Steel plate enamel high-temperature antimony molybdenum bottom glaze without fluorinated salt and nitrate, and preparation method and application thereof

Abstract

The application discloses a steel plate enamel high-temperature antimony molybdenum ground glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The ground glaze is composed of quartz, zero-water borax, soda ash, potassium carbonate, calcium carbonate, potassium feldspar, antimony oxide, sodium tripolyphosphate and barium molybdate 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 ground 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 enamel surface, gloss and high-temperature firing adaptability, is suitable for a steel plate substrate, has a firing temperature of 840-880 DEG C, and can be used for the production of green and environmentally-friendly enamel products.

Description

Technical Field

[0001] This invention belongs to the field of enamel technology, specifically relating to a high-temperature antimony-molybdenum base enamel for steel plates that is free of fluoride salts and nitrates, its preparation method, and its application. Background Technology

[0002] As the transition layer between the metal substrate and the top glaze, the adhesion and high-temperature firing performance of enamel base glaze directly affect product quality, while its environmental friendliness impacts the industry's survival and sustainable development. Traditional enamel base glaze formulations typically include fluoride salts (such as fluorite and sodium fluorosilicate) (1-15%) as fluxes and adhesion enhancers. Fluoride salts are not optional additives in traditional enamel base glazes, but rather indispensable structural components. Through multiple synergistic effects, such as lowering melting temperature, forming an alloy layer at the corrosion interface, creating a mechanical anchoring effect, and improving opacity and wettability, they lay the foundation for a strong bond between the glaze and the metal substrate from both physical and chemical dimensions. Simply and crudely removing fluoride salts is tantamount to removing the load-bearing walls of a building; the result is not a "decrease" in performance, but the "collapse" of the entire enamel system. Any attempt at fluorine-free enamel must be based on finding or inventing a new material or process system that can completely simulate or replace these multiple functions, which remains a major technical challenge in the field of enamel processing. Therefore, the importance of fluoride salts in traditional processes cannot be overstated. However, research confirms that:

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

[0004] 2. The EU REACH regulation lists fluorides as Substances of Very High Concern (SVHC). Fluoride salt products cannot meet the EU REACH regulations' requirements for fluoride, with a fluoride (F) limit of 20 mg / kg.

[0005] 3. The end-of-pipe environmental treatment equipment is blocked by fluoride crystals, which seriously restricts the normal production of enterprises.

[0006] Meanwhile, nitrates, as traditional oxidants and adhesion promoters, readily produce nitrogen oxides (NOx) during high-temperature decomposition. x Similarly, they also face environmental pressures. Currently, the removal of nitrates from enamel glazes has solved the problem of nitrogen oxide emissions (such as CN114368912B, CN114315150B, CN114315151B, etc.). Further achieving fluorine-free production and promoting the research and development of fluorine-free and nitrate-free systems is not only an inevitable choice to comply with regulations, but also a forward-looking technological layout for the future.

[0007] The replacement of fluoride salts is a major technological bottleneck at present, mainly reflected in:

[0008] (1) Strong dependence on fluoride salts and prominent environmental risks: CN119710693A (high temperature resistant enamel glaze) uses cryolite (Na3AlF6) as a flux, which improves the temperature resistance but does not solve the problem of fluorine emission; CN112342544A (low temperature acid and alkali resistant cast iron enamel) contains sodium fluorosilicate (5-7 parts) in its surface glaze formula.

[0009] (2) Non-fluorine alternatives have functional defects: CN105800935A (enamel base glaze material) attempts to enhance adhesion with lanthanide oxides, but it still requires the addition of 8% fluoride to assist melting, and the high cost of rare earth makes it difficult to promote. CN116854374A (black enamel composite glaze) adopts a cobalt-nickel base glaze system, but the explosion retardant it uses contains 8-10% fluorite powder.

[0010] (3) In the ceramics field, there are fluorine-free solutions, but they are difficult to transfer and apply: CN110885189A relates to zirconium-free mutton fat glaze and positioning crystal flower ceramic tiles made using it; CN115626774A relates to soft-light skin-feel ceramic slabs and their preparation methods; CN112979271A relates to the preparation method of lightweight, high-strength, pure-color polished glazed tiles; CN118754723A relates to a hydrophilic self-cleaning antique tile based on phase separation and its preparation method. Although the above-mentioned prior art does not involve the use of fluoride salts, its technical essence belongs to the category of building ceramic glazes, which is a different technical field from enamel base glazes. Ceramic glazes and metal-based enamel glazes have essential differences in thermal expansion coefficients (the two expansion coefficients differ by an order of magnitude), firing temperatures (the firing temperature of ceramic glazes is more than 200℃ higher than that of enamel glazes), and bonding mechanisms (the base of ceramic glazes is porcelain clay, while the base of enamel glazes is metal), thus they cannot be directly transferred and applied to the field of metal-based enamel.

[0011] In summary, addressing the issue of fluoride removal on the basis of nitrate removal, while simultaneously improving the quality of enamel products, is of great practical significance for promoting the green, low-carbon, and high-quality development of the enamel industry. Summary of the Invention

[0012] In response to the technical problems of excessive fluoride emissions during the existing enamel glaze production process, which cause harm to health and the environment, the inability of fluoride-containing salt products to meet the fluoride requirements of the EU REACH regulation, and the clogging of environmental protection facilities by emitted fluoride salts, which seriously restricts the normal production of enterprises, this invention provides a high-temperature antimony-molybdenum base enamel for steel plates that is free of fluoride salts and nitrates, as well as its preparation method and application.

[0013] The high-temperature antimony-molybdenum base enamel for steel plates of the present invention, which is free of fluoride salts and nitrates, is composed of the following components in parts by weight: 28-32 parts quartz, 18-21 parts anhydrous borax, 19-24 parts soda ash, 3.5-4.5 parts potassium carbonate, 2-3 parts calcium carbonate, 25-27 parts potassium feldspar, 2.2-2.5 parts antimony oxide, 1-2 parts sodium tripolyphosphate, and 0.05-0.4 parts barium molybdate.

[0014] Further, the composition includes 29-31 parts quartz, 18-20 parts anhydrous borax, 19-23 parts soda ash, 4-4.5 parts potassium carbonate, 2-2.5 parts calcium carbonate, 25.5-27 parts potassium feldspar, 2.3-2.5 parts antimony oxide, 1.6-2 parts sodium tripolyphosphate, and 0.1-0.3 parts barium molybdate.

[0015] Furthermore, the mass percentage of SiO2 in the quartz is ≥99.5%, the mass percentage of SiO2 in the potassium feldspar is ≥71%, K2O+Na2O is ≥11%, the antimony oxide is Sb2O3 with a mass purity of ≥99.5%, and the other raw materials are of industrial grade purity.

[0016] The preparation method of the above-mentioned high-temperature antimony-molybdenum base enamel for steel plates that is free of fluoride salts and nitrates includes the following steps:

[0017] (1) Weigh each component raw material according to the above mass proportions;

[0018] (2) Stir and mix the raw materials described in step (1) until they are evenly mixed;

[0019] (3) Add the mixed material into the melting furnace for melting. The melting furnace is in a pure oxygen environment and the temperature is controlled at 1290±10℃.

[0020] (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.

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

[0022] Furthermore, in step (5), the rapid cooling is achieved by water quenching or tableting.

[0023] The above-mentioned high-temperature antimony-molybdenum base enamel for steel plates, which is free of fluoride salts and nitrates, is applied to blanks with steel plates as the base material. The firing temperature of the finished product is 840-880℃, excluding the endpoint value of 840℃.

[0024] This invention significantly increases the content of antimony oxide as an adhesive in the high-temperature antimony-molybdenum base glaze formulation for steel plate enamel, allowing it to work better synergistically with trace amounts of barium molybdate. Simultaneously, the introduction of phosphate forms a eutectic composite fluxing system of "multi-carbonate + phosphate + borate," which works together with other components to not only significantly enhance the adhesion and fluxing of the base glaze but also strengthen the synergistic effect between components, promoting improvements in the surface finish, gloss, and other properties of the base glaze.

[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) Maintain the core performance of the base glaze without decay: By increasing the content of antimony oxide as an adhesive, it works better with trace amounts of barium molybdate, while strengthening the interaction with other components and replacing the adhesive enhancement effect of fluoride. According to the test, the adhesive level is 2-3 (the traditional high-temperature fluorine-containing base glaze is 2-3).

[0030] (5) Good adaptability to high temperature firing: The low eutectic composite flux system (multi-carbonate + phosphate + borate) interacts with other components to keep the firing temperature stable at 840-880℃. The leveling properties and bubble elimination rate of the ceramic layer are comparable to those of fluorine-containing base glaze. 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 printing 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 28.0 parts, anhydrous borax 21.0 parts, soda ash 24 parts, potassium carbonate 3.5 parts, calcium carbonate 3 parts, potassium feldspar 25 parts, antimony oxide 2.2 parts, sodium tripolyphosphate 1 part, barium molybdate 0.05 parts.

[0041] The quartz contains ≥99.5% SiO2 by mass, the potassium feldspar contains ≥71% SiO2 by mass, K2O+Na2O≥11, the antimony oxide has a purity of ≥99.5%, and other raw materials are of industrial grade purity.

[0042] (2) Mix the above raw materials evenly.

[0043] (3) Add the mixed materials into the melting furnace for melting. The melting furnace is in a pure oxygen environment and the temperature is controlled at 1290±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 that the glass wire is completely melted within 1 meter.

[0045] (5) The molten borosilicate glass body is quenched with water to obtain the product.

[0046] 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, the high-temperature antimony-molybdenum base enamel for steel plates, which is free of fluoride salts and nitrates, has a good porcelain surface, excellent high-temperature firing performance and adhesion performance, and is widely used in steel plate one-time enameling products.

[0047] Example 2

[0048] The preparation process of this embodiment is basically the same as that of Example 1, except that the mass parts of each component in step (1) are: quartz 32.0 parts, anhydrous borax 19.0 parts, soda ash 21.0 parts, potassium carbonate 4 parts, calcium carbonate 2.5 parts, potassium feldspar 26 parts, antimony oxide 2.4 parts, sodium tripolyphosphate 1.5 parts, and barium molybdate 0.4 parts.

[0049] Example 3

[0050] The preparation process of this embodiment is basically the same as that of Example 1, except that the mass parts of each component in step (1) are: 29 parts of quartz, 20.0 parts of anhydrous borax, 23.0 parts of soda ash, 4.5 parts of potassium carbonate, 2.0 parts of calcium carbonate, 27.0 parts of potassium feldspar, 2.3 parts of antimony oxide, 1.6 parts of sodium tripolyphosphate, and 0.1 parts of barium molybdate.

[0051] Example 4

[0052] The preparation process of this embodiment is basically the same as that of Example 1, except that the mass parts of each component in step (1) are: quartz 31.0 parts, anhydrous borax 18.0 parts, soda ash 19.0 parts, potassium carbonate 4 parts, calcium carbonate 2 parts, potassium feldspar 25.5 parts, antimony oxide 2.5 parts, sodium tripolyphosphate 2.5 parts, and barium molybdate 0.3 parts.

[0053] Comparative Example 1

[0054] The rest is the same as in Example 1, except that the mass parts of each component in step (1) are: quartz 29.4 parts, anhydrous borax 18.2 g, soda ash 14.5 parts, fluorite 8.2 parts, potassium feldspar 21.1 parts, calcium carbonate 1.5 parts, antimony oxide 1.0 parts, sodium fluorosilicate 7.5 parts, and barium molybdate 0.05 parts.

[0055] The test results of the products obtained from the above embodiments and comparative examples are shown in Table 1 below.

[0056] Table 1. Test results of products obtained from each embodiment and comparative example.

[0057]

[0058] The above embodiments and test results demonstrate that the high-temperature antimony-molybdenum base enamel 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. The various properties of the resulting product (ceramic surface, gloss, adhesion, firing temperature) meet the requirements of high-temperature antimony-molybdenum base enamel 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 existing high-temperature antimony-molybdenum base enamel for steel plates generating fluoride gas emissions that pollute the environment and clogging environmental protection facilities with emitted fluoride salts during the production process.

Claims

1. A high-temperature antimony-molybdenum base enamel for steel plates that is free of fluoride salts and nitrates, characterized in that, Its formula consists of the following components by weight: quartz 28-32 parts, anhydrous borax 18-21 parts, soda ash 19-24 parts, potassium carbonate 3.5-4.5 parts, calcium carbonate 2-3 parts, potassium feldspar 25-27 parts, antimony oxide 2.2-2.5 parts, sodium tripolyphosphate 1-2 parts, and barium molybdate 0.05-0.4 parts.

2. The high-temperature antimony-molybdenum base enamel for steel plates that is free of fluoride salts and nitrates as described in claim 1, characterized in that, Quartz 29-31 parts, anhydrous borax 18-20 parts, soda ash 19-23 parts, potassium carbonate 4-4.5 parts, calcium carbonate 2-2.5 parts, potassium feldspar 25.5-27 parts, antimony oxide 2.3-2.5 parts, sodium tripolyphosphate 1.6-2 parts, barium molybdate 0.1-0.3 parts.

3. The high-temperature antimony-molybdenum enamel base 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 ≥99.5%.

4. The high-temperature antimony-molybdenum enamel base 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 high-temperature antimony-molybdenum enamel base glaze for steel plates that is free of fluoride salts and nitrates as described in claim 1 or 2, characterized in that, Antimony oxide is Sb₂O₃, with a purity of ≥99.5%.

6. The method for preparing a high-temperature antimony-molybdenum base enamel 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 for melting. The melting furnace is in a pure oxygen environment and the temperature is controlled at 1290±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.

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 antimony-molybdenum base enamel 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 with steel plates as the base material, and the firing temperature of the finished product is 840-880℃, excluding the endpoint value of 840℃.

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