Anti-hydration super-hydrophobic magnesium-calcium refractory material and preparation method thereof

Abstract

The invention relates to a hydration-resistant super-hydrophobic magnesium-calcium refractory material and a preparation method thereof. According to the technical scheme, an organic acid and a magnesium-calcium refractory material are subjected to ball milling modification, or an organic acid ethanol solution is sprayed to the surface of the magnesium-calcium refractory material for modification, and the modified magnesium-calcium refractory material is prepared. And placing the modified magnesium-calcium refractory material in an atmosphere furnace, heating to 200-400 DEG C under the conditions that the gas flow is 10-80 mL / min and the heating rate is 5-15 DEG C / min, preserving heat, and cooling along with the furnace to obtain the hydration-resistant super-hydrophobic magnesium-calcium refractory material. The preparation method is simple in process, low in energy consumption and low in production cost, and the prepared hydration-resistant super-hydrophobic magnesium-calcium refractory material has the characteristics of good super-hydrophobicity, excellent hydration resistance, excellent erosion resistance, strong thermal shock resistance and good molten steel purification performance.

Description

Technical Field

[0001] This invention belongs to the technical field of magnesium-calcium refractory materials. Specifically, it relates to a superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. Background Technology

[0002] Magnesia-calcium refractories possess excellent properties such as high refractoriness, high-temperature stability, good high-temperature vacuum stability, strong resistance to alkaline slag erosion, and the ability to purify molten steel. Therefore, they are commonly used as furnace lining materials in high-temperature industries such as continuous casting tundishes and cement kiln firing zones. However, the free CaO in these refractories readily reacts with water to form Ca(OH)₂, accompanied by a significant volume expansion (~96%), leading to complete pulverization of the refractory material. This hinders its transportation, storage, and use, severely restricting the development and application of magnesia-calcium refractories. The development of anti-hydration methods for magnesia-calcium refractories has attracted considerable attention from researchers. 1) The patented technology "A Preparation Process of Hydration-Resistant Synthetic Magnesia-Calcium Sand" (CN120328885A) uses dolomite and magnesite as raw materials and cerium oxide and iron oxide as additives to prepare magnesium-calcium refractory materials. However, cerium oxide is expensive and not suitable for mass production. Furthermore, this method reduces the content of free calcium oxide, thereby decreasing its thermal shock resistance and corrosion resistance, and also reducing its effectiveness in purifying molten steel. 2) Reference I (Mohammadihooyeh M, Karamian E, Emadi R. The impact of MgAl2O4 nano-particles on the hydration-resistance improvement of dolomite-based refractories[J].Ceramics International, 2019, 45(16):20674-20677.) added 8wt% nano-MgAl2O4 spinel to magnesia-calcium refractories and improved their density by high-temperature sintering. However, the sintering temperature of this method is 1650℃, which consumes a lot of energy, and the prepared magnesia-calcium refractories are still prone to hydration.

[0003] 3) "A method for preparing hydration-resistant magnesium-calcium sand" (CN107445628A) involves first using a hydration-carbonation process to carbonate both the interior and exterior of lightly calcined dolomite particles, followed by coating the particles with ultrafine silica gel to obtain magnesium-calcium sand. However, this method is complex, requiring multiple calcinations, which is not conducive to large-scale industrial applications. Furthermore, this method only relies on physical barriers and does not alter the hydrophilic properties of the material surface, resulting in insufficient stability and durability of its hydration resistance.

[0004] 4) "A method for preparing hydration-resistant magnesium calcium sand" (CN106495665B) This method involves spraying organosilicon resin onto the surface of magnesium calcium sand at 100~300℃, which improves its hydration resistance, but the hydration resistance of the prepared magnesium calcium sand is limited.

[0005] In summary, the shortcomings of the existing technology are as follows: First, the high-temperature sintering method has high energy consumption, and the price of rare earth oxides such as cerium oxide is expensive, which increases the production cost; second, the anti-hydration effect is not ideal, the process is relatively complicated, and the introduction of silicon also reduces the high-temperature performance and the ability to purify molten steel of magnesium calcium sand; third, the effect of using only physical barriers to improve the anti-hydration performance of magnesium calcium refractories is limited. Summary of the Invention

[0006] The present invention aims to overcome the defects of the prior art and provides a method for preparing a superhydrophobic magnesium-calcium refractory material with simple process, low energy consumption and low production cost. The superhydrophobic magnesium-calcium refractory material prepared by the method has good superhydrophobicity, excellent hydration resistance, excellent erosion resistance, strong thermal shock resistance and good steel molten steel purification performance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention comprises the following steps: Step 1: Modify the magnesia-calcium refractory material by ball milling the organic acid and the magnesia-calcium refractory material at a mass ratio of 1~10:100, or by spraying the organic acid ethanol solution onto the surface of the magnesia-calcium refractory material at a mass ratio of 1~10:100, to obtain the modified magnesia-calcium refractory material.

[0008] The organic acid is one of fatty acids, polybasic acids, and aromatic acids.

[0009] The magnesium-calcium refractory material has a calcium oxide content of 20-60 wt%, a magnesium oxide content of 38-79 wt%, and a total content of 95-99 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace and heat it to 200-400°C under conditions of a gas flow rate of 10-80 mL / min and a heating rate of 5-15°C / min. Hold the temperature and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0010] The organic acid ethanol solution is one of fatty acid ethanol solution, polybasic acid ethanol solution, and aromatic acid ethanol solution; the concentration of the organic acid ethanol solution is 0.1~1 mol / L.

[0011] The magnesium-calcium refractory material is one of the matrix, aggregate, and product; wherein: The particle size of the matrix is ​​less than 0.074 mm; The aggregate particle size is one of the following: less than 1 mm, greater than or equal to 1 mm and less than 3 mm, and greater than or equal to 3 mm and less than 5 mm. The product has a size of either 25×25×140mm or 10×10×2mm, and the apparent porosity of the product is 5-20%.

[0012] The ball milling rate is 5~20 r / min, the ball milling time is 3~16 h, the ball milling medium is zirconium oxide, and the ball-to-material mass ratio is 1.5~2.5:1.

[0013] The gas is one of carbon dioxide, nitrogen, and argon; the purity of the gas is ≥99 mol.

[0014] The fatty acid is one of decaic acid, dodecaic acid, tetradecanoic acid, or octadecanoic acid.

[0015] The polyacid is one of succinic acid, adipic acid, and sebacic acid.

[0016] The aromatic acid is one of salicylic acid, benzoic acid, and caffeic acid.

[0017] The heat preservation time is 0.5~5 hours.

[0018] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. This invention modifies magnesium-calcium refractory materials by ball milling organic acids or by spraying an organic acid ethanol solution onto the surface of magnesium-calcium refractory materials. The materials are then placed in an atmosphere furnace and held at 200-400°C for 0.5-5 hours, followed by furnace cooling, to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration. This invention features a simple process, controllable operation, low required pyrolysis temperature, and low energy consumption.

[0019] 2. This invention modifies magnesium-calcium refractory materials, and the prepared hydration-resistant superhydrophobic magnesium-calcium refractory material has excellent thermal shock resistance, slag resistance, and steel purification properties. This is attributed to its high content of free calcium oxide, which can effectively buffer thermal stress and thus improve thermal shock resistance. At the same time, calcium oxide reacts with alumina and silicon oxide in the slag to form a high-melting-point phase, which increases the viscosity of the slag. This phase is adsorbed on the surface of the magnesium-calcium refractory material and hinders the erosion and penetration of the slag, thereby improving the slag resistance of the hydration-resistant superhydrophobic magnesium-calcium refractory material.

[0020] 3. The organic acid used in this invention is an industrial product, characterized by stable supply and low cost. Utilizing the hydrophobic properties of the organic acid, through ball milling and spraying modification, the superhydrophobic magnesium-calcium refractory material, resistant to hydration, acquires superhydrophobic properties, effectively reducing water vapor adsorption and thus hindering water vapor erosion. Subsequent heat treatment in an atmosphere furnace causes partial pyrolysis of the organic acid, producing small amounts of water and carbon dioxide. This converts the free calcium oxide on the surface of the magnesium-calcium refractory material into calcium carbonate, forming a coating layer that further inhibits water vapor erosion. This method effectively solves the hydration problems encountered during factory storage, transportation, and use at room temperature.

[0021] The superhydrophobic magnesium-calcium refractory material prepared by this invention has a static water contact angle of 150-160° and a hydration weight gain of 0.12-1 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0022] Therefore, the preparation method of the present invention has the characteristics of simple process, low energy consumption and low production cost. The prepared superhydrophobic magnesium-calcium refractory material with water resistance has the characteristics of superhydrophobic properties, excellent water resistance, excellent erosion resistance, strong thermal shock resistance and good steel molten steel purification performance. Attached Figure Description

[0023] Figure 1 This is a photograph of the water contact angle of magnesium-calcium aggregate with a particle size of less than 1 mm used in this invention. Figure 2 To Figure 1 The image shown is a photograph of the water contact angle of a superhydrophobic magnesium-calcium aggregate prepared by modifying the raw material with octadecanoic acid. Figure 3 for Figure 1 XRD comparison diagram of the raw material and the superhydrophobic magnesium-calcium aggregate prepared by modifying the raw material with octadecanoic acid. Figure 4 for Figure 1 The graph shows a comparison of the hydration weight gain of the raw material and the hydration-resistant superhydrophobic magnesium-calcium aggregate prepared by modifying the raw material with octadecanoic acid. Detailed Implementation

[0024] The invention will now be further described with reference to the accompanying drawings, but this is not intended to limit its scope of protection.

[0025] A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this specific embodiment are as follows: Step 1: Modify the magnesia-calcium refractory material by ball milling the organic acid and the magnesia-calcium refractory material at a mass ratio of 1~10:100, or by spraying the organic acid ethanol solution onto the surface of the magnesia-calcium refractory material at a mass ratio of 1~10:100, to obtain the modified magnesia-calcium refractory material.

[0026] The organic acid is one of fatty acids, polybasic acids, and aromatic acids.

[0027] The magnesium-calcium refractory material has a calcium oxide content of 20-60 wt%, a magnesium oxide content of 38-79 wt%, and a total content of 95-99 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace and heat it to 200-400°C under conditions of a gas flow rate of 10-80 mL / min and a heating rate of 5-15°C / min. Hold the temperature and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0028] The organic acid ethanol solution is one of fatty acid ethanol solution, polybasic acid ethanol solution, and aromatic acid ethanol solution; the concentration of the organic acid ethanol solution is 0.1~1 mol / L.

[0029] The magnesium-calcium refractory material is one of the matrix, aggregate, and product; wherein: The aggregate particle size is one of the following: less than 1 mm, greater than or equal to 1 mm and less than 3 mm, and greater than or equal to 3 mm and less than 5 mm. The product has a size of either 25×25×140mm or 10×10×2mm, and the apparent porosity of the product is 5-20%.

[0030] The ball milling rate is 5~20 r / min, the ball milling time is 3~16 h, and the ball-to-material mass ratio is 1.5~2.5:1.

[0031] The gas is one of carbon dioxide, nitrogen, or argon.

[0032] The fatty acid is one of decaic acid, dodecaic acid, tetradecanoic acid, or octadecanoic acid.

[0033] The polyacid is one of succinic acid, adipic acid, and sebacic acid.

[0034] The aromatic acid is one of salicylic acid, benzoic acid, and caffeic acid.

[0035] The heat preservation time is 0.5~5 hours.

[0036] In this specific implementation: The particle size of the matrix is ​​less than 0.074 mm; The purity of the gas is ≥99 mol%; The ball milling media is zirconium oxide.

[0037] The details will not be repeated in the examples.

[0038] The superhydrophobic magnesium-calcium refractory material with water resistance was tested and found to have a water contact angle of 150-160° and a hydration weight gain rate of 0.12-1 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0039] Example 1 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified at a mass ratio of 1:100 to obtain the modified magnesium-calcium refractory.

[0040] The organic acid is a fatty acid.

[0041] The magnesium-calcium refractory material has a calcium oxide content of 20 wt%, a magnesium oxide content of 79 wt%, and a total content of 99 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 200°C under the conditions of a gas flow rate of 10 mL / min and a heating rate of 5°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0042] The magnesium-calcium refractory material is the matrix.

[0043] The ball milling rate is 5 r / min, the milling time is 3 h, and the ball-to-material mass ratio is 1.5:1.

[0044] The gas is argon.

[0045] The fatty acid in question is tetradecanoic acid.

[0046] The heat preservation time is 0.5 hours.

[0047] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 152° and a hydration weight gain of 0.12 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0048] Example 2 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 2:100 to obtain modified magnesium-calcium refractory.

[0049] The organic acid is a fatty acid.

[0050] The magnesium-calcium refractory material has a calcium oxide content of 30 wt%, a magnesium oxide content of 67 wt%, and a total content of 97 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 220°C under the conditions of a gas flow rate of 20 mL / min and a heating rate of 8°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0051] The magnesium-calcium refractory material is an aggregate with a particle size of less than 1 mm.

[0052] The ball milling rate is 8 r / min, the milling time is 5 h, and the ball-to-material mass ratio is 1.8:1.

[0053] The gas is nitrogen.

[0054] The fatty acid is octadecanoic acid.

[0055] The heat preservation time is 1 hour.

[0056] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 156° and a hydration weight gain of 0.24 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0057] Example 3 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 3:100 to obtain modified magnesium-calcium refractory.

[0058] The organic acid is a fatty acid.

[0059] The magnesium-calcium refractory material has a calcium oxide content of 40 wt%, a magnesium oxide content of 58 wt%, and a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 250°C under the conditions of a gas flow rate of 30 mL / min and a heating rate of 10°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0060] The magnesium-calcium refractory material is the matrix.

[0061] The ball milling rate is 12 r / min, the milling time is 7 h, and the ball-to-material mass ratio is 2:1.

[0062] The gas is carbon dioxide.

[0063] The fatty acid in question is dodecanoic acid.

[0064] The heat preservation time is 1.5 hours.

[0065] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 158° and a hydration weight gain of 0.35 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0066] Example 4 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 4:100 to obtain modified magnesium-calcium refractory.

[0067] The organic acid is a fatty acid.

[0068] The magnesium-calcium refractory material has a calcium oxide content of 50 wt% and a magnesium oxide content of 45 wt%, with a total content of 95 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 280°C under the conditions of a gas flow rate of 40 mL / min and a heating rate of 12°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0069] The magnesium-calcium refractory material is an aggregate with a particle size greater than or equal to 1 mm and less than 3 mm.

[0070] The ball milling rate was 15 r / min, the milling time was 9 h, and the ball-to-material mass ratio was 2.2:1.

[0071] The gas is argon.

[0072] The fatty acid is a decacarboxylic acid.

[0073] The heat preservation time is 2 hours.

[0074] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 150° and a hydration weight gain of 0.46 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0075] Example 5 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 5:100 to obtain modified magnesium-calcium refractory.

[0076] The organic acid is a polybasic acid.

[0077] The magnesium-calcium refractory material has a calcium oxide content of 60 wt% and a magnesium oxide content of 38 wt%, with a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 300°C under the conditions of a gas flow rate of 50 mL / min and a heating rate of 15°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0078] The magnesium-calcium refractory material is the matrix.

[0079] The ball milling rate was 18 r / min, the milling time was 11 h, and the ball-to-material mass ratio was 2.5:1.

[0080] The gas is nitrogen.

[0081] The polyacid is succinic acid.

[0082] The heat preservation time is 2.5 hours.

[0083] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 151° and a hydration weight gain of 0.67 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0084] Example 6 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 6:100 to obtain modified magnesium-calcium refractory.

[0085] The organic acid is a polybasic acid.

[0086] The magnesium-calcium refractory material has a calcium oxide content of 20 wt%, a magnesium oxide content of 78 wt%, and a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 320°C under the conditions of a gas flow rate of 60 mL / min and a heating rate of 5°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0087] The magnesium-calcium refractory material is an aggregate with a particle size greater than or equal to 3 mm and less than 5 mm.

[0088] The ball milling rate was 20 r / min, the milling time was 13 h, and the ball-to-material mass ratio was 1.6:1.

[0089] The gas is carbon dioxide.

[0090] The polyacid is adipic acid.

[0091] The heat preservation time is 3 hours.

[0092] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 153° and a hydration weight gain of 0.74 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0093] Example 7 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 7:100 to obtain modified magnesium-calcium refractory.

[0094] The organic acid is a polybasic acid.

[0095] The magnesium-calcium refractory material has a calcium oxide content of 30 wt%, a magnesium oxide content of 67 wt%, and a total content of 97 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 350°C under the conditions of a gas flow rate of 70 mL / min and a heating rate of 8°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0096] The magnesium-calcium refractory material is the matrix.

[0097] The ball milling rate is 5 r / min, the ball milling time is 15 h, and the ball-to-material mass ratio is 1.7:1.

[0098] The gas is argon.

[0099] The polyacid is sebacic acid.

[0100] The heat preservation time is 3.5 hours.

[0101] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 154° and a hydration weight gain of 0.55 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0102] Example 8 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 8:100 to obtain modified magnesium-calcium refractory.

[0103] The organic acid is an aromatic acid.

[0104] The magnesium-calcium refractory material has a calcium oxide content of 40 wt%, a magnesium oxide content of 57 wt%, and a total content of 97 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 380°C under the conditions of a gas flow rate of 80 mL / min and a heating rate of 10°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0105] The magnesium-calcium refractory material is an aggregate with a particle size of less than 1 mm.

[0106] The ball milling rate is 8 r / min, the milling time is 16 h, and the ball-to-material mass ratio is 1.9:1.

[0107] The gas is nitrogen.

[0108] The polyacid is salicylic acid.

[0109] The heat preservation time is 4 hours.

[0110] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 155° and a hydration weight gain of 0.85 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0111] Example 9 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 9:100 to obtain modified magnesium-calcium refractory.

[0112] The organic acid is an aromatic acid.

[0113] The magnesium-calcium refractory material has a calcium oxide content of 50 wt%, a magnesium oxide content of 46 wt%, and a total content of 96 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 400°C under the conditions of a gas flow rate of 10 mL / min and a heating rate of 12°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0114] The magnesium-calcium refractory material is an aggregate with a particle size greater than or equal to 1 mm and less than 3 mm.

[0115] The ball milling rate is 10 r / min, the ball milling time is 8 h, and the ball-to-material mass ratio is 2.1:1.

[0116] The gas is carbon dioxide.

[0117] The polyacid is benzoic acid.

[0118] The heat preservation time is 4.5 hours.

[0119] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 160° and a hydration weight gain of 0.94 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0120] Example 10 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid and the magnesium-calcium refractory are ball-milled and modified according to the mass ratio of organic acid to magnesium-calcium refractory of 10:100 to obtain modified magnesium-calcium refractory.

[0121] The organic acid is an aromatic acid.

[0122] The magnesium-calcium refractory material has a calcium oxide content of 60 wt% and a magnesium oxide content of 38 wt%, with a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 390°C under the conditions of a gas flow rate of 20 mL / min and a heating rate of 15°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0123] The magnesium-calcium refractory material is the matrix.

[0124] The ball milling rate was 12 r / min, the milling time was 10 h, and the ball-to-material mass ratio was 2.3:1.

[0125] The gas is argon.

[0126] The polyacid is caffeic acid.

[0127] The heat preservation time is 5 hours.

[0128] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 159° and a hydration weight gain of 1 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0129] Example 11 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 1:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0130] The magnesium-calcium refractory material has a calcium oxide content of 20 wt%, a magnesium oxide content of 79 wt%, and a total content of 99 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 200°C under the conditions of a gas flow rate of 10 mL / min and a heating rate of 5°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0131] The organic acid ethanol solution is a fatty acid ethanol solution with a concentration of 0.1 mol / L.

[0132] The magnesium-calcium refractory material is a product with dimensions of 25×25×140mm and an apparent porosity of 5%.

[0133] The gas is argon.

[0134] The fatty acid is octadecanoic acid.

[0135] The heat preservation time is 0.5 hours.

[0136] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 151° and a hydration weight gain of 0.26 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0137] Example 12 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 2:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0138] The magnesium-calcium refractory material has a calcium oxide content of 30 wt%, a magnesium oxide content of 67 wt%, and a total content of 97 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 220°C under the conditions of a gas flow rate of 20 mL / min and a heating rate of 8°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0139] The organic acid ethanol solution is a fatty acid ethanol solution with a concentration of 0.2 mol / L.

[0140] The magnesium-calcium refractory material is an aggregate with a particle size of less than 1 mm.

[0141] The gas is nitrogen.

[0142] The fatty acid in question is tetradecanoic acid.

[0143] The heat preservation time is 1 hour.

[0144] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 152° and a hydration weight gain of 0.12 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0145] Example 13 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 3:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0146] The magnesium-calcium refractory material has a calcium oxide content of 40 wt%, a magnesium oxide content of 58 wt%, and a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 250°C under the conditions of a gas flow rate of 30 mL / min and a heating rate of 10°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0147] The organic acid ethanol solution is a fatty acid ethanol solution with a concentration of 0.3 mol / L.

[0148] The magnesium-calcium refractory material is the matrix.

[0149] The gas is carbon dioxide.

[0150] The fatty acid in question is dodecanoic acid.

[0151] The heat preservation time is 1.5 hours.

[0152] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 156° and a hydration weight gain of 0.34 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0153] Example 14 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 4:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0154] The magnesium-calcium refractory material has a calcium oxide content of 50 wt% and a magnesium oxide content of 45 wt%, with a total content of 95 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 280°C under the conditions of a gas flow rate of 40 mL / min and a heating rate of 12°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0155] The organic acid ethanol solution is a fatty acid ethanol solution with a concentration of 0.4 mol / L.

[0156] The magnesium-calcium refractory material is a product with dimensions of 10×10×2mm and an apparent porosity of 10%.

[0157] The gas is argon.

[0158] The fatty acid is a decacarboxylic acid.

[0159] The heat preservation time is 2 hours.

[0160] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 157° and a hydration weight gain of 0.75 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0161] Example 15 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 5:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0162] The magnesium-calcium refractory material has a calcium oxide content of 60 wt% and a magnesium oxide content of 38 wt%, with a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 300°C under the conditions of a gas flow rate of 50 mL / min and a heating rate of 15°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0163] The organic acid ethanol solution is a polybasic acid ethanol solution with a concentration of 0.5 mol / L.

[0164] The magnesium-calcium refractory material is an aggregate with a particle size greater than or equal to 1 mm and less than 3 mm.

[0165] The gas is nitrogen.

[0166] The polyacid is succinic acid.

[0167] The heat preservation time is 2.5 hours.

[0168] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 153° and a hydration weight gain of 0.87 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0169] Example 16 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 6:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0170] The magnesium-calcium refractory material has a calcium oxide content of 20 wt%, a magnesium oxide content of 78 wt%, and a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 320°C under the conditions of a gas flow rate of 60 mL / min and a heating rate of 5°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0171] The organic acid ethanol solution is a polybasic acid ethanol solution with a concentration of 0.6 mol / L.

[0172] The magnesium-calcium refractory material is the matrix.

[0173] The gas is carbon dioxide.

[0174] The polyacid is adipic acid.

[0175] The heat preservation time is 3 hours.

[0176] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 150° and a hydration weight gain of 0.45 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0177] Example 17 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 7:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0178] The magnesium-calcium refractory material has a calcium oxide content of 30 wt%, a magnesium oxide content of 67 wt%, and a total content of 97 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 350°C under the conditions of a gas flow rate of 70 mL / min and a heating rate of 8°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0179] The organic acid ethanol solution is a polybasic acid ethanol solution with a concentration of 0.7 mol / L.

[0180] The magnesium-calcium refractory material is a product with dimensions of 25×25×140mm and an apparent porosity of 15%.

[0181] The gas is argon.

[0182] The polyacid is sebacic acid.

[0183] The heat preservation time is 3.5 hours.

[0184] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 160° and a hydration weight gain of 0.94 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0185] Example 18 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 8:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0186] The magnesium-calcium refractory material has a calcium oxide content of 40 wt%, a magnesium oxide content of 57 wt%, and a total content of 97 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 380°C under the conditions of a gas flow rate of 80 mL / min and a heating rate of 10°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0187] The organic acid ethanol solution is an aromatic acid ethanol solution with a concentration of 0.8 mol / L.

[0188] The magnesium-calcium refractory material is an aggregate with a particle size greater than or equal to 3 mm and less than 5 mm.

[0189] The gas is nitrogen.

[0190] The aromatic acid is salicylic acid.

[0191] The heat preservation time is 4 hours.

[0192] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 153° and a hydration weight gain of 0.68 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0193] Example 19 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 9:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0194] The magnesium-calcium refractory material has a calcium oxide content of 50 wt%, a magnesium oxide content of 46 wt%, and a total content of 96 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 400°C under the conditions of a gas flow rate of 10 mL / min and a heating rate of 12°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0195] The organic acid ethanol solution is an aromatic acid ethanol solution with a concentration of 0.9 mol / L.

[0196] The magnesium-calcium refractory material is the matrix.

[0197] The gas is carbon dioxide.

[0198] The aromatic acid is benzoic acid.

[0199] The heat preservation time is 4.5 hours.

[0200] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 156° and a hydration weight gain of 1 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0201] Example 20 A superhydrophobic magnesium-calcium refractory material resistant to hydration and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: The organic acid ethanol solution is sprayed onto the surface of the magnesium-calcium refractory material at a mass ratio of 10:100 to modify the material, thus obtaining the modified magnesium-calcium refractory material.

[0202] The magnesium-calcium refractory material has a calcium oxide content of 60 wt% and a magnesium oxide content of 38 wt%, with a total content of 98 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace, heat it to 370°C under the conditions of a gas flow rate of 20 mL / min and a heating rate of 15°C / min, hold it at that temperature, and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

[0203] The organic acid ethanol solution is an aromatic acid ethanol solution with a concentration of 1 mol / L.

[0204] The magnesium-calcium refractory material is a product with dimensions of 10×10×2mm and an apparent porosity of 20%.

[0205] The gas is argon.

[0206] The aromatic acid is caffeic acid.

[0207] The heat preservation time is 5 hours.

[0208] The superhydrophobic magnesium-calcium refractory material prepared in this embodiment was tested and found to have a water contact angle of 154° and a hydration weight gain of 0.53 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0209] Compared with the prior art, the present invention has the following advantages: 1. This invention modifies magnesium-calcium refractory materials by ball milling organic acids or by spraying an organic acid ethanol solution onto the surface of magnesium-calcium refractory materials. The materials are then placed in an atmosphere furnace and held at 200-400°C for 0.5-5 hours, followed by furnace cooling, to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration. This invention features a simple process, controllable operation, low required pyrolysis temperature, and low energy consumption.

[0210] 2. This invention modifies magnesium-calcium refractory materials, and the resulting superhydrophobic magnesium-calcium refractory material with resistance to hydration also exhibits excellent thermal shock resistance, slag resistance, and steel purification properties. This is attributed to its high content of free calcium oxide, which effectively buffers thermal stress and thus improves thermal shock resistance. Simultaneously, calcium oxide reacts with alumina and silica in the slag to form a high-melting-point phase, increasing the viscosity of the slag. This phase adsorbs onto the surface of the magnesium-calcium refractory material and hinders the erosion and penetration of the slag, thereby improving the slag resistance of the superhydrophobic magnesium-calcium refractory material with resistance to hydration.

[0211] 3. The organic acid used in this invention is an industrial product, characterized by stable supply and low cost. Utilizing the hydrophobic properties of the organic acid, through ball milling and spraying modification, the superhydrophobic magnesium-calcium refractory material resistant to hydration exhibits superhydrophobic properties, effectively reducing water vapor adsorption and thus hindering water vapor erosion. Subsequent heat treatment in an atmosphere furnace causes partial pyrolysis of the organic acid, producing small amounts of water and carbon dioxide. This converts the free calcium oxide on the surface of the magnesium-calcium refractory material into calcium carbonate, forming a coating layer that further inhibits water vapor erosion. The superhydrophobic magnesium-calcium refractory material resistant to hydration prepared in this specific embodiment is shown in the attached figure. Figure 1 This is a photograph of the water contact angle of magnesium-calcium aggregate with a particle size of less than 1 mm used in Example 2. Figure 2 To Figure 1 The image shown is a photograph of the water contact angle of a superhydrophobic magnesium-calcium aggregate prepared by modifying the raw material with octadecanoic acid. Figure 3 for Figure 1 XRD comparison diagram of the raw material and the superhydrophobic magnesium-calcium aggregate prepared by modifying the raw material with octadecanoic acid. Figure 4 for Figure 1 The chart shows a comparison of the hydration weight gain of the raw material and the superhydrophobic magnesium-calcium aggregate modified with octadecanoic acid (50℃ / 90%RH / 10h). From... Figure 1 It can be seen that the water contact angle of the raw materials used is in a hydrophilic state; from Figure 2 It can be seen that the prepared superhydrophobic magnesium-calcium aggregate, which is resistant to water erosion, is in a superhydrophobic state; from Figure 3 and Figure 4 It can be seen that the prepared hydration-resistant superhydrophobic magnesium-calcium aggregate exhibits a calcium carbonate peak, and the hydration weight gain rate decreases significantly. This method effectively solves the hydration problems during factory storage, transportation, and use at room temperature.

[0212] The superhydrophobic magnesium-calcium refractory material prepared by this invention has a static water contact angle of 150-160° and a hydration weight gain of 0.12-1 wt% after being placed at 50°C and 90% relative humidity for 10 hours.

[0213] Therefore, the preparation method of the present invention has the characteristics of simple process, low energy consumption and low production cost. The prepared superhydrophobic magnesium-calcium refractory material with water resistance has the characteristics of superhydrophobic properties, excellent water resistance, excellent erosion resistance, strong thermal shock resistance and good steel molten steel purification performance.

Claims

1. A method for preparing a superhydrophobic magnesium-calcium refractory material resistant to hydration, characterized in that... The preparation method comprises the following steps: Step 1: Modify the magnesia-calcium refractory material by ball milling the organic acid and the magnesia-calcium refractory material at a mass ratio of 1~10:100, or by spraying the organic acid ethanol solution onto the surface of the magnesia-calcium refractory material at a mass ratio of 1~10:100, to obtain the modified magnesia-calcium refractory material. The organic acid is one of fatty acids, polybasic acids, and aromatic acids; The magnesium-calcium refractory material has a calcium oxide content of 20-60 wt%, a magnesium oxide content of 38-79 wt%, and a total content of 95-99 wt%. Step 2: Place the modified magnesium-calcium refractory material in an atmosphere furnace and heat it to 200-400°C under conditions of a gas flow rate of 10-80 mL / min and a heating rate of 5-15°C / min. Hold the temperature and cool it with the furnace to obtain a superhydrophobic magnesium-calcium refractory material resistant to hydration.

2. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The organic acid ethanol solution is one of fatty acid ethanol solution, polybasic acid ethanol solution, and aromatic acid ethanol solution; the concentration of the organic acid ethanol solution is 0.1~1 mol / L.

3. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The magnesium-calcium refractory material is one of the matrix, aggregate, and product; wherein: The particle size of the matrix is ​​less than 0.074 mm. The aggregate particle size is one of the following: less than 1 mm, greater than or equal to 1 mm and less than 3 mm, and greater than or equal to 3 mm and less than 5 mm. The product has a size of either 25×25×140mm or 10×10×2mm, and the apparent porosity of the product is 5-20%.

4. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The ball milling rate is 5~20 r / min, the ball milling time is 3~16 h, the ball milling medium is zirconium oxide, and the ball-to-material mass ratio is 1.5~2.5:

1.

5. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The gas is one of carbon dioxide, nitrogen, and argon; the purity of the gas is ≥99 mol.

6. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The fatty acid is one of decaic acid, dodecaic acid, tetradecanoic acid, or octadecanoic acid.

7. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The polyacid is one of succinic acid, adipic acid, and sebacic acid.

8. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The aromatic acid is one of salicylic acid, benzoic acid, and caffeic acid.

9. The method for preparing the superhydrophobic magnesium-calcium refractory material resistant to hydration according to claim 1, characterized in that, The heat preservation time is 0.5~5 hours.

10. A method for preparing a superhydrophobic magnesium-calcium refractory material resistant to hydration, characterized in that... The aforementioned water-resistant superhydrophobic magnesium-calcium refractory material is the water-resistant superhydrophobic magnesium-calcium refractory material prepared by the preparation method of the water-resistant superhydrophobic magnesium-calcium refractory material according to claims 1 to 9. The water contact angle of the hydration-resistant superhydrophobic magnesium-calcium refractory material is 150~160°, and the hydration weight gain rate after being placed at 50℃ and 90% relative humidity for 10 hours is 0.12~1wt%.

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