Steel plate enamel high temperature pearlite glaze without fluorinated salt and nitrate and its preparation method and application

Abstract

The application discloses a steel plate enamel high-temperature pearlescent glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The pearlescent glaze is composed of quartz, zero-water borax, titanium dioxide, magnesium carbonate, sodium tripolyphosphate, potassium carbonate, lithium carbonate, potassium feldspar, zinc oxide 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 pearlescent 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 high-temperature sintering adaptability, is suitable for a steel plate substrate, has a sintering temperature of 830-860 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 high-temperature pearlescent glaze free of fluorinated salt and nitrate salt and a preparation method and application thereof. BACKGROUND

[0002] The steel plate enamel high-temperature pearlescent glaze needs to meet four core indexes, including high brightness of the enamel surface, keeping the original color of the pearlescent pigment (i.e. not dissolving the pearlescent pigment), good opalescence and high-temperature firing. The traditional formula relies on fluorinated salt (fluorite / fluorosilicate accounts for 1-12%) to achieve fluxing, improve opalescence and other performances. 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 synergies such as reducing the melting temperature, improving the opalescence and wettability, simply and roughly removing the fluorinated salt is equivalent to removing the load-bearing wall of the building, which leads to not "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 has so far been 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 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 by fluorinated salt crystallization, which seriously restricts normal production of enterprises.

[0006] At the same time, nitrate salt, as a traditional oxidizing agent and adhesion promoting component, is prone to produce nitrogen oxides (NO x ) during high-temperature decomposition, also facing 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 research and development 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 therefrom, 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. 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, which seriously restricts the normal production of enterprises, the present application provides a steel plate enamel high-temperature pearl glaze without fluorinated salt and nitrate, as well as a preparation method and application thereof.

[0013] The enamel high-temperature pearl gloss of the steel plate without fluorinated salt and nitrate of the application is composed of the following components by mass fraction: quartz 50-55 parts, borax 18-23 parts, titanium white 10-16 parts, magnesium carbonate 1-3 parts, sodium tripolyphosphate 2-6 parts, potassium carbonate 3-5 parts, lithium carbonate 2-3 parts, potassium feldspar 2-3 parts, zinc oxide 1-2 parts, and V-26 2-6 parts, wherein the V-26 is a fluxing agent including soda ash, rutile, potassium carbonate, and borax.

[0014] Further, the enamel high-temperature pearl gloss is composed of the following components by mass fraction: quartz 52-54 parts, borax 21-23 parts, titanium white 12-16 parts, magnesium carbonate 1.7-3 parts, sodium tripolyphosphate 4.5-6 parts, potassium carbonate 3.5-4 parts, lithium carbonate 2-3 parts, potassium feldspar 2.5-3 parts, zinc oxide 1.5-1.6 parts, and V-26 3-6 parts.

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

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

[0017] Further, the preparation method of the V-26 includes the following steps: uniformly mixing the components of the fluxing agent, melting the fluxing agent at 1280℃±10℃ for 2 to 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 the quartz is ≥99%, the mass percentage of TiO2 in the titanium white is ≥99%, the mass percentage of SiO2 in the potassium feldspar is ≥71%, and K2O+Na2O is ≥11%, and the zinc oxide is prepared by distilling and oxidizing metallic zinc, and the mass purity is ≥99.7%.

[0019] The preparation method of the enamel high-temperature pearl gloss of the steel plate without fluorinated salt and nitrate, which includes the following steps:

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

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

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

[0023] (4) after the material in step (3) is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body is drilled, and is quickly drawn into a glass filament of 1.2-1.5 meters for detection, and the detection requirement is that no knot continues to melt for 2-5 minutes within 1 meter of the glass filament, and the melting is completed;

[0024] (5) the molten borosilicate glass body is rapidly cooled, and the product is obtained.

[0025] Further, in step (5), the rapid cooling is achieved by using a water quenching or tablet pressing process.

[0026] The above-mentioned steel plate enamel high-temperature pearlescent glaze without fluorinated salt and nitrate is applied to a blank with a steel plate as a base body, and the firing temperature of the finished product is 830-860 DEG C and does not include the end point value 830 DEG C.

[0027] In the steel plate enamel high-temperature pearlescent glaze formula, zinc oxide is introduced to cooperate with titanium dioxide in titanium white powder, ZnO / TiO2 reduces the liquid viscosity, accelerates ion and bubble diffusion, the amount of phosphate is increased, on the one hand, the phosphate provides [PO4] 3- group promotes feldspar nucleation, and on the other hand, a eutectic complex fluxing system of "multi-carbonate + phosphate + borate" is formed to strengthen the fluxing together with the V-26 flux, and each component cooperates to promote the improvement of the gloss, pearlescent pigment color development, opacity, firing performance and other performances of the enamel.

[0028] The beneficial effects of the present application are as follows:

[0029] (1) fluoride is discharged at an ultra-low standard;

[0030] (2) the product is detected by SGS, the fluoride detection result shows that no fluoride is detected, and the limit value requirement of SVHC (high concern substance) of the European Union REACH regulation is met.

[0031] (3) the end environmental protection equipment blockage problem is solved: by completely removing fluorides (fluorite, sodium fluorosilicate, etc.), the fluorinated salt crystallization source is eliminated from the source, and the end environmental protection equipment blockage problem is solved. 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.

[0032] (4) good high-temperature firing adaptability: the eutectic complex fluxing system (multi-carbonate + phosphate + borate) interacts with other components, so that the firing temperature is stably controlled at 830-860 DEG C, and the enamel surface has good leveling property.

[0033] (5) the amount of phosphate is increased, the phosphate provides [PO4] 3-The group promotes the nucleation of feldspar; the increase of zinc oxide, ZnO / TiO2 reduces the viscosity of the liquid phase, accelerates ion diffusion, increases V-26 flux, reduces the viscosity of the liquid phase, synergizes with other components, improves the surface gloss and pearl pigment color development of the enamel, increases the enamel opalescence, and reduces the firing temperature of the enamel. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The photo of the enamel plate made of the product obtained in Example 1 of the present application applied to a steel plate. DETAILED DESCRIPTION

[0035] The present application will be further described in detail below in conjunction with specific examples, but the present application is not limited thereto.

[0036] The equipment used in the example of the present application is as follows:

[0037] Batching: A full-automatic batching and mixing system is used. The system is fully automatic computer controlled, and has the characteristics of accurate weighing, uniform mixing, and high batching efficiency.

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

[0039] Packaging: An automatic packaging system is used.

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

[0041] Example 1

[0042] (1) The raw materials are weighed according to the mass parts of each component as follows:

[0043] Quartz 50 parts, zero-water borax 18 parts, titanium white 13 parts, magnesium carbonate 2 parts, sodium tripolyphosphate 3.8 parts, potassium carbonate 4.5 parts, lithium carbonate 2.2 parts, potassium feldspar 2.5 parts, zinc oxide 1 part, and V-26 5 parts;

[0044] V-26 is composed of the following components in weight percentage:

[0045] Soda ash 20%, rutile (titanium dioxide) 12%, potassium carbonate 25%, zero-water borax 40%, and the rest is unavoidable impurities;

[0046] The mass percentage of SiO2 in quartz is ≥99%, the mass percentage of TiO2 in titanium white is ≥99%, the mass percentage of SiO2 in potassium feldspar is ≥71%, and K2O+Na2O is ≥11%, and the zinc oxide is prepared by distillation of metallic zinc and oxidation, and the mass purity is ≥99.7%.

[0047] (2) The above raw materials are stirred and mixed uniformly.

[0048] (3) The mixed material is added into a melting furnace, and melted under pure oxygen condition, with the melting temperature controlled at 1300±10℃.

[0049] (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 glass filament of 1.2-1.5 meters for detection. The detection requirement is that no knot is found within 1 meter of the glass filament, and the melting is completed after 5 minutes of continuous melting.

[0050] (5) The melted borosilicate glass body is rapidly cooled (water quenching), and the product is obtained.

[0051] The photo of the enamel plate made of the product of Example 1 is shown in Figure 1 The enamel plate made of the product of Example 1 is shown in

[0052] Example 2

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

[0054] The mass parts of each component in step (1) are: quartz 55 parts, zero-water borax 20 parts, titanium white 10 parts, magnesium carbonate 1 part, sodium tripolyphosphate 2 parts, potassium carbonate 2.5 parts, lithium carbonate 2.5 parts, potassium feldspar 2 parts, zinc oxide 2 parts, and V-26 4 parts.

[0055] In step (5), the rapid cooling of the melted borosilicate glass body is carried out by using a tablet pressing process.

[0056] Example 3

[0057] The preparation process of this example is basically the same as that of Example 1, except that:

[0058] The mass parts of each component in step (1) are: quartz 54 parts, zero-water borax 23 parts, titanium white 12 parts, magnesium carbonate 1.7 parts, sodium tripolyphosphate 4.5 parts, potassium carbonate 4 parts, lithium carbonate 3 parts, potassium feldspar 3 parts, zinc oxide 1.6 parts, and V-26 6 parts.

[0059] Example 4

[0060] The preparation process of this example is basically the same as that of Example 1, except that:

[0061] The mass parts of each component in step (1) are: quartz 52 parts, zero-water borax 21 parts, titanium white 16 parts, magnesium carbonate 3 parts, sodium tripolyphosphate 6 parts, potassium carbonate 3.5 parts, lithium carbonate 2 parts, potassium feldspar 2.5 parts, zinc oxide 1.5 parts, and V-26 3 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 53.5 parts, zero-water borax 22 parts, titanium oxide 11 parts, sodium fluorosilicate 9 parts, potassium feldspar 2.5 parts, lithium carbonate 2.2 parts, magnesium carbonate 1.5 parts, and sodium tripolyphosphate 1.5 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 the products obtained in the examples and comparative examples

[0066]

[0067] The above examples and test results prove that the steel plate enamel high-temperature pearlescent glaze produced by the method of the present application does not contain fluorinated salt and nitrate, no fluorinated compound is produced during the preparation process, the properties (gloss, pearlescent pigment color development, opacity, firing temperature) of the obtained product all meet the requirements of steel plate enamel high-temperature pearlescent glaze, the fluorinated compound test result of the product shows that it is not detected, it meets the limit requirements of SVHC (substance of very high concern) of the EU REACH regulation, and fundamentally solves the technical problems of the existing steel plate enamel high-temperature pearlescent glaze, i.e. the production process produces fluorinated compound gas emission which pollutes the environment and the emitted fluorinated salt which blocks the environmental protection treatment facilities.

Claims

1. Steel plate enamel high temperature opal 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 50-55 parts, zero-water borax 18-23 parts, titanium white 10-16 parts, magnesium carbonate 1-3 parts, sodium tripolyphosphate 2-6 parts, potassium carbonate 3-5 parts, lithium carbonate 2-3 parts, potassium feldspar 2-3 parts, zinc oxide 1-2 parts, V-26 2-6 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 rest being inevitable impurities.

2. The steel plate enamel high temperature spangle-free, fluoride-free and nitrate-free of claim 1, wherein, Quartz 52-54 parts, zero-water borax 21-23 parts, titanium white 12-16 parts, magnesium carbonate 1.7-3 parts, sodium tripolyphosphate 4.5-6 parts, potassium carbonate 3.5-4 parts, lithium carbonate 2-3 parts, potassium feldspar 2.5-3 parts, zinc oxide 1.5-1.6 parts, V-26 3-6 parts.

3. The steel plate enamel high temperature spangle-free, fluoride-free and nitrate-free enamel 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 steel plate enamel high temperature spangle-free, fluoride-free and nitrate-free of claim 1 or 2, characterized in that, The mass percentage of SiO2 in the quartz is ≥99%, and the mass percentage of TiO2 in the titanium white is ≥99%.

5. The steel plate enamel high temperature spangle-free, fluoride-free and nitrate-free of claim 1 or 2, characterized in that, The mass percentage of SiO2 in the potassium feldspar is ≥71%, and K2O+Na2O is ≥11%.

6. The steel plate enamel high temperature spangle-free, fluoride-free and nitrate-free of claim 1 or 2, characterized in that, The zinc oxide is prepared by distillation of metallic zinc followed by oxidation, and the mass purity thereof is ≥99.7%.

7. The method of producing a steel plate enamel high temperature spangle free of fluorinated salts and nitrates according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: (1) weighing each component raw material; (2) uniformly mixing the raw materials in 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 in step (3) are completely melted, and the melted borosilicate glass body is tapped and quickly drawn 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 continued for 2-5 minutes to complete the melting; (5) rapidly cooling the melted borosilicate glass body to obtain the product.

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

9. Use of a steel sheet enamel according to any one of claims 1 to 6, characterized in that, When applied to a blank with a steel plate as the base body, the firing temperature of the finished product is 830-860℃, and the end point value 830℃ is not included.

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