Steel plate enamel low-temperature cobalt ground coat free of fluoride salt and nitrate as well as preparation method and application of steel plate enamel low-temperature cobalt ground coat

Abstract

The invention discloses fluoride-salt-free and nitrate-free low-temperature cobalt ground glaze for steel plate enamel as well as a preparation method and application of the low-temperature cobalt ground glaze, and belongs to the technical field of enamel. The ground coat is prepared from quartz, anhydrous borax, sodium carbonate, potassium carbonate, calcium carbonate, potassium feldspar, antimony oxide, cerium oxide and a recycled ternary battery positive electrode material according to a specific mass ratio. The preparation method comprises the following steps: mixing the raw materials, melting at 1230 + / -10 DEG C in a pure oxygen environment, and quenching after wiredrawing and detecting a molten state. According to the ground coat, the use of fluoride salt and nitrate is completely avoided, the problems of fluoride emission and environmental protection equipment blockage are solved from the source, the fluorine content of a product is not detected, and the European Union REACH regulation limit value requirements are met. Meanwhile, by introducing the recycled ternary battery material, not only is the adherence of the ground glaze obviously enhanced, but also the synergistic effect among the components is enhanced, the improvement of other properties is promoted, and the cyclic utilization of resources and the reduction of cost are realized.

Description

TECHNICAL FIELD

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

[0002] As a transition layer between the metal substrate and the face glaze, the adhesion and 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. In the traditional enamel ground glaze formula, fluorinated salt (such as fluorite, sodium fluorosilicate) (accounting for 1-15%) is usually added 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 due to fluorinated salt crystallization, severely restricting 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 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) 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 and 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 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 low-temperature cobalt underglaze without fluorinated salt and nitrate, as well as a preparation method and application thereof.

[0013] The enamel low-temperature cobalt underglaze of the steel plate without fluorinated salt and nitrate of the application is prepared by the following steps:

[0014] Further, the quartz is 34-35 parts by mass, the anhydrous borax is 24-25 parts by mass, the soda ash is 6-7 parts by mass, the potassium carbonate is 2.5-3.5 parts by mass, the calcium carbonate is 3.7-4.4 parts by mass, the potassium feldspar is 19-22.5 parts by mass, the antimony oxide is 0.5-0.6 parts by mass, the cerium oxide is 2.1-2.2 parts by mass, and the recycled ternary battery cathode material is 2.8-3.2 parts by mass.

[0015] Further, the mass percentage of SiO2 in the quartz is ≥99%, the mass percentage 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 in the recycled ternary battery cathode material, Co is ≥42.7 wt%, Mn is ≥12.2 wt%, and Li is ≥5.9 wt%, and the other raw materials are of industrial purity.

[0016] Further, the recycled ternary battery cathode material is a commercially available material, which meets the above-mentioned percentage contents of lithium, cobalt and manganese, and other impurities contained do not affect the performance and use of the underglaze.

[0017] The preparation method of the above-mentioned enamel low-temperature cobalt underglaze of the steel plate without fluorinated salt and nitrate, comprising the following steps:

[0018] (1) the raw materials are weighed according to the above-mentioned mass parts;

[0019] (2) the raw materials in step (1) are stirred and mixed uniformly;

[0020] (3) the uniformly mixed material is added to a melting furnace for melting, and pure oxygen environment is used in the melting furnace during melting, and the temperature is controlled at 1230±10℃;

[0021] (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 that there is no knot within 1 meter of the glass filament, which means that the melting is completed;

[0022] (5) the molten borosilicate glass body is rapidly cooled, and the product is obtained.

[0023] Further, in step (5), the quenching is performed by water quenching or tabletting.

[0024] The enamel low-temperature cobalt base glaze of the steel plate without fluorinated salt and nitrate salt is applied to a blank with a steel plate as a base body, and the firing temperature of a finished product is 760-800 DEG C.

[0025] The application introduces the recycled ternary battery positive material into the enamel low-temperature cobalt base glaze formula of the steel plate, so that the adhesion of the base glaze is obviously enhanced, the synergistic effect between components is strengthened, and the promotion of the base glaze porcelain surface, gloss and other performances is promoted.

[0026] The application has the following beneficial effects:

[0027] (1) The fluorinated salt is discharged in an ultra-low standard;

[0028] (2) The product is detected by SGS, and the detection result of fluorinated salt shows that it is not detected, which meets the limit requirement of the SVHC (high concern substance) of the EU REACH regulation.

[0029] (3) The end environmental protection equipment blockage problem is solved: by completely removing the fluorinated salt (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 cycle of the equipment is prolonged from the original 10-15 days to more than 180 days, and the maintenance cost is significantly reduced.

[0030] (4) The core performance of the base glaze is not attenuated: by replacing the fluorinated salt with the recycled ternary battery positive material, the adhesion grade is 1-2 (the traditional fluorine-containing base glaze is 1-2).

[0031] (5) Low-temperature firing adaptability: the eutectic composite fluxing system (multi-element carbonate + borate) interacts with other components, so that the firing temperature is stably controlled at 760-800 DEG C, the porcelain layer flow flatness and bubble elimination rate are equivalent to those of the fluorine-containing base glaze.

[0032] (6) Resource recycling and cost optimization: the use of recycled ternary battery positive material not only reduces the cobalt lithium raw material cost by more than 25%, but also avoids heavy metal waste pollution. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The photo of the enamel plate made of the product obtained in example 1 of the application. DETAILED DESCRIPTION

[0034] The application will be further described in detail below in combination with specific embodiments, but the application is not limited thereto.

[0035] The device used in the embodiment of the application is:

[0036] 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.

[0037] Melting: an automatic feeding system, an automatic pure oxygen combustion control system and an automatic discharging system are adopted.

[0038] Packaging: an automatic packaging system is adopted.

[0039] In addition to the recovered ternary battery positive electrode material, the purity of the raw materials used in the embodiment of the application meets the requirements of the industrial grade.

[0040] Embodiment 1

[0041] (1) The raw materials are weighed according to the mass parts of each component as follows:

[0042] 33 parts of quartz, 24 parts of anhydrous borax, 5 parts of soda ash, 2.5 parts of potassium carbonate, 3.5 parts of calcium carbonate, 18.5 parts of potassium feldspar, 0.5 parts of antimony oxide, 2.1 parts of cerium oxide and 2.2 parts of recovered ternary battery positive electrode material.

[0043] The mass percentage of SiO2 in quartz is ≥99%, the mass percentage of SiO2 in potassium feldspar is ≥71%, K2O+Na2O is ≥11%, the antimony oxide is Sb2O3, and the mass purity is ≥99.5%, in the recovered ternary battery positive electrode material, the Co is ≥42.7 wt%, the Mn is ≥12.2 wt%, the Li is ≥5.9 wt%, and the other raw materials are of industrial grade purity.

[0044] (2) The above raw materials are stirred and mixed uniformly.

[0045] (3) The uniformly mixed material is added to a melting furnace for melting, and pure oxygen environment is adopted in the melting furnace during melting, and the temperature is controlled at 1230±10℃ for melting.

[0046] (4) After the above material is completely melted, a borosilicate glass body is obtained, the melted borosilicate glass body is tapped, and is quickly drawn into a glass filament of 1.2-1.5 meters for detection. The detection requirement is that there is no knot within 1 meter of the glass filament, and the melting is completed.

[0047] (5) The melted borosilicate glass body is water quenched, and the product is obtained.

[0048] The photos of the porcelain enamel plate made of steel plate and applied to the product obtained in Embodiment 1 are as follows: Figure 1The enamel low-temperature cobalt bottom glaze for steel plate without fluorinated salt and nitrate salt has good enamel surface, low-temperature firing performance and adhesion, and is widely applied to primary coating enamel products of steel plate.

[0049] Example 2

[0050] The rest is the same as example 1, except that the mass parts of each component in step (1) are: quartz 36 parts, zero-water borax 26 parts, soda ash 8 parts, potassium carbonate 4 parts, calcium carbonate 4.5 parts, potassium feldspar 23.5 parts, antimony oxide 0.6 parts, cerium oxide 2.2 parts, and recovered ternary battery positive material 3.4 parts.

[0051] Example 3

[0052] The rest is the same as example 1, except that the mass parts of each component in step (1) are: quartz 35 parts, zero-water borax 24 parts, soda ash 6 parts, potassium carbonate 3.0 parts, calcium carbonate 4.1 parts, potassium feldspar 22.5 parts, antimony oxide 0.5 parts, cerium oxide 2.1 parts, and recovered ternary battery positive material 2.8 parts.

[0053] Example 4

[0054] The rest is the same as example 1, except that the mass parts of each component in step (1) are: quartz 35 parts, zero-water borax 25 parts, soda ash 7 parts, potassium carbonate 2.5 parts, calcium carbonate 4.4 parts, potassium feldspar 22 parts, antimony oxide 0.5 parts, cerium oxide 2.2 parts, and recovered ternary battery positive material 3.0 parts.

[0055] Comparative example 1

[0056] The rest is the same as example 1, except that the mass parts of each component in step (1) are: quartz 33.0 parts, zero-water borax 24.0 parts, soda ash 6.0 parts, calcium carbonate 3.7 parts, fluorite 9.1 parts, potassium feldspar 22.0 parts, manganese oxide 2.6 parts, cobalt oxide 0.8 parts, and cerium oxide 2.2 parts.

[0057] The test results of the products obtained in the above examples and comparative examples are shown in Table 1 below.

[0058] Table 1 Test results of products obtained in examples and comparative examples

[0059]

[0060] The above examples and detection results prove that the enamel low-temperature cobalt base glaze of the steel plate produced by the method of the application does not contain fluorinated salt and nitrate, no fluorinated salt is generated in the preparation process, and after defluorination, the properties (porcelain surface, gloss, adhesion, sintering temperature) of the obtained product can meet the requirements of the enamel low-temperature cobalt base glaze of the steel plate, the fluorinated salt detection result of the product shows that no fluorinated salt is detected, which meets the limit requirements of the SVHC (substance of very high concern) of the EU REACH regulation, and fundamentally solves the technical problems that the existing enamel low-temperature cobalt base glaze of the steel plate generates fluorinated salt gas emission to pollute the environment and the discharged fluorinated salt blocks the environmental protection treatment facilities in the production process.

Claims

1. A low-temperature cobalt base enamel for steel plates that is free of fluoride salts and nitrates, characterized in that, The formula consists of the following components by weight: 33-36 parts quartz, 24-26 parts anhydrous borax, 5-8 parts soda ash, 2.5-4.0 parts potassium carbonate, 3.5-4.5 parts calcium carbonate, 18.5-23.5 parts potassium feldspar, 0.5-0.6 parts antimony oxide, 2.1-2.2 parts cerium oxide, and 2.2-3.4 parts recycled ternary battery cathode material, wherein the recycled ternary battery cathode material is a powder material containing lithium, cobalt, and manganese obtained by recycling waste ternary lithium battery cathode material.

2. The low-temperature cobalt base enamel for steel plates that is free of fluoride salts and nitrates as described in claim 1, characterized in that, Quartz 34-35 parts, anhydrous borax 24-25 parts, soda ash 6-7 parts, potassium carbonate 2.5-3.5 parts, calcium carbonate 3.7-4.4 parts, potassium feldspar 19-22.5 parts, antimony oxide 0.5-0.6 parts, cerium oxide 2.1-2.2 parts, and recycled ternary battery cathode material 2.8-3.2 parts.

3. The low-temperature cobalt base enamel for steel plates that is free of fluoride salts and nitrates as described in claim 1 or 2, characterized in that, In the recycling of ternary battery cathode materials, the percentage of metal mass in the total mass of the materials is as follows: Co ≥ 42.7 wt%, Mn ≥ 12.2 wt%, and Li ≥ 5.9 wt%.

4. The low-temperature cobalt base enamel 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. The low-temperature cobalt base enamel 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%.

6. The low-temperature cobalt base enamel 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%.

7. The method for preparing a low-temperature cobalt base enamel 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 for melting. The melting furnace is in a pure oxygen environment and the temperature is controlled at 1230±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 cobalt base enamel 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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