Lightweight wear-resistant heat-insulating composite brick for rotary kiln and preparation method thereof

Abstract

The application discloses a light-weight wear-resistant heat-insulating composite brick for a rotary kiln and a preparation method thereof, and belongs to the technical field of composite brick preparation, which comprises a heat-insulating base layer, the lower end of the heat-insulating base layer is fixedly connected with a light-weight refractory layer, the upper and lower outer walls of the heat-insulating base layer are each provided with an arc-shaped groove, a connecting column is arranged between the two heat-insulating base layers in connection, and the connecting column is located in the arc-shaped groove; the preparation method comprises the following steps of S1, raw material mixing; S2, pressing of a brick blank; S3, preparation of the connecting column; and S4, sintering; the heat-insulating base layer of the composite brick has strong heat-insulating performance, can effectively lock the heat of the rotary kiln, reduces heat loss of the rotary kiln, the light-weight refractory layer is light in weight and is not prone to falling off and cracking, and has high wear resistance and fire resistance.

Description

Technical Field

[0001] This invention relates to the field of composite brick preparation technology, specifically to a lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns and its preparation method. Background Technology

[0002] A rotary kiln is a large-scale piece of equipment widely used in many production industries such as building materials, metallurgy, chemicals, and environmental protection. It is a rotary calcining device, typically composed of a kiln shell, kiln head, kiln tail, transmission device, and support device. The main function of a rotary kiln is to subject solid materials to chemical reactions such as calcination, sintering, and melting under high-temperature conditions to produce the desired products.

[0003] The working principle of a rotary kiln is as follows: Material enters the kiln from the kiln head. As the kiln rotates, the material is continuously tumbled and mixed, and comes into full contact with the air inside the kiln, thus achieving a chemical reaction. Simultaneously, the temperature inside the kiln shell continuously rises, and the material is gradually sintered and melted. At the kiln tail, after cooling and separation, the desired product is obtained.

[0004] Composite bricks for rotary kilns are brick structures composed of multiple layers of bricks made of different materials. The design of composite bricks can effectively improve the wear resistance, corrosion resistance, and high-temperature resistance of the kiln lining, thereby extending the service life of the kiln and reducing maintenance and replacement costs. However, the existing composite bricks for rotary kilns have unsatisfactory heat insulation performance, leading to heat loss inside the rotary kiln and increased energy consumption. The composite bricks also have poor wear resistance and thermal shock resistance, making them prone to cracking. During the rotation of the rotary kiln, the upper and lower composite bricks are subjected to uneven stress, which can easily cause problems such as falling off, resulting in a reduced service life of the composite bricks. Therefore, there is a need for a lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns and its preparation method.

[0006] The technical solution of the present invention is: a lightweight wear-resistant and heat-insulating composite brick for rotary kilns, comprising a heat-insulating base layer, a lightweight refractory layer fixedly connected to the lower end of the heat-insulating base layer, an arc-shaped groove provided on each of the upper and lower outer walls of the heat-insulating base layer, and a connecting column provided between two connected heat-insulating base layers, the connecting column being located in the arc-shaped groove;

[0007] The heat insulation base layer is composed of the following components in parts by weight: 10-15 parts fine silica powder, 4-7 parts aluminum silicate, 3-5 parts aluminum silicate fiber, and 1-3 parts polyacrylamide.

[0008] The lightweight refractory layer is composed of the following components by weight: 4-7 parts of cenospheres, 5-8 parts of alumina hollow spheres, 2-5 parts of zirconia hollow spheres, 6-9 parts of expanded perlite, 3-7 parts of dolomite powder, and 7-12 parts of kaolin.

[0009] The connecting column is composed of the following components in parts by weight: 2-5 parts composite fiber, 1-3 parts expanded vermiculite, 2-7 parts alumina powder, and 3-5 parts magnesium oxide.

[0010] Furthermore, the composite fiber in the connecting column is composed of the following components in parts by weight: 1-2 parts alumina fiber, 0.5-1.5 parts carbon fiber, and 0.5-1.5 parts graphite fiber. The alumina fiber has a length of 2-3 cm, the carbon fiber has a length of 1-3 cm, the graphite fiber has a length of 0.5-2 cm, the expanded vermiculite has a particle size of 0.5-1.5 mm, the alumina powder has a particle size of 60-80 μm, and the magnesium oxide has a particle size of 20-60 μm.

[0011] Note: The connecting column prepared by the length of the composite fiber and the particle size of each powder has good high temperature resistance and high strength under stress.

[0012] Furthermore, the silica fine powder in the heat insulation base layer has a particle size of 40-80μm, the aluminum silicate has a particle size of 80-120μm, the aluminum silicate fiber has a length of 1-2cm, and the polyacrylamide has a particle size of 20-30μm.

[0013] Note: The particle size of each powder in the above-mentioned heat insulation base layer can effectively enhance the stress strength and heat insulation performance of the heat insulation base layer, and reduce the heat loss of the rotary kiln.

[0014] Furthermore, the lightweight refractory layer contains cenospheres with a particle size of 1-2 mm, hollow alumina spheres with a particle size of 0.5-1 mm, hollow zirconia spheres with a particle size of 1-1.5 mm, expanded perlite with a particle size of 1-2 mm, dolomite powder with a particle size of 20-40 μm, and kaolin with a particle size of 60-100 μm.

[0015] Note: The particle size of the above-mentioned lightweight refractory materials can effectively reduce the weight of the lightweight refractory layer and reduce the risk of the lightweight refractory layer falling off.

[0016] Furthermore, the preparation method of the above-mentioned lightweight wear-resistant and heat-insulating composite brick for rotary kilns includes the following steps:

[0017] S1. Raw material mixing:

[0018] Fine silica powder, aluminum silicate, aluminum silicate fiber, and polyacrylamide are mixed in a mixer according to the above proportions to obtain heat insulation base powder. Cenospheres, hollow alumina spheres, hollow zirconia spheres, expanded perlite, dolomite powder, and kaolin are mixed in a material exchanger to obtain lightweight refractory layer powder. Composite fibers, expanded vermiculite, alumina powder, and magnesium oxide are mixed in a mixer according to the above proportions to obtain connecting column powder.

[0019] S2. Pressing brick blanks:

[0020] The heat insulation base powder and the lightweight refractory layer powder are poured into the heat insulation base cavity and the lightweight refractory cavity of the mold, respectively. After pouring, the middle partition is removed, and then the brick blank is pressed by a press. After pressing, the brick blank is obtained.

[0021] S3. Preparation of the connecting column:

[0022] Place the connecting column powder into the rubber sleeve and compact it repeatedly 5-8 times. Then, put it into a cold isostatic press for pressing. After pressing, remove the rubber sleeve to obtain the connecting column blank.

[0023] S4, Sintering:

[0024] The brick blanks obtained in step S2 and the connecting column blanks obtained in step S3 are respectively placed in a sintering furnace for high-temperature sintering. The sintering temperature of the brick blanks is 1300-1600℃ and the sintering time is 8-12h. The sintering temperature of the connecting column blanks is 1500-1700℃ and the sintering time is 5-8h. After sintering, composite bricks and connecting columns are obtained.

[0025] Note: The composite bricks prepared in the above manner have high fire resistance and thermal shock resistance, and can effectively reduce heat loss in rotary kilns.

[0026] Furthermore, the mold includes a mold shell, the interior of which is provided with a heat-insulating base cavity and a lightweight refractory cavity, a partition is movably inserted between the heat-insulating base cavity and the lightweight refractory cavity, an arc-shaped protrusion is fixedly connected to the bottom of the mold shell, a pressure plate is provided to the top of the mold shell, and an arc-shaped protrusion is fixedly connected to the lower surface of the pressure plate.

[0027] Note: The above mold can improve the molding strength of composite bricks and enhance the connection reliability between the heat insulation base layer and the lightweight refractory layer.

[0028] Furthermore, in step S2, the pressing pressure of the press is 2.4-2.6 MPa, and the pressing number is 3-5 times. In step S3, the working pressure of the cold isostatic press is 8.5-9.3 MPa, and the pressing time is 20-30 minutes.

[0029] Note: Under the above pressing parameters, the composite brick has high strength, good thermal shock resistance, and is not easy to crack or fall off. The connecting column has high strength, which can effectively distribute the weight of the composite brick and effectively enhance the impact resistance and wear resistance of the composite brick.

[0030] Furthermore, in step S1, the mixing speed of the mixer during the mixing of the heat insulation base layer powder is 80-100 r / min, and the mixing time is 20-30 min; the mixing speed of the mixer during the mixing of the lightweight refractory layer powder is 60-80 r / min, and the mixing time is 40-60 min; and the mixing time of the connecting column powder is 100-120 r / min, and the mixing time is 5-10 min.

[0031] Note: Under the above mixing parameters, the mixing efficiency of the heat insulation base layer material, the lightweight refractory layer powder, and the connecting column powder is high, and the mixing effect is good.

[0032] Furthermore, in the above-mentioned installation method of lightweight wear-resistant heat-insulating composite bricks for rotary kilns, the heat-insulating base layer of the composite bricks is fixedly connected to the inner wall of the rotary kiln by anchors. When laying the composite bricks, the bottom of the rotary kiln is laid first, and then they are laid out to both sides in sequence until a ring of inner wall is laid. After the surface of the connecting column is coated with adhesive, it is inserted into the arc groove between two adjacent composite bricks. The adhesive coating thickness is 0.5-1cm. Then the second ring of inner wall is laid until the entire rotary kiln is laid.

[0033] Note: The above method is highly efficient for installing composite bricks, thus improving the overall installation efficiency.

[0034] Furthermore, the adhesive is composed of the following components in parts by weight: 7-10 parts high-alumina cement, 1-3 parts phenolic resin, 4-5 parts alumina powder, and 6-8 parts water.

[0035] Note: The above adhesive can effectively reduce the fixing of the connecting column and the composite brick, and reduce the risk of individual composite bricks falling off.

[0036] The beneficial effects of this invention are:

[0037] (1) Compared with existing composite bricks, the composite bricks of the present invention connect two adjacent composite bricks through connecting columns, so that the composite brick layer of the rotary kiln forms a whole, reducing the risk of individual composite bricks falling off, enhancing the impact resistance of composite bricks, and improving installation efficiency.

[0038] (2) The heat insulation performance of the brick insulation base layer of the present invention is strong, which can effectively lock the heat of the rotary kiln and reduce the heat loss of the rotary kiln. The lightweight refractory layer is lightweight and not easy to fall off or crack, and has high wear resistance and fire resistance. Attached Figure Description

[0039] Figure 1This is a top view of the composite brick of the present invention.

[0040] Figure 2 This is a right view of the composite brick of the present invention.

[0041] Figure 3 This is a top view of the mold of the present invention.

[0042] Figure 4 This is a right view of the mold of the present invention.

[0043] Among them, 1-heat insulation base layer, 2-lightweight fire-resistant layer, 3-arc groove, 4-connecting column, 5-mold shell, 6-heat insulation base cavity, 7-lightweight fire-resistant cavity, 8-partition, 9-pressure plate, 51-arc protrusion one, 91-arc protrusion two. Detailed Implementation

[0044] Example 1:

[0045] like Figure 1-2 As shown, a lightweight wear-resistant and heat-insulating composite brick for rotary kilns includes a heat-insulating base layer 1, a lightweight refractory layer 2 fixedly connected to the lower end of the heat-insulating base layer 1, an arc-shaped groove 3 on each of the upper and lower outer walls of the heat-insulating base layer 1, and a connecting column 4 between two connected heat-insulating base layers 1, with the connecting column 4 located in the arc-shaped groove 3.

[0046] The heat insulation base layer 1 is composed of the following components by weight: 10 parts fine silica powder, 4 parts aluminum silicate, 3 parts aluminum silicate fiber, and 1 part polyacrylamide.

[0047] The lightweight refractory layer 2 is composed of the following components by weight: 4 parts cenospheres, 5 parts alumina hollow spheres, 2 parts zirconia hollow spheres, 6 parts expanded perlite, 3 parts dolomite powder, and 7 parts kaolin.

[0048] The connecting column 4 is composed of the following components by weight: 2 parts composite fiber, 1 part expanded vermiculite, 2 parts alumina powder, and 3 parts magnesium oxide.

[0049] The composite fiber in connecting column 4 is composed of the following components by weight: 1 part alumina fiber, 0.5 parts carbon fiber, 0.5 parts graphite fiber, the alumina fiber is 2 cm long, the carbon fiber is 1 cm long, the graphite fiber is 0.5-2 cm long, the expanded vermiculite has a particle size of 0.5 mm, the alumina powder has a particle size of 60-80 μm, and the magnesium oxide has a particle size of 20-60 μm.

[0050] The insulating base layer 1 contains silica fine powder with a particle size of 40-80μm, aluminum silicate with a particle size of 80-120μm, aluminum silicate fiber with a length of 1cm, and polyacrylamide with a particle size of 20-30μm.

[0051] In the lightweight refractory layer 2, the particle size of the cenospheres is 1mm, the particle size of the alumina hollow spheres is 0.5mm, the particle size of the zirconia hollow spheres is 1mm, the particle size of the expanded perlite is 1mm, the particle size of the dolomite powder is 20-40μm, and the particle size of the kaolin is 60-100μm.

[0052] Example 2:

[0053] like Figure 1-2 As shown, a lightweight wear-resistant and heat-insulating composite brick for rotary kilns includes a heat-insulating base layer 1, a lightweight refractory layer 2 fixedly connected to the lower end of the heat-insulating base layer 1, an arc-shaped groove 3 on each of the upper and lower outer walls of the heat-insulating base layer 1, and a connecting column 4 between two connected heat-insulating base layers 1, with the connecting column 4 located in the arc-shaped groove 3.

[0054] The heat insulation base layer 1 is composed of the following components by weight: 13 parts fine silica powder, 6 parts aluminum silicate, 4 parts aluminum silicate fiber, and 2 parts polyacrylamide.

[0055] The lightweight refractory layer 2 is composed of the following components by weight: 5 parts cenospheres, 6 parts alumina hollow spheres, 4 parts zirconia hollow spheres, 8 parts expanded perlite, 5 parts dolomite powder, and 10 parts kaolin.

[0056] The connecting column 4 is composed of the following components in parts by weight: 3.1 parts composite fiber, 2 parts expanded vermiculite, 5 parts alumina powder, and 4 parts magnesium oxide.

[0057] The composite fiber in connecting column 4 is composed of the following components by weight: 1.5 parts alumina fiber, 0.8 parts carbon fiber, and 0.8 parts graphite fiber. The length of the alumina fiber is 2.5 cm, the length of the carbon fiber is 2 cm, the length of the graphite fiber is 0.8 cm, the particle size of the expanded vermiculite is 0.8 mm, the particle size of the alumina powder is 60-80 μm, and the particle size of the magnesium oxide is 20-60 μm.

[0058] The insulating base layer 1 contains silica fine powder with a particle size of 40-80μm, aluminum silicate with a particle size of 80-120μm, aluminum silicate fiber with a length of 1.5cm, and polyacrylamide with a particle size of 20-30μm.

[0059] In the lightweight refractory layer 2, the particle size of the cenospheres is 1.5 mm, the particle size of the alumina hollow spheres is 0.8 mm, the particle size of the zirconia hollow spheres is 1.3 mm, the particle size of the expanded perlite is 1.5 mm, the particle size of the dolomite powder is 20-40 μm, and the particle size of the kaolin is 60-100 μm.

[0060] Example 3:

[0061] like Figure 1-2As shown, a lightweight wear-resistant and heat-insulating composite brick for rotary kilns includes a heat-insulating base layer 1, a lightweight refractory layer 2 fixedly connected to the lower end of the heat-insulating base layer 1, an arc-shaped groove 3 on each of the upper and lower outer walls of the heat-insulating base layer 1, and a connecting column 4 between two connected heat-insulating base layers 1, with the connecting column 4 located in the arc-shaped groove 3.

[0062] The heat insulation base layer 1 is composed of the following components by weight: 15 parts fine silica powder, 7 parts aluminum silicate, 5 parts aluminum silicate fiber, and 3 parts polyacrylamide.

[0063] The lightweight refractory layer 2 is composed of the following components by weight: 7 parts cenospheres, 8 parts alumina hollow spheres, 5 parts zirconia hollow spheres, 9 parts expanded perlite, 7 parts dolomite powder, and 12 parts kaolin.

[0064] The connecting column 4 is composed of the following components by weight: 5 parts composite fiber, 3 parts expanded vermiculite, 7 parts alumina powder, and 5 parts magnesium oxide.

[0065] The composite fiber in the connecting column 4 is composed of the following components by weight: 2 parts alumina fiber, 1.5 parts carbon fiber, 1.5 parts graphite fiber, the alumina fiber is 3 cm long, the carbon fiber is 3 cm long, the graphite fiber is 2 cm long, the expanded vermiculite particle size is 1.5 mm, the alumina powder particle size is 60-80 μm, and the magnesium oxide particle size is 20-60 μm.

[0066] The insulating base layer 1 contains silica fine powder with a particle size of 40-80μm, aluminum silicate with a particle size of 80-120μm, aluminum silicate fiber with a length of 2cm, and polyacrylamide with a particle size of 20-30μm.

[0067] In the lightweight refractory layer 2, the particle size of the cenospheres is 2mm, the particle size of the alumina hollow spheres is 1mm, the particle size of the zirconia hollow spheres is 1.5mm, the particle size of the expanded perlite is 2mm, the particle size of the dolomite powder is 20-40μm, and the particle size of the kaolin is 60-100μm.

[0068] Comparing Examples 1-3, the composite brick prepared in Example 3 exhibits the best high-temperature resistance, wear resistance, and thermal shock resistance; therefore, Example 3 is the optimal example.

[0069] Example 4:

[0070] Based on Example 3, Example 4 provides a method for preparing lightweight, wear-resistant, and heat-insulating composite bricks for rotary kilns, comprising the following steps:

[0071] S1. Raw material mixing:

[0072] Fine silica powder, aluminum silicate, aluminum silicate fiber, and polyacrylamide are mixed in a mixer according to the above proportions to obtain heat insulation base powder. Cenospheres, hollow alumina spheres, hollow zirconia spheres, expanded perlite, dolomite powder, and kaolin are mixed in a material exchanger to obtain lightweight refractory layer powder. Composite fibers, expanded vermiculite, alumina powder, and magnesium oxide are mixed in a mixer according to the above proportions to obtain connecting column powder.

[0073] S2. Pressing brick blanks:

[0074] The heat insulation base powder and the lightweight refractory layer powder are poured into the heat insulation base cavity 6 and the lightweight refractory cavity 7 in the mold, respectively. After pouring, the middle partition 8 is removed, and then the brick blank is pressed by a press. After pressing, the brick blank is obtained.

[0075] S3, Preparation of connecting column 4:

[0076] The connecting column powder is placed into the rubber sleeve and compacted repeatedly 5 times. Then it is placed into a cold isostatic press for pressing. After pressing, the rubber sleeve is removed to obtain the connecting column blank.

[0077] S4, Sintering:

[0078] The brick blanks obtained in step S2 and the connecting column blanks obtained in step S3 are respectively placed in a sintering furnace for high-temperature sintering. The sintering temperature of the brick blanks is 1300℃ and the sintering time is 8h. The sintering temperature of the connecting column blanks is 1500℃ and the sintering time is 5h. After sintering, composite bricks and connecting columns 4 are obtained.

[0079] like Figure 3-4 As shown, the mold includes a mold shell 5. The interior of the mold shell 5 is provided with a heat-insulating base cavity 6 and a lightweight refractory cavity 7. A partition 8 is movably inserted between the heat-insulating base cavity 6 and the lightweight refractory cavity 7. An arc-shaped protrusion 51 is fixedly connected to the bottom of the mold shell 5. A pressure plate 9 is provided on the top of the mold shell 5. An arc-shaped protrusion 91 is fixedly connected to the lower surface of the pressure plate 9.

[0080] In step S2, the pressing pressure of the press is 2.4 MPa, and the pressing is performed 3 times. In step S3, the working pressure of the cold isostatic press is 8.5 MPa, and the pressing time is 20 minutes.

[0081] In step S1, the mixing speed of the mixer is 80 r / min and the mixing time is 20 min when mixing the thermal insulation base powder; the mixing speed of the mixer is 60 r / min and the mixing time is 40 min when mixing the lightweight refractory layer powder; and the mixing time of the connecting column powder is 100 r / min and the mixing time is 5 min when mixing the connecting column powder.

[0082] Example 5:

[0083] Based on Example 3, Example 5 provides a method for preparing lightweight, wear-resistant, and heat-insulating composite bricks for rotary kilns, comprising the following steps:

[0084] S1. Raw material mixing:

[0085] Fine silica powder, aluminum silicate, aluminum silicate fiber, and polyacrylamide are mixed in a mixer according to the above proportions to obtain heat insulation base powder. Cenospheres, hollow alumina spheres, hollow zirconia spheres, expanded perlite, dolomite powder, and kaolin are mixed in a material exchanger to obtain lightweight refractory layer powder. Composite fibers, expanded vermiculite, alumina powder, and magnesium oxide are mixed in a mixer according to the above proportions to obtain connecting column powder.

[0086] S2. Pressing brick blanks:

[0087] The heat insulation base powder and the lightweight refractory layer powder are poured into the heat insulation base cavity 6 and the lightweight refractory cavity 7 in the mold, respectively. After pouring, the middle partition 8 is removed, and then the brick blank is pressed by a press. After pressing, the brick blank is obtained.

[0088] S3, Preparation of connecting column 4:

[0089] The connecting column powder is placed into the rubber sleeve and compacted repeatedly 7 times. Then it is placed into a cold isostatic press for pressing. After pressing, the rubber sleeve is removed to obtain the connecting column blank.

[0090] S4, Sintering:

[0091] The brick blanks obtained in step S2 and the connecting column blanks obtained in step S3 are respectively placed in a sintering furnace for high-temperature sintering. The sintering temperature of the brick blanks is 1500℃ and the sintering time is 10h. The sintering temperature of the connecting column blanks is 1600℃ and the sintering time is 7h. After sintering, composite bricks and connecting columns 4 are obtained.

[0092] like Figure 3-4 As shown, the mold includes a mold shell 5. The interior of the mold shell 5 is provided with a heat-insulating base cavity 6 and a lightweight refractory cavity 7. A partition 8 is movably inserted between the heat-insulating base cavity 6 and the lightweight refractory cavity 7. An arc-shaped protrusion 51 is fixedly connected to the bottom of the mold shell 5. A pressure plate 9 is provided on the top of the mold shell 5. An arc-shaped protrusion 91 is fixedly connected to the lower surface of the pressure plate 9.

[0093] In step S2, the pressing pressure of the press is 2.5 MPa, and the pressing is performed 4 times. In step S3, the working pressure of the cold isostatic press is 9 MPa, and the pressing time is 25 minutes.

[0094] In step S1, the mixing speed of the mixer is 90 r / min and the mixing time is 25 min when mixing the thermal insulation base powder; the mixing speed of the mixer is 70 r / min and the mixing time is 50 min when mixing the lightweight refractory layer powder; and the mixing time of the connecting column powder is 110 r / min and the mixing time is 9 min when mixing the connecting column powder.

[0095] Example 6:

[0096] Based on Example 3, Example 6 provides a method for preparing lightweight, wear-resistant, and heat-insulating composite bricks for rotary kilns, comprising the following steps:

[0097] S1. Raw material mixing:

[0098] Fine silica powder, aluminum silicate, aluminum silicate fiber, and polyacrylamide are mixed in a mixer according to the above proportions to obtain heat insulation base powder. Cenospheres, hollow alumina spheres, hollow zirconia spheres, expanded perlite, dolomite powder, and kaolin are mixed in a material exchanger to obtain lightweight refractory layer powder. Composite fibers, expanded vermiculite, alumina powder, and magnesium oxide are mixed in a mixer according to the above proportions to obtain connecting column powder.

[0099] S2. Pressing brick blanks:

[0100] The heat insulation base powder and the lightweight refractory layer powder are poured into the heat insulation base cavity 6 and the lightweight refractory cavity 7 in the mold, respectively. After pouring, the middle partition 8 is removed, and then the brick blank is pressed by a press. After pressing, the brick blank is obtained.

[0101] S3, Preparation of connecting column 4:

[0102] The connecting column powder is placed into the rubber sleeve and compacted repeatedly 8 times. Then it is placed into a cold isostatic press for pressing. After pressing, the rubber sleeve is removed to obtain the connecting column blank.

[0103] S4, Sintering:

[0104] The brick blanks obtained in step S2 and the connecting column blanks obtained in step S3 are respectively placed in a sintering furnace for high-temperature sintering. The sintering temperature of the brick blanks is 1600℃ and the sintering time is 12h. The sintering temperature of the connecting column blanks is 1700℃ and the sintering time is 8h. After sintering, composite bricks and connecting columns 4 are obtained.

[0105] like Figure 3-4 As shown, the mold includes a mold shell 5. The interior of the mold shell 5 is provided with a heat-insulating base cavity 6 and a lightweight refractory cavity 7. A partition 8 is movably inserted between the heat-insulating base cavity 6 and the lightweight refractory cavity 7. An arc-shaped protrusion 51 is fixedly connected to the bottom of the mold shell 5. A pressure plate 9 is provided on the top of the mold shell 5. An arc-shaped protrusion 91 is fixedly connected to the lower surface of the pressure plate 9.

[0106] In step S2, the pressing pressure of the press is 2.6 MPa, and the pressing number is 5. In step S3, the working pressure of the cold isostatic press is 9.3 MPa, and the pressing time is 30 minutes.

[0107] In step S1, the mixing speed of the mixer is 100 r / min and the mixing time is 30 min when mixing the thermal insulation base powder; the mixing speed of the mixer is 80 r / min and the mixing time is 60 min when mixing the lightweight refractory layer powder; and the mixing time of the connecting column powder is 120 r / min and the mixing time is 10 min.

[0108] Compared with Examples 4-6, the lightweight wear-resistant and heat-insulating composite brick prepared in Example 5 has the best heat insulation performance, fire resistance and thermal shock resistance. Therefore, Example 5 is the best example.

[0109] Example 7:

[0110] Based on Example 3, Example 7 provides an installation method for lightweight wear-resistant heat-insulating composite bricks for rotary kilns. The heat-insulating base layer 1 of the composite bricks is fixedly connected to the inner wall of the rotary kiln by anchors. When laying the composite bricks, the bottom of the rotary kiln is laid first, and then they are laid out to both sides in sequence until a ring-shaped inner wall is laid. After the surface of the connecting column 4 is coated with adhesive, it is inserted into the arc-shaped groove 3 between two adjacent composite bricks. The adhesive coating thickness is 0.5cm. Then the second ring-shaped inner wall is laid until the entire rotary kiln is laid.

[0111] The adhesive consists of the following components by weight: 7 parts high-alumina cement, 1 part phenolic resin, 4 parts alumina powder, and 6 parts water.

[0112] Example 8:

[0113] Based on Example 7, Example 8 differs from Example 7 in that the adhesive coating thickness is 0.8 cm, and the adhesive is composed of the following components by weight: 8 parts high-alumina cement, 2 parts phenolic resin, 4.5 parts alumina powder, and 7 parts water.

[0114] Example 9:

[0115] Based on Example 7, Example 9 differs from Example 7 in that the adhesive coating thickness is 1 cm, and the adhesive is composed of the following components by weight: 10 parts high-alumina cement, 3 parts phenolic resin, 5 parts alumina powder, and 8 parts water.

[0116] Comparing Examples 7-9, Example 9 showed the best installation effect, with the composite brick having a long service life and the best impact resistance.

Claims

1. A lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns, characterized in that, It includes a heat insulation base layer (1), a lightweight fire-resistant layer (2) is fixedly connected to the lower end of the heat insulation base layer (1), and an arc-shaped groove (3) is provided on the upper and lower outer walls of the heat insulation base layer (1). A connecting column (4) is provided between two connected heat insulation base layers (1), and the connecting column (4) is located in the arc-shaped groove (3). The heat insulation base layer (1) is composed of the following components in parts by weight: 10-15 parts fine silica powder, 4-7 parts aluminum silicate, 3-5 parts aluminum silicate fiber, and 1-3 parts polyacrylamide. The lightweight refractory layer (2) is composed of the following components in parts by weight: 4-7 parts of cenospheres, 5-8 parts of alumina hollow spheres, 2-5 parts of zirconia hollow spheres, 6-9 parts of expanded perlite, 3-7 parts of dolomite powder, and 7-12 parts of kaolin. The connecting column (4) is composed of the following components in parts by weight: 2-5 parts composite fiber, 1-3 parts expanded vermiculite, 2-7 parts alumina powder, and 3-5 parts magnesium oxide.

2. The lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns as described in claim 1, characterized in that, The composite fiber in the connecting column (4) is composed of the following components in parts by weight: 1-2 parts alumina fiber, 0.5-1.5 parts carbon fiber, 0.5-1.5 parts graphite fiber, wherein the length of the alumina fiber is 2-3 cm, the length of the carbon fiber is 1-3 cm, the length of the graphite fiber is 0.5-2 cm, the particle size of the expanded vermiculite is 0.5-1.5 mm, the particle size of the alumina powder is 60-80 μm, and the particle size of the magnesium oxide is 20-60 μm.

3. The lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns as described in claim 1, characterized in that, The heat insulation base layer (1) contains silica fine powder with a particle size of 40-80μm, aluminum silicate with a particle size of 80-120μm, aluminum silicate fiber with a length of 1-2cm, and polyacrylamide with a particle size of 20-30μm.

4. The lightweight, wear-resistant, and heat-insulating composite brick for rotary kilns as described in claim 1, characterized in that, The lightweight refractory layer (2) contains cenospheres with a particle size of 1-2 mm, hollow alumina spheres with a particle size of 0.5-1 mm, hollow zirconia spheres with a particle size of 1-1.5 mm, expanded perlite with a particle size of 1-2 mm, dolomite powder with a particle size of 20-40 μm, and kaolin with a particle size of 60-100 μm.

5. The method for preparing a lightweight, wear-resistant, and heat-insulating composite brick for a rotary kiln as described in claim 1, characterized in that, Includes the following steps: S1. Raw material mixing: Fine silica powder, aluminum silicate, aluminum silicate fiber, and polyacrylamide are mixed in a mixer according to the above proportions to obtain heat insulation base powder. Cenospheres, hollow alumina spheres, hollow zirconia spheres, expanded perlite, dolomite powder, and kaolin are mixed in a material exchanger to obtain lightweight refractory layer powder. Composite fibers, expanded vermiculite, alumina powder, and magnesium oxide are mixed in a mixer according to the above proportions to obtain connecting column powder. S2. Pressing brick blanks: The heat insulation base powder and the lightweight refractory layer powder are poured into the heat insulation base cavity (6) and the lightweight refractory cavity (7) in the mold, respectively. After pouring, the middle partition (8) is removed and then pressed by a press. After pressing, the brick blank is obtained. S3, Preparation of connecting column (4): Place the connecting column powder into the rubber sleeve and compact it repeatedly 5-8 times. Then, put it into a cold isostatic press for pressing. After pressing, remove the rubber sleeve to obtain the connecting column blank. S4, Sintering: The brick blanks obtained in step S2 and the connecting column blanks obtained in step S3 are respectively placed in a sintering furnace for high-temperature sintering. The sintering temperature of the brick blanks is 1300-1600℃ and the sintering time is 8-12h. The sintering temperature of the connecting column blanks is 1500-1700℃ and the sintering time is 5-8h. After sintering, composite bricks and connecting columns (4) are obtained.

6. The method for preparing a lightweight, wear-resistant, and heat-insulating composite brick for a rotary kiln as described in claim 5, characterized in that, The mold includes a mold shell (5), the interior of which is provided with a heat-insulating base cavity (6) and a lightweight refractory cavity (7), a partition plate (8) is movably inserted between the heat-insulating base cavity (6) and the lightweight refractory cavity (7), an arc-shaped protrusion (51) is fixedly connected to the bottom of the mold shell (5), a pressure plate (9) is provided on the top of the mold shell (5), and an arc-shaped protrusion (91) is fixedly connected to the lower surface of the pressure plate (9).

7. The method for preparing a lightweight, wear-resistant, and heat-insulating composite brick for a rotary kiln as described in claim 5, characterized in that, In step S2, the pressing pressure of the press is 2.4-2.6 MPa, and the pressing number is 3-5 times. In step S3, the working pressure of the cold isostatic press is 8.5-9.3 MPa, and the pressing time is 20-30 minutes.

8. The method for preparing a lightweight, wear-resistant, and heat-insulating composite brick for a rotary kiln as described in claim 5, characterized in that, In step S1, the mixing speed of the mixer is 80-100 r / min and the mixing time is 20-30 min when mixing the thermal insulation base powder; the mixing speed of the mixer is 60-80 r / min and the mixing time is 40-60 min when mixing the lightweight refractory layer powder; and the mixing time of the connecting column powder is 100-120 r / min and the mixing time is 5-10 min.

9. The installation method of lightweight wear-resistant and heat-insulating composite bricks for rotary kilns as described in claim 1, characterized in that, The heat insulation base layer (1) of the composite brick is fixedly connected to the inner wall of the rotary kiln by anchors. When laying the composite brick, the bottom of the rotary kiln is laid first, and then the bricks are laid in sequence to both sides until a ring inner wall is laid. After the surface of the connecting column (4) is coated with adhesive, it is inserted into the arc groove (3) between two adjacent composite bricks. The adhesive coating thickness is 0.5-1cm. Then the second ring inner wall is laid until the entire rotary kiln is laid.

10. The installation method of lightweight wear-resistant and heat-insulating composite bricks for rotary kilns as described in claim 1, characterized in that, The heat insulation base layer (1) of the composite brick is fixedly connected to the inner wall of the rotary kiln by anchors. When laying the composite brick, the bottom of the rotary kiln is laid first, and then the bricks are laid in sequence to both sides until a ring inner wall is laid. After the laying is completed, the surface of the connecting column (4) is coated with adhesive and inserted into the arc groove (3) between two adjacent composite bricks. Then the second ring inner wall is laid until the entire rotary kiln is laid.

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