A wear-resistant refractory brick and its preparation method

Abstract

The invention relates to a wear-resistant refractory brick and a preparation method thereof. The wear-resistant refractory brick is made of the following raw materials in parts by mass: clay sand casting dust removal ash, water glass sand regeneration dust removal ash, calcium hydroxide powder, aluminum sol, bauxite, foundry waste sand, and aluminum dihydrogen phosphate. The preparation method of the wear-resistant refractory brick comprises the following steps: mixing 200-300 parts of clay sand casting dust removal ash, 50-100 parts of water glass sand regeneration dust removal ash, and 5-10 parts of calcium hydroxide powder to form a powder; mixing 100 parts of the powder with 50-60 parts of the aluminum sol and adding water to form a slurry; mixing 100 parts of the slurry with 60-80 parts of bauxite and 30-40 parts of foundry waste sand; spraying an aluminum dihydrogen phosphate solution with a solution mass percentage concentration of 12-15%, wherein the amount of the aluminum dihydrogen phosphate solution sprayed is 1-2% by mass of the slurry, bauxite, and foundry waste sand; vacuum extrusion, blanking, and high-temperature firing. The wear-resistant refractory bricks prepared by the method have excellent wear resistance, fire resistance and strength properties.

Description

Technical Field

[0001] The present invention relates to the field of refractory materials, and in particular to a wear-resistant refractory brick and a preparation method thereof. Background Art

[0002] Refractory bricks, as a high-temperature building material, play an indispensable role in industrial production. They are widely used in high-temperature industrial production applications such as steelmaking, ceramic production, cement manufacturing, glassmaking, and heat treatment. In these applications, refractory bricks are often used as lining materials for high-temperature equipment. For example, in steelmaking, blast furnaces, converters, and electric furnaces require refractory bricks for their hearths and flues. In ceramic production, refractory bricks are used as lining materials for high-temperature kilns. The quality of refractory bricks is crucial to the stability and safety of the production process and the lifespan of the equipment, necessitating high demands on their ability to withstand high temperatures and high pressures. Therefore, improving refractory bricks' resistance to high temperatures, wear, and pressure is a major research focus in the refractory field. With the global consensus on environmental protection and sustainable development, the development of more environmentally friendly production processes and materials, reducing solid waste, wastewater, and exhaust emissions, and achieving efficient resource utilization and a circular economy are also becoming mainstream trends in the refractory industry.

[0003] The foundry industry, a downstream industry of steelmaking, generates significant amounts of solid waste. For example, during the casting process, metal melts and oxidizes to produce large quantities of metal oxides. These metal oxides form gaseous phases at high temperatures, are discharged with flue gases, and upon cooling, condense into solid particles, forming dust. Coal and coke, used to dissolve metals, also vaporize at high temperatures and are discharged as dust. The regeneration of commonly used water glass sand for foundry molding produces dust. Repeated use of molded sand also generates large quantities of waste sand. Reusing these solid wastes is crucial for reducing industrial costs and achieving a green and circular economy. Therefore, how to process high-performance materials from solid waste is a crucial technical challenge facing both the industrial and materials sectors.

[0004] Invention patent CN103011698A discloses a method for producing carbon bricks from associated waste. The method uses industrial solid waste to produce carbon bricks, specifically utilizing associated resources such as dust removal ash and iron oxide from steelmaking systems. While this method achieves the goal of utilizing industrial solid waste, the process only increases brick density and strength through vibration, resulting in low heat and wear resistance. With industrial development, the requirements for high-temperature resistance in equipment are further increasing. Developing refractory bricks that combine high refractoriness, high compressive strength, long service life, and low cost is a challenge facing the field of high-temperature building materials. Summary of the Invention

[0005] The present invention aims to solve the above problems, make up for the deficiencies of the prior art, and provide a wear-resistant refractory brick and a preparation method thereof to solve the problems arising from the above background technology.

[0006] The first aspect of the present invention provides a wear-resistant refractory brick, the raw materials of which are composed of a slurry, bauxite, foundry waste sand and an aluminum dihydrogen phosphate solution accounting for 1-2% of the mass percentage of the sum of the slurry, bauxite and foundry waste sand in a mass ratio of 10:6-8:3-4, wherein the mass percentage concentration of the aluminum dihydrogen phosphate solution is 12-15%; the slurry is mixed with powder and aluminum sol in a mass ratio of 10:5-6, and water is added to form a slurry with a moisture content of 40-50%; the powder is made of clay sand casting dust ash, water glass sand regeneration dust ash and calcium hydroxide in a mass ratio of 20-30:5-10:0.5-1.

[0007] Residual waterglass in the recycled ash from waterglass sand, along with added calcium hydroxide powder, creates an alkaline environment for the clay sand casting dust removal ash. Specifically, the waterglass in the inorganic recycled ash hydrolyzes to produce strongly alkaline hydroxide ions. The insoluble silicon and aluminum elements in the clay sand recycled ash, which cannot enter the gel system, are activated and dissolved by the alkaline solution, converting them into ionic forms. The ionic silicon and aluminum react with silicate and hydroxide ions to form small gel particles, which aggregate to form a gel skeleton, ultimately forming a stable gel structure. This reactivates the clay sand casting dust removal ash, which has been inactivated by high-temperature treatment, and increases its viscosity, facilitating subsequent brick extrusion. Furthermore, the waterglass neutralizes the acidity of the sol and, when mixed with the aluminum sol, forms a composite gel of aluminate and silicate. This enhances the strength of the green bricks, allowing for denser and higher stacking of bricks, thereby improving machine efficiency and reducing energy consumption.

[0008] Preferably, the mass ratio of the clay sand casting dust ash, the water glass sand regeneration dust ash and the calcium hydroxide is 20-30:5-7:0.5-1.

[0009] Preferably, the mass ratio of the powder to the aluminum sol is 10:6.

[0010] Preferably, the mass ratio of the slurry, the bauxite and the waste foundry sand is 10:6-7:3.5-4.

[0011] Preferably, the frequency of the ultrasonic treatment is 28-32 kHz, and the time is 1-2 min.

[0012] Preferably, the solid content of the aluminum sol is 10-12%.

[0013] The second aspect of the present invention also provides a method for preparing wear-resistant refractory bricks, the method comprising the following steps:

[0014] 1) Powder preparation: calcining the clay sand casting dust ash, cooling it to room temperature, mixing the clay sand casting dust ash with water glass sand regeneration dust ash and calcium hydroxide powder in a mass ratio of 20-30:5-10:0.5-1, stirring, grinding, and sieving to prepare a powder;

[0015] 2) Slurry preparation: the powder prepared in step (1) is mixed with aluminum sol and water, and stirred to prepare a slurry with a water content of 40-50%;

[0016] 3) Wet material preparation: the slurry prepared in step (2) is mixed with bauxite and foundry waste sand in a mass ratio of 10:6-8:3-4, and a 12-15% by mass concentration of aluminum dihydrogen phosphate solution is sprayed into the mixture, wherein the amount of aluminum dihydrogen phosphate solution accounts for 1-2% of the total mass of the slurry, bauxite and foundry waste sand to prepare a wet material;

[0017] 4) Blank making: the wet material prepared in step (3) is made into brick blanks;

[0018] 5) Drying: drying the bricks obtained in step (4) at a constant temperature, and then drying them with hot air;

[0019] 6) Firing: Firing the bricks dried in step (5) to obtain finished bricks.

[0020] Preferably, the slurry prepared in step 2) is subjected to an ultrasonic treatment step at a frequency of 28-32 kHz for 1-2 minutes. The ultrasonic treatment uniformly disperses the aluminum sol in the slurry system, encapsulating the less refractory raw materials so that they do not soften and break down when exposed to high temperatures.

[0021] Preferably, the calcination temperature in the step 1) is 600-700°C, and the calcination is stopped when the clay sand casting dust ash completely changes from black to yellow. The clay sand casting dust ash is mixed with organic dust generated during the combustion of fuel. By calcining, the organic matter in the clay sand casting dust ash is removed, which can improve the strength, stability and safety of the brick during the production process. If the calcination temperature is too low, the organic matter will not be completely decomposed. In the subsequent brick firing process, the organic matter will decompose at high temperature, produce gas, and form pores in the brick body, thereby reducing the density and strength of the brick. If the calcination temperature is too high, the activity of the clay sand casting dust ash will be further destroyed, the viscosity will be reduced, and the brick blanks will be difficult to form. The calcination temperature is between 600-700°C, which can not only completely remove the organic residues, but also retain a certain activity of the clay sand casting dust ash. Specifically, the calcination temperature is 600° C., 620° C., 640° C., 650° C., 670° C., 690° C., 700° C. or an interval value thereof.

[0022] Preferably, the stirring speed is 1000-1500 rpm.

[0023] Preferably, the grinding is performed using a ball mill, and the particle size of the powder is ≤74 μm.

[0024] Preferably, in step 4), vacuum extrusion molding is adopted, the extrusion pressure is 3 to 4 MPa, and the vacuum degree is -0.096 to -0.08 MPa.

[0025] Preferably, the constant temperature drying temperature in step 5) is 20-25° C., and the drying time is 24-36 hours; the hot air drying temperature is 60-80° C., and the drying is stopped when the moisture content of the bricks is ≤2.5%.

[0026] Preferably, the firing in step 6) is preheating at 200-300°C for 3-4h, heating to 950-1150°C at an average rate of 1.5°C / min and keeping warm for 1-2h, heating to 1350-1450°C at an average rate of 1.5°C / min and keeping warm for 2-3h, and cooling to room temperature to obtain finished bricks.

[0027] Compared with bricks in the prior art, the present invention has the following advantages:

[0028] (1) Compared with the traditional raw materials for preparing wear-resistant refractory bricks, the raw materials of the present invention adopt industrial solid wastes such as clay sand casting dust ash and water glass sand regeneration dust ash, which is not only environmentally friendly but also greatly reduces the production cost of bricks.

[0029] (2) The water glass component and calcium hydroxide in the water glass sand regeneration dust ash in the wear-resistant refractory brick raw material of the present invention can stimulate the viscosity of the high-temperature inactivated sand casting dust ash, making the bricks easy to extrude and form. The brick pressing equipment does not need high pressure output, energy consumption is reduced, and production costs are further reduced.

[0030] (3) High strength of wet bricks: The aluminum sol added to the raw materials can generate a composite gel of aluminate and silicate in the alkaline environment created by water glass and calcium hydroxide, which makes the particles of casting dust more tightly bonded, the wet bricks more dense, and the strength increases. The bricks can be stacked denser and higher, and the efficiency of transferring wet bricks is higher, which reduces the energy consumption of brick production.

[0031] (4) The present invention adds an ultrasonic treatment step to the brick preparation process. Ultrasonic waves reduce the agglomeration of particles and promote more uniform wrapping of the composite sol on the surface of the dust particles, thereby improving the uniformity, density and fire resistance of the bricks, and further significantly improving the flexural strength and compressive strength of the bricks.

[0032] (5) The addition of bauxite to the raw materials greatly improves the wear resistance and fire resistance of the bricks. During the high-temperature firing process of the bricks, the diaspore and kaolinite in the bauxite undergo different chemical reactions and phase changes in different temperature ranges, and eventually form a network interwoven structure of mullite phase and glass phase inside the brick body, which enhances the bonding strength, high temperature resistance and wear resistance of the material.

[0033] (6) The wear-resistant refractory bricks prepared by the preparation method of the present invention have a refractoriness of ≥1500°C, a compressive strength of ≥25Mpa, a flexural strength of ≥5Mpa, and a water absorption rate of ≤8.5%. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0035] The embodiment of the present invention solves the problem in the prior art that refractory bricks have poor high temperature resistance and wear resistance and cannot take into account the cost by providing a wear-resistant refractory brick and a preparation method thereof.

[0036] The parts in the present invention refer to parts by mass.

[0037] Example 1

[0038] A wear-resistant refractory brick is prepared by the following method:

[0039] (1) Powder preparation: Clay sand casting dust removal ash is calcined at 600° C. until the clay sand casting dust removal ash completely changes from black to yellow, and then cooled to room temperature. 200 parts by mass of the calcined and cooled clay sand casting dust removal ash are mixed with 50 parts by mass of water glass sand regeneration dust removal ash and 5 parts by mass of calcium hydroxide powder in a high-speed stirrer at 1000 rpm. The mixture is ground in a ball mill and passed through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0040] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were mixed with 50 parts of aluminum sol having a solid content of 10%, and an appropriate amount of water was added to prepare a slurry having a water content of 40%. The slurry was ultrasonically treated at a frequency of 28 kHz for 1 min.

[0041] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 60 parts of bauxite and 30 parts of foundry waste sand; 1.9 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 15%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0042] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine, and the brick making machine is set to an extrusion pressure of 4 MPa and a vacuum degree of -0.095 MPa.

[0043] (5) Drying: Place the finished bricks in a drying chamber and dry at 20°C for 36 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0044] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 200°C for 4 hours, then heated to 950°C at an average rate of 1.5°C / min and kept for 2 hours, and then heated to 1350°C at an average rate of 1.5°C / min and kept for 3 hours. After firing, they are cooled to obtain finished bricks.

[0045] Example 2

[0046] A wear-resistant refractory brick is prepared by the following method:

[0047] (1) Powder preparation: Clay sand casting dust removal ash is calcined at 700° C. until the clay sand casting dust removal ash completely changes from black to yellow and is cooled to room temperature. 300 parts by mass of the calcined and cooled clay sand casting dust removal ash are mixed with 100 parts of water glass sand regeneration dust removal ash and 10 parts of calcium hydroxide powder in a high-speed stirrer at 1500 rpm. The mixture is ground in a ball mill and passed through a 200-mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0048] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were mixed with 60 parts of aluminum sol having a solid content of 12%, and an appropriate amount of water was added to prepare a slurry having a water content of 50%. The slurry was ultrasonically treated at a frequency of 32 kHz for 2 minutes.

[0049] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 80 parts of bauxite and 40 parts of foundry waste sand; 4.4 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 12%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0050] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine, and the brick making machine is set to an extrusion pressure of 3 MPa and a vacuum degree of -0.08 MPa.

[0051] (5) Drying: Place the finished bricks in a drying chamber and dry them at 25°C for 28 hours. Then, introduce hot air at 70°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0052] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 200°C for 3 hours, then heated to 1150°C at an average rate of 1.5°C / min and kept for 1 hour. Then, they are heated to 1450°C at an average rate of 1.5°C / min and kept for 2 hours. After firing, they are gradually cooled to obtain finished bricks.

[0053] Example 3

[0054] A wear-resistant refractory brick is prepared by the following method:

[0055] (1) Powder preparation: Clay sand casting dust removal ash is calcined at 650°C until the clay sand casting dust removal ash completely changes from black to yellow, and then cooled to room temperature. 250 parts by mass of the calcined and cooled clay sand casting dust removal ash are mixed with 75 parts by mass of water glass sand regeneration dust removal ash and 8 parts by mass of calcium hydroxide powder under stirring in a high-speed stirrer at 1250 rpm. The mixture is ground in a ball mill and passed through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0056] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were mixed with 55 parts of aluminum sol having a solid content of 12%, and an appropriate amount of water was added to prepare a slurry having a water content of 45%. The slurry was ultrasonically treated at a frequency of 30 kHz for 1 min.

[0057] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 70 parts of bauxite and 35 parts of foundry waste sand; 3 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 13.5%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0058] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine, and the brick making machine is set to an extrusion pressure of 3.5 MPa and a vacuum degree of -0.09 MPa.

[0059] (5) Drying: Place the finished bricks in a drying chamber and dry them at 23°C for 24 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0060] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 250°C for 3.5 hours, then heated to 1050°C at an average rate of 1.5°C / min and kept for 1.5 hours. Then, they are heated to 1400°C at an average rate of 1.5°C / min and kept for 2.5 hours. After firing, they are gradually cooled to obtain finished bricks.

[0061] Example 4

[0062] The difference between Example 4 and Example 3 is that ultrasonic treatment is not performed in step (2); the other steps are the same.

[0063] Comparative Example 1

[0064] A wear-resistant refractory brick is prepared by the following method:

[0065] (1) Powder preparation: calcining the clay sand casting dust removal ash at 650° C. until the clay sand casting dust removal ash completely changes from black to yellow, cooling to room temperature, grinding the calcined clay sand casting dust removal ash in a ball mill, and passing through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0066] (2) Slurry preparation: 100 parts by mass of the powder prepared in step (1) were mixed with 55 parts of aluminum sol having a solid content of 12%, and an appropriate amount of water was added to prepare a slurry having a water content of 45%. The slurry was ultrasonically treated at a frequency of 30 kHz for 1 min.

[0067] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 70 parts of bauxite and 35 parts of foundry waste sand; 3 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 13.5%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0068] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine, and the brick making machine is set to an extrusion pressure of 3.5 MPa and a vacuum degree of -0.09 MPa.

[0069] (5) Drying: Place the finished bricks in a drying chamber and dry them at 23°C for 24 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0070] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 250°C for 3.5 hours, then heated to 1050°C at an average rate of 1.5°C / min and kept for 1.5 hours. Then, they are heated to 1450°C at an average rate of 1.5°C / min and kept for 2 hours. After firing, they are gradually cooled to obtain finished bricks.

[0071] Comparative Example 2

[0072] A wear-resistant refractory brick is prepared by the following method:

[0073] (1) Powder preparation: Clay sand casting dust removal ash is calcined at 650°C until the clay sand casting dust removal ash completely changes from black to yellow, and then cooled to room temperature. 250 parts by mass of the calcined and cooled clay sand casting dust removal ash are mixed with 75 parts by mass of water glass sand regeneration dust removal ash and 8 parts by mass of calcium hydroxide powder under stirring in a high-speed stirrer at 1250 rpm. The mixture is ground in a ball mill and passed through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0074] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were taken, and an appropriate amount of water was added to prepare a slurry with a water content of 45%. The slurry was subjected to ultrasonic treatment at a frequency of 30 kHz for 1 min.

[0075] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 70 parts of bauxite and 35 parts of foundry waste sand; 3 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 13.5%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0076] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine, and the brick making machine is set to an extrusion pressure of 3.5 MPa and a vacuum degree of -0.09 MPa.

[0077] (5) Drying: Place the finished bricks in a drying chamber and dry them at 23°C for 24 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0078] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 250°C for 3.5 hours, then heated to 1050°C at an average rate of 1.5°C / min and kept for 1.5 hours. Then, they are heated to 1400°C at an average rate of 1.5°C / min and kept for 2.5 hours. After firing, they are gradually cooled to obtain finished bricks.

[0079] Comparative Example 3

[0080] A wear-resistant refractory brick is prepared by the following method:

[0081] (1) Powder preparation: Clay sand casting dust removal ash is calcined at 650°C until the clay sand casting dust removal ash completely changes from black to yellow, and then cooled to room temperature. 250 parts by mass of the calcined and cooled clay sand casting dust removal ash are mixed with 75 parts by mass of water glass sand regeneration dust removal ash and 8 parts by mass of calcium hydroxide powder under stirring in a high-speed stirrer at 1250 rpm. The mixture is ground in a ball mill and passed through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0082] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were mixed with 55 parts of aluminum sol having a solid content of 12%, and an appropriate amount of water was added to prepare a slurry having a water content of 45%. The slurry was ultrasonically treated at a frequency of 30 kHz for 1 min.

[0083] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 35 parts of foundry waste sand; 3 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 13.5%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0084] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine. The brick making machine is set to an extrusion pressure of 3.5 MPa and a vacuum degree of -0.09 MPa.

[0085] (5) Drying: Place the finished bricks in a drying chamber and dry them at 23°C for 24 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0086] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 250°C for 3.5 hours, then heated to 1050°C at an average rate of 1.5°C / min and kept for 1.5 hours. Then, they are heated to 1400°C at an average rate of 1.5°C / min and kept for 2.5 hours. After firing, they are gradually cooled to obtain finished bricks.

[0087] Comparative Example 4

[0088] A wear-resistant refractory brick is prepared by the following method:

[0089] (1) Powder preparation: Clay sand casting dust removal ash is calcined at 650° C. until the clay sand casting dust removal ash completely changes from black to yellow, and then cooled to room temperature. 250 parts by mass of the calcined and cooled clay sand casting dust removal ash are mixed with 45 parts by mass of water glass sand regeneration dust removal ash and 8 parts by mass of calcium hydroxide powder under stirring in a high-speed stirrer at 1250 rpm. The mixture is ground in a ball mill and passed through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0090] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were mixed with 55 parts of aluminum sol having a solid content of 12%, and an appropriate amount of water was added to prepare a slurry having a water content of 45%. The slurry was ultrasonically treated at a frequency of 30 kHz for 1 min.

[0091] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 70 parts of bauxite and 35 parts of foundry waste sand; 3 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 13.5%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0092] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine, and the brick making machine is set to an extrusion pressure of 3.5 MPa and a vacuum degree of -0.09 MPa.

[0093] (5) Drying: Place the finished bricks in a drying chamber and dry them at 23°C for 24 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0094] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 250°C for 3.5 hours, then heated to 1050°C at an average rate of 1.5°C / min and kept for 1.5 hours. Then, they are heated to 1400°C at an average rate of 1.5°C / min and kept for 2.5 hours. After firing, they are gradually cooled to obtain finished bricks.

[0095] Comparative Example 5

[0096] A wear-resistant refractory brick is prepared by the following method:

[0097] (1) Powder preparation: Clay sand casting dust removal ash was calcined at 650°C until the clay sand casting dust removal ash completely turned from black to yellow, and then cooled to room temperature. 250 parts by mass of the calcined and cooled clay sand casting dust removal ash was mixed with 75 parts by mass of water glass sand regeneration dust removal ash and 8 parts by mass of calcium hydroxide powder in a high-speed stirrer at 1250 rpm. The mixture was ground in a ball mill and passed through a 200 mesh sieve to prepare a powder with a particle size of ≤74 μm.

[0098] (2) Slurry preparation: 100 parts of the powder prepared in step (1) were mixed with 55 parts of aluminum sol having a solid content of 12%, and an appropriate amount of water was added to prepare a slurry having a water content of 45%. The slurry was ultrasonically treated at a frequency of 30 kHz for 1 min.

[0099] (3) Preparation of wet material: 100 parts of the ultrasonically treated slurry were mixed evenly with 55 parts of bauxite and 35 parts of foundry waste sand; 3 parts of aluminum dihydrogen phosphate were taken to prepare an aluminum dihydrogen phosphate solution with a mass percentage concentration of 13.5%; and all of the above-mentioned dihydrogen phosphate solution was sprayed into the mixture to prepare the wet material.

[0100] (4) Blank making: The wet material in step (3) is made into brick blanks using a brick making machine. The brick making machine is set to an extrusion pressure of 3.5 MPa and a vacuum degree of -0.09 MPa.

[0101] (5) Drying: Place the finished bricks in a drying chamber and dry them at 23°C for 24 hours. Then, introduce hot air at 60°C until the moisture content in the bricks is ≤2.5%. The moisture content here is measured using a conventional electronic moisture meter.

[0102] (6) Firing: The dried bricks are stacked and sent into the tunnel kiln by a pushing device. They are kept in a preheating zone at 250°C for 3.5 hours, then heated to 1050°C at an average rate of 1.5°C / min and kept for 1.5 hours. Then, they are heated to 1450°C at an average rate of 1.5°C / min and kept for 2 hours. After firing, they are gradually cooled to obtain finished bricks.

[0103] Comparative Example 6

[0104] Wear-resistant refractory bricks purchased in the building materials market.

[0105] Examples 1-4 and Comparative Examples 1-6 were tested for refractoriness, compressive strength, flexural strength, and water absorption. Compressive strength was tested using a conventional fully automatic pressure testing machine. Flexural strength was tested using the conventional three-point bending method. Water absorption was tested using the conventional gravimetric method.

[0106] The main performance test results of the wear-resistant refractory bricks prepared in the above examples and comparative examples are shown in the following table:

[0107] Table 1

[0108] Example Refractoriness (℃) Compressive strength (Mpa) Flexural strength (Mpa) Water absorption (%) Example 1 1550 28.8 5.8 8.3 Example 2 1600 28.5 5.9 8.5 Example 3 1600 30.6 6.6 7.4 Example 4 1580 29.3 6.1 7.9 Comparative Example 1 1550 26.2 5.3 9.1 Comparative Example 2 1400 28.3 5.7 8.8 Comparative Example 3 1300 26.2 5.1 9.6 Comparative Example 4 1480 27.8 5.9 8.9 Comparative Example 5 1350 27.5 5.9 8.6 Comparative Example 6 1450 25.6 5.3 9.2

[0109] The test results of Examples 1-4 and Comparative Examples 1-6 show that the wear-resistant refractory bricks produced by the present invention have a refractoriness of ≥1500°C, a compressive strength of ≥25 MPa, a flexural strength of ≥5 MPa, and a water absorption of ≤8.5%, significantly outperforming the refractory bricks produced in the comparative examples. A comparison of Examples 3 and 4 shows that incorporating an ultrasonic treatment step into the production process of wear-resistant refractory bricks improves the compressive strength, flexural strength, and refractoriness of the bricks. This improvement in compressive and flexural strengths also enhances the wear resistance of the bricks. This is because ultrasonic waves can reduce dust particle agglomeration and promote more uniform coating of the composite sol of aluminum sol and silicate on the surface of the dust particles, resulting in a more uniform and dense brick structure. A comparison of Example 3 and Comparative Example 1 shows that for bricks produced using clay sand casting dust removal ash, water glass and an alkaline environment are key components for brick formation and strength. Comparative Example 4 shows that when water glass is not added or the amount added is outside the range of the present invention, the compressive and flexural strengths of the bricks decrease significantly. The reason for this is that the alkalinity provided by water glass and calcium hydroxide is too low, and the activation ability of the clay sand casting dust ash is insufficient. At the same time, aluminate and silicate cannot form a composite gel, so the bonding between the dust ash particles is insufficient, resulting in a decrease in the compressive and flexural strength of the brick body. The appropriate proportion of water glass components set by the present invention can overcome the above problems. By comparing Example 3 with Comparative Example 2, it can be seen that the addition of aluminum sol to the components of the brick significantly improves the flexural strength of the brick body. In the alkaline environment provided by water glass, the aluminum sol forms a composite gel with silicate, further improving the density of the brick. By comparing Example 3 with Comparative Examples 3 and 5, it can be seen that bauxite is a component that improves the refractory properties of the brick body. Within the appropriate addition range of the present invention, bauxite can greatly improve the refractory properties. Thus, the refractory and wear-resistant bricks of the present invention are prepared by combining water glass regeneration dust ash, calcium hydroxide, aluminum sol, bauxite, foundry waste sand, and clay sand foundry dust ash in a reasonable ratio and the synergistic effect of the above ingredients. The bricks have high uniformity and density, high compressive strength, flexural strength, and wear and fire resistance. At the same time, due to the dense structure, the water absorption capacity is reduced. Thus, the wear-resistant and refractory bricks prepared by the present invention have excellent performance.

[0110] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A wear-resistant refractory brick, characterized in that: The raw materials are composed of slurry, bauxite, foundry waste sand and an aluminum dihydrogen phosphate solution accounting for 1-2% of the mass percentage of the sum of the slurry, bauxite and foundry waste sand in a mass ratio of 10:6-8:3-4, wherein the mass percentage concentration of the aluminum dihydrogen phosphate solution is 12-15%; the slurry is made by mixing powder and aluminum sol in a mass ratio of 10:5-6, and adding water to form a slurry with a moisture content of 40-50%; the powder is made of clay sand casting dust ash, water glass sand regeneration dust ash and calcium hydroxide in a mass ratio of 20-30:5-10:0.5-1.

2. A wear-resistant refractory brick according to claim 1, characterized in that: The mass ratio of the clay sand casting dust ash, the water glass sand regeneration dust ash and the calcium hydroxide is 20-30:5-7.5:0.5-1; and / or the mass ratio of the powder and the aluminum sol is 10:6; and / or the mass ratio of the slurry, the bauxite and the casting waste sand is 10:6-7:3.5-4.

3. A wear-resistant refractory brick according to claim 1, characterized in that: The slurry is subjected to ultrasonic treatment, wherein the frequency of the ultrasonic treatment is 28-32 kHz and the time is 1-2 minutes.

4. A wear-resistant refractory brick according to claim 1, characterized in that: The solid content of the aluminum sol is 10-12%.

5. A method for preparing a wear-resistant refractory brick according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) Powder preparation: calcining the clay sand casting dust ash, cooling it to room temperature, mixing the clay sand casting dust ash with the water glass sand regeneration dust ash and the calcium hydroxide powder in a mass ratio of 20-30:5-10:0.5-1, stirring, grinding, and sieving to prepare a powder; 2) Slurry preparation: mixing the powder prepared in step (1) with the aluminum sol and water, stirring to prepare a slurry with a water content of 40-50%; 3) Wet material preparation: the slurry prepared in step (2) is mixed with the bauxite and the foundry waste sand in a mass ratio of 10:6-8:3-4, and a 12-15% by mass concentration of aluminum dihydrogen phosphate solution is sprayed into the mixture, wherein the amount of the aluminum dihydrogen phosphate solution accounts for 1-2% of the total mass of the slurry, bauxite and foundry waste sand to prepare a wet material; 4) Blank making: the wet material prepared in step (3) is made into brick blanks; 5) Drying: drying the bricks obtained in step (4) at a constant temperature, and then drying them with hot air; 6) Firing: Firing the bricks dried in step (5) to obtain finished bricks.

6. The method for preparing a wear-resistant refractory brick according to claim 5, characterized in that: The method further comprises subjecting the slurry prepared in step 2) to ultrasonic treatment, wherein the frequency of the ultrasonic treatment is 28-32 kHz and the time is 1-2 minutes.

7. The method for preparing a wear-resistant refractory brick according to claim 5, characterized in that: The calcination temperature in step 1) is 600-700° C., the stirring speed is 1000-1500 rpm, and the particle size of the powder is ≤74 μm.

8. The method for preparing a wear-resistant refractory brick according to claim 5, characterized in that: In the step 4), the bricks are formed by vacuum extrusion, the extrusion pressure is 3 to 4 MPa, and the vacuum degree is -0.096 to -0.08 MPa.

9. The method for preparing a wear-resistant refractory brick according to claim 5, characterized in that: The constant temperature drying temperature in step 5) is 20-25° C., and the drying time is 24-36 hours; the hot air drying temperature is 60-80° C., and the drying is stopped when the moisture content of the bricks is ≤2.5%.

10. The method for preparing wear-resistant refractory bricks according to claim 5, characterized in that: The firing process in step 6) is specifically as follows: preheating at 200-300° C. for 3-4 hours, heating to 950-1150° C. and keeping warm for 1-2 hours, heating to 1350-1450° C. and keeping warm for 2-3 hours, and cooling to room temperature to obtain finished bricks.