A ladle anti-sticking slag coating and a preparation method thereof

Abstract

This invention proposes an anti-sticking coating for slag containers and its preparation method, relating to the field of metallurgical solid waste resource utilization. The anti-sticking coating comprises compounded sludge and water added at 25%–35% of the total mass of the compounded sludge. The compounded sludge consists of hot-quenched steel slag sludge, cold-rolled chromium-containing sludge, and additives. This invention achieves a synergistic effect with multiple benefits. It innovatively identifies hot-quenched steel slag sludge and cold-rolled chromium-containing sludge as core raw materials. Through precise proportioning design and thermal decomposition and pre-carbonization treatment, the abundant calcium, chromium, and other elements in these materials synergistically act under high-temperature conditions, solving the problem of slag adhesion to containers and achieving the harmlessness and resource utilization of hazardous waste. By designing the preparation method and optimizing the application performance of the raw materials, the durability of the coating is fully ensured. Ultimately, the anti-sticking coating for slag containers combines anti-sticking properties, cost advantages, environmental friendliness, and industrial applicability.

Description

Technical Field

[0001] This invention relates to the field of metallurgical solid waste resource utilization technology, specifically to a slag bag anti-sticking coating and its preparation method. Background Technology

[0002] In the iron and steel metallurgy industry, slag adhesion to the inner wall of converter slag ladles is a long-standing and persistent problem. Slag adhesion reduces the effective volume of the vessel, prolongs the smelting cycle, makes cleaning operations arduous, and seriously threatens the safety of overhead crane operations. To address this challenge, the industry has mainly developed two types of technologies: one is to apply an anti-slag adhesion coating to the inner wall of the vessel to form a physical isolation layer; the other is to add slag modifiers to the molten pool to change the properties of the slag and reduce its adhesion.

[0003] However, existing technologies still have room for improvement. For coating solutions, such as those based on calcium oxide or alumina, while they offer some anti-slag adhesion, they often require high-purity raw materials, resulting in high costs. Furthermore, some formulations contain fluorite, which can cause fluorine to dissolve from steel slag during use, leading to pollution. In addition, current coating solutions only focus on the "anti-sticking" function itself. Calcium oxide, one of their main raw materials, is present in various metallurgical wastes, but existing technologies fail to address another significant challenge faced by steel companies: the disposal of industrial solid waste / hazardous waste.

[0004] For example, the calcium oxide coating for preventing slag adhesion in steelmaking containers disclosed in existing technology CN01145587.X utilizes the reaction of the CaO component in the coating with acidic oxides in the slag, such as Al2O3 and SiO2, at high temperatures to generate low-melting-point calcium aluminates or calcium silicates, thereby reducing the viscosity of the slag and making it less likely to adhere firmly to the inner wall of the steelmaking container. This technical solution focuses on interfacial chemical conditioning, effectively replacing fluorine- or carbon-containing coatings in specific periods to alleviate environmental pollution and carbonization problems in molten steel. However, the anti-adhesion effect of this coating largely depends on ideal chemical reaction conditions between CaO and slag components, and its applicability is limited by the specific chemical composition of the slag system. If the slag composition fluctuates or does not conform to the preset conditions, the sufficiency and effectiveness of the reaction will be greatly reduced, leading to unstable anti-adhesion effects, i.e., a lack of consideration for the durability of the coating under harsh working conditions. Furthermore, this formulation mainly uses commercial-grade raw materials, resulting in relatively high costs, and does not involve the resource utilization of industrial waste. In today's context of emphasizing a circular economy, there is room for further improvement in its environmental friendliness and economic efficiency.

[0005] For example, the existing patent CN101519713B innovatively proposes a fluorine-free slag conditioner. By adding specific additives to ladle slag, it actively alters the physicochemical properties of the slag itself, lowering the melting point and improving fluidity, thereby fundamentally reducing the slag's tendency to wet and adhere to refractory materials. This method, through active slag system control, not only avoids pollution from fluorides but also helps improve refining efficiency. However, as an additive, the effectiveness of the slag conditioner largely depends on thorough mixing and reaction with the existing slag system. In actual large-scale production, there is a risk of uneven mixing, affecting the consistency of the effect. Secondly, the use of the slag conditioner requires judgment of the slag condition of each ladle of molten steel, making process control relatively complex and requiring high operational precision. In addition, this solution does not utilize industrial by-products; the slag conditioner itself still needs to be specially produced, limiting its cost and environmental advantages.

[0006] For example, the existing patent CN110255980B discloses a calcium-based anti-slag-sticking spray coating for converter mouths. This coating is applied to areas with prominent slag adhesion problems at the converter mouth. By designing the coating's formula, it creates a separation effect between the coating and the subsequently adhering slag, enabling quick and convenient cleaning. However, the design of this spray coating focuses on solving short-term slag-sticking cleaning efficiency, rather than providing long-term anti-sticking protection. Therefore, the material's durability is insufficient, requiring frequent spraying and increasing additional operating costs. Furthermore, its applicability in steelmaking equipment is poor. The existing patent application CN120888200A discloses an anti-slag-sticking coating based on recycled alumina powder. It innovatively uses recycled alumina powder as the main raw material, and the product is VOC-free and cures at room temperature. It aims to provide a physical barrier through the high melting point and chemical inertness of recycled alumina. However, the composition, purity, particle size distribution and other properties of recycled alumina powder may fluctuate greatly due to different sources, which leads to risks to the consistency and reliability of the final coating performance. In addition, although room temperature curing simplifies construction, the high temperature strength of the coating, the adhesion to the substrate and the long-term durability against slag erosion and scouring are insufficient. Especially for extreme high temperature and strong scouring environments such as the inner wall of steelmaking containers, its long-term protective effect needs to be verified in practice.

[0007] Metallurgical wastes, such as slag sludge generated during converter steelmaking and chromium-containing wastewater sludge from cold rolling processes, are costly to treat and pose environmental risks. How to safely and efficiently dispose of these wastes without introducing secondary pollution, while simultaneously solving the problem of slag adhesion to containers, has become a key bottleneck restricting the green and low-cost development of the steel industry. Therefore, there is an urgent need in this field to develop an innovative technology that combines metallurgical waste with the need for high-temperature anti-slag adhesion, possessing excellent anti-adhesion performance, extreme cost advantages, and environmentally friendly characteristics. Summary of the Invention

[0008] The purpose of this invention is to provide a slag bag anti-sticking coating and its preparation method. It innovatively combines two types of negative-cost sludge from steel plants, hot slag sludge and cold-rolled chromium-containing sludge, to produce a coating that can effectively prevent slag bag adhesion. By utilizing the effective components in the sludge, a coating that meets the high-temperature anti-sticking requirements of steelmaking equipment is obtained. This not only improves the utilization value of solid waste, but also has important significance for realizing the high-value utilization of solid waste and the greening of steel plants.

[0009] To achieve the above objectives, the present invention proposes the following technical solution: In a first aspect, this invention provides a slag bag anti-sticking coating, comprising compounded sludge and water; the compounded sludge is composed of the following chemical components by mass percentage: Steel slag hot-curing sludge, 40-70%; Cold-rolled chromium-containing sludge, 30-60%; Additives, 0-6%; The amount of water added is 25% to 35% of the total mass of the compound sludge; The core component of the hot-curing sludge of steel slag is Ca(OH)2, and the mass percentage of Ca(OH)2 is not less than 60%; the core component of the cold-rolled chromium-containing sludge is Cr(OH)3, and the mass percentage of Cr(OH)3 is not less than 50%.

[0010] Furthermore, the mass ratio of hot-cured steel slag sludge to cold-rolled chromium-containing sludge in the slag bag anti-sticking coating is 1.5:1 to 2:1.

[0011] Furthermore, the additives include one or more of dispersants and thickeners; The dispersant is selected from polycarboxylate superplasticizers or sodium polyphosphate, and the thickener is hydroxymethyl cellulose or xanthan gum. Preferably, the additives are a combination of the dispersant and the thickener.

[0012] Optionally, the dispersant has a mass percentage of 1-3%, and the thickener has a mass percentage of 1-3%.

[0013] Furthermore, the particle size of both the hot-cured steel slag sludge and the cold-rolled chromium-containing sludge is in the micrometer range.

[0014] In a second aspect, the present invention provides a method for preparing a slag-resistant anti-sticking coating, comprising: The steps for thermal decomposition of cold-rolled chromium-containing sludge; wherein the core component of the cold-rolled chromium-containing sludge is Cr(OH)3, and the mass percentage of Cr(OH)3 is not less than 50%; The steps for pre-carbonization treatment of steel slag thermal curing sludge; wherein, the core component of steel slag thermal curing sludge is Ca(OH)2, and the mass percentage of Ca(OH)2 is not less than 60%; The step of mixing cold-rolled chromium-containing sludge, hot-quenched steel slag sludge and additives in a certain proportion to obtain compound sludge; The step of adding water to the compound sludge and stirring to obtain a sludge-coated anti-sticking coating; the compound sludge is composed of the following chemical components by mass percentage: Steel slag hot-curing sludge, 40-70%; cold-rolled chromium-containing sludge, 30-60%; additives, 0-6%; The amount of water added is 25% to 35% of the total mass of the compound sludge.

[0015] Furthermore, the process of thermal decomposition of the cold-rolled chromium-containing sludge is as follows: The cold-rolled chromium-containing sludge is reacted at a temperature of 500~600℃ for 3~6h; the thermal decomposition aims to convert Cr(OH)3 in the cold-rolled chromium-containing sludge into Cr2O3.

[0016] Furthermore, the process of pre-carbonizing the steel slag hot-quenching sludge is as follows: CO2 gas is introduced into the hot-cured steel slag sludge to carry out a carbonization reaction until the pH value of the sludge reaches 8.5-9.5. The purpose of the carbonization reaction is to convert Ca(OH)2 in the hot-cured steel slag sludge into CaCO3.

[0017] Preferably, the CO2 gas is CO2 gas from the tail gas of a steel plant.

[0018] Furthermore, the process of pre-carbonizing the steel slag hot-quenching sludge also includes: The hot-cured steel slag sludge is added to the cold-rolled chromium-containing sludge after thermal decomposition reaction in a certain proportion, and the residual heat from the thermal decomposition reaction of the cold-rolled chromium-containing sludge is used to heat the pre-carbonization process of the hot-cured steel slag sludge; wherein, the mass ratio of the hot-cured steel slag sludge to the cold-rolled chromium-containing sludge is 1.5:1~2:1.

[0019] Furthermore, the process of pre-carbonizing the steel slag hot-quenching sludge also includes: The hot-cooked steel slag sludge is added to the cold-rolled chromium-containing sludge after thermal decomposition reaction in a certain proportion, and then water is added in an amount of 15-19% of the total mass of sludge to make a slurry. CO2 gas is introduced into the slurry to carry out a carbonization reaction until the pH value of the slurry is 8.5-9.5.

[0020] In a third aspect, the present invention provides a method for applying the anti-sticking coating for slag bags disclosed in the first aspect of the present invention or the anti-sticking coating for slag bags prepared by the method disclosed in the second aspect of the present invention, comprising: The step of spraying an anti-sticking coating onto the inner wall of a preheated slag bag to form a coating; wherein the preheating temperature of the slag bag is 100~250℃ and the thickness of the coating is 5~10mm.

[0021] Furthermore, it also includes the steps of coating drying and sintering; The coating drying and sintering step is as follows: before the slag ladle is heated with steel, the coating is kept at the preheating temperature of the slag ladle for 10 to 30 minutes.

[0022] As can be seen from the above technical solutions, the technical solutions of the present invention have achieved the following beneficial effects: This invention discloses a slag bag anti-sticking coating and its preparation method. The slag bag anti-sticking coating comprises compound sludge and water added at a ratio of 25% to 35% of the total mass of the compound sludge. The compound sludge is composed of the following chemical components by mass percentage: hot-quenched steel slag sludge, 40% to 70%; cold-rolled chromium-containing sludge, 30% to 60%; and additives, 0% to 6%. The significant advantage of this coating lies in its synergistic effect achieved through its technical approach. First, this invention innovatively identifies hot-quenched steel slag sludge and cold-rolled chromium-containing sludge, two difficult-to-treat solid wastes on-site, as core raw materials. Through precise proportioning design and thermal decomposition and pre-carbonization treatment, the calcium, chromium, and other elements rich in these materials exert a synergistic effect under high-temperature conditions. The calcium component effectively reduces slag adhesion through chemical conditioning, while the chromium component constructs a high-temperature resistant physical barrier. The two complement each other, not only solving the production problem of slag adhesion to containers but also achieving the harmlessness and resource utilization of hazardous waste. Secondly, the pre-carbonization process is introduced into the preparation method to further optimize the construction performance of the materials from the raw material level, ensuring that the final structure of the coating will not crack due to the rapid evaporation of water vapor at low temperature, thus possessing durability; that is, the implementation effect of the present invention combines anti-sticking, cost advantage, environmental friendliness and industrial applicability.

[0023] Furthermore, the sludge of the present invention contains multiple components that can be further compounded to generate various solid solutions when applied in specific high-temperature scenarios after coating. These solid solutions further improve the structural density and stability of the coating, as well as its high-temperature durability and impact resistance. This enables the slag bag anti-sticking coating of the present invention to maintain a larger number of furnaces and a shorter slag removal time, thereby improving steelmaking efficiency.

[0024] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0025] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0026] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating the process of preparing the anti-sticking coating for slag bags according to the present invention. Figure 2 The image shown is the XRD pattern of the coating slag removal product of Example 2 of the present invention. Figure 3 The image shows the XRD pattern of the coating slag product of Comparative Example 6 of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0028] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

[0029] Existing anti-slag-sticking coating solutions for addressing slag adhesion on the inner wall of converter slag ladles often suffer from drawbacks, including high costs and spillage pollution, despite their effectiveness. Researchers have discovered that calcium oxide, a key raw material for anti-slag-sticking coatings, is widely found in metallurgical waste from steel mills. Using this waste to address slag adhesion not only reduces costs but also enables the resource utilization of metallurgical waste. Therefore, this invention aims to innovatively develop a solution combining metallurgical waste with steel slag hot-quenching sludge and cold-rolled chromium-containing sludge to create an anti-slag-sticking coating. This coating combines excellent anti-sticking properties, significant cost advantages, and environmental friendliness.

[0030] Specifically, the preparation method of the anti-sticking coating for slag bags disclosed in this invention includes: The steps for thermal decomposition of cold-rolled chromium-containing sludge; wherein the core component of the cold-rolled chromium-containing sludge is Cr(OH)3, and the mass percentage of Cr(OH)3 is not less than 50%; The steps for pre-carbonization treatment of steel slag thermal curing sludge; wherein, the core component of steel slag thermal curing sludge is Ca(OH)2, and the mass percentage of Ca(OH)2 is not less than 60%; The step of mixing cold-rolled chromium-containing sludge, hot-quenched steel slag sludge and additives in a certain proportion to obtain compound sludge; The step of adding water to the compound sludge and stirring to obtain a sludge-coated anti-sticking coating; the compound sludge is composed of the following chemical components by mass percentage: Steel slag hot-curing sludge, 40-70%; cold-rolled chromium-containing sludge, 30-60%; additives, 0-6%; wherein, the additives include one or more of dispersants and thickeners; the dispersant is selected from polycarboxylate superplasticizers or sodium polyphosphate, and the thickener is hydroxymethyl cellulose or xanthan gum; The amount of water added is 25% to 35% of the total mass of the compound sludge. If the amount of water added is too small, it will not be enough to bind the various components, making stirring difficult and coating adhesion difficult. If the amount of water added is too large, the sludge will easily settle and separate, making it difficult to control the coating thickness. Furthermore, if too much water remains during coating sintering, it will easily produce pores, cracking and peeling.

[0031] The process of thermal decomposition of cold-rolled chromium-containing sludge is as follows: the cold-rolled chromium-containing sludge reacts at a temperature of 500~600℃ for 3~6 hours.

[0032] The pre-carbonization treatment of steel slag hot-curing sludge is as follows: CO2 gas is introduced into the steel slag hot-curing sludge to carry out a carbonization reaction until the pH value of the steel slag hot-curing sludge is 8.5~9.5; To accelerate the reaction rate, the pre-carbonization treatment of steel slag hot-quenching sludge also includes: The hot-cured steel slag sludge is added to the cold-rolled chromium-containing sludge after thermal decomposition reaction at a mass ratio of 1.5:1 to 2:1. The residual heat from the thermal decomposition reaction of the cold-rolled chromium-containing sludge is used to heat the pre-carbonization treatment process of the hot-cured steel slag sludge. The hot-cured steel slag sludge is added to the cold-rolled chromium-containing sludge after thermal decomposition reaction in a certain proportion, and water is added at an amount of 15 to 19% of the total mass of sludge to make a slurry. CO2 gas is introduced into the slurry to carry out a carbonization reaction until the pH value of the slurry is 8.5 to 9.5.

[0033] The slag-packing anti-sticking coating prepared by the above method can be used in the following specific applications: The step of spraying an anti-sticking coating onto the inner wall of a preheated slag bag to form a coating; wherein the preheating temperature of the slag bag is 100~250℃ and the thickness of the coating is 5~10mm.

[0034] The coating drying and sintering step involves maintaining the coating at the preheating temperature of the slag ladle for 10-30 minutes before the slag ladle is subjected to steel.

[0035] The following detailed description, in conjunction with specific embodiments, further illustrates the slag bag anti-sticking coating and its preparation method disclosed in this invention. Specifically, in Examples 1-4 and Comparative Examples 1-6, the steel slag hot-curing sludge contains 65.25% Ca(OH)2 by mass, and the cold-rolled chromium-containing sludge contains 54.71% Cr(OH)3 by mass, as shown in Tables 1 and 2 below. The core components refer to components with a mass percentage of not less than 0.5%.

[0036] Example 1

[0037] This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 380 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 570 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of polycarboxylate superplasticizer and 30 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (4) Add 100kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is denoted as coating A; (5) Preheat the slag bag to 200°C, apply coating A evenly to a thickness of 5 mm and dry and sinter for 10 min. Example 2

[0038] This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 640 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of polycarboxylate superplasticizer and 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (4) Add 100kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is called coating B; (5) Preheat the slag bag to 200°C, apply coating B evenly to a thickness of 5 mm and dry and sinter for 10 min. Example 3

[0039] This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 640 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of polycarboxylate superplasticizer and 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (4) Add 100 kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is denoted as coating C; (5) Preheat the slag bag to 200°C, apply coating C evenly to a thickness of 10 mm and dry and sinter for 10 min. Example 4

[0040] This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 100 kg of water to 640 kg of hot-cured steel slag sludge to make a slurry, and introduce CO2 gas into the slurry until the pH of the slurry drops to 9.5; (3) Add the pretreated hot-steamed steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 50 kg of water and stir. (4) Add 20 kg of polycarboxylate superplasticizer and 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (5) Add 100 kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is denoted as coating D; (6) Preheat the slag bag to 200°C, apply coating C evenly to a thickness of 5 mm and dry and sinter for 10 min. Compared with Example 2, the only difference between Example 4 and Example 2 is that the reaction time in step (2) is increased by about twice, that is, the hot-cooked steel slag sludge is directly added to the cold-rolled chromium-containing sludge after the thermal decomposition reaction, in order to utilize the residual heat of the thermal decomposition reaction to increase the reaction rate.

[0041] Comparative Example 1 This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 640 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 320 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of polycarboxylate superplasticizer and 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (4) Add 100kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is denoted as coating E1; (5) Preheat the slag bag to 200°C, apply coating E1 evenly to a thickness of 5 mm and dry and sinter for 10 min.

[0042] Comparative Example 2 This invention provides an anti-slag coating, comprising the following preparation process: (1) 335 kg of cold-rolled chromium-containing sludge was selected and subjected to thermal decomposition reaction at 500℃ for 3 h; (2) Add 670 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 100kg of water to the slurry and mix and stir to obtain the anti-slag coating, which is denoted as coating E2; (4) Preheat the slag bag to 200°C, apply E2 coating evenly to a thickness of 5 mm and dry and sinter for 10 min.

[0043] Comparative Example 3 This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 640 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of polycarboxylate superplasticizer to the slurry and stir evenly to obtain compound sludge; (4) Add 100kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is called coating E3; (5) Preheat the slag bag to 200°C, apply E3 coating evenly to a thickness of 5 mm and dry and sinter for 10 min.

[0044] Comparative Example 4 This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 640 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (4) Add 100kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is denoted as coating E4; (5) Preheat the slag bag to 200°C, apply E4 coating evenly to a thickness of 5 mm and dry and sinter for 10 min.

[0045] Comparative Example 5 This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of cold-rolled chromium-containing sludge and carry out a thermal decomposition reaction at 500℃ for 3 h; (2) Add 640 kg of hot-smelling steel slag sludge to the cold-rolled chromium-containing sludge after thermal decomposition reaction, and then add 150 kg of water to make a slurry. Pass CO2 gas into the slurry until the pH of the slurry drops to 9.5. (3) Add 20 kg of polycarboxylate superplasticizer and 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain compound sludge; (4) Add 100kg of water to the compound sludge and mix and stir to obtain the anti-slag coating, which is called coating E5; (5) Preheat the slag bag to 200°C, apply E5 coating evenly to a thickness of 20 mm and dry and sinter for 10 min.

[0046] Comparative Example 6 This invention provides an anti-slag coating, comprising the following preparation process: (1) Select 320 kg of Cr2O3 and 640 kg of CaCO3, add 100 kg of water and mix them. (2) Add 20 kg of polycarboxylate superplasticizer and 20 kg of hydroxymethyl cellulose to the slurry and stir evenly to obtain the compound slurry; (3) Add 100kg of water to the compound slurry and mix and stir to obtain the anti-slag coating, which is denoted as coating E6; (4) Preheat the slag bag to 200°C, apply E6 coating evenly to a thickness of 5 mm and dry and sinter for 10 min.

[0047] The anti-slag-sticking coatings prepared in Examples 1-4 and Comparative Examples 1-6 were sprayed onto the converter inlet, while the blank group was not sprayed with the anti-slag-sticking coating. The spraying process and implementation effect are shown in Table 3.

[0048]

[0049] The implementation data in Table 3 clearly demonstrates that the ratio of core raw materials is the primary factor determining coating performance. Based on the implementation data from Examples 1-4, it is known that when the mass ratio of hot-cured steel slag sludge to cold-rolled chromium-containing sludge is in the range of 1.5:1 to 2:1, the system can provide sufficient CaO. This not only ensures a strongly alkaline environment to effectively inhibit the formation of hexavalent Cr ions, but also guarantees sufficient reaction with Cr2O3 to form a high-strength CaCr2O4 composite phase, thereby achieving excellent anti-slag adhesion effect. In Comparative Example 1, the ratio of hot-cured steel slag sludge to cold-rolled chromium-containing sludge is unbalanced, with the CaO content significantly reduced compared to the Cr2O3 content, leading to a sharp deterioration in coating performance. This fully verifies the decisive role of controlling the ratio range.

[0050] Based on the established optimized formulation, the introduction of the additive system is key to the engineering application of waste-based coatings. Data from Comparative Examples 2-4 show that the synergistic effect of polycarboxylate superplasticizer and hydroxymethyl cellulose effectively improves the dispersibility and stability of the slurry, laying the foundation for a uniform and dense coating. Even with the optimized formulation of hot-cured steel slag sludge and cold-rolled chromium-containing sludge, Comparative Examples 2-4 suffer from deteriorated workability due to the lack of additives, and their effect is even worse than the unbalanced formulation. This highlights the indispensability of additives in ensuring the quality of the coating base.

[0051] Furthermore, the coating thickness was found to have a clear optimization range. In Example 2, the 5mm coating achieved the best balance between protection and reliability. However, when the coating was too thick, such as the 20mm coating in Comparative Example 5, cracks and a loose structure occurred due to uneven drying shrinkage and insufficient sintering, resulting in a significant decrease in performance. This proves that the perception that "the thicker the coating, the better" does not apply to this system, and that an appropriate thickness is crucial for maintaining the integrity of the coating structure.

[0052] Furthermore, the significant performance differences between Examples 1-4, Comparative Example 6, and the embodiments of the present invention clearly demonstrate that the present invention has discovered that hot-curing sludge of steel slag and cold-rolled chromium-containing sludge can be combined to form a slag bag anti-sticking coating. Moreover, the implementation data in Table 3 clearly show that its technical effect does not solely originate from the two chemical components CaO and Cr2O3, but rather from the utilization of the unique physicochemical properties of the two specific industrial sludges, including the high reactivity of specific components and multi-component synergy. Through an innovative pre-carbonization process, the activation of components and the regulation of the process are achieved, thereby producing a synergistic effect that cannot be achieved by pure chemical formulations.

[0053] Specific combination Figure 2 and Figure 3 The XRD data of the slag removal products shown indicate that the slag removal products corresponding to the slag bag anti-sticking coating disclosed in this invention have a more complex composition compared to the slag removal products of the pure phase coating provided in Comparative Example 6. This is because the abundant components of the raw sludge can be further combined and improve the coating performance in coating applications. Specifically, for example, dicalcium ferrite (Ca2Fe2O5, abbreviated as C2F) is the most common compound in the CaO-Fe2O3 system, with a low melting point (approximately 1445°C). Its presence can significantly reduce the liquid phase formation temperature of the coating system, promote sintering, and enable the coating to become dense at lower temperatures. At the same time, it can react with FeO in the slag, acting as a "flux" and helping to prevent sticking. Calcium aluminoferrite solid solution, due to the simultaneous presence of Al2O3 in both types of sludge, will form Ca2(Al,Fe)2O5 solid solution, which has similar properties to C2F but is more complex and stable. Magnesia-periasite solid solution (Mg,Fe,Mn)O: MgO (periasite) can form a continuous cubic lattice solid solution with FeO and MnO. This phase has an extremely high melting point (MgO melting point 2852°C) and is chemically very stable. It serves as an "aggregate" or "reinforcing phase" in coatings, providing high-temperature resistance and erosion resistance, and significantly improving the coating's erosion resistance. Another example is dicalcium silicate (Ca2SiO4, abbreviated as C2S): a common phase in alkaline slags and refractory materials; in hot-quenched steel slag sludge containing components such as P2O5 and Al2O3, it usually forms a solid solution, for example, by being coated with P... 5+ Al 3+It is a stable α or γ type C2S; it has a high melting point (~2130°C) and good medium and high temperature strength, which can further enhance the high temperature resistance of the coating. That is, the coating formed by the coating of the present invention has a more complex composition than that of pure phase coatings, with higher density, higher high temperature resistance, and better impact resistance. When applied, it can not only maintain more furnaces, but also requires less slag removal time.

[0054] Finally, the pre-carbonization treatment, as an innovative step in this invention, plays a crucial role in improving the coating's durability. This step, by converting Ca(OH)2 into CaCO3, not only optimizes the slurry's workability but also avoids the risk of coating cracking due to rapid evaporation of low-temperature moisture by controlling the decomposition temperature. Comparative Example 4, under optimal formulation and additive conditions, showed a significant performance decrease simply by omitting the pre-carbonization step, directly demonstrating that this process is an indispensable technical means for obtaining long-lasting and stable coatings.

[0055] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A slag bag anti-sticking coating, characterized in that, It includes compounded sludge and water; the compounded sludge consists of the following chemical components by mass percentage: Steel slag hot-curing sludge, 40-70%; Cold-rolled chromium-containing sludge, 30-60%; Additives, 0-6%; The amount of water added is 25% to 35% of the total mass of the compound sludge; The core component of the hot-curing sludge of steel slag is Ca(OH)2, and the mass percentage of Ca(OH)2 is not less than 60%; the core component of the cold-rolled chromium-containing sludge is Cr(OH)3, and the mass percentage of Cr(OH)3 is not less than 50%.

2. The anti-sticking coating for slag bags according to claim 1, characterized in that, The mass ratio of hot-cured steel slag sludge to cold-rolled chromium-containing sludge in the slag bag anti-sticking coating is 1.5:1 to 2:

1.

3. The anti-sticking coating for slag bags according to claim 1, characterized in that, The additives include one or more of dispersants and thickeners; The dispersant is selected from polycarboxylate superplasticizers or sodium polyphosphate, and the thickener is hydroxymethyl cellulose or xanthan gum.

4. A method for preparing a slag-resistant anti-sticking coating, characterized in that, include: The steps for thermal decomposition of cold-rolled chromium-containing sludge; wherein the core component of the cold-rolled chromium-containing sludge is Cr(OH)3, and the mass percentage of Cr(OH)3 is not less than 50%; The steps for pre-carbonization treatment of steel slag thermal curing sludge; wherein, the core component of steel slag thermal curing sludge is Ca(OH)2, and the mass percentage of Ca(OH)2 is not less than 60%; The step of mixing cold-rolled chromium-containing sludge, hot-quenched steel slag sludge and additives in a certain proportion to obtain compound sludge; The step of adding water to the compound sludge and stirring to obtain a sludge-coated anti-sticking coating; the compound sludge is composed of the following chemical components by mass percentage: Steel slag hot-curing sludge, 40-70%; cold-rolled chromium-containing sludge, 30-60%; additives, 0-6%; The amount of water added is 25% to 35% of the total mass of the compound sludge.

5. The preparation method of the anti-sticking coating for slag bags according to claim 4, characterized in that, The process of thermal decomposition of the cold-rolled chromium-containing sludge is as follows: Cold-rolled chromium-containing sludge is reacted at a temperature of 500~600℃ for 3~6 hours.

6. The method for preparing the anti-sticking coating for slag bags according to claim 4, characterized in that, The process of pre-carbonizing the steel slag hot-quenching sludge is as follows: CO2 gas is introduced into the hot-cured steel slag sludge to carry out a carbonization reaction until the pH value of the hot-cured steel slag sludge is 8.5~9.

5.

7. The method for preparing the anti-sticking coating for slag bags according to claim 6, characterized in that, The process of pre-carbonizing the steel slag hot-quenching sludge also includes: The hot-cured steel slag sludge is added to the cold-rolled chromium-containing sludge after thermal decomposition reaction in a certain proportion, and the residual heat from the thermal decomposition reaction of the cold-rolled chromium-containing sludge is used to heat the pre-carbonization process of the hot-cured steel slag sludge; wherein, the mass ratio of the hot-cured steel slag sludge to the cold-rolled chromium-containing sludge is 1.5:1~2:

1.

8. The method for preparing the anti-sticking coating for slag bags according to claim 7, characterized in that, The process of pre-carbonizing the steel slag hot-quenching sludge also includes: The hot-cooked steel slag sludge is added to the cold-rolled chromium-containing sludge after thermal decomposition reaction in a certain proportion, and then water is added in an amount of 15-19% of the total mass of sludge to make a slurry. CO2 gas is introduced into the slurry to carry out a carbonization reaction until the pH value of the slurry is 8.5-9.

5.

9. A method for applying a slag bag anti-sticking coating as described in any one of claims 1-3 or a slag bag anti-sticking coating prepared by the method described in any one of claims 4-8, characterized in that, include: The step of spraying an anti-sticking coating onto the inner wall of a preheated slag bag to form a coating; wherein the preheating temperature of the slag bag is 100~250℃ and the thickness of the coating is 5~10mm.

10. The application method of the anti-sticking coating for slag bags according to claim 9, characterized in that, It also includes: the steps of coating drying and sintering; The coating drying and sintering step is as follows: before the slag ladle is heated with steel, the coating is kept at the preheating temperature of the slag ladle for 10 to 30 minutes.

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