Stainless steel enamel low temperature titanium white face glaze without fluorinated salt and nitrate and its preparation method and application

Abstract

The application discloses a stainless steel enamel low-temperature titanium white face glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The titanium white face glaze is composed of quartz, zero-water borax, titanium white powder, magnesium carbonate, potassium dihydrogen phosphate, potassium carbonate, lithium carbonate, aluminum hydroxide and V-26 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 titanium white face 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 stainless steel substrate, has a firing temperature of 740-780 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 stainless steel enamel low-temperature titanium white face glaze free of fluorinated salt and nitrate salt as well as a preparation method and application thereof. BACKGROUND

[0002] The stainless steel enamel low-temperature titanium white face glaze needs to meet core indexes such as high brightness, whiteness, excellent opalescence and low-temperature firing (740-760 DEG C) of the enamel face. The traditional formula relies on fluorinated salt (fluorite / fluorosilicate accounts for 1-12%) to realize fluxing, improve opalescence and the like. The fluorinated salt is not an "optional" additive in the traditional enamel face glaze, but an "indispensable" skeleton component. Since the fluorinated salt has multiple synergistic effects such as reducing the melting temperature, improving opalescence and wettability, simply and roughly removing the fluorinated salt is equivalent to removing the load-bearing wall of the mansion, which leads to not "performance decline", but "collapse" of the entire enamel system. Any fluorine-free attempt must be based on finding or inventing a new substance or new process system that can completely simulate or replace the above multiple functions, and this is still a major technical challenge in the enamel process field. Therefore, the importance of fluorinated salt in the traditional process cannot be overemphasized. However, research has confirmed that:

[0003] 1. Hydrogen fluoride (HF) and silicon tetrafluoride (SiF4) gases released during high-temperature melting process cause damage 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 salt, as a traditional oxidizing agent and close-promoting component, is prone to produce nitrogen oxides (NO x ) during high-temperature decomposition, also facing environmental pressure. Currently, the denitration of enamel glaze has solved the problem of nitrogen oxide emission (such as CN114368912B, CN114315150B, CN114315151B, etc.), and further realization 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 glaze) uses cryolite (Na3AlF6) as a fluxing agent, although it improves temperature resistance, but does not solve the problem of fluorine emission; CN112342544A (low-temperature acid and alkali-resistant cast iron enamel) contains sodium fluoride (5-7 parts) in the face glaze formula.

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

[0010] (3) The field of ceramics involves fluorine-free schemes, but it is difficult to apply: CN110885189A relates to a zirconium-free lanolin enamel and a positioning crystal flower ceramic tile made using the same, CN115626774A relates to a soft light skin ceramic rock plate and a method for preparing the same, CN112979271A relates to a method for preparing 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 method for preparing the same. Although the above-mentioned prior art does not involve the use of fluorinated salt, its technical essence belongs to the field of building ceramic glaze, which is different from the field of enamel underglaze. There are essential differences between ceramic glaze and metal-based enamel glaze in terms of thermal expansion coefficient (the difference in expansion coefficient between the two is one order of magnitude), firing temperature (the firing temperature of ceramic glaze is higher than that of enamel glaze by more than 200°C), and bonding mechanism (the body of ceramic glaze is porcelain clay, while the body of enamel glaze is metal), thus it 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 the environment, the fluorinated salt-containing products cannot meet the requirements of the EU REACH regulation on fluorine, and the emitted fluorinated salt blocks environmental management facilities, seriously restricting the normal production of enterprises, the present application provides a stainless steel enamel low-temperature titanium white face glaze without fluorinated salt and nitrate, as well as a preparation method and application thereof.

[0013] The fluorine-free salt-free and nitrate-free stainless steel enamel low-temperature titanium white face glaze of the present application is composed of the following ingredients in parts by mass: quartz 32-37 parts, anhydrous borax 19-24 parts, titanium white powder 19-22 parts, magnesium carbonate 0.5-1 part, potassium dihydrogen phosphate 3-6 parts, potassium carbonate 6-10 parts, lithium carbonate 3-8 parts, aluminum hydroxide 0.5-3 parts, V-26 4-8 parts, the V-26 being a fluxing agent including soda ash, rutile, potassium carbonate and anhydrous borax.

[0014] Further, quartz 35-37 parts, anhydrous borax 19-22 parts, titanium white powder 19-21 parts, magnesium carbonate 0.7-1 part, potassium dihydrogen phosphate 4-6 parts, potassium carbonate 6-8 parts, lithium carbonate 3-6 parts, aluminum hydroxide 1.5-3 parts, V-26 5-8 parts.

[0015] Further, the V-26 is composed of the following ingredients in percentage by weight:

[0016] Soda ash 10%~30%, rutile (titanium dioxide) 5%~15%, potassium carbonate 10%~40%, anhydrous borax 20%~60%, and the rest being inevitable impurities.

[0017] Further, the preparation method of the V-26 includes: uniformly mixing the ingredients of the fluxing agent, melting at 1280°C±10°C for 2~2.2 hours, and then cooling to room temperature to obtain a glassy fluxing agent. The fluxing agent is mainly used to reduce the melting temperature of other porcelain glazes, improve the fluidity and gloss.

[0018] Further, the mass percentage of SiO2 in quartz is ≥99%, and the mass percentage of TiO2 in titanium white powder is ≥99%.

[0019] The preparation method of the above-mentioned fluorine-free salt-free and nitrate-free stainless steel enamel low-temperature titanium white face glaze includes the following steps:

[0020] (1) The raw materials are weighed according to the above-mentioned mass parts;

[0021] (2) The raw materials in step (1) are stirred and mixed uniformly;

[0022] (3) The uniformly mixed material is added to a melting furnace and melted under pure oxygen conditions, and the melting temperature is controlled at 1300±10°C;

[0023] (4) After the material in step (3) is completely melted, a borosilicate glass body is obtained, the melted borosilicate glass body is tapped, and is quickly drawn into a glass filament of 1.2~1.5 meters for detection, and the detection requirement is that the glass filament continues to melt for 2-5 minutes without joints within 1 meter of the glass filament, and the melting is completed;

[0024] (5) The borosilicate glass body prepared in step (4) is rapidly cooled to obtain the product.

[0025] Further, in step (5), the rapid cooling is achieved by water quenching or tabletting.

[0026] The application of the stainless steel enamel low-temperature titanium white face glaze without fluorinated salt and nitrate salt is applied to blanks with stainless steel as the base body, and the firing temperature of the finished product is 740-780 DEG C.

[0027] The V-26 flux and the low-eutectic complex flux system of "multi-carbonate + phosphate + borate" in the formula of the stainless steel enamel low-temperature titanium white face glaze of the application are jointly strengthened, the components synergize, and the gloss, whiteness, opacity, firing performance and other performances of the enamel are promoted.

[0028] The application has the following beneficial effects:

[0029] (1) The fluorinated salt is discharged at an ultra-low standard;

[0030] (2) The product is detected by SGS, and the fluorinated salt detection result shows that no fluorinated salt is detected, which meets the limit requirement of the SVHC (high concern substance) of the EU REACH regulation.

[0031] (3) The problem of the blockage of the end environmental protection equipment is solved: the fluorinated salt is completely removed (fluorite, sodium fluorosilicate, etc.), the fluorinated salt crystallization source is eliminated from the source, and the problem of the blockage of the end environmental protection equipment is solved. According to the actual measurement of the production line, the continuous operation cycle of the equipment is prolonged from the original 10-15 days to more than 180 days, and the maintenance cost is significantly reduced.

[0032] (4) The low-temperature firing adaptability is good: the low-eutectic complex flux system (multi-carbonate + phosphate + borate) interacts with other components, so that the firing temperature is stably controlled at 740-780 DEG C, and the enamel surface has good leveling property.

[0033] (5) The amount of the phosphate is increased, the phosphate provides [PO4] 3- group to promote the crystallization and nucleation of titanium oxide, the V-26 flux and the low-eutectic complex flux system are jointly strengthened, the components synergize, and the gloss, whiteness, opacity, firing performance and other performances of the enamel are promoted. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The photo of the enamel plate made of stainless steel for the product obtained in Example 1 of the application. DETAILED DESCRIPTION

[0035] The application will be further described in detail in combination with specific embodiments, but the application is not limited thereto.

[0036] The device used in the embodiment of the application is:

[0037] Batching: a full-automatic batching and mixing system is adopted.

[0038] Melting: an automatic feeding system, an automatic pure oxygen combustion control system and an automatic discharging system are adopted.

[0039] Packaging: an automatic packaging system is adopted.

[0040] The purity of the raw materials used in the embodiment of the application meets the requirements of an industrial grade.

[0041] Example 1

[0042] (1) The raw materials are weighed according to the following mass parts: quartz 32 parts, zero-water borax 24 parts, titanium dioxide 22 parts, magnesium carbonate 0.5 parts, potassium dihydrogen phosphate 3 parts, potassium carbonate 6 parts, lithium carbonate 8 parts, aluminum hydroxide 0.5 parts, and V-26 4 parts.

[0043] The V-26 is composed of the following ingredients in percentage by weight:

[0044] Soda ash 20%, rutile (titanium dioxide) 12%, potassium carbonate 25%, zero-water borax 40%, and the rest is inevitable impurities;

[0045] The mass proportion of SiO2 in the quartz is ≥99%, and the mass proportion of TiO2 in the titanium dioxide is ≥99%.

[0046] (2) The above raw materials are stirred and mixed uniformly.

[0047] (3) The uniformly mixed material is added into a melting furnace, and melting is carried out under pure oxygen conditions, with the melting temperature controlled at 1300±10℃.

[0048] (4) After the above material is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body is tapped, and is quickly drawn into a glass filament of 1.2-1.5 meters for detection.

[0049] (5) The melted borosilicate glass body is rapidly cooled (water quenching), and the product is obtained.

[0050] The product obtained in Example 1 of the application is applied to a porcelain enamel plate made of stainless steel, as shown in Figure 1 The stainless steel enamel low-temperature titanium white face enamel surface is flat and delicate, and has no obvious defects in appearance, and has excellent low-temperature gloss and whiteness performance, and the product quality meets the requirements of enterprise standards.

[0051] Example 2

[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 34 parts, zero-water borax 23 parts, titanium white 20 parts, magnesium carbonate 0.5 part, potassium dihydrogen phosphate 4.5 parts, potassium carbonate 10 parts, lithium carbonate 5 parts, aluminum hydroxide 1 part, and V-26 6 parts.

[0054] In step (5), the borosilicate glass body prepared by melting is rapidly cooled by a tabletting process.

[0055] Example 3

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

[0057] The mass parts of each component in step (1) are: quartz 35 parts, zero-water borax 22 parts, titanium white 21 parts, magnesium carbonate 1 part, potassium dihydrogen phosphate 4 parts, potassium carbonate 8 parts, lithium carbonate 6 parts, aluminum hydroxide 1.5 parts, and V-26 5 parts.

[0058] Example 4

[0059] The preparation process of this example is basically the same as that of Example 1, except that:

[0060] The mass parts of each component in step (1) are:

[0061] quartz 37 parts, zero-water borax 19 parts, titanium white 19 parts, magnesium carbonate 0.7 part, potassium dihydrogen phosphate 6 parts, potassium carbonate 6 parts, lithium carbonate 3 parts, aluminum hydroxide 3 parts, and V-26 8 parts.

[0062] Comparative Example 1

[0063] The rest is the same as Example 1, except that the mass parts of each component in step (1) are: quartz 36 parts, zero-water borax 23 parts, titanium white 19.2 parts, magnesium carbonate 0.6 part, potassium dihydrogen phosphate 1.3 parts, lithium carbonate 6.5 parts, aluminum hydroxide 0.9 parts, and sodium fluorosilicate 8.3 parts.

[0064] The test results of the products obtained in the above examples and comparative examples are shown in Table 1 below.

[0065] Table 1 Test results of products obtained in examples and comparative examples

[0066]

[0067] The above examples and detection results prove that the stainless steel enamel low-temperature titanium white face glaze produced by the method of the application does not contain fluorinated salt and nitrate, no fluorinated salt is generated in the preparation process, the properties (high brightness, whiteness, good opalescence, firing temperature) of the obtained product meet the requirements of the stainless steel enamel low-temperature titanium white face glaze, the fluorinated salt detection result of the product shows that no fluorinated salt is detected, the limit requirement of the SVHC (substance of very high concern) of the EU REACH regulation is met, and the technical problems of the existing stainless steel enamel low-temperature titanium white face glaze in the production process, i.e. the fluorinated gas emission pollutes the environment and the fluorinated salt emission blocks the environmental protection treatment facilities, are fundamentally solved.

Claims

1. A stainless steel enamel low temperature titanium white face glaze free of fluorinated salts and free of nitrates, characterized in that, The formula thereof is composed of the following components in parts by mass: quartz 32-37 parts, zero-water borax 19-24 parts, titanium white 19-22 parts, magnesium carbonate 0.5-1 part, potassium dihydrogen phosphate 3-6 parts, potassium carbonate 6-10 parts, lithium carbonate 3-8 parts, aluminum hydroxide 0.5-3 parts, V-26 4-8 parts, the V-26 being a fluxing agent comprising soda ash, rutile, potassium carbonate and zero-water borax, the V-26 being composed of the following components in percentage by weight: soda ash 10%-30%, rutile 5%-15%, potassium carbonate 10%-40%, zero-water borax 20%-60%, and the balance being inevitable impurities.

2. The fluorine-free salt-free nitrate-free stainless steel enamel low temperature titanium white face glaze according to claim 1, characterized in that, Quartz 35-37 parts, zero-water borax 19-22 parts, titanium white 19-21 parts, magnesium carbonate 0.7-1 part, potassium dihydrogen phosphate 4-6 parts, potassium carbonate 6-8 parts, lithium carbonate 3-6 parts, aluminum hydroxide 1.5-3 parts, V-26 5-8 parts.

3. The fluorine-free salt-free and nitrate-free stainless steel enamel cryogenic titanium white face glaze according to claim 1 or 2, characterized in that, The preparation method of the V-26 comprises uniformly mixing the components of the fluxing agent, melting at 1280℃±10℃ for 2-2.2 hours, and then cooling to room temperature to obtain a glassy fluxing agent.

4. The fluorine-free salt-free nitrate-free stainless steel enamel cryogenic titanium white face glaze according to claim 1 or 2, characterized in that, The mass percentage of SiO2 in the quartz is ≥99%.

5. The fluorine-free salt-free and nitrate-free stainless steel enamel cryogenic titanium white face glaze according to claim 1 or 2, characterized in that, The mass percentage of TiO2 in the titanium white is ≥99%.

6. A process for the production of a fluorine-free salt-free and nitrate-free stainless steel enamel cryogenic titanium white face glaze according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: (1) weighing the raw materials of each component; (2) uniformly mixing the raw materials of step (1); (3) adding the uniformly mixed materials into a melting furnace, and melting under pure oxygen condition, with the melting temperature controlled at 1300±10℃; (4) obtaining a borosilicate glass body after the materials of step (3) are completely melted, tapping the molten borosilicate glass body, and quickly drawing it into a 1.2-1.5 meter glass filament 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 2-5 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 tabletting process.

8. Use of a fluorine-free salt-free and nitrate-free stainless steel enamel cryogenic titanium white face glaze according to any one of claims 1 to 5, characterized in that, The product is applied to a blank with a stainless steel base, and the firing temperature of the finished product is 740-780℃.

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