Non-fluoride salt and non-nitrate salt steel plate enamel medium temperature antimony molybdenum underglaze and its preparation method and application

Abstract

The application discloses a steel plate enamel medium-temperature antimony molybdenum base glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The base glaze is composed of quartz, zero-water borax, soda ash, potassium carbonate, potassium feldspar, sodium 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 base glaze is completely free of fluorinated salt and nitrate, avoids fluoride 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 medium-temperature firing adaptability, is suitable for a steel plate substrate, has a firing temperature of 800-840 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 field of enamel technology, and particularly relates to a steel plate enamel medium-temperature antimony molybdenum ground glaze without fluorinated salt and nitrate, and a preparation method and application thereof. BACKGROUND

[0002] As a transition layer between the metal substrate and the face glaze, the adhesion and medium-temperature firing performance of the enamel ground glaze directly affect the product quality, and the green environmental protection affects the survival and sustainable development of the industry. Fluorinated salt (such as fluorite, sodium fluorosilicate) (accounting for 1-15%) is usually added in the traditional enamel ground glaze formula as a fluxing agent and adhesion enhancer. The fluorinated salt is not an "optional" additive in the traditional enamel ground glaze, but an "indispensable" skeleton component. It lays the foundation for the firm combination of the glaze and the metal substrate from the physical and chemical dimensions through multiple synergies 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 the 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 eliminate 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 has so far been 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 fluorides 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 by fluorinated salt crystallization, severely restricting normal production of enterprises.

[0006] At the same time, nitrate, 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 emissions (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) Fluoride 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 fluoride emissions; 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% fluoride to assist melting, and the high cost of rare earths 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 fluoride-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 fluoride salts, the technical essence belongs to the field of building ceramic glazes, 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 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 enamel glaze, which causes damage to health and the environment, the fluorine-containing salt products cannot meet the requirements of the EU REACH regulation on fluorine, and the emitted fluoride salt blocks environmental management facilities, which seriously restricts the normal production of enterprises, the present application provides a steel plate enamel medium-temperature antimony-molybdenum underglaze without fluorine-containing salt and nitrate, as well as a preparation method and application thereof.

[0013] The steel plate enamel medium temperature antimony molybdenum base glaze without fluorinated salt and nitrate of the application is prepared by the following steps: (1) weighing the raw materials according to the above-mentioned mass fraction; (2) stirring and mixing the raw materials uniformly; (3) melting the mixed materials in a melting furnace, and controlling the temperature at 1260±10 DEG C in a pure oxygen environment; (4) obtaining borosilicate glass after the materials are completely melted, and detecting the borosilicate glass by rapidly drawing it into a 1.2-1.5-meter glass filament; (5) rapidly cooling the melted borosilicate glass to obtain the product.

[0014] Further, the quartz is 23-25 parts by mass, the anhydrous borax is 24-25 parts by mass, the soda ash is 18-21 parts by mass, the potassium carbonate is 4-5.5 parts by mass, the potassium feldspar is 23-24 parts by mass, the sodium feldspar is 2.5-4 parts by mass, the antimony oxide is 2.5-2.9 parts by mass, the sodium tripolyphosphate is 1.5-2 parts by mass, and the barium molybdate is 0.2-0.4 parts by mass.

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

[0016] The preparation method of the steel plate enamel medium temperature antimony molybdenum base glaze without fluorinated salt and nitrate comprises the following steps:

[0017] (1) weighing the raw materials according to the above-mentioned mass fraction;

[0018] (2) stirring and mixing the raw materials uniformly;

[0019] (3) melting the mixed materials in a melting furnace, and controlling the temperature at 1260±10 DEG C in a pure oxygen environment;

[0020] (4) obtaining borosilicate glass after the materials are completely melted, and detecting the borosilicate glass by rapidly drawing it into a 1.2-1.5-meter glass filament;

[0021] (5) rapidly cooling the melted borosilicate glass to obtain the product.

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

[0023] The steel plate enamel medium temperature antimony molybdenum base 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 800-840 DEG C, and the end point value 800 DEG C is not included.

[0024] The application significantly increases the content of the adhesion agent antimony oxide in the steel plate enamel medium-temperature molybdenum antimony underglaze formula, and the trace barium molybdate better synergizes, meanwhile, the introduction of the phosphate forms a low-eutectic complex fluxing system of'multinary carbonate + phosphate + borate', which, together with other components, finally not only significantly enhances the adhesion and fluxing of the underglaze, but also strengthens the synergistic effect between the components, and promotes the improvement of other performances such as the underglaze porcelain surface and gloss.

[0025] The application has the beneficial effects that:

[0026] (1) fluoride ultra-low standard emission is realized;

[0027] (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) in the EU REACH regulation is met.

[0028] (3) the end environmental protection equipment blockage problem is solved: the application completely removes fluoride (fluorite, sodium fluorosilicate, etc.), eliminates the fluoride salt crystallization source from the source, and solves the end environmental protection equipment blockage problem. 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) the core performance of the underglaze is maintained without attenuation: by increasing the content of the adhesion agent antimony oxide, the trace barium molybdate better synergizes, and the interaction with other components is strengthened, the adhesion enhancement effect of the fluoride is replaced, and the adhesion level is tested to be 1-2 level (the traditional fluoride-containing underglaze is 1-2 level).

[0030] (5) good medium-temperature firing adaptability: the low-eutectic complex fluxing system (multinary carbonate + phosphate + borate) interacts with other components, so that the firing temperature is stably controlled at 800-840℃, and the porcelain layer flow flatness and bubble elimination rate are equivalent to those of the fluoride-containing underglaze. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0033] The equipment used in the application example is:

[0034] Batching: a full-automatic batching and mixing system is adopted. The system is fully automatic computer controlled, and has the characteristics of accurate weighing, uniform mixing and high batching efficiency.

[0035] Melting: Automatic feeding system, automatic pure oxygen combustion control system, automatic discharge system.

[0036] Packaging: Automatic packaging system.

[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 22.0 parts, zero-water borax 26.0 parts, soda ash 19.9 parts, potassium carbonate 3.5 parts, potassium feldspar 23.0 parts, sodium feldspar 2.0 parts, antimony oxide 3.0 parts, sodium tripolyphosphate 2 parts, barium molybdate 0.1 parts.

[0041] The mass fraction of SiO2 in quartz is ≥99.5%, the mass fraction of SiO2 in potassium feldspar is ≥71%, K2O+Na2O is ≥11%, the purity of antimony oxide is ≥99.5%, and the other raw materials are of industrial purity.

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

[0043] (3) The uniformly mixed material is added to the melting furnace for melting, and pure oxygen environment is used in the melting furnace during melting, and the temperature is controlled at 1260±10℃ for melting.

[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, and the detection requirement is that there is no knot within 1 meter of the glass filament, which is the completion of melting.

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

[0046] The product obtained in Example 1 is applied to the photos of enamel plate made of steel plate as shown in Figure 1 The enamel plate of the steel plate containing no fluorinated salt and no nitrate has a good porcelain surface, excellent medium temperature sintering performance and adhesion performance, and is widely used in one-time enamel coated steel plate products.

[0047] Example 2

[0048] The preparation process of this embodiment is basically the same as that of Example 1, except that in step (1), the mass parts of each component are: quartz 26.0 parts, zero-water borax 24.5 parts, soda ash 17.0 parts, potassium carbonate 3.9 parts, potassium feldspar 25 parts, sodium feldspar 3.0 parts, antimony oxide 2.4 parts, sodium tripolyphosphate 1.8 parts, and barium molybdate 0.6 parts.

[0049] Example 3

[0050] The preparation process of the embodiment is basically the same as that of Example 1, except that the mass parts of the components in step (1) are: quartz 23 parts, zero-water borax 24.0 parts, soda ash 21 parts, potassium carbonate 4 parts, potassium feldspar 23 parts, sodium feldspar 4.0 parts, antimony oxide 2.5 parts, sodium tripolyphosphate 1.5 parts, and barium molybdate 0.2 parts.

[0051] Example 4

[0052] The preparation process of the embodiment is basically the same as that of Example 1, except that the mass parts of the components in step (1) are: quartz 25 parts, zero-water borax 25 parts, soda ash 18 parts, potassium carbonate 5.5 parts, potassium feldspar 24 parts, sodium feldspar 2.5 parts, antimony oxide 2.9 parts, sodium tripolyphosphate 2.0 parts, and barium molybdate 0.4 parts.

[0053] Comparative Example 1

[0054] The rest is the same as Example 1, except that the mass parts of the components in step (1) are: quartz 26.0 parts, zero-water borax 24.0 parts, soda ash 17.0 parts, fluorite 6.6 parts, potassium feldspar 24.0 parts, sodium feldspar 3.0 parts, antimony oxide 1.2 parts, sodium fluosilicate 3.2 parts, and barium molybdate 0.1 parts.

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

[0056] Table 1 Test results of the products obtained in the examples and comparative examples

[0057]

[0058] The above examples and test results prove that the steel plate enamel medium-temperature antimony molybdenum base glaze produced by the method of the present application does not contain fluorinated salt and nitrate, no fluorinated compound is generated in the preparation process, the properties (porcelain surface, gloss, adhesion, firing temperature) of the obtained product all meet the requirements of steel plate enamel medium-temperature antimony molybdenum base 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 EU REACH regulation, and fundamentally solves the technical problems of environmental pollution caused by fluorinated compound gas emission and fluorinated salt emission blocking environmental protection treatment facilities in the production process of the existing steel plate enamel medium-temperature antimony molybdenum base glaze.

Claims

1. Steel plate enamel low temperature antimony molybdenum underglaze free of fluorinated salts and nitrates, characterized in that, The formula is composed of the following components in mass parts: quartz 22-26 parts, zero-water borax 24-26 parts, soda ash 17-21 parts, potassium carbonate 3.5-5.5 parts, potassium feldspar 23-25 parts, sodium feldspar 2-4 parts, antimony oxide 2.4-3.0 parts, sodium tripolyphosphate 1-2 parts, and barium molybdate 0.1-0.6 parts.

2. The steel plate enamel mid-temperature antimony molybdenum base enamel without fluorinated salt and nitrate according to claim 1, characterized in that, Quartz 23-25 parts, zero-water borax 24-25 parts, soda ash 18-21 parts, potassium carbonate 4-5.5 parts, potassium feldspar 23-24 parts, sodium feldspar 2.5-4 parts, antimony oxide 2.5-2.9 parts, sodium tripolyphosphate 1.5-2 parts, and barium molybdate 0.2-0.4 parts.

3. The non-fluoride-salt-free and non-nitrate-salt-free steel plate medium temperature enamel molybdenum antimony base enamel according to claim 1 or 2, characterized in that, The mass percentage of SiO2 in quartz is ≥99.5%.

4. The non-fluoride-salt-free and non-nitrate-salt-free steel plate medium temperature enamel molybdenum antimony base enamel according to claim 1 or 2, characterized in that, The mass percentage of SiO2 in potassium feldspar is ≥71%, and K2O+Na2O is ≥11%.

5. The non-fluoride-salt-free and non-nitrate-salt-free steel plate medium temperature enamel molybdenum antimony base enamel according to claim 1 or 2, characterized in that, The antimony oxide is Sb2O3, and the mass purity is ≥99.5%.

6. A process for the production of a medium temperature enamel molybdenum antimony underglaze for steel sheets containing fluorinated salts and free of nitrates according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: (1) weighing each component raw material; (2) stirring and mixing the raw materials in step (1) uniformly; (3) melting the mixed material in a melting furnace, and using pure oxygen environment in the melting furnace, and controlling the temperature at 1260±10℃; (4) obtaining a borosilicate glass body after the material in step (3) is completely melted, and the molten borosilicate glass body is hammered and quickly drawn into a 1.2-1.5 meter glass filament for detection, and the detection requirement is that there is no knot within 1 meter of the glass filament, which means that the melting is completed; (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 tablet pressing process.

8. Use of a steel sheet enamel according to any one of claims 1 to 5, characterized in that, When applied to a blank with a steel plate as a base body, the firing temperature of the finished product is 800-840℃, and the end point value 800℃ is not included.

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