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

Abstract

The application discloses a steel plate enamel high-temperature matte glaze free of fluorinated salt and nitrate, and a preparation method and application thereof, and belongs to the technical field of enamel. The matte glaze is prepared from quartz, borax pentahydrate, soda ash, titanium dioxide, magnesium oxide, potassium dihydrogen phosphate, calcium carbonate, zinc oxide, magnesium carbonate, lithium carbonate, aluminum oxide and zirconium silicate according to specific mass proportions. The preparation comprises raw material mixing, melting at 1300±10 DEG C under a pure oxygen environment, and rapid cooling after wire drawing detection of the melting state. The matte glaze completely avoids the use of fluorinated salt and nitrate, eliminates the problems of fluoride emission and environmental protection equipment blockage from the source, the fluorine content of the product is not detected through detection, and the product meets the limit value requirements of the EU REACH regulation. The addition of zinc oxide and zirconium silicate has a synergistic effect, the ZnO / ZrO2 strengthens the opalescence effect, reduces the liquid phase viscosity, accelerates ion diffusion, and has a synergistic effect with other components, and enhances the opacity (opalescence performance) and gloss of the enamel glaze.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of enamel, and particularly relates to a steel plate enamel high-temperature matte glaze free of fluorinated salt and nitrate salt and a preparation method and application thereof. BACKGROUND

[0002] The steel plate enamel high-temperature matte glaze requires high-temperature (840-880) ℃ firing, and has no defects in appearance, a smooth porcelain surface and a gloss (≤10). Fluorinated salt (fluorite / sodium fluorosilicate, 1-15%) is usually added as a fluxing agent and adhesion enhancer in the traditional steel plate enamel high-temperature matte glaze formula. Fluorinated salt is not an "optional" additive in the traditional high-temperature matte glaze, but an "indispensable" skeleton component. Since fluorinated salt has multiple synergistic effects such as reducing the melting temperature, forming an alloy layer by corroding the interface, creating a mechanical anchoring effect, improving opalescence and wettability, simply and roughly removing fluorinated salt is equivalent to removing the load-bearing wall of the building, which does 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 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 shown that:

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

[0004] 2. The European Union REACH regulation lists fluorinated compounds 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 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 systems promotes the development of fluorine-free and nitrate-free systems, 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 migrate applications: 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 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, a steel plate enamel high-temperature matte glaze without fluorinated salt and nitrate and a preparation method and application thereof are provided.

[0013] The enamel high-temperature matte glaze of the steel plate without fluorinated salt and nitrate of the application is made of the following components in the following mass parts: quartz 41-45 parts, borax pentahydrate 4-5 parts, soda ash 12-15 parts, titanium white 4-7 parts, magnesium oxide 12-15 parts, potassium dihydrogen phosphate 1-4 parts, calcium carbonate 2-4 parts, zinc oxide 2-4 parts, magnesium carbonate 6-10 parts, lithium carbonate 1-1.5 parts, aluminum oxide 1-3 parts, and zirconium silicate 6-8 parts.

[0014] Further, the enamel high-temperature matte glaze of the steel plate without fluorinated salt and nitrate of the application is made of the following components in the following mass parts: quartz 42-43 parts, borax pentahydrate 4.5-5 parts, soda ash 13-14.5 parts, titanium white 4.8-6 parts, magnesium oxide 13-14 parts, potassium dihydrogen phosphate 2-3.5 parts, calcium carbonate 2.5-3 parts, zinc oxide 2.8-3.4 parts, magnesium carbonate 8-10 parts, lithium carbonate 1.2-1.4 parts, aluminum oxide 1.8-2.5 parts, and zirconium silicate 6.7-7.5 parts.

[0015] Further, in the quartz, the mass ratio of SiO2 and Fe2O3 is: SiO2≥99%, Fe2O3≤0.05%; in the titanium white, the mass ratio of TiO2 is: TiO2≥99%; the zinc oxide is prepared by distillation of metallic zinc and then oxidation, and the mass purity is ≥99.7%.

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

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

[0018] (2) the raw materials in step (1) are stirred and mixed uniformly;

[0019] (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℃;

[0020] (4) after the material in step (3) 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, and the detection requirement is: no knot within 1 meter of the glass filament, and continue to melt for 5-10 minutes to complete the melting;

[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 water quenching or tabletting process.

[0023] The application of the enamel high-temperature matte glaze of the steel plate without fluorinated salt and nitrate is applied to the blank or base glaze with steel plate as the base body, and the firing temperature of the finished product is 840-880℃, and does not include the end point value 840℃.

[0024] Furthermore, by adjusting the composition and amount of the non-fluorinated salt flux in the formulation of this invention, the melting of the enamel glaze can be completed as required even without the flux of fluorinated salts. This invention introduces zinc oxide and zirconium silicate into the low-temperature matte enamel glaze formulation for steel plates. The two work synergistically, and ZnO / ZrO2 enhances the opacification effect. The eutectic composite flux system of "multi-carbonate + phosphate + borate" strengthens the fluxing, and the synergistic effect of each component promotes the improvement of various properties of the glaze, such as gloss, opacity, and firing performance.

[0025] The beneficial effects of this invention are as follows:

[0026] (1) Achieve ultra-low emission standards for fluorides.

[0027] (2) The product was tested by SGS and the fluoride test results showed that it was not detected, which meets the EU REACH regulation's limit requirements for SVHC (substances of very high concern).

[0028] (3) The problem of clogging in end-of-line environmental protection equipment is solved: This invention completely removes fluorides (fluorite, sodium fluorosilicate, etc.), eliminating the source of fluoride salt crystallization from the source, thus solving the problem of clogging in end-of-line environmental protection equipment. According to actual production line tests, the continuous operation cycle of the equipment has been extended from the original 10-15 days to more than 180 days, and the maintenance cost has been significantly reduced.

[0029] (4) Good firing adaptability: The low eutectic composite flux system (multi-carbonate + phosphate + borate) interacts with other components to keep the firing temperature stable at 840-880℃, and the porcelain surface has good leveling properties.

[0030] (5) Adding zinc oxide and zirconium silicate, the two work together to enhance the opacity effect of ZnO / ZrO2, and ZnO / TiO2 reduces the viscosity of the liquid phase and accelerates ion diffusion. Together with other components, it enhances the opacity (opacity performance) and gloss of the porcelain enamel. Attached Figure Description

[0031] Figure 1 This is a photograph of the product obtained in Embodiment 1 of the present invention applied to a ceramic enamel plate made of steel plate. Detailed Implementation

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

[0033] The equipment used in this embodiment of the invention is:

[0034] Ingredient preparation: A fully automated batching and mixing system is used. This system is fully automated and computer-controlled, featuring 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 adopted.

[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 41 parts, borax pentahydrate 4 parts, soda ash 12 parts, titanium dioxide 4 parts, magnesium oxide 12 parts, potassium dihydrogen phosphate 1 part, calcium carbonate 2 parts, zinc oxide 2 parts, magnesium carbonate 6 parts, lithium carbonate 1 part, aluminum oxide 1 part, zirconium silicate 6 parts.

[0041] In the quartz, the mass percentages of SiO2 and Fe2O3 are: SiO2≥99% and Fe2O3≤0.05%; in the titanium dioxide, the mass percentage of TiO2 is: TiO2≥99%; zinc oxide is obtained by oxidation after distillation of metallic zinc, and its mass purity is ≥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: after the glass wire is drawn into 1 meter without knots, continue to melt for 5 minutes to complete the melting.

[0045] (5) Press the molten borosilicate glass into a sheet to obtain the product.

[0046] The product prepared by this invention is applied to blanks or base glazes with steel plates as the base material, and the firing temperature of the finished product is 840-880℃.

[0047] 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, high-temperature matte enamel glaze for steel plates that is free of fluoride salts and nitrates has a good porcelain surface, excellent high-temperature firing performance and matte performance, and is widely used in steel plate one-time enameling products.

[0048] Example 2

[0049] Everything else is the same as in Example 1, except that:

[0050] The mass fractions of each component in step (1) are:

[0051] Quartz 45 parts, borax pentahydrate 5 parts, soda ash 15 parts, titanium dioxide 7 parts, magnesium oxide 15 parts, potassium dihydrogen phosphate 4 parts, calcium carbonate 4 parts, zinc oxide 4 parts, magnesium carbonate 10 parts, lithium carbonate 1.5 parts, aluminum oxide 3 parts, zirconium silicate 8 parts.

[0052] In step (5), the molten borosilicate glass body is rapidly cooled by water quenching.

[0053] Example 3

[0054] Everything else is the same as in Example 1, except that:

[0055] The mass fractions of each component in step (1) are:

[0056] Quartz 42 parts, borax pentahydrate 4.5 parts, soda ash 13 parts, titanium dioxide 4.8 parts, magnesium oxide 13 parts, potassium dihydrogen phosphate 2 parts, calcium carbonate 3 parts, zinc oxide 2.8 parts, magnesium carbonate 8 parts, lithium carbonate 1.2 parts, aluminum oxide 1.8 parts, zirconium silicate 6.7 parts.

[0057] Example 4

[0058] Everything else is the same as in Example 1, except that:

[0059] The mass fractions of each component in step (1) are:

[0060] Quartz 43 parts, borax pentahydrate 4.7 parts, soda ash 14.5 parts, titanium dioxide 6 parts, magnesium oxide 14 parts, potassium dihydrogen phosphate 3.5 parts, calcium carbonate 2.5 parts, zinc oxide 3.4 parts, magnesium carbonate 9.2 parts, lithium carbonate 1.4 parts, aluminum oxide 2.5 parts, zirconium silicate 7.5 parts.

[0061] Comparative Example 1

[0062] The rest is the same as in Example 1, except that the mass parts of each component in step (1) are: quartz 43.5 parts, borax pentahydrate 6.7 parts, titanium dioxide 5.8 parts, zirconium silicate 5.1 parts, sodium fluorosilicate 3.8 parts, soda ash 15.2 parts, calcium carbonate 4.8 parts, alumina 2.5 parts, magnesium carbonate 8.8 parts, and lithium carbonate 1.8 parts.

[0063] The test results of the products obtained from the above embodiments and comparative examples are shown in Table 1 below.

[0064] Table 1. Test results of products obtained from each embodiment and comparative example.

[0065]

[0066] The above embodiments and test results demonstrate that the high-temperature matte enamel glaze for steel plates produced by the method of the present invention, which is free of fluoride salts and nitrates, produces no fluorides during the preparation process. After defluorination, the various properties of the resulting product (appearance, porcelain surface, gloss, and firing temperature) meet the requirements of high-temperature matte enamel glaze for steel plates. The fluoride test results show that no fluoride was detected, which meets the limit requirements of the EU REACH regulation for SVHC (substances of very high concern). This fundamentally solves the technical problems of environmental pollution caused by the emission of fluoride gas during the production process of existing high-temperature matte enamel glazes for steel plates, as well as the blockage of environmental protection facilities by the emitted fluoride salts.

Claims

1. A high-temperature matte 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 41-45 parts, borax pentahydrate 4-5 parts, soda ash 12-15 parts, titanium dioxide 4-7 parts, magnesium oxide 12-15 parts, potassium dihydrogen phosphate 1-4 parts, calcium carbonate 2-4 parts, zinc oxide 2-4 parts, magnesium carbonate 6-10 parts, lithium carbonate 1-1.5 parts, aluminum oxide 1-3 parts, and zirconium silicate 6-8 parts.

2. The high-temperature matte enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1, characterized in that, Quartz 42-43 parts, borax pentahydrate 4.5-5 parts, soda ash 13-14.5 parts, titanium dioxide 4.8-6 parts, magnesium oxide 13-14 parts, potassium dihydrogen phosphate 2-3.5 parts, calcium carbonate 2.5-3 parts, zinc oxide 2.8-3.4 parts, magnesium carbonate 8-10 parts, lithium carbonate 1.2-1.4 parts, aluminum oxide 1.8-2.5 parts, zirconium silicate 6.7-7.5 parts.

3. The high-temperature matte enamel glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1 or 2, characterized in that, In quartz, the mass percentages of SiO2 and Fe2O3 are: SiO2 ≥ 99% and Fe2O3 ≤ 0.05%.

4. The high-temperature matte 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 TiO2 in the titanium dioxide is: TiO2≥99%.

5. The high-temperature matte 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 high-temperature matte 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, 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 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 drawn into a 1-meter length without any knots. After that, the melting process is completed after 5 to 10 minutes. (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 high-temperature matte 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 or base glazes with steel plates as the base material. The firing temperature of the finished product is 840-880℃, excluding the endpoint value of 840℃.

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