discloses a steel plate enamel medium-temperature acid-resistant transparent glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The transparent glaze is composed of quartz, zero-water borax, fumed silica, titanium dioxide, barium carbonate, aluminum oxide, lithium carbonate, soda ash and zinc oxide 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 transparent 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 800-840 DEG C, and can be used for the production of green and environment-friendly enamel products.

Description

TECHNICAL FIELD

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

[0002] The steel plate enamel mid-temperature acid-resistant transparent glaze needs to meet the requirements of acid resistance (≥ A level), mid-temperature firing (800-840 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. Since fluorinated salt has multiple synergistic effects such as reducing melting temperature, improving gloss and increasing stability of crystals, simply and roughly 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 substances of very high concern (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 by fluorinated salt crystallization, which seriously restricts normal production of enterprises.

[0006] At the same time, nitrate, as a traditional oxidizing agent and adhesion 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) Fluoride 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 (medium-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-explosion agent used contains 8-10% of fluorite powder.

[0010] (3) The field of ceramics involves fluoride-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 fluoride salt, but its technical essence belongs to the field of building ceramic glaze, which is different from the field of enamel base glaze for metal substrate. There are essential differences between ceramic glaze and metal-based enamel in 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 by more than 200℃), and bonding mechanism (the base of ceramic glaze is porcelain clay, while the base of enamel is metal), which cannot be directly applied to the field of metal-based enamel.

[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 fluorine-containing salt products cannot meet the requirements of EU REACH regulations on fluorine, and the emitted fluoride salt blocks environmental management facilities, which seriously restricts the normal production of enterprises. The present application provides a steel plate enamel medium-temperature acid-resistant transparent glaze without fluoride salt and nitrate, as well as a preparation method and application thereof.

[0013] The enamel of the steel plate without fluorinated salt and nitrate in the application is prepared by the following steps: (1) weighing the raw materials according to the above mass parts; (2) stirring and mixing the raw materials in step (1) uniformly; (3) putting the mixed material into a melting furnace and melting under the condition of pure oxygen, and the melting temperature is controlled at 1260±10 DEG C; (4) after the material in step (3) is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body 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 node within 1 meter of the glass filament; and (5) rapidly cooling the melted borosilicate glass body to obtain the product.

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

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

[0016] The preparation method of the enamel of the steel plate without fluorinated salt and nitrate in the application, comprising the following steps:

[0017] (1) weighing the raw materials according to the above mass parts;

[0018] (2) stirring and mixing the raw materials in step (1) uniformly;

[0019] (3) putting the mixed material into a melting furnace and melting under the condition of pure oxygen, and the melting temperature is controlled at 1260±10 DEG C;

[0020] (4) after the material in step (3) is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body 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 node within 1 meter of the glass filament; and (5) rapidly cooling the melted borosilicate glass body to obtain the product.

[0021] (4) after the material in step (3) is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body 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 node within 1 meter of the glass filament; and (5) rapidly cooling the melted borosilicate glass body to obtain the product.

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

[0023] The enamel of the steel plate without fluorinated salt and nitrate in the application is applied to a blank with a steel plate as a base body, and the firing temperature of the finished product is 800-840 DEG C, and does not include the end point value 800 DEG C.

[0024] The application introduces fumed silica into the formula of the steel plate enamel medium-temperature acid-resistant transparent glaze, which not only strengthens the fluxing of the eutectic complex fluxing system of'multi-carbonate + borate', but also improves the acid resistance, and the introduction of zinc oxide cooperates with titanium dioxide, and ZnO / TiO2 reduces the liquid viscosity, accelerates the diffusion of ions and bubbles; the components cooperate to promote the improvement of the enamel surface, gloss, acid resistance, transparency, sintering performance and other performances of the steel plate enamel low-temperature acid-resistant transparent glaze.

[0025] The application has the beneficial effects that:

[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 it is not detected, which meets the limit requirement of the SVHC (high concern substance) 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 fluorine 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 medium-temperature sintering adaptability: the eutectic complex fluxing system (multi-carbonate + borate) interacts with other components, so that the sintering temperature is stably controlled at 800-840 DEG C, and the enamel surface has good flowability.

[0030] (5) The introduction of fumed silica effectively promotes the solid phase reaction due to its high surface energy, accelerates the melting process from the kinetic point of view, and the dissolved SiO2 can more efficiently saturate the erosion liquid and improve the acid resistance.

[0031] (6) The increase of zinc oxide cooperates with TiO2 in titanium white powder, ZnO / TiO2 reduces the liquid viscosity, accelerates the ion diffusion, and cooperates with other components to promote the improvement of the enamel surface, gloss, acid resistance, transparency, sintering performance and other performances of the steel plate enamel medium-temperature acid-resistant transparent glaze. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The photo of the enamel plate made of the product obtained in example 1 of the application. DETAILED DESCRIPTION

[0033] The application will be further described in detail in combination with specific examples, but the application is not limited thereto.

[0034] The equipment used in the examples of the application is:

[0035] Ingredients: The full-automatic ingredient mixing system is adopted. The system is fully automatic computer control, and has the characteristics of accurate weighing, uniform mixing and high ingredient efficiency.

[0036] Melting: The automatic feeding system, automatic pure oxygen combustion control system and automatic discharging system are adopted.

[0037] Packaging: The automatic packaging system is adopted.

[0038] The purity of the raw materials used in the embodiment of the application meets the requirements of the industrial grade.

[0039] Example 1

[0040] (1) The raw materials are weighed according to the mass parts of each component as follows:

[0041] Quartz 42 parts, zero-water borax 26 parts, fumed silica 11 parts, titanium white 4 parts, barium carbonate 5 parts, aluminum oxide 4 parts, lithium carbonate 3 parts, soda ash 14 parts, and zinc oxide 5 parts;

[0042] The mass proportion of SiO2 in quartz is ≥99%, the mass proportion of TiO2 in titanium white is ≥99%, and the mass purity of zinc oxide prepared by distillation of metallic zinc and oxidation is ≥99.7%.

[0043] (2) The above raw materials are stirred and mixed uniformly.

[0044] (3) The uniformly mixed material is added to a melting furnace, and melting is carried out under pure oxygen conditions, with the melting temperature controlled at 1260±10℃.

[0045] (4) After the above material is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body is drilled, and is quickly drawn into a 1.2-1.5 meter glass filament for detection. The detection requirement is that no knot is continued to melt for 10 minutes within 1 meter of the glass filament, and the melting is completed.

[0046] (5) The molten borosilicate glass body is rapidly cooled (water quenching), and the product is obtained.

[0047] The product obtained in Example 1 of the application is applied to a porcelain enamel plate made of steel plate, as shown in Figure 1 The enamel plate made of steel plate does not contain fluorinated salt and nitrate, and the enamel surface of the enamel plate is smooth and delicate, the appearance has no obvious defects, the gloss and color performance are excellent, the acid resistance is A or above, and the product quality meets the enterprise standard requirements.

[0048] Example 2

[0049] The preparation process of this embodiment is basically the same as that of Example 1, and the difference is that:

[0050] The mass fractions of each component in step (1) are: 46 parts quartz, 24 parts anhydrous borax, 8 parts fumed silica, 5 parts titanium dioxide, 4 parts barium carbonate, 3 parts aluminum oxide, 4 parts lithium carbonate, 13 parts soda ash, and 6 parts zinc oxide.

[0051] In step (5), the molten borosilicate glass body is rapidly cooled by pressing.

[0052] Example 3

[0053] The preparation process in this embodiment is basically the same as that in Example 1, except that:

[0054] The mass fractions of each component in step (1) are: 45 parts quartz, 25 parts anhydrous borax, 9 parts fumed silica, 6 parts titanium dioxide, 3 parts barium carbonate, 3.5 parts aluminum oxide, 4 parts lithium carbonate, 12 parts soda ash, and 7 parts zinc oxide.

[0055] Example 4

[0056] The preparation process in this embodiment is basically the same as that in Example 1, except that:

[0057] The mass fractions of each component in step (1) are: 43 parts quartz, 23 parts anhydrous borax, 10 parts fumed silica, 4.5 parts titanium dioxide, 4.5 parts barium carbonate, 4 parts aluminum oxide, 3.5 parts lithium carbonate, 13.5 parts soda ash, and 6 parts zinc oxide.

[0058] The product prepared by this invention is applied to a blank with a steel plate as the base material, and the firing temperature of the finished product is 800-840℃.

[0059] Comparative Example 1

[0060] The rest is the same as in Example 1, except that the mass parts of each component in step (1) are: quartz 44.0 parts, anhydrous borax 23.2 parts, soda ash 12.5 parts, fluorite 6.8 parts, titanium dioxide 6.1 parts, barium carbonate 4.3 parts, and alumina 7.1 parts.

[0061] The test results of the products obtained from the above embodiments and comparative examples are shown in Table 1 below.

[0062] Table 1. Test results of products obtained from each embodiment and comparative example.

[0063]

[0064] The above examples and detection results prove that the enamel mid-temperature acid-resistant transparent glaze of the steel plate produced by the method of the application does not contain fluorinated salt and nitrate, no fluorinated salt is generated in the preparation process, and the properties (appearance, porcelain surface, acid resistance, transparency, gloss, sintering temperature) of the obtained product meet the requirements of the steel plate enamel acid-resistant semi-transparent glaze, the fluorinated salt detection result of the product shows that no fluorinated salt is detected, the limit requirement of the European Union REACH regulation on SVHC (substance of very high concern) is met, and the technical problems of the existing steel plate enamel mid-temperature acid-resistant transparent glaze in the production process, such as the generation of fluorinated gas emission to pollute the environment and the emission of fluorinated salt to block the environmental protection treatment facilities, are fundamentally solved.

Claims

1. Steel plate enamel for medium temperature acid-resistant transparent glaze free of fluorinated salts and nitrates, characterized in that, The formula thereof is composed of the following components in parts by mass: quartz 42-46 parts, zero-water borax 23-26 parts, fumed silica 8-11 parts, titanium white 4-6 parts, barium carbonate 3-5 parts, alumina 3-4 parts, lithium carbonate 3-4 parts, soda ash 12-14 parts, and zinc oxide 5-7 parts.

2. The steel plate enamel free of fluorinated salts and nitrate according to claim 1, characterized in that, Quartz 43-45 parts, zero-water borax 23-25 parts, fumed silica 9-10 parts, titanium white 4.5-6 parts, barium carbonate 3-4.5 parts, alumina 3.5-4 parts, lithium carbonate 3.5-4 parts, soda ash 12-13.5 parts, and zinc oxide 6-7 parts.

3. The non-fluoride-salt-free and non-nitrate-salt-free steel plate enamel transparent glaze at medium temperature acid resistance according to claim 1 or 2, characterized in that, The mass percentage of SiO2 in quartz is ≥99%.

4. The non-fluoride-salt-free and non-nitrate-salt-free steel plate enamel transparent glaze for medium temperature acid resistance according to claim 1 or 2, characterized in that, The mass percentage of TiO2 in titanium white is ≥99%.

5. The non-fluoride-salt-free and non-nitrate-salt-free steel plate enamel transparent glaze for medium temperature acid resistance according to claim 1 or 2, characterized in that, Zinc oxide is prepared by distillation of metallic zinc followed by oxidation, and the mass purity thereof is ≥99.7%.

6. The method of producing a non-fluoride-salt-free and non-nitrate-salt-free steel plate enamel for transparent enamel for acid resistance at a medium temperature according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: (1) weighing each component raw material; (2) stirring and mixing the raw materials in step (1) uniformly; (3) adding the mixed material into a melting furnace, and melting under pure oxygen condition, with the melting temperature controlled at 1260±10℃; (4) obtaining a borosilicate glass body after the material in step (3) is completely melted, and the molten borosilicate glass body is drawn into a glass filament of 1.2-1.5 meters for detection, with the detection requirement being that no knot is observed within 1 meter of the glass filament, and the melting is completed after 10-15 minutes of continuous melting; (5) rapidly cooling the melted borosilicate glass body, and obtaining the product.

7. The production method according to claim 6, wherein In step (5), the rapid cooling is achieved by water quenching or tablet pressing process.

8. Use of a steel sheet according to any one of claims 1 to 5, which is free of fluorinated salts and free of nitrates, for a porcelain enamel transparent glaze for medium temperature resistant to acid, characterized in that, When applied to a blank with a steel plate as a base body, the firing temperature of the finished product is 800-840℃, and the end point value 800℃ is not included.

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