Medium-temperature cobalt ground coat for steel plate enamel without fluoride salt and nitrate as well as preparation method and application of medium-temperature cobalt ground coat

Abstract

The invention discloses a fluoride-salt-free and nitrate-free medium-temperature cobalt ground coat for steel plate enamel as well as a preparation method and application of the medium-temperature cobalt ground coat, 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 1260 + / -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 medium-temperature cobalt underglaze 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 enamel, the adhesion and firing performance of the enamel underglaze 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 underglaze formula as a fluxing agent and adhesion enhancer. The fluorinated salt is not an "optional" additive in the traditional enamel underglaze, but an "indispensable" skeleton component. It lays the foundation for the firm combination of the enamel 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 the opalescence and wettability. Simply and roughly removing the fluorinated salt is equivalent to removing the load-bearing wall of the building, which does not lead to a "decrease" in performance, but a "collapse" of the entire enamel system. Any attempt to eliminate fluorinated salt must be based on the discovery or invention of a new substance or new process system that can completely simulate or replace the above-mentioned multiple functions, and this has so far been 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 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, 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 enamel has solved the problem of nitrogen oxide emissions (such as CN114368912B, CN114315150B, CN114315151B, etc.), and further implementation of fluorine-free and nitrate-free systems 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, the present application provides a steel plate enamel medium-temperature cobalt underglaze without fluorinated salt and nitrate, as well as a preparation method and application thereof.

[0013] The enamel medium temperature cobalt underglaze of the steel plate without fluorinated salt and nitrate of the application is composed of the following components in the following mass parts: quartz 40-44 parts, zero-water borax 22-24 parts, soda ash 4-6 parts, potassium carbonate 2-4 parts, calcium carbonate 3-5 parts, potassium feldspar 14.5-18 parts, antimony oxide 0.5-0.6 parts, cerium oxide 2.1-2.2 parts, and recycled ternary battery positive material 3.2-4.4 parts, wherein the recycled ternary battery positive material is a lithium, cobalt and manganese-containing powder material recovered from waste ternary lithium battery positive material.

[0014] Further, the quartz is 41-43 parts, the zero-water borax is 22.5-23.5 parts, the soda ash is 4.5-5.5 parts, the potassium carbonate is 2.5-3.5 parts, the calcium carbonate is 3.5-4.5 parts, the potassium feldspar is 15-17.5 parts, the antimony oxide is 0.5-0.6 parts, the cerium oxide is 2.1-2.2 parts, and the recycled ternary battery positive material is 3.8-4.2 parts.

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

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

[0017] The preparation method of the enamel medium temperature cobalt underglaze of the steel plate without fluorinated salt and nitrate, comprises the following steps:

[0018] (1) the raw materials are weighed according to the above 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, pure oxygen is used in the melting furnace during melting, and the temperature is controlled at 1260±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 of the steel plate without fluorinated salt and nitrate is applied to a blank with a steel plate as a base body, and the firing temperature of a finished product is 800-840 DEG C and does not include the end point value 800 DEG C.

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

[0026] The application has the advantages that:

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

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

[0029] (3) The end environmental protection equipment blockage problem is solved: the fluorinated salt crystallization source is eliminated from the source by completely removing the fluorinated salt (fluorite, sodium fluorosilicate, etc.), and the end environmental protection equipment blockage problem is solved. 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.

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

[0031] (5) The firing adaptability is good: the eutectic complex fluxing system (multi-element carbonate + borate) interacts with other components, so that the firing temperature is stably controlled at 800-840 DEG C, the porcelain layer flow flatness and bubble elimination rate are equivalent to those of the fluorine-containing enamel.

[0032] (6) Resource recycling and cost optimization: the recycled ternary battery positive material is used, which not only reduces the cost of cobalt lithium raw materials 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.

[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] Quartz 40 parts, zero-water borax 22 parts, soda ash 4 parts, potassium carbonate 2 parts, calcium carbonate 3 parts, potassium feldspar 14.5 parts, antimony oxide 0.5 parts, cerium oxide 2.1 parts, and recovered ternary battery positive electrode material 3.2 parts.

[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 mass purity of antimony oxide is Sb2O3 and is ≥99.5%, in the recovered ternary battery positive electrode material, the mass percentage of Co, Mn and Li in the total mass of the material is ≥42.7 wt%, ≥12.2 wt% and ≥5.9 wt% respectively, and the other raw materials are of industrial 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, a pure oxygen environment is adopted in the melting furnace during melting, and the temperature is controlled at 1260±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, and the detection requirement is that there is no knot within 1 meter of the glass filament, which means that the melting is completed.

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

[0048] The photo of the enamel plate made of steel plate and applied to the product obtained in Embodiment 1 is shown in Figure 1 The enamel plate enamel for steel plate without fluorinated salt and nitrate has a good porcelain surface, excellent medium-temperature sintering performance and adhesion performance, and is widely applied to primary enamel coated steel plate products.

[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 44 parts, zero-water borax 24 parts, soda ash 6 parts, potassium carbonate 4 parts, calcium carbonate 5 parts, potassium feldspar 18 parts, antimony oxide 0.6 parts, cerium oxide 2.2 parts, and recycled ternary battery positive electrode material 4.4 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 42 parts, zero-water borax 23 parts, soda ash 5 parts, potassium carbonate 2.5 parts, calcium carbonate 3.5 parts, potassium feldspar 17.5 parts, antimony oxide 0.5 parts, cerium oxide 2.2 parts, and recycled ternary battery positive electrode material 3.8 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 43 parts, zero-water borax 23 parts, soda ash 4.5 parts, potassium carbonate 2.5 parts, calcium carbonate 3 parts, potassium feldspar 15.2 parts, antimony oxide 0.5 parts, cerium oxide 2.1 parts, and recycled ternary battery positive electrode material 4.2 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 40.0 parts, zero-water borax 22.0 parts, soda ash 8.0 parts, calcium carbonate 3.7 parts, fluorite 9.1 parts, potassium feldspar 15.0 parts, manganese oxide 2.6 parts, cobalt oxide 1.1 parts, and cerium oxide 2.1 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 each example and comparative example

[0059]

[0060] The above examples and detection results prove that the enamel medium-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 medium-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 medium-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 medium-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: quartz 40-44 parts, anhydrous borax 22-24 parts, soda ash 4-6 parts, potassium carbonate 2-4 parts, calcium carbonate 3-5 parts, potassium feldspar 14.5-18 parts, antimony oxide 0.5-0.6 parts, cerium oxide 2.1-2.2 parts, and recycled ternary battery cathode material 3.2-4.4 parts. The recycled ternary battery cathode material is a powder material containing lithium, cobalt, and manganese obtained by recycling waste ternary lithium battery cathode materials.

2. The medium-temperature cobalt base enamel for steel plates that is free of fluoride salts and nitrates as described in claim 1, characterized in that, Quartz 41-43 parts, anhydrous borax 22.5-23.5 parts, soda ash 4.5-5.5 parts, potassium carbonate 2.5-3.5 parts, calcium carbonate 3.5-4.5 parts, potassium feldspar 15-17.5 parts, antimony oxide 0.5-0.6 parts, cerium oxide 2.1-2.2 parts, and recycled ternary battery cathode material 3.8-4.2 parts.

3. The medium-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 medium-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 medium-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 medium-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 medium-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 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 medium-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 800-840℃, excluding the endpoint value of 800℃.

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