High-strength continuous casting protective slag based on modified zirconia and production process thereof

Abstract

The present application relates to continuous casting protective slag technical field, specifically, it relates to a kind of high-strength continuous casting protective slag based on modified zirconia and its production process.The mass percentage of its component is as follows:CaO:30-65%;SiO2:20-35%;Al2O3:4-12%;Na2O:5-18%;Li2O:2-7%;Fe2O3:5-12%;MnO2:1-6%;C:4-10%;BaO:2-8%;Modified zirconia particles:5-10%;The rest is inevitable impurity;Modified zirconia particles are prepared by modifying zirconia particles with siloxane modifier.In the continuous casting protective slag, modified zirconia particles, the surface and interface characteristics of modified zirconia particles can chemically react with oxides in slag liquid, form stable compounds or chemical bonds, improve the slag liquid's resistance to slag erosion performance, can reduce the possibility of continuous casting protective slag broken by external pressure and particle collision, friction and other factors, can reduce the reaction and erosion of slag liquid and metal surface, improve the metal surface quality in continuous casting process.

Description

Technical Field

[0001] This invention relates to the field of continuous casting protective slag technology, and more specifically, to a high-strength continuous casting protective slag based on modified zirconia and its production process. Background Technology

[0002] Continuous casting flux is a molten material used to protect the surface of molten metal during continuous casting. In continuous casting, molten metal flows out of the casting furnace and passes through the continuous casting mold or mold to form a continuous billet or ingot. To prevent the molten metal from contacting air and oxidizing during the flow process, and to prevent hot cracks or defects from forming after the metal solidifies, continuous casting flux is needed to form a protective layer on the surface of the molten metal.

[0003] The particle strength of continuous casting flux is an important parameter for evaluating the quality of continuous casting flux products. Fluid flux with high particle strength will affect the structural layer of flux melting in the crystallizer. Fluid flux with low particle strength is prone to breakage during product transportation and storage and during automatic slag feeding in continuous casting due to external pressure and factors such as particle collision and friction. This causes changes in the morphological characteristics and internal structure of the flux, thereby affecting the physical and chemical properties of the continuous casting flux. Ultimately, this affects the permeability, heat preservation and heat transfer characteristics of the flux during its application in the continuous casting crystallizer. In view of this, we propose a high-strength continuous casting flux based on modified zirconia and its production process. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength continuous casting protective slag based on modified zirconia and its production process, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, on the one hand, the present invention provides a high-strength continuous casting protective slag based on modified zirconia, the composition of which is as follows by mass percentage:

[0006]

[0007] The remainder are unavoidable impurities;

[0008] The modified zirconia particles are prepared by modifying zirconia particles with a siloxane modifier.

[0009] Preferably, the specific ratio of the zirconium oxide particles to the siloxane modifier is 1:0.2-0.5%, wherein the specific preparation method of the modified zirconium oxide is as follows:

[0010] S1: Prepare dry zirconium oxide particles and siloxane modifier, and select an appropriate solvent as the reaction medium. Pour the solvent into the reaction vessel, heat and stir to provide a uniform reaction environment.

[0011] S2: Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 800-2000 rpm. Continue stirring for 80-120 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0012] Preferably, the siloxane modifier modifies the zirconium oxide particles, and the specific chemical equation is as follows:

[0013] ZrO2+TMOS→ZrO2-TMOS;

[0014] In the siloxane modification, tetramethyl orthosilicate (TMOS) is used as the siloxane. TMOS reacts with the hydroxyl groups on the zirconium oxide surface: the silicon-oxygen bond (Si-O) in TMOS can react with the hydroxyl groups (OH) on the zirconium oxide particle surface to form a silicon-oxygen bond (Si-O-Zr), which can enhance the bonding force and interaction between the siloxane and the zirconium oxide particles. Furthermore, the methyl ester group (OCH3) of the siloxane is replaced by the hydroxyl group, and methanol (CH3OH) is released at the same time, which leads to the formation of chemical bonds between the zirconium oxide particle surface and the siloxane, firmly fixing the siloxane molecules on the zirconium oxide surface. The reaction formula is: TMOS + ZrOH2 → ZrOSi(CH3)3 + CH3OH.

[0015] Among them, after siloxane-modified zirconium oxide particles, siloxane molecules will cover the surface of the zirconium oxide particles, forming a coating layer, which improves the stability and dispersibility of the zirconium oxide particles.

[0016] At the same time, it can also enhance the bonding strength between zirconia particles and other components in the continuous casting protective slag, which helps to improve the overall structural strength and wear resistance of the slag, reduce particle spalling and loss, further increase the slag corrosion resistance of zirconia particles, reduce the degree of erosion and damage to them by slag during continuous casting, and help extend the service life and stability of the continuous casting protective slag.

[0017] Preferably, the solvent is any one of toluene, ethanol, and dimethylformamide.

[0018] The heating temperature range for toluene solvent is 110-140℃;

[0019] The heating temperature range for ethanol solvent is 76-100℃;

[0020] The heating temperature range of dimethylformamide is 150-156℃; preferably, dimethylformamide is used as the reaction medium in this invention.

[0021] Preferably, the modified zirconia particles have a particle size range of 20-30 nm, and the relative standard deviation of the particle size distribution is no greater than 10%. Ensuring that the particle sizes of the modified zirconia particles are not significantly different is beneficial for maintaining the uniformity and stability of the continuous casting protective slag. The particle size can be measured and controlled using sieving or other particle size analysis methods.

[0022] Furthermore, modified zirconia particles can significantly enhance the performance of continuous casting protective slag, with the modified zirconia particles playing a major role in enhancing and improving the slag properties, specifically:

[0023] Enhanced structural strength: Modified zirconia particles have high hardness and strength. Adding them to the continuous casting protective slag can enhance the structural strength of the slag, help prevent the slag from cracking or deforming during continuous casting, and improve the stability and slag erosion resistance of the slag.

[0024] Improved resistance to slag erosion: The surface and interface properties of modified zirconia particles can react chemically with oxides in the slag liquid to form stable compounds or chemical bonds, which can improve the slag liquid's resistance to slag erosion. This can reduce the likelihood of continuous casting protective slag breaking under external pressure and due to particle collisions and friction. At the same time, it can reduce the reaction and erosion between the slag liquid and the metal surface, thereby improving the surface quality of the metal during the continuous casting process.

[0025] Improved lubrication performance: Modified zirconia particles have good lubrication properties. Adding them to the continuous casting protective slag can reduce friction and wear between the metal and the slag, help improve the fluidity of the metal during the continuous casting process, and reduce friction loss and surface defects.

[0026] Improved thermal conductivity: Modified zirconia particles have high thermal conductivity, and their addition can improve the thermal conductivity of continuous casting flux. This helps to better conduct and disperse heat, improving temperature control and uniformity during metal solidification.

[0027] Improving slag erosion resistance involves multiple reaction processes, the specific chemical reaction equations are as follows:

[0028] TMOS reacts with calcium oxide (CaO):

[0029] Si(OMe)4 + CaO → Ca(OMe)2 + SiO2 (dimethyl silicate);

[0030] Among them, the formation of reaction products Ca(OMe)2 and SiO2 can improve the slag erosion resistance of continuous casting protective slag, and the formation of dimethyl silicate helps to form a protective layer and reduce the formation of slag scale.

[0031] Furthermore, TMOS reacts with aluminum oxide (Al2O3):

[0032] Si(OMe)4 + Al2O3 → Al(OMe)3 + SiO2 (dimethyl silicate);

[0033] Among them, the formation of reaction products Al(OMe)3 and SiO2 can enhance the slag erosion resistance of continuous casting protective slag, and the formation of dimethyl silicate helps to form a stable slag film and reduce the reaction between slag and metal surface.

[0034] TMOS reacts with iron oxide (Fe2O3):

[0035] Si(OMe)4 + Fe2O3 → Fe(OMe)3 + SiO2 (dimethyl silicate);

[0036] The formation of reaction products Fe(OMe)2 and SiO2 can improve the slag erosion resistance of continuous casting protective slag, and the formation of dimethyl silicate helps to reduce the reaction between slag liquid and metal surface and the oxidation of metal.

[0037] Among them, the silicon-oxygen bonds in the siloxane modifier and the hydroxyl groups (OH) on the zirconium oxide surface may form hydrogen bond interactions; hydrogen bond is a weak non-covalent interaction force that can provide additional binding energy and stability at the interface; the siloxane modifier has high surface activity and can be adsorbed on the zirconium oxide surface to form a monolayer or multilayer; this adsorption can change the surface energy and surface properties, making the interface region more stable and promoting the interaction between siloxane and slag material.

[0038] Furthermore, Si(OMe)4 represents tetramethyl orthosilicate. In the chemical formula, Si represents silicon and OMe represents methoxy (-OCH3). Therefore, Si(OMe)4 represents a compound in which one silicon atom is bonded to four methoxy groups (-OCH3).

[0039] Preferably, the present invention also provides a method for preparing a high-strength continuous casting protective slag based on modified zirconia, comprising the high-strength continuous casting protective slag based on modified zirconia described in any one of the above-mentioned methods, wherein the method for preparing the continuous casting protective slag is as follows:

[0040] S3: Weigh the raw materials prepared by weighing the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia;

[0041] S4: Mix the modified zirconia particles with other components in the continuous casting protective slag formula to obtain a modified mixture of continuous casting protective slag, and use a mechanical stirring device to mix and stir to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid;

[0042] S5: Adjust parameters such as temperature and pH of the mixing system to promote the interaction and stability of particles with other components;

[0043] S6: The modified mixture of continuous casting protective slag is reacted and cured under appropriate temperature conditions, so that the modified zirconia particles react chemically with other components in the continuous casting protective slag or form a stable structure; a high-temperature furnace can be used for heating and curing when curing the continuous casting protective slag. The high-temperature furnace can provide the required curing temperature and ensure the uniformity and stability of the temperature.

[0044] S7: Cool and grind the solidified continuous casting protective slag modified mixture to obtain grinding powder, and granulate the grinding powder to obtain continuous casting protective slag.

[0045] Preferably, the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1000-1300℃. This temperature range can prevent the crystallizer from burning out due to excessive temperature, and can also prevent the zirconium oxide particles from completely melting. Using unmelted zirconium oxide particles as protective slag increases the stability of the slag layer, improves the coating performance, and lowers the melting point. The slag layer has better stability and can play a role in filling and thickening. At the same time, it can also provide physical protection and isolation for the slag layer, preventing the molten metal from contacting the outside world and oxidizing. However, if the temperature is too high, it may lead to excessive melting of the components and the generation of bubbles, which will affect the quality and uniformity of the slag layer.

[0046] The mixing reaction time range of the mixed system is 90-150 min;

[0047] The pH range of the mixed system is 8-11. Under alkaline conditions, the reactivity of the siloxane modifier may be enhanced, making it easier for it to react chemically with components in zirconium oxide and continuous casting flux.

[0048] At high temperatures, the reaction rates of raw materials such as CaO, SiO2, and Al2O3 increase, which can promote more complete chemical reactions and interactions.

[0049] Preferably, the curing temperature range of the modified continuous casting protective slag mixture is 400-800℃; the curing time range is 6-12h.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] 1. In the high-strength continuous casting protective slag based on modified zirconia and its production process, siloxane-modified zirconia particles are used. Siloxane molecules cover the surface of the zirconia particles, forming a coating layer, which improves the stability and dispersibility of the zirconia particles, further enhances the bonding strength between the zirconia particles and other components in the continuous casting protective slag, helps to improve the overall structural strength and wear resistance of the slag material, and reduces particle spalling and loss.

[0052] 2. In the high-strength continuous casting protective slag based on modified zirconia and its production process, modified zirconia particles are added to the continuous casting protective slag. While improving the structural strength of the continuous casting protective slag, the surface and interface characteristics of the modified zirconia particles can chemically react with oxides in the slag liquid to form stable compounds or chemical bonds. This can improve the slag liquid's resistance to slag erosion and reduce the possibility of the continuous casting protective slag easily breaking due to external pressure and particle collisions and friction. At the same time, it can reduce the reaction and erosion between the slag liquid and the metal surface, and improve the metal surface quality during the continuous casting process. Detailed Implementation

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] This invention provides a high-strength continuous casting protective slag based on modified zirconia and its production process. Modified zirconia particles are added to the raw materials for preparing the continuous casting protective slag. After the zirconia particles are modified with siloxane, the siloxane molecules will cover the surface of the zirconia particles, forming a coating layer, which improves the stability and dispersibility of the zirconia particles. It can also enhance the bonding strength between the zirconia particles and other components in the continuous casting protective slag, which helps to improve the overall structural strength and wear resistance of the slag, reduce particle spalling and loss, reduce the degree of erosion and damage to the slag during continuous casting, and reduce the possibility of the continuous casting protective slag easily breaking due to external pressure and collision and friction between particles.

[0055] Since the particle strength of continuous casting protective slag is an important parameter for evaluating the quality of continuous casting protective slag products, high particle strength protective slag will affect the structural layer of the protective slag melting in the crystallizer. Low particle strength protective slag is prone to breakage during product transportation and storage and during the automatic slag feeding process of continuous casting due to external pressure and factors such as particle collision and friction. This causes changes in the morphological characteristics and internal structure of the protective slag, thereby affecting its physical and chemical properties. Ultimately, this affects the air permeability, heat preservation and heat transfer characteristics of the protective slag during the application of the continuous casting crystallizer. Therefore, it is particularly important to carry out research on the strength test method standard of continuous casting protective slag, which is of great significance for guiding continuous casting protective slag production enterprises to produce qualified protective slag.

[0056] Example 1

[0057] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0058] I. Preparation of modified zirconium oxide:

[0059] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.3%. Dimethylformamide solvent is selected as the reaction medium. Pour the dimethylformamide solvent into the reaction vessel, heat it to 150°C, and stir to provide a uniform reaction environment.

[0060] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0061] II. Preparation of Continuous Casting Protective Slag:

[0062] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0063]

[0064] S4. A modified continuous casting molded slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting molded slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting molded slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting molded slag or form a stable structure. The solidified modified continuous casting molded slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting molded slag.

[0065] Example 2

[0066] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0067] I. Preparation of modified zirconium oxide:

[0068] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.3%. Dimethylformamide solvent is selected as the reaction medium. Pour the dimethylformamide solvent into the reaction vessel, heat it to 150°C, and stir to provide a uniform reaction environment.

[0069] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0070] II. Preparation of Continuous Casting Protective Slag:

[0071] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0072]

[0073] S4. A modified continuous casting protective slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting protective slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting protective slag or form a stable structure. The solidified modified continuous casting protective slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting protective slag.

[0074] Example 3

[0075] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0076] I. Preparation of modified zirconium oxide:

[0077] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.3%. Dimethylformamide solvent is selected as the reaction medium. Pour the dimethylformamide solvent into the reaction vessel, heat it to 150°C, and stir to provide a uniform reaction environment.

[0078] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0079] II. Preparation of Continuous Casting Protective Slag:

[0080] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0081]

[0082]

[0083] S4. A modified continuous casting protective slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting protective slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting protective slag or form a stable structure. The solidified modified continuous casting protective slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting protective slag.

[0084] Example 4

[0085] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0086] I. Preparation of modified zirconium oxide:

[0087] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.3%. Dimethylformamide solvent is selected as the reaction medium. Pour the dimethylformamide solvent into the reaction vessel, heat it to 150°C, and stir to provide a uniform reaction environment.

[0088] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0089] II. Preparation of Continuous Casting Protective Slag:

[0090] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0091]

[0092] S4. A modified continuous casting protective slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting protective slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting protective slag or form a stable structure. The solidified modified continuous casting protective slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting protective slag.

[0093] Example 5

[0094] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0095] I. Preparation of modified zirconium oxide:

[0096] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.2%. Dimethylformamide solvent is selected as the reaction medium. Pour the dimethylformamide solvent into the reaction vessel, heat it to 150°C, and stir to provide a uniform reaction environment.

[0097] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0098] II. Preparation of Continuous Casting Protective Slag:

[0099] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0100]

[0101] S4. A modified continuous casting protective slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting protective slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting protective slag or form a stable structure. The solidified modified continuous casting protective slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting protective slag.

[0102] Example 6

[0103] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0104] I. Preparation of modified zirconium oxide:

[0105] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.5%. Dimethylformamide solvent is selected as the reaction medium. Pour dimethylformamide solvent into the reaction vessel, heat to 150°C, and stir to provide a uniform reaction environment.

[0106] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0107] II. Preparation of Continuous Casting Protective Slag:

[0108] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0109]

[0110]

[0111] S4. A modified continuous casting protective slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting protective slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting protective slag or form a stable structure. The solidified modified continuous casting protective slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting protective slag.

[0112] Example 7

[0113] A method for preparing a high-strength continuous casting protective slag based on modified zirconia is as follows:

[0114] I. Preparation of modified zirconium oxide:

[0115] S1. Prepare dry zirconium oxide particles and siloxane modifier. The specific ratio of zirconium oxide particles to siloxane modifier is 1:0.3%. Dimethylformamide solvent is selected as the reaction medium. Pour the dimethylformamide solvent into the reaction vessel, heat it to 150°C, and stir to provide a uniform reaction environment.

[0116] S2. Add zirconia particles to a mixing container, and gradually add the siloxane modifier to the mixing container to ensure that the modifier can evenly cover the surface of the zirconia particles. Use a stirring rod to stir and mix to ensure that the modifier and particles are fully in contact and mixed. The stirring speed range is 1800 rpm. Continue stirring for 100 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconia particles to remove residual solvent and unreacted substances.

[0117] II. Preparation of Continuous Casting Protective Slag:

[0118] S3. Weigh the raw materials prepared according to the mass percentage of the components of the high-strength continuous casting protective slag based on modified zirconia and mix them, wherein,

[0119]

[0120] S4. A modified continuous casting protective slag mixture is obtained by mixing, wherein the mixing reaction temperature range of the modified continuous casting protective slag mixture is 1300℃; the mixing reaction time range of the mixing system is 120min; and the pH range of the mixing system is 10. Mechanical stirring is used to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid to promote the interaction and stability of the particles with other components. The modified continuous casting protective slag mixture is then reacted and solidified under appropriate temperature conditions, with a solidification temperature range of 600℃ and a solidification time range of 10h, allowing the modified zirconia particles to chemically react with other components in the continuous casting protective slag or form a stable structure. The solidified modified continuous casting protective slag mixture is cooled and ground to obtain a powder, which is then granulated to obtain the continuous casting protective slag.

[0121] Comparative Example 1

[0122] Using the method of Example 7, the siloxane modifier was removed, and unmodified zirconium oxide particles were used to prepare continuous casting protective slag.

[0123] Comparative Example 2

[0124] The modified zirconium oxide particles in the components of the continuous casting protective slag were removed using the method of Example 1.

[0125] The high-strength continuous casting protective slag based on modified zirconia particles prepared by this invention exhibits good structural strength, as shown in the following test results:

[0126] Test method for particle strength of continuous casting protective slag:

[0127] In the high-strength continuous casting protective slag based on modified zirconia prepared in Examples 1-7 and Comparative Examples 1-2 above, the samples were placed in a drum containing steel balls under certain conditions, in accordance with national standards such as GB / T30202.3, GB / T 12496.6, and GB / T 7702.3. The samples were worn down by the mechanical rotation of the drum, and then removed and sieved. The percentage of the sample mass on the test sieve relative to the total sample mass was taken as the sample strength.

[0128] Currently, national standards such as GB / T 30202.3, GB / T 12496.6, and GB / T 7702.3 all use a strength tester to determine the strength of activated carbon particles. This equipment is a dedicated device for determining particle strength. Therefore, this standard uses a strength tester based on the strength of high-strength continuous casting protective slag modified with zirconia.

[0129] To avoid interference from powdery slag, small granular slag, and broken slag in the protective slag sample on the test results, it is necessary to remove protective slag particles smaller than 0.2 mm using a test sieve. The selected test sieve model conforms to the requirements of YB / T 188 "Test Method for Particle Size Distribution of Continuous Casting Protective Slag", specifically 0.160 mm; referring to YB / T 188 "Test Method for Particle Size Distribution of Continuous Casting Protective Slag", the drying temperature is 110±5℃.

[0130] This standard adopts the strength testing instrument method:

[0131] Weigh 100g of continuous casting protective slag sample, take 50g of protective slag particles with a particle size of 0.2-0.8mm through a vibrating screen, and put them into a drum with an inner diameter of φ80mm. The rotation speed is 100r / min, and the drum is rotated for 5min. Then, the sample after testing is sieved using a standard vibrating screen and the mass of the material passing through the screen is measured. The breakage rate of the continuous casting protective slag particles is calculated according to the following formula. Divide the breakage rate by 50g to obtain the breakage rate. Use the breakage rate to measure the particle strength.

[0132] Table 1. Breakage rate data of high-strength continuous casting flux based on modified zirconia in Examples 1-7 and Comparative Examples 1-2.

[0133] Example Initial weight / g After grinding / g Breakage rate / % Example 1 49.99 45.89 9.6 Example 2 50.00 45.45 9.1 Example 3 50.00 45.91 8.2 Example 4 50.01 45.20 8.1 Example 5 49.99 44.89 10.2 Example 6 50.01 46.1 7.8 Example 7 50.00 45.56 8.9 Comparative Example 1 50.00 41.2 17.6 Comparative Example 2 50.02 38.9 22.3

[0134] The above data clearly demonstrates that, compared to Comparative Examples 1-2, the breakage rate of Examples 1-7 refers to the degree of breakage of the continuous casting protective slag under specific test conditions. Because this invention uses modified zirconia particles to prepare a high-strength continuous casting protective slag based on modified zirconia, and modifies the zirconia particles with a siloxane modifier, the mechanical properties of the zirconia particles are significantly improved. As the amount of siloxane modifier in the zirconia particles increases and the concentration of modified zirconia particles in the total formula continuously increases, the breakage rate of the high-strength continuous casting protective slag based on modified zirconia is effectively reduced, as detailed below:

[0135] As can be seen from Examples 1-7, when the proportion of modified zirconia particles in the continuous casting protective slag changes, the breakage rate of the continuous casting protective slag increases significantly with the increase of the proportion of modified zirconia particles. Specifically, according to Examples 5-7, when the proportion of siloxane modifier in zirconia particles decreases, the breakage rate of the continuous casting protective slag also decreases. It can be concluded that the physical properties of modified zirconia particles are related to the proportion of siloxane modifier, and when the proportion of siloxane modifier increases, the modified zirconia particles have a certain effect on reducing the breakage rate of the continuous casting protective slag. The increase in the content of modified zirconia particles has a significant inhibitory effect on the breakage rate of the continuous casting protective slag, and can effectively reduce the breakage rate of the continuous casting protective slag.

[0136] Furthermore, it can be seen from Examples 1-4 and Example 7 that when the concentration of modified zirconia particles in the continuous casting protective slag is changed, the breakage rate of the continuous casting protective slag changes, and as the proportion of modified zirconia particles in the total formula increases, the breakage rate of the continuous casting protective slag decreases significantly.

[0137] A comparison of Examples 1-7 and Comparative Examples 1-2 shows that the breakage rate of continuous casting protective slag significantly increased after removing the modified zirconia particles. Furthermore, the breakage rate of continuous casting protective slag also significantly increased when unmodified zirconia particles were used to prepare the slag. Therefore, it can be concluded that modified zirconia particles obtained by modifying zirconia particles with a siloxane modifier play a dominant role in the breakage rate test of continuous casting protective slag.

[0138] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-strength continuous casting protective slag based on modified zirconia, characterized in that: Its constituent components by mass percentage are: CaO: 30-32%; SiO2: 20-35%; Al2O3: 4-12%; Na2O: 5-18%; Li2O: 2-7%; Fe2O3: 5-12%; MnO2: 1-6%; C： 4-10％； BaO: 2-8%; Modified zirconia particles: 5-10%; The remainder are unavoidable impurities; Among them, the modified zirconia particles are prepared by modifying zirconia particles with a siloxane modifier; The specific ratio of the zirconium oxide particles to the siloxane modifier is 1:0.2-0.5%, and the specific preparation method of the modified zirconium oxide is as follows: S1: Prepare dry zirconium oxide particles and siloxane modifier, and select an appropriate solvent as the reaction medium. Pour the solvent into the reaction vessel, heat and stir to provide a uniform reaction environment. S2: Add zirconium oxide particles to a mixing container, and gradually add the siloxane modifier to the mixing container. Use a stirring rod to stir and mix, with a stirring speed range of 800-2000 rpm. Continue stirring for 80-120 minutes until the particles and siloxane modifier are uniformly dispersed. After ensuring that the modifier and particles are uniformly mixed, filter, wash and dry the mixed modified zirconium oxide particles to remove residual solvent and unreacted substances. The particle size range of the modified zirconium oxide particles is 20-30 nm.

2. The high-strength continuous casting protective slag based on modified zirconia according to claim 1, characterized in that: The siloxane modifier modifies the zirconium oxide particles, and the specific chemical equation is as follows: ZrO2+TMOS→ZrO2-TMOS; In the siloxane modification, tetramethyl orthosilicate is used as the siloxane.

3. The high-strength continuous casting protective slag based on modified zirconia according to claim 1, characterized in that: The solvent is any one of toluene, ethanol, and dimethylformamide.

4. A production process for a high-strength continuous casting protective slag based on modified zirconia as described in any one of claims 1-3, characterized in that: The preparation method of the continuous casting protective slag is as follows: S3: Weigh the raw materials according to the percentage of the high-strength continuous casting protective slag based on modified zirconia as described in any one of claims 1-3; S4: Mix the modified zirconia particles with other components in the continuous casting protective slag formula to obtain a modified mixture of continuous casting protective slag, and use a mechanical stirring device to mix and stir to ensure that the modified zirconia particles are uniformly dispersed in the slag liquid; S5: Adjust the temperature and pH parameters of the continuous casting protective slag modified mixture to promote the interaction and stability of particles with other components; S6: The modified mixture of continuous casting protective slag is reacted and solidified under appropriate temperature conditions, so that the modified zirconium oxide particles react chemically with other components in the continuous casting protective slag to form a stable structure. S7: Cool and grind the solidified continuous casting protective slag modified mixture to obtain grinding powder, and granulate the grinding powder to obtain continuous casting protective slag.

5. The production process of high-strength continuous casting protective slag based on modified zirconia according to claim 4, characterized in that: The mixing reaction temperature range of the modified continuous casting protective slag mixture is 1000-1300℃; The mixing reaction time range of the modified continuous casting protective slag mixture is 90-150 min. The pH range of the modified continuous casting protective slag mixture is 8-11.

6. The production process of high-strength continuous casting protective slag based on modified zirconia according to claim 5, characterized in that: The curing temperature range of the modified continuous casting protective slag mixture is 400-800°C; the curing time range is 6-12h.

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