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

Abstract

The application discloses a steel plate enamel low-temperature 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, potassium feldspar, borax pentahydrate, soda ash, titanium dioxide, potassium carbonate, zinc oxide and sodium tripolyphosphate 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 present application belongs to the technical field of enamel, and particularly relates to a steel plate enamel low-temperature translucent glaze free of fluorinated salt and nitrate salt and a preparation method and application thereof. BACKGROUND

[0002] The steel plate enamel low-temperature translucent glaze needs to be fired at a low temperature (760-800 DEG C) and has no defects in appearance, a smooth porcelain surface and a glossiness of greater than or equal to 80. The traditional formula relies on fluorinated salt (fluorite / fluorosilicate accounts for 1-12%) to achieve fluxing, increase gloss and improve transparency, and the fluorinated salt is not an "optional" additive but an "indispensable" skeleton component in the traditional enamel base glaze. Since the fluorinated salt has multiple synergistic effects of reducing the melting temperature, increasing the gloss and improving the stability of the crystal, simply and roughly removing the fluorinated salt does not result in "decrease" in performance but "collapse" of the entire enamel system. Any attempt to remove fluorinated salt 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 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 damage 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 requirements of the European Union REACH regulation on 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 adhesion promoting component, is prone to produce nitrogen oxides (NO x ) during high-temperature decomposition, and 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 promotes the research and development of fluorine-free and nitrate-free system, which 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 steel plate enamel low-temperature semi-transparent glaze without fluorinated salt and nitrate, as well as a preparation method and application thereof.

[0013] The steel plate enamel low-temperature translucent glaze without fluorinated salt and nitrate of the application is prepared by using the following components: quartz 20-25 parts, potassium feldspar 24-28 parts, borax pentahydrate 20-25 parts, soda ash 10-12 parts, titanium dioxide 4-6 parts, potassium carbonate 3-5 parts, zinc oxide 4-7 parts, and sodium tripolyphosphate 1-4 parts.

[0014] Further, the steel plate enamel low-temperature translucent glaze is prepared by using the following components: quartz 21-24 parts, potassium feldspar 24-26 parts, borax pentahydrate 22-25 parts, soda ash 10.5-11.5 parts, titanium dioxide 4.5-5.5 parts, potassium carbonate 3.5-4.5 parts, zinc oxide 5-6 parts, and sodium tripolyphosphate 2-3 parts.

[0015] Further, the mass percentage of SiO2 in quartz is ≥99%, the mass percentage of SiO2 in potassium feldspar is ≥71%, K2O+Na2O is ≥11%, the mass percentage of TiO2 in titanium dioxide 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 steel plate enamel low-temperature translucent glaze without fluorinated salt and nitrate comprises the following steps:

[0017] (1) the components are weighed according to the above mass parts;

[0018] (2) the components are stirred and mixed uniformly;

[0019] (3) the uniformly mixed components are added into a melting furnace, and melting is carried out under pure oxygen condition, and the melting temperature is controlled at 1260±10℃;

[0020] (4) after the components in step (3) are 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 there is no node within 1 meter of the glass filament, which means that the melting is completed;

[0021] (5) the molten borosilicate glass body is rapidly cooled to obtain the product.

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

[0023] The steel plate enamel low-temperature translucent 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 760-800℃.

[0024] The application adds phosphates in the steel plate enamel low-temperature translucent glaze formula, and provides [PO4] 3-The group promotes the nucleation of feldspar, and a eutectic complex fluxing system of'multicomponent carbonate + phosphate + borate' is formed to strengthen fluxing, the introduction of zinc oxide cooperates with titanium dioxide, ZnO / TiO2 reduces the viscosity of the liquid phase, and accelerates the diffusion of ions and bubbles; the synergistic effect of the components promotes the improvement of the performance of the semi-transparent glaze in terms of porcelain surface, luster, transparency, firing performance and the like.

[0025] The present application has the following advantages:

[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 problem of blockage of the end environmental protection equipment is solved: the present application completely removes fluoride (fluorite, sodium fluorosilicate, etc.), eliminates the fluoride salt crystallization source from the source, and solves the problem of blockage of the end environmental protection equipment. 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 firing adaptability: the eutectic complex fluxing system (multicomponent carbonate + phosphate + borate) interacts with other components to stably control the firing temperature at 760-800℃, and the porcelain surface has good leveling property.

[0030] (5) The addition of phosphate and zinc oxide provides [PO4] 3- The group promotes the nucleation of feldspar, and a eutectic complex fluxing system of'multicomponent carbonate + phosphate + borate' is formed to strengthen fluxing, the introduction of zinc oxide cooperates with titanium dioxide, ZnO / TiO2 reduces the viscosity of the liquid phase, and accelerates the diffusion of ions and bubbles; the synergistic effect of the components promotes the improvement of the performance of the semi-transparent glaze in terms of porcelain surface, luster, transparency, firing performance and the like. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

[0034] 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.

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

[0036] Packaging: Automatic packaging system is adopted.

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

[0038] Example 1

[0039] (1) The raw materials are weighed according to the mass parts of each component as follows:

[0040] Quartz 20 parts, potassium feldspar 28 parts, borax pentahydrate 20 parts, soda ash 12 parts, titanium dioxide 6.0 parts, potassium carbonate 3 parts, zinc oxide 7 parts, sodium tripolyphosphate 4 parts;

[0041] The mass percentage of SiO2 in quartz is ≥99%, the mass percentage of SiO2 in potassium feldspar is ≥71%, K2O+Na2O is ≥11%, the mass percentage of TiO2 in titanium dioxide is ≥99%, and the mass purity of zinc oxide prepared by distillation of metallic zinc and oxidation is ≥99.7%.

[0042] (2) The above raw materials are stirred and mixed uniformly.

[0043] (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℃.

[0044] (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, with the detection requirement being that there are no nodes within 1 meter of the glass filament, indicating that the melting is complete.

[0045] (5) The melted borosilicate glass body is rapidly cooled (water quenching), and the product is obtained.

[0046] The product obtained in Example 1 of the present application is applied to a porcelain enamel plate made of steel plate, as shown in Figure 1 The enamel enamel surface of the steel plate enamel enamel with no fluorinated salt and no nitrate is flat and delicate, the appearance has no obvious defects, the gloss and color performance are excellent, and the product quality meets the requirements of enterprise standards.

[0047] Example 2

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

[0049] In step (1), the mass parts of each component are: quartz 22 parts, potassium feldspar 27 parts, borax pentahydrate 23 parts, soda ash 10 parts, titanium dioxide 4 parts, potassium carbonate 5 parts, zinc oxide 4 parts, and sodium tripolyphosphate 1 part.

[0050] In step (5), the melted borosilicate glass body is rapidly cooled by using a water quenching process.

[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 21 parts, potassium feldspar 26 parts, borax pentahydrate 22 parts, soda ash 10.5 parts, titanium dioxide 4.5 parts, potassium carbonate 3.5 parts, zinc oxide 5 parts, and sodium tripolyphosphate 3 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 24 parts, potassium feldspar 24 parts, borax pentahydrate 25 parts, soda ash 11.5 parts, titanium dioxide 5.5 parts, potassium carbonate 4.5 parts, zinc oxide 6 parts, and sodium tripolyphosphate 2 parts.

[0057] Comparative Example 1

[0058] The rest is the same as Example 1, except that the mass parts of each component in step (1) are: quartz 24.3 parts, potassium feldspar 27.6 parts, borax pentahydrate 26.4 parts, soda ash 9.8 parts, titanium dioxide 4.5 parts, potassium carbonate 2.9 parts, and sodium fluosilicate 4 parts.

[0059] The test results of the products obtained in the above examples and comparative examples are shown in Table 1 below.

[0060] Table 1 Test results of products obtained in each example and comparative example

[0061]

[0062] The above examples and test results prove that the steel plate enamel low-temperature translucent glaze produced by the method of the present application does not contain fluorinated salt and nitrate, no fluorinated compound is generated during the preparation process, and the performance (appearance, enamel surface, gloss, transparency, firing temperature) of the obtained product meets the requirements of steel plate enamel low-temperature translucent glaze, the fluorinated compound test result of the product shows no detection, which meets the limit requirements of SVHC (substance of very high concern) of the European Union 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 existing steel plate enamel low-temperature translucent glaze.

Claims

1. A low-temperature 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: 20-25 parts quartz, 24-28 parts potassium feldspar, 20-25 parts borax pentahydrate, 10-12 parts soda ash, 4-6 parts titanium dioxide, 3-5 parts potassium carbonate, 4-7 parts zinc oxide, and 1-4 parts sodium tripolyphosphate.

2. The low-temperature translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1, characterized in that, Quartz 21-24 parts, potassium feldspar 24-26 parts, borax pentahydrate 22-25 parts, soda ash 10.5-11.5 parts, titanium dioxide 4.5-5.5 parts, potassium carbonate 3.5-4.5 parts, zinc oxide 5-6 parts, sodium tripolyphosphate 2-3 parts.

3. The low-temperature 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 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 potassium feldspar is ≥71%, and the mass percentage of K2O+Na2O is ≥11%.

5. The low-temperature 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.

6. The low-temperature 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%.

7. The method for preparing a low-temperature translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in any one of claims 1 to 6, 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 1260±10℃. (4) After the material described in step (3) is completely melted, a borosilicate glass body is obtained. The molten borosilicate glass body is then drilled and quickly drawn into a glass wire of 1.2 to 1.5 meters for testing. The testing requirement is that the glass wire is completely melted within 1 meter. (5) The molten borosilicate glass body is rapidly cooled to obtain the product.

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

9. The application of the low-temperature translucent enamel glaze for steel plates that is free of fluoride salts and nitrates as described in any one of claims 1 to 6, 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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