A method for assembling a sleeve type lime kiln arch bridge turning brick

Abstract

The present application relates to lime kiln refractory construction technology field, specifically disclose a sleeve type lime kiln arch bridge turning brick assembly method, the method comprises: based on the arch bridge geometric parameter grouping and numbering to turning brick;Lay the arc-shaped jig frame matching the inner profile of the arch bridge on the ground;Assemble the turning brick on the jig frame block by block, and sequentially set the first adhesive, metal framework and the second adhesive between adjacent turning bricks, form a composite sandwich structure;After the adhesive solidifies, form a modular unit;Through the lifting equipment, the modular unit is hoisted to the construction position as a whole and installed, and the final closure is completed.The present application solves the problems of high risk of high-altitude operation in limited space, poor single-brick masonry precision and easy disassembly of overall hoisting through the synergistic reinforcement technology of ground modular pre-assembly, double adhesive system and metal framework, significantly improves the construction efficiency and the high-temperature stability of the arch bridge structure.

Description

Technical Field

[0001] This invention relates to the field of refractory material construction technology for lime kilns, and more specifically, to a method for assembling the turning bricks of a sleeve-type lime kiln arch bridge. Background Technology

[0002] Sleeve-type lime kilns are widely used in metallurgy, chemical industry, and other sectors due to their high thermal efficiency and good lime activity. The arch bridge structure connecting the inner and outer sleeves is the core component of this type of kiln, primarily responsible for supporting the weight of the inner sleeve and guiding the flow of cooling air. Because the arch bridge structure is subjected to complex conditions of high temperature, heavy load, and airflow erosion over a long period, its refractory lining is prone to spalling, collapse, and other damage, making it a key and challenging area during major overhauls of lime kilns.

[0003] Currently, the maintenance and replacement of the turning bricks in the arch bridge of the sleeve-type lime kiln mainly adopts the high-altitude bulk loading process inside the furnace. This traditional construction method has the following significant drawbacks: 1. High construction safety risks: The working environment is a typical confined space high-altitude operation with poor ventilation and dim lighting. Due to the special location of the arch bridge, personnel need to look up or bend down for long periods of time to operate, which greatly increases the risk of falls; at the same time, loose bricks and tools falling from a height also pose a serious threat to workers below.

[0004] 2. Low construction efficiency and long shutdown period: Due to the limited space inside the kiln, large mechanical equipment cannot be used, and only manual single-brick construction can be carried out. In addition, the refractory mortar takes time to harden, and the removal of the arch is delayed, resulting in a long overall overhaul period and huge production losses for the enterprise.

[0005] 3. Difficulty in controlling masonry quality: Arch bridge structures have extremely high requirements for geometric dimensions and mortar joint thickness. When working at heights on site, the arch bricks are prone to falling and misaligning due to gravity, and the uniformity of manually applied mortar is difficult to guarantee, which can easily lead to crushing and cracking, seriously affecting the service life of the arch bridge.

[0006] To overcome these shortcomings, the industry has attempted a modular construction approach combining ground pre-assembly with overall hoisting. However, existing modular technologies face two major technical bottlenecks: First, insufficient early strength. Conventional refractory mortar sets slowly and is brittle, unable to withstand the tensile and shear forces generated by the enormous weight of the refractory bricks during hoisting, causing the modules to disintegrate during turning or lifting. Second, poor thermal expansion matching. Some technical solutions attempt to improve overall integrity by wrapping with steel shells or reinforcing with thick steel plates, but the thermal expansion coefficient of metals is much greater than that of refractory materials. During the high-temperature operation of the kiln, excessive expansion of metal components often cracks the refractory bricks, causing structural collapse.

[0007] Therefore, there is an urgent need to develop a method for assembling the rotating bricks of a sleeve-type lime kiln arch bridge that can achieve rapid and high-strength assembly on the ground, ensure structural stability at high temperatures, and is suitable for overall hoisting. Summary of the Invention

[0008] To address the challenges of complex on-site operations and insufficient safety in related technologies, as well as the problems of long curing cycles, poor overall integrity, uneven brick joints, and localized stress concentration caused by traditional wet masonry methods, this invention provides a method for assembling the turning bricks of a sleeve-type lime kiln arch bridge.

[0009] This invention provides a method for assembling the turning bricks of a sleeve-type lime kiln arch bridge, employing the following technical solution: A method for assembling the turning bricks of a sleeve-type lime kiln arch bridge specifically includes the following steps: S1. Based on the structure of the sleeve-type lime kiln arch bridge, the inner arc radius R, spatial drop h, and span parameters of the arch bridge are determined. Based on the above parameters, the turning bricks required at the same arch bridge location are divided into several groups, and numbered and marked according to the installation sequence. S2. Prepare the turning bricks, metal frame, first adhesive, second adhesive and flexible fasteners that match the position of the arch bridge; S3. On a flat ground, lay out the arch bridge at a 1:1 scale according to the geometric parameters of the arch bridge, and draw the inner arc baseline, end face control line and brick position number line of the turning brick unit. S4. Assemble the turning bricks in the order of their numbers. Apply the first adhesive between adjacent turning bricks, embed the metal frame, and apply the second adhesive to form a pre-assembled unit. Let it stand at room temperature for 15-30 minutes. Set at least one flexible fastener along the circumferential direction on the arch back side of the pre-assembled unit and apply a centripetal pre-tightening force to form a modular unit. S5. Inspect the modular unit's external dimensions, end face flatness, and overall stability. After passing the inspection, number and mark the unit according to the arch bridge installation location and store it on a special storage rack. S6. Use hoisting equipment to hoist the modular unit as a whole to the arch bridge installation position, so that both ends of the module are placed on the designed support positions and temporary supports are provided. After the module enters the arch-shaped stress state, remove the flexible fasteners. S7. After the modular units are installed in sequence, the last one or more turning bricks are installed at the reserved closure position, and all closure gaps are filled with the first adhesive to complete the overall closure of the arch bridge turning brick structure.

[0010] Preferably, in step S1, the inner arc radius R of the arch bridge is 3.0-5.0m, the spatial drop h is 150-600mm, the central angle of the arch bridge corresponding to a single set of modular units of turning bricks is 10°-30°, and a single set of modular units contains 5-8 turning bricks.

[0011] Preferably, the turning brick in step S2 is a corundum-mullite refractory brick, which has a double-sided wedge-shaped structure that conforms to the curvature of the arch bridge; the ratio of the width of the inner large end to the width of the outer small end of the turning brick is determined according to the radius of the arch bridge.

[0012] Preferably, in step S2, the metal frame is one of a stainless steel perforated plate with a thickness of 0.8mm-1.2mm, a heat-resistant alloy steel plate, or a low-carbon steel plate that has undergone rust prevention treatment.

[0013] Preferably, the flexible fastening element in step S2 is a ratchet tensioning strap or a plastic-steel strapping.

[0014] Preferably, the method for preparing the first adhesive includes the following steps: A1. Place aluminum dihydrogen phosphate solution in a reaction vessel, add sodium hexametaphosphate and carboxymethyl cellulose while stirring, and stir until completely dissolved to form a modified base solution; A2. Place mullite powder, white corundum micro powder and nano silica in a conical mixer, add 3-aminopropyltriethoxysilane, mix evenly to obtain a mixed powder; A3. Place the modified base liquid in a planetary mixer, and add the mixed powder into the mixer while stirring. After the powder is added, continue to stir evenly to form a paste. A4. Transfer the paste-like material into a sealed container and let it stand to age, thus obtaining the first binder.

[0015] Preferably, in step A1, the mass ratio of aluminum dihydrogen phosphate solution, sodium hexametaphosphate, and carboxymethyl cellulose is 100:4-5:0.3-0.5.

[0016] Preferably, the stirring in step A1 refers to stirring for 20-30 minutes at room temperature and a speed of 300-500 r / min.

[0017] Preferably, in step A2, the mass ratio of mullite powder, white corundum micro powder, nano silica and 3-aminopropyltriethoxysilane is 60-75:20-30:6-8:1-1.5.

[0018] Preferably, the term "uniform mixing" in step A2 refers to mixing for 15-20 minutes at room temperature and a rotation speed of 15-25 r / min.

[0019] Preferably, the mass ratio of the modified base liquid to the mixed powder in step A3 is 1:2.5-3.5.

[0020] Preferably, in step A3, the stirring speed is 60-100 r / min, and the stirring time is 15-25 min.

[0021] Preferably, the static aging in step A4 refers to aging for 24-36 hours in a constant temperature and humidity environment of 25-30℃ and 50-60% relative humidity.

[0022] Preferably, the method for preparing the second adhesive includes the following steps: B1. Mix water glass and ultrafine talc powder in a planetary mixer, add water-based epoxy emulsion, and stir evenly to obtain the inorganic main agent; B2. Mix water-based epoxy resin curing agent and propylene carbonate, add organic bentonite, stir and disperse to obtain organic curing agent; B3. Place the inorganic main agent and the organic curing agent in a dual-tube static mixing glue gun, and extrude them through the mixing tube to obtain the second adhesive.

[0023] Preferably, in step B1, the mass ratio of water glass, ultrafine talc powder, and aqueous epoxy emulsion is 100:40-50:10-20.

[0024] Preferably, in step B1, the water glass has a mass fraction of 40-45% and a modulus of 2.4-3.5.

[0025] Preferably, the term "stirring evenly" in step B1 refers to stirring for 20-30 minutes at room temperature and a rotation speed of 400-600 r / min.

[0026] Preferably, in step B2, the mass ratio of waterborne epoxy resin curing agent, propylene carbonate, and organobentonite is 100:15-20:5-6.

[0027] Preferably, the stirring and dispersing in step B2 refers to stirring and dispersing for 15-25 minutes at room temperature and a rotation speed of 1000-1500 r / min.

[0028] Preferably, the mass ratio of the inorganic main agent to the organic curing agent in step B3 is 3-5:1.

[0029] Preferably, in step S4, the thickness of the first adhesive is 1.0-2.0 mm, and the second adhesive is applied in a dotted manner, with each dot having a thickness of 0.5-1 mm.

[0030] Preferably, the centripetal pre-tightening force in step S4 refers to the tension applied to the flexible fastener by a ratchet fastener or a manual tensioning tool, with the tension controlled at 3-5 kN, until the first adhesive between adjacent turning bricks is evenly squeezed out from the gap, and the modular unit as a whole has no looseness.

[0031] Preferably, in step S4, during the assembly process, the flatness error of the inner working surface of the turning brick is controlled to be no more than 2.0 mm, and the width of the brick joint between adjacent turning bricks is 2.0-4.0 mm.

[0032] Preferably, the detection in step S5 refers to: using an arc template ruler to check the fit between the inner arc surface and the layout line, the inner arc chord length deviation ≤ ±2mm, the arch height deviation ≤ ±1.5mm, the end face flatness deviation ≤ 1mm, and there is no abnormal noise or relative shaking inside when the module is shaken forcefully.

[0033] Preferably, in step S6, temporary support refers to: after the modular unit is seated, driving hardwood wedges between the bottom surface of the module and the kiln support to make fine adjustments to the elevation and verticality, and setting adjustable spiral jacks or steel brackets on the arch back side of the module to assist in bearing the load until the first adhesive reaches the structural strength.

[0034] Preferably, in step S6, the hoisting is carried out using flexible hoisting straps for overall lifting, and adjustments are made according to the center of gravity position of the modular unit during the hoisting process.

[0035] In summary, the present invention has the following beneficial effects: 1. This invention transfers the complex arch bridge masonry process to the ground through a 1:1 ground layout and pre-assembly process, so that the inner arc radius, end face flatness and geometric dimensions of the bricks can be precisely controlled and corrected in a flat and stable environment; at the same time, this modular construction method supports parallel operation of multiple units, which helps to shorten the construction cycle.

[0036] 2. This invention, by setting a metal skeleton and adhesive between the brick joints and applying centripetal pre-tightening force with flexible clamping components, transforms the originally discrete refractory bricks into an integral structure with compressive stress in the circumferential direction. The mechanical interlocking effect of the metal skeleton and the chemical adhesive force of the adhesive work synergistically to ensure the integrity and stability of the modular unit during turning and hoisting, preventing brick slippage.

[0037] 3. The dual-adhesive system combining the second and first adhesives used in this invention utilizes the rapid curing characteristics of the fast-drying components at room temperature to meet the strength requirements for rapid transfer and hoisting of modular units. The second adhesive, containing water glass and ultrafine talc powder, allows the inorganic components to form a ceramic phase framework and fill pores after the organic components decompose at high temperatures, thus ensuring excellent high-temperature airtightness and structural integrity. The ceramicization characteristics of the high-temperature resistant components ensure the bonding strength of the arch bridge structure under high-temperature conditions, adapting to the working environment inside the lime kiln.

[0038] 4. The flexible clamping component used in this invention is removed after the module is seated and subjected to force, and the internal metal skeleton is completely sealed within the mortar joint, resulting in no exposed metal components on the working surface of the final arch bridge. This structural design ensures the consistency of the thermal expansion coefficient of the materials in all parts of the arch bridge, which is beneficial for maintaining the structural stability during the high-temperature operation of the kiln.

[0039] 5. This invention establishes a complete set of quantitative construction standards, from ground layout and marking, pre-tension control during pre-assembly, to dimensional inspection after module forming, and fine-tuning of supports after final placement. Through data control at each stage, accumulated installation errors can be effectively reduced, ensuring alignment and fit during the arch bridge's closure. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the embodiments.

[0041] The specific parameters of the raw materials used in this invention are as follows: Aluminum dihydrogen phosphate solution: Brand: FUER, Model: PAL-1, CAS No.: 13540-50-2, Aluminum dihydrogen phosphate content: 40%, provided by Guangzhou FUER Chemical Technology Co., Ltd. Sodium hexametaphosphate: CAS No.: 10124-56-8, provided by Wuhan Jiyesheng Chemical Co., Ltd.; Carboxymethyl cellulose: CAS No.: 9000-11-7, provided by Shanghai Yuanye Biotechnology Co., Ltd.; Mullite powder: Specification: 200 mesh, supplied by Lingshou County Tianhao Mineral Products Processing Plant; White corundum micro powder: Brand: Lichuan, Specification: 800#, provided by Guangdong Lichuan Technology Co., Ltd. Nano silica: Brand: Zhente, Specification: Hydrophilic 618, provided by Shijiazhuang Zhente New Material Technology Co., Ltd. 3-Aminopropyltriethoxysilane: CAS No.: 919-30-2, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; Water-based epoxy resin curing agent: Brand: Huaxiang Kejie, Model: WH-900, provided by Wuhan Huaxiang Kejie Biotechnology Co., Ltd. Propylene carbonate: CAS No.: 108-32-7, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; Organic bentonite: Brand: Yifeng, Specification: BP-183, provided by Guangzhou Yifeng Chemical Technology Co., Ltd. Corundum-mullite refractory bricks: Brand: Molex, Item No.: 025, Material: Alumina, Refractory temperature: 1790℃, Compressive strength: 100MPa, provided by Zhengzhou Qingheng Refractory Materials Co., Ltd. Stainless steel perforated sheet: Material: 304, Size: 0.8 1219 C, Thickness: 0.8mm, provided by Wuxi Hefengli Metal Materials Co., Ltd.; Ratchet tensioner: Brand: Bangliwen, provided by Shanghai Yilai Textile Co., Ltd.; Ultrafine talc powder: Specification: TP9500, provided by Dongguan Xinmate Industrial Investment Co., Ltd. Waterborne epoxy emulsion: Brand: Tuoda, Model: TD-98, provided by Tuoda (Shandong) New Material Technology Industry Group Co., Ltd. Epoxy resin adhesive: Brand: Maifei, provided by Shandong Maifei Chemical Co., Ltd. Water glass: Brand: Zhonghe Shengtai, sodium silicate content 40%, modulus: 3.1, provided by Tianjin Zhonghe Shengtai Chemical Co., Ltd.

[0042] Examples 1-3 provide a method for assembling the turning bricks of a sleeve-type lime kiln arch bridge.

[0043] Example 1 The preparation method of the first adhesive includes the following steps: A1. Control the mass ratio of aluminum dihydrogen phosphate solution, sodium hexametaphosphate and carboxymethyl cellulose to be 100:4:0.3. Place the aluminum dihydrogen phosphate solution in a reaction vessel, add sodium hexametaphosphate and carboxymethyl cellulose under stirring, and stir for 30 minutes at room temperature and 300 r / min until completely dissolved to form a modified base solution. A2. Control the mass ratio of mullite powder, white fused alumina powder, nano silica and 3-aminopropyltriethoxysilane to 60:20:8:1. Place the mullite powder, white fused alumina powder and nano silica in a conical mixer, add 3-aminopropyltriethoxysilane, and mix for 20 min at room temperature and a speed of 15 r / min to obtain a mixed powder. A3. Control the mass ratio of modified base liquid and mixed powder to 1:2.5. Place the modified base liquid in a planetary mixer. Add the mixed powder to the mixer at room temperature and a speed of 60 r / min. After the powder is added, continue to stir for 25 min to form a paste. A4. Transfer the paste material into a sealed container and age it for 36 hours in a constant temperature and humidity environment of 25°C and 50% relative humidity to obtain the first binder. The preparation method of the second adhesive includes the following steps: B1. Control the mass ratio of water glass, ultrafine talc powder and waterborne epoxy emulsion to 100:40:10. Mix water glass and ultrafine talc powder in a planetary mixer, add waterborne epoxy emulsion, and stir for 30 minutes at room temperature and 400 r / min to obtain inorganic main agent. B2. Control the mass ratio of waterborne epoxy resin curing agent, propylene carbonate and organo-bentonite to 100:15:5. Mix the waterborne epoxy resin curing agent and propylene carbonate, add organo-bentonite, and stir and disperse for 25 minutes at room temperature and 1000 r / min to obtain the organic curing agent. B3. Control the mass ratio of inorganic main agent and organic curing agent to 3:1, place the inorganic main agent and organic curing agent in a dual-tube static mixing glue gun, and extrude them through the mixing tube to obtain the second adhesive; A method for assembling the turning bricks of a sleeve-type lime kiln arch bridge specifically includes the following steps: S1. Based on the structure of the sleeve-type lime kiln arch bridge, the inner arc radius R of the arch bridge is 3.0m, the spatial drop h is 300mm, and the central angle of the arch bridge corresponding to a single set of modular units of turning bricks is 15°. Based on the above parameters, the turning bricks required for the same arch bridge position are divided into 24 groups, each group containing 6 turning bricks, and numbered and marked according to the installation sequence. S2. Prepare corundum mullite refractory bricks, stainless steel perforated plates, first adhesive, second adhesive, and ratchet tensioning belts that match the position of the arch bridge. S3. On a flat ground, lay out the arch bridge at a 1:1 scale according to the geometric parameters of the arch bridge, and draw the inner arc baseline, end face control line and brick position number line of the turning brick unit. S4. Assemble the turning bricks in sequence according to the numbering order. On the joint surface of adjacent turning bricks, firstly apply a first adhesive with a thickness of 1.0mm evenly and embed a stainless steel perforated plate. Then, apply a second adhesive with a thickness of 0.5mm in a dotted manner to form a pre-assembled unit. During the assembly process, strictly control the width of the brick joint between adjacent turning bricks to 2.0mm and ensure that the flatness error of the inner working surface of the modular unit of turning bricks is no more than 2.0mm. After the assembly is completed, let the pre-assembled unit stand at room temperature for 15 minutes. Set at least one ratchet tensioning band along the circumferential direction on the arched back side of the pre-assembled unit. Apply a tension of 3kN to the ratchet tensioning band through the ratchet fastener. The centripetal pre-tightening force generated by this tension forces the adjacent turning bricks to be further compacted until the first adhesive is evenly squeezed out from the gap and the modular unit as a whole has no looseness, thus completing the final molding of the modular unit. S5. Inspect the external dimensions, end face flatness and overall stability of the modular unit. Use an arc template ruler to check the fit between the inner arc surface and the layout line. The inner arc chord length deviation is ≤ ±2mm, the arch height deviation is ≤ ±1.5mm, the end face flatness deviation is ≤1mm, and there is no abnormal noise or relative shaking inside when the module is shaken vigorously. After passing the inspection, number and mark the position according to the arch bridge installation position and place it on a special storage rack. S6. Use flexible lifting straps to lift the modular unit as a whole to the arch bridge installation position. During the lifting process, adjust according to the center of gravity of the modular unit so that both ends of the module are seated on the designed support positions. After the modular unit is seated, drive hardwood wedges between the bottom surface of the module and the kiln body support for fine adjustment of elevation and verticality. Set adjustable screw jacks on the arch back side of the module to assist in bearing the load until the first adhesive reaches the structural strength. When the module enters the arch stress state, remove the ratchet tension strap. S7. After the modular units are installed in sequence, the last one or more turning bricks are installed at the reserved closure position, and all closure gaps are filled with the first adhesive to complete the overall closure of the arch bridge turning brick structure.

[0044] Example 2 The preparation method of the first adhesive includes the following steps: A1. Control the mass ratio of aluminum dihydrogen phosphate solution, sodium hexametaphosphate and carboxymethyl cellulose to be 100:4.5:0.4. Place the aluminum dihydrogen phosphate solution in a reaction vessel, add sodium hexametaphosphate and carboxymethyl cellulose under stirring, and stir for 25 minutes at room temperature and 400 r / min until completely dissolved to form a modified base solution. A2. Control the mass ratio of mullite powder, white fused alumina powder, nano silica and 3-aminopropyltriethoxysilane to 70:25:7:1.25. Place the mullite powder, white fused alumina powder and nano silica in a conical mixer, add 3-aminopropyltriethoxysilane, and mix for 17.5 min at room temperature and a rotation speed of 20 r / min to obtain a mixed powder. A3. Control the mass ratio of modified base liquid and mixed powder to 1:3. Place the modified base liquid in a planetary mixer. Add the mixed powder to the mixer at room temperature and a speed of 80 r / min. After the powder is added, continue to stir for 20 minutes to form a paste. A4. Transfer the paste material into a sealed container and age it for 30 hours in a constant temperature and humidity environment of 28°C and 55% relative humidity to obtain the first binder. The preparation method of the second adhesive includes the following steps: B1. Control the mass ratio of water glass, ultrafine talc powder and waterborne epoxy emulsion to 100:45:15. Mix water glass and ultrafine talc powder in a planetary mixer, add waterborne epoxy emulsion, and stir for 25 minutes at room temperature and 500 r / min to obtain inorganic main agent. B2. Control the mass ratio of waterborne epoxy resin curing agent, propylene carbonate and organo-bentonite to be 100:17.5:5.5. Mix the waterborne epoxy resin curing agent and propylene carbonate, add organo-bentonite, and stir and disperse for 20 minutes at room temperature and 1250 r / min to obtain the organo-curing agent. B3. Control the mass ratio of inorganic main agent and organic curing agent to 4:1, place the inorganic main agent and organic curing agent in a dual-tube static mixing gun, and extrude them through the mixing tube to obtain the second adhesive; A method for assembling the turning bricks of a sleeve-type lime kiln arch bridge specifically includes the following steps: S1. Based on the structure of the sleeve-type lime kiln arch bridge, the inner arc radius R of the arch bridge is 4.0m, the spatial drop h is 500mm, and the central angle of the arch bridge corresponding to a single set of modular units of turning bricks is 20°. Based on the above parameters, the turning bricks required for the same arch bridge position are divided into 18 sets, each set containing 7 turning bricks, and numbered and marked according to the installation sequence. S2. Prepare corundum mullite refractory bricks, stainless steel perforated plates, first adhesive, second adhesive, and ratchet tensioning belts that match the position of the arch bridge. S3. On a flat ground, lay out the arch bridge at a 1:1 scale according to the geometric parameters of the arch bridge, and draw the inner arc baseline, end face control line and brick position number line of the turning brick unit. S4. Assemble the turning bricks in sequence according to the numbering order. On the joint surface of adjacent turning bricks, firstly apply a first adhesive with a thickness of 1.5mm evenly and embed a stainless steel perforated plate. Then, apply a second adhesive with a thickness of 0.8mm in a dotted manner to form a pre-assembled unit. During the assembly process, strictly control the width of the brick joint between adjacent turning bricks to 3.0mm and ensure that the flatness error of the inner working surface of the modular unit of turning bricks is no more than 2.0mm. After the assembly is completed, let the pre-assembled unit stand at room temperature for 22 minutes. Set at least one ratchet tensioning band along the circumferential direction on the arched back side of the pre-assembled unit. Apply a tension of 4kN to the ratchet tensioning band through the ratchet fastener. The centripetal pre-tightening force generated by this tension forces the adjacent turning bricks to be further compacted until the first adhesive is evenly squeezed out from the gap and the modular unit as a whole has no looseness, thus completing the final molding of the modular unit. S5. Inspect the external dimensions, end face flatness and overall stability of the modular unit. Use an arc template ruler to check the fit between the inner arc surface and the layout line. The inner arc chord length deviation is ≤ ±2mm, the arch height deviation is ≤ ±1.5mm, the end face flatness deviation is ≤1mm, and there is no abnormal noise or relative shaking inside when the module is shaken vigorously. After passing the inspection, number and mark the position according to the arch bridge installation position and place it on a special storage rack. S6. Use flexible lifting straps to lift the modular unit as a whole to the arch bridge installation position. During the lifting process, adjust according to the center of gravity of the modular unit so that both ends of the module are seated on the designed support positions. After the modular unit is seated, drive hardwood wedges between the bottom surface of the module and the kiln body support for fine adjustment of elevation and verticality. Set adjustable screw jacks on the arch back side of the module to assist in bearing the load until the first adhesive reaches the structural strength. When the module enters the arch stress state, remove the ratchet tension strap. S7. After the modular units are installed in sequence, the last one or more turning bricks are installed at the reserved closure position, and all closure gaps are filled with the first adhesive to complete the overall closure of the arch bridge turning brick structure.

[0045] Example 3 The preparation method of the first adhesive includes the following steps: A1. Control the mass ratio of aluminum dihydrogen phosphate solution, sodium hexametaphosphate and carboxymethyl cellulose to 100:5:0.5. Place the aluminum dihydrogen phosphate solution in a reaction vessel, add sodium hexametaphosphate and carboxymethyl cellulose under stirring, and stir for 20 minutes at room temperature and 500 r / min until completely dissolved to form a modified base solution. A2. Control the mass ratio of mullite powder, white fused alumina powder, nano silica and 3-aminopropyltriethoxysilane to 75:30:6:1.5. Place the mullite powder, white fused alumina powder and nano silica in a conical mixer, add 3-aminopropyltriethoxysilane, and mix for 15 min at room temperature and a speed of 25 r / min to obtain a mixed powder. A3. Control the mass ratio of modified base liquid and mixed powder to 1:3.5. Place the modified base liquid in a planetary mixer. Add the mixed powder to the mixer at room temperature and a speed of 100 r / min. After the powder is added, continue to stir for 15 min to form a paste. A4. Transfer the paste material into a sealed container and age it for 24 hours in a constant temperature and humidity environment of 30°C and 60% to obtain the first binder. The preparation method of the second adhesive includes the following steps: B1. Control the mass ratio of water glass, ultrafine talc powder and waterborne epoxy emulsion to 100:50:20. Mix water glass and ultrafine talc powder in a planetary mixer, add waterborne epoxy emulsion, and stir for 20 minutes at room temperature and 600 r / min to obtain inorganic main agent. B2. Control the mass ratio of waterborne epoxy resin curing agent, propylene carbonate and organo-bentonite to 100:20:6. Mix the waterborne epoxy resin curing agent and propylene carbonate, add organo-bentonite, and stir and disperse for 15 minutes at room temperature and a speed of 1500 r / min to obtain the organo-curing agent. B3. Control the mass ratio of inorganic main agent and organic curing agent to 5:1, place the inorganic main agent and organic curing agent in a dual-tube static mixing gun, and extrude them through the mixing tube to obtain the second adhesive; A method for assembling the turning bricks of a sleeve-type lime kiln arch bridge specifically includes the following steps: S1. Based on the structure of the sleeve-type lime kiln arch bridge, the inner arc radius R of the arch bridge is 5.0m, the spatial drop h is 600mm, and the central angle of the arch bridge corresponding to a single set of modular units of turning bricks is 30°. Based on the above parameters, the turning bricks required for the same arch bridge position are divided into 12 groups, each group containing 8 turning bricks, and numbered and marked according to the installation sequence. S2. Prepare corundum mullite refractory bricks, stainless steel perforated plates, first adhesive, second adhesive, and ratchet tensioning belts that match the position of the arch bridge. S3. On a flat ground, lay out the arch bridge at a 1:1 scale according to the geometric parameters of the arch bridge, and draw the inner arc baseline, end face control line and brick position number line of the turning brick unit. S4. Assemble the turning bricks in sequence according to the numbering order. On the joint surface of adjacent turning bricks, firstly apply a first adhesive with a thickness of 2.0mm evenly and embed a stainless steel perforated plate. Then, apply a second adhesive with a thickness of 1.0mm in a dotted manner to form a pre-assembled unit. During the assembly process, strictly control the width of the brick joint between adjacent turning bricks to 4.0mm and ensure that the flatness error of the inner working surface of the modular unit of turning bricks is no more than 2.0mm. After the assembly is completed, let the pre-assembled unit stand at room temperature for 30 minutes. Set at least one ratchet tensioning band along the circumferential direction on the arched back side of the pre-assembled unit. Apply a 5kN tension to the ratchet tensioning band through the ratchet fastener. The centripetal pre-tightening force generated by this tension forces the adjacent turning bricks to be further compacted until the first adhesive is evenly squeezed out from the gap and the modular unit as a whole has no looseness, thus completing the final molding of the modular unit. S5. Inspect the external dimensions, end face flatness and overall stability of the modular unit. Use an arc template ruler to check the fit between the inner arc surface and the layout line. The inner arc chord length deviation is ≤ ±2mm, the arch height deviation is ≤ ±1.5mm, the end face flatness deviation is ≤1mm, and there is no abnormal noise or relative shaking inside when the module is shaken vigorously. After passing the inspection, number and mark the position according to the arch bridge installation position and place it on a special storage rack. S6. Use flexible lifting straps to lift the modular unit as a whole to the arch bridge installation position. During the lifting process, adjust according to the center of gravity of the modular unit so that both ends of the module are seated on the designed support positions. After the modular unit is seated, drive hardwood wedges between the bottom surface of the module and the kiln body support for fine adjustment of elevation and verticality. Set adjustable screw jacks on the arch back side of the module to assist in bearing the load until the first adhesive reaches the structural strength. When the module enters the arch stress state, remove the ratchet tension strap. S7. After the modular units are installed in sequence, the last one or more turning bricks are installed at the reserved closure position, and all closure gaps are filled with the first adhesive to complete the overall closure of the arch bridge turning brick structure.

[0046] Comparative Example 1 The difference between this comparative example and Example 1 is that 3-aminopropyltriethoxysilane is not added when preparing the first adhesive, while the remaining steps and raw materials are the same as in Example 1. The preparation method of the first adhesive includes the following steps: A1. Control the mass ratio of aluminum dihydrogen phosphate solution, sodium hexametaphosphate and carboxymethyl cellulose to be 100:4:0.3. Place the aluminum dihydrogen phosphate solution in a reaction vessel, add sodium hexametaphosphate and carboxymethyl cellulose under stirring, and stir for 30 minutes at room temperature and 300 r / min until completely dissolved to form a modified base solution. A2. Control the mass ratio of mullite powder, white fused alumina powder and nano silica to 60:20:8. Place the mullite powder, white fused alumina powder and nano silica in a conical mixer and mix for 20 minutes at room temperature and a speed of 15 r / min to obtain a mixed powder. A3. Control the mass ratio of modified base liquid and mixed powder to 1:2.5. Place the modified base liquid in a planetary mixer. Add the mixed powder to the mixer at room temperature and a speed of 60 r / min. After the powder is added, continue to stir for 25 min to form a paste. A4. Transfer the paste-like material into a sealed container and age it for 36 hours in a constant temperature and humidity environment of 25°C and 50% relative humidity to obtain the first binder.

[0047] Comparative Example 2 The difference between this comparative example and Example 1 is that in step S4, the second adhesive is replaced with epoxy resin glue of equal mass, while the remaining steps and raw materials are the same as in Example 1. S4. Assemble the turning bricks in sequence according to their numbers. On the joint surfaces of adjacent turning bricks, firstly apply a 1.0mm thick first adhesive evenly and embed a stainless steel perforated plate. Then, apply a 0.5mm thick epoxy resin adhesive in a dotted manner to form a pre-assembled unit. During the assembly process, strictly control the width of the brick joint between adjacent turning bricks to 2.0mm and ensure that the flatness error of the inner working surface of the modular unit of turning bricks is no more than 2.0mm. After the assembly is completed, let the pre-assembled unit stand at room temperature for 15 minutes. Then, set at least one ratchet tensioning strap along the circumferential direction on the arched back side of the pre-assembled unit. Apply a 3kN tension to the ratchet tensioning strap through the ratchet fastener. The centripetal pre-tightening force generated by this tension forces the adjacent turning bricks to be further compacted until the first adhesive is evenly squeezed out from the gap and the modular unit as a whole has no looseness, thus completing the final molding of the modular unit.

[0048] Comparative Example 3 The difference between this comparative example and Example 1 is that in step S4, a stainless steel perforated plate and a second adhesive are not used; only the first adhesive is used to directly coat the bonding surface of the brick. The remaining steps and raw materials are the same as in Example 1. S4. Assemble the turning bricks in sequence according to their numbers. Apply a 1.0mm thick first adhesive evenly to the joint surfaces of adjacent turning bricks to form a pre-assembled unit. During the assembly process, strictly control the width of the brick joint between adjacent turning bricks to be 2.0mm and ensure that the flatness error of the inner working surface of the modular unit is no more than 2.0mm. After the assembly is completed, let the pre-assembled unit stand at room temperature for 15 minutes. Set at least one ratchet tensioning strap along the circumferential direction on the arched back side of the pre-assembled unit. Apply a 3kN tension to the ratchet tensioning strap through the ratchet fastener. The centripetal pre-tightening force generated by this tension forces the adjacent turning bricks to be further compacted until the first adhesive is evenly squeezed out from the gap and the modular unit as a whole has no looseness, thus completing the final molding of the modular unit.

[0049] Performance testing The modular units prepared in Examples 1-3 and Comparative Examples 1-3 were tested, and the results are recorded in Table 1.

[0050] 1. Flexural bond strength at room temperature (MPa) The test was conducted in accordance with the standard GB / T 22459.4-2008 "Refractory Mortar Part 4: Test Method for Flexural Bond Strength at Room Temperature". After the modular unit was cured for 24 hours, a three-point bending test was performed on a universal testing machine to determine its maximum modulus at fracture. This indicator reflects the safety during hoisting.

[0051] 2. High-temperature flexural bond strength (MPa) The test was conducted in accordance with the standard GB / T 3002-2017 "Test Method for High Temperature Flexural Strength of Refractory Materials". The modular unit was placed in a high temperature furnace and heated to 1200℃ at a rate of 5℃ / min. After holding at that temperature for 3 hours, its flexural bond strength was directly tested under hot conditions.

[0052] 3. Breathability The test was conducted in accordance with the standard GB / T 3000-2016 "Test Method for Air Permeability of Dense Shaped Refractory Products". After the modular unit was fired at 1200℃, the gas permeability perpendicular to the glue joint was tested. The lower the value, the better the air tightness and the better it can prevent short circuit of hot air flow in the kiln.

[0053] 4. Thermal shock resistance (strength retention rate) The test was conducted in accordance with standard YB / T 376.3-2004 "Test Method for Thermal Shock Resistance of Refractory Products Part 3 - Water Quenching-Crack Judgment Method". First, the initial flexural strength of the modular unit was tested. Then, the modular unit was heated to 1100℃ and held for 20 minutes. It was then removed and immediately immersed in flowing cold water to cool for 5 minutes. After that, it was removed and air-dried naturally. This was one cycle. After five cycles, the room temperature flexural strength of the sample was measured. The strength retention rate was calculated as (flexural strength after cycle / initial flexural strength) × 100%.

[0054] The performance test results and experimental results are shown in Table 1.

[0055] Table 1: Performance test results of the modular units prepared in Examples 1-3 and Comparative Examples 1-3 As shown in Table 1, the modular units prepared in Examples 1-3 of this invention exhibit excellent comprehensive performance in terms of flexural bonding strength at room temperature and high temperature, high temperature airtightness, and thermal shock resistance, which are significantly better than those in Comparative Examples 1-3.

[0056] As can be seen from the data shown in Example 1 and Comparative Example 1, 3-aminopropyltriethoxysilane was not added when preparing the first binder in Comparative Example 1. The interfacial bonding strength inside the mortar was insufficient, which made the refractory material more prone to peeling and cracking when subjected to rapid cooling and heating and high temperature loads.

[0057] As can be seen from the data shown in Example 1 and Comparative Example 2, Comparative Example 2 used epoxy resin adhesive to replace the second adhesive. Epoxy resin adhesive is an organic material, which will be completely oxidized and burned off at a high temperature of 1200℃, leaving a large number of through pores, resulting in serious air leakage at the joints of the bricks and a significant decrease in high temperature flexural strength.

[0058] As can be seen from the data shown in Example 1 and Comparative Example 3, Comparative Example 3 removed the second adhesive and the stainless steel perforated plate during the assembly process, relying solely on the first adhesive for bonding, which resulted in a significant decrease in the bending resistance of the bonding surface.

[0059] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for assembling the turning bricks of a sleeve-type lime kiln arch bridge, characterized in that, Specifically, the following steps are included: S1. Based on the structure of the sleeve-type lime kiln arch bridge, the inner arc radius R, spatial drop h, and span parameters of the arch bridge are determined. Based on the above parameters, the turning bricks required at the same arch bridge location are divided into several groups, and numbered and marked according to the installation sequence. S2. Prepare the turning bricks, metal frame, first adhesive, second adhesive and flexible fasteners that match the position of the arch bridge; S3. On a flat ground, lay out the arch bridge at a 1:1 scale according to the geometric parameters of the arch bridge, and draw the inner arc baseline, end face control line and brick position number line of the turning brick unit. S4. Assemble the turning bricks in the order of their numbers. Apply the first adhesive between adjacent turning bricks, embed the metal frame, and apply the second adhesive to form a pre-assembled unit. Let it stand at room temperature for 15-30 minutes. Set at least one flexible fastener along the circumferential direction on the arch back side of the pre-assembled unit and apply a centripetal pre-tightening force to form a modular unit. S5. Inspect the modular unit's external dimensions, end face flatness, and overall stability. After passing the inspection, number and mark the unit according to the arch bridge installation location and store it on a special storage rack. S6. Use hoisting equipment to hoist the modular unit as a whole to the arch bridge installation position, so that both ends of the module are placed on the designed support positions and temporary supports are provided. After the module enters the arch-shaped stress state, remove the flexible fasteners. S7. After the modular units are installed in sequence, the last one or more turning bricks are installed at the reserved closure position, and all closure gaps are filled with the first adhesive to complete the overall closure of the arch bridge turning brick structure.

2. The method for assembling the rotating bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, In step S1, the inner arc radius R of the arch bridge is 3.0-5.0m, the spatial drop h is 150-600mm, the central angle of the arch bridge corresponding to a single set of modular units of turning bricks is 10°-30°, and a single set of modular units contains 5-8 turning bricks.

3. The method for assembling the rotating bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, In step S2, the metal frame is one of the following: a stainless steel perforated plate with a thickness of 0.8mm-1.2mm, a heat-resistant alloy steel plate, or a low-carbon steel plate that has undergone rust prevention treatment.

4. The method for assembling the turning bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, In step S2, the flexible fastening component is a ratchet tensioning strap or a plastic steel strapping.

5. The method for assembling the turning bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, The preparation method of the first adhesive in step S2 includes the following steps: A1. Place aluminum dihydrogen phosphate solution in a reaction vessel, add sodium hexametaphosphate and carboxymethyl cellulose while stirring, and stir until completely dissolved to form a modified base solution; A2. Place mullite powder, white corundum micro powder and nano silica in a conical mixer, add 3-aminopropyltriethoxysilane, mix evenly to obtain a mixed powder; A3. Place the modified base liquid in a planetary mixer, and add the mixed powder into the mixer while stirring. After the powder is added, continue to stir evenly to form a paste. A4. Transfer the paste-like material into a sealed container and let it stand to age, thus obtaining the first binder.

6. The method for assembling the rotating bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, The preparation method of the second adhesive in step S2 includes the following steps: B1. Mix water glass and ultrafine talc powder in a planetary mixer, add water-based epoxy emulsion, and stir evenly to obtain the inorganic main agent; B2. Mix water-based epoxy resin curing agent and propylene carbonate, add organic bentonite, stir and disperse to obtain organic curing agent; B3. Place the inorganic main agent and the organic curing agent in a dual-tube static mixing glue gun, and extrude them through the mixing tube to obtain the second adhesive.

7. The method for assembling the turning bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, In step S4, the thickness of the first adhesive is 1.0-2.0 mm, and the second adhesive is applied in a dotted manner, with each dot having a thickness of 0.5-1 mm.

8. The method for assembling the turning bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, In step S4, during the assembly process, the flatness error of the inner working surface of the turning brick is controlled to be no more than 2.0mm, and the width of the brick joint between adjacent turning bricks is 2.0-4.0mm.

9. The method for assembling the turning bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, The detection in step S5 refers to: using an arc template ruler to check the fit between the inner arc surface and the layout line, the inner arc chord length deviation ≤ ±2mm, the arch height deviation ≤ ±1.5mm, the end face flatness deviation ≤ 1mm, and there is no abnormal noise or relative shaking inside when the module is shaken forcefully.

10. The method for assembling the turning bricks of a sleeve-type lime kiln arch bridge according to claim 1, characterized in that, In step S6, temporary support refers to: after the modular unit is placed, hardwood wedges are driven between the bottom surface of the module and the kiln support to make fine adjustments to the elevation and verticality, and adjustable spiral jacks or steel brackets are set on the arch back side of the module to assist in bearing the load until the first adhesive reaches the structural strength.

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