A preparation method for cordierite lightweight refractory bricks, characterized in that it uses 40-85 wt% porous cordierite ceramic particles, 3-12 wt% magnesite powder, 6-24 wt% Al(OH)3 powder, and 6-24 wt% silica powder as raw materials, plus 3-10 wt% binder of the raw materials, stirred evenly, and mechanically pressed into shape; then the shaped body is dried at 110℃ for 8-36 hours, and then heat-retained at 1300-1410℃ for 2-10 hours to obtain cordierite lightweight refractory bricks; the preparation method of porous cordierite ceramic particles is: mix 8-12 wt% coal gangue powder, 33-37 wt% Al(OH)3 powder, 8-12 wt% talc powder, 13-17 wt% magnesite powder, and 28-32 wt% silica powder, plus 3-12 wt% water of the above mixture, stirred evenly, *** shaped; then the shaped body is dried at 110℃ for 8-36 hours, and then heat-retained at 1300-1400℃ for 1-6 hours to sinter, thus obtaining porous cordierite ceramics; *** crush the porous cordierite ceramics into particles smaller than 8mm to obtain porous cordierite ceramic particles.
The invention will be further described below in conjunction with specific embodiments, without limiting the scope of protection: To avoid repetition, the preparation method of porous cordierite ceramic particles in this specific embodiment is described as follows, and will not be repeated in the examples: The preparation method of porous cordierite ceramic particles is as follows: Mix 8~12wt% of coal gangue powder, 33~37wt% of Al(OH)3 powder, 8~12wt% of talc powder, 13~17wt% of magnesite powder, and 28~32wt% of silica powder, and add 3~12wt% of water to the mixture and stir evenly, *** then shape; then dry the shaped body at 110℃ for 8~36 hours, and then sinter it at 1300~1400℃ for 1~6 hours to obtain porous cordierite ceramics. *** Crush the porous cordierite ceramics to particles smaller than 8mm to obtain porous cordierite ceramic particles.
Example 1: A cordierite lightweight refractory brick and its preparation method. Initially, 50-76 wt% porous cordierite ceramic particles, 6-10 wt% magnesite fine powder, 12-20 wt% Al(OH)3 fine powder, and 12-20 wt% silica fine powder are used as raw materials, with an additional 3-8 wt% *** pulp waste liquid added. The mixture is stirred evenly and then pressed into shape under a pressure of 50-100 MPa. The molded body is then dried at 110°C for 8-16 hours, followed by heat preservation at 1340-1380°C for 3-6 hours, to obtain the cordierite lightweight refractory brick. In this example: the particle size of the magnesite fine powder is less than 50 μm; the particle size of the Al(OH)3 fine powder is less than 50 μm; the particle size of the silica fine powder is less than 25 μm; the apparent porosity of the porous cordierite ceramic particles is 35-40%, with an average pore diameter of 10-20 μm; the particle size distribution ratio of the porous cordierite ceramic particles is as follows: 8-5 mm accounts for 6-12 wt% of the raw materials; 5-3 mm accounts for 18-24 wt% of the raw materials; 3-1 mm accounts for 18-24 wt% of the raw materials; less than 1 mm accounts for 8-16 wt% of the raw materials. The cordierite lightweight refractory brick prepared in this example has an apparent porosity of 30-38%; an average pore diameter of 10-20 μm; a bulk density of 1.56-1.65 g/cm3; and a compressive strength at room temperature of 60-80 MPa.
Example 2: A cordierite lightweight refractory brick and its preparation method. Initially, 50-76 wt% porous cordierite ceramic particles, 6-10 wt% magnesite fine powder, 12-20 wt% Al(OH)3 fine powder, and 12-20 wt% silica fine powder are used as raw materials, with an additional 5-10 wt% silica sol added. The mixture is stirred evenly and then press-formed under a pressure of 80-120 MPa. The molded body is then dried at 110°C for 12-20 hours, and subsequently heat-treated at 1370-1410°C for 4-8 hours to obtain the cordierite lightweight refractory brick. In this example: the particle size of magnesite fine powder is less than 74 μm; the particle size of Al(OH)3 fine powder is less than 88 μm; the particle size of silica fine powder is less than 44 μm; the silica sol concentration is 25-30 wt%; the apparent porosity of porous cordierite ceramic particles is 38-46%, with an average pore diameter of 20-30 μm; the particle size distribution of porous cordierite ceramic particles is as follows: 8-5 mm accounts for 6-12 wt% of the raw materials; 5-3 mm accounts for 18-24 wt% of the raw materials; 3-1 mm accounts for 18-24 wt% of the raw materials; less than 1 mm accounts for 8-16 wt% of the raw materials. The cordierite lightweight refractory brick prepared in this example has an apparent porosity of 38-46%; an average pore diameter of 20-30 μm; a bulk density of 1.40-1.56 g/cm3; and a compressive strength at room temperature of 40-60 MPa.
Example 3: A cordierite lightweight refractory brick and its preparation method. Initially, 40-60 wt% porous cordierite ceramic particles, 8-12 wt% magnesite fine powder, 16-24 wt% Al(OH)3 fine powder, and 16-24 wt% silica fine powder are used as raw materials, along with 3-5 wt% silica sol and 3-5 wt% *** pulp waste liquid added to the raw materials. The mixture is stirred evenly and then press-formed under a pressure of 50-80 MPa. The molded body is then dried at 110°C for 24-36 hours, and subsequently heat-treated at 1320-1380°C for 5-10 hours to obtain the cordierite lightweight refractory brick. In this example: the particle size of magnesite fine powder is less than 88 μm; the particle size of Al(OH)3 fine powder is less than 88 μm; the particle size of silica fine powder is less than 88 μm; the concentration of silica sol is 20-25 wt%; the apparent porosity of porous cordierite ceramic particles is 45-55%, with an average pore diameter of 15-25 μm; the particle size distribution ratio of porous cordierite ceramic particles is as follows: 5-3 mm accounts for 15-22 wt% of the raw materials; 3-1 mm accounts for 15-22 wt% of the raw materials; less than 1 mm accounts for 10-16 wt% of the raw materials. The cordierite lightweight refractory brick prepared in this example has an apparent porosity of 46-54%; an average pore diameter of 15-25 μm; a bulk density of 1.29-1.40 g/cm3; and a compressive strength at room temperature of 25-55 MPa.
Example 4: A cordierite lightweight refractory brick and its preparation method. Initially, 65-85 wt% porous cordierite ceramic particles, 3-7 wt% magnesite fine powder, 6-14 wt% Al(OH)3 fine powder, and 6-14 wt% silica fine powder are used as raw materials, with an additional 5-10 wt% *** paper pulp waste liquid added. The mixture is stirred evenly and then pressed into shape under a pressure of 80-120 MPa. The molded body is then dried at 110°C for 12-20 hours, and subsequently heat-treated at 1300-1350°C for 4-8 hours to obtain the cordierite lightweight refractory brick. In this example: the particle size of the magnesite fine powder is less than 44 μm; the particle size of the Al(OH)3 fine powder is less than 74 μm; the particle size of the silica fine powder is less than 44 μm; the porous cordierite ceramic particles have a porosity of 35-42% and an average pore diameter of 10-20 μm; the particle size distribution of the porous cordierite ceramic particles is as follows: 5-3 mm accounts for 20-30 wt% of the raw materials; 3-1 mm accounts for 25-30 wt% of the raw materials; less than 1 mm accounts for 20-25 wt% of the raw materials. The cordierite lightweight refractory brick prepared in this example has a porosity of 34-44%; an average pore diameter of 10-20 μm; a bulk density of 1.40-1.60 g/cm3; and a compressive strength at room temperature of 50-70 MPa.
Example 5: A cordierite lightweight refractory brick and its preparation method. Initially, 65-85 wt% porous cordierite ceramic particles, 3-7 wt% magnesite powder, 6-14 wt% Al(OH)3 powder, and 6-14 wt% silica powder are used as raw materials, with an additional 6-10 wt% silica sol added. The mixture is stirred evenly and then press-formed under a pressure of 50-80 MPa. The molded body is then dried at 110℃ for 16-24 hours, and subsequently heat-treated at 1300-1350℃ for 2-6 hours to obtain the cordierite lightweight refractory brick. In this example: the particle size of magnesite powder is less than 88 μm; the particle size of Al(OH)3 powder is less than 88 μm; the particle size of silica powder is less than 74 μm; the silica sol concentration is 30-35 wt%; the apparent porosity of porous cordierite ceramic particles is 48-55%, with an average pore diameter of 20-30 μm; the particle size distribution of porous cordierite ceramic particles is as follows: 3-1 mm particles account for 45-60 wt% of the raw materials, and particles smaller than 1 mm account for 20-25 wt% of the raw materials. The cordierite lightweight refractory brick prepared in this example has an apparent porosity of 46-55%; an average pore diameter of 20-30 μm; a bulk density of 1.28-1.34 g/cm3; and a compressive strength at room temperature of 20-40 MPa.
Example 6: A cordierite lightweight refractory brick and its preparation method. Initially, 50-76 wt% porous cordierite ceramic particles, 6-10 wt% magnesite fine powder, 12-20 wt% Al(OH)3 fine powder, and 12-20 wt% silica fine powder are used as raw materials, with an additional 3-8 wt% silica sol added. The mixture is stirred evenly and then pressed into shape under a pressure of 100-150 MPa. The molded body is then dried at 110°C for 8-16 hours, followed by heat preservation at 1360-1410°C for 6-10 hours, to obtain the cordierite lightweight refractory brick. In this example: the particle size of magnesite fine powder is less than 74 μm; the particle size of Al(OH)3 fine powder is less than 44 μm; the particle size of silica fine powder is less than 60 μm; the silica sol concentration is 35-40 wt%; the apparent porosity of porous cordierite ceramic particles is 35-40%, with an average pore diameter of 10-20 μm; the particle size distribution ratio of porous cordierite ceramic particles is as follows: 8-5 mm accounts for 6-12 wt% of the raw materials; 5-3 mm accounts for 18-24 wt% of the raw materials; 3-1 mm accounts for 18-24 wt% of the raw materials; less than 1 mm accounts for 8-16 wt% of the raw materials. The cordierite lightweight refractory brick prepared in this example has an apparent porosity of 30-35%; an average pore diameter of 10-20 μm; a bulk density of 1.60-1.65 g/cm3; and a compressive strength at room temperature of 70-100 MPa. This specific embodiment utilizes porous cordierite ceramic particles produced by the technology of "A porous cordierite ceramic material and its preparation method (CN201110038289.2)"*** applied by the applicant. Using the produced porous cordierite ceramic particles as aggregates, and magnesite, Al(OH)3, and silica fine powder as the matrix, a porous structure is formed in the matrix through the self-decomposition of magnesite and Al(OH)3. The MgO and Al2O3 generated from the decomposition of magnesite and Al(OH)3 form high-purity porous cordierite in situ with silica, preparing cordierite lightweight refractory bricks bonded with high-purity porous cordierite and porous cordierite ceramic aggregates.
This method ensures that the prepared material possesses both high strength and thermal insulation properties, as well as excellent thermal shock resistance and resistance to medium erosion. The main chemical components of the cordierite lightweight refractory brick prepared in this specific embodiment are MgO, Al2O3, and SiO2, with the main crystalline phase being cordierite. The apparent porosity is 30~55%, the average pore size is 10~30μm, the bulk density is 1.28~1.65 g/cm3, and the compressive strength at room temperature is 20~100MPa. Therefore, this specific embodiment features controllable apparent porosity and pore size of the aggregate and matrix, environmental friendliness, and small volume changes after firing. The prepared cordierite lightweight refractory brick exhibits advantages such as high apparent porosity, small average pore size, high strength, low thermal conductivity, good thermal shock resistance, and strong resistance to medium erosion. This lightweight refractory brick is suitable for use as the *** layer and working layer of high-temperature kilns or containers with operating temperatures below 1380℃.
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