Refractory mortar sheet-shaped prefabricated body as well as preparation method and construction method thereof

Abstract

The invention discloses a refractory mortar sheet-shaped prefabricated body as well as a preparation method and a construction method thereof, and belongs to the technical field of refractory mortar. The refractory mortar flaky preform is prepared from the following raw materials: 70 to 80 percent of porous bauxite clinker, 5 to 10 percent of quartz powder, 5 to 10 percent of silica powder, 0.5 to 1.0 percent of isothiazolinone derivative, 3 to 6 percent of passivated aluminum powder, 0.1 to 0.3 percent of tricalcium aluminate and 3 to 5 percent of yellow dextrin. 10-15% of a polyvinyl alcohol solution is added; the mass ratio of polyvinyl alcohol to water in the polyvinyl alcohol solution is 1: (18-20); the preparation method comprises the following steps: uniformly mixing the raw materials, pressing into slices and curing. The refractory mortar sheet-shaped prefabricated body has a rich microporous structure, has heat insulation property and moisture permeability, also has good forming strength and good plasticity and high-temperature performance after wetting, realizes a construction mode of on-site unpacking and ready-to-use, greatly improves the construction efficiency, and is suitable for high-efficiency masonry of industrial kiln masonry.

Description

Technical Field

[0001] This invention belongs to the field of refractory slurry technology, specifically relating to a refractory slurry sheet preform, its preparation method, and its construction method. Background Technology

[0002] Refractory mortar is mainly used for filling and bonding gaps between refractory bricks, between precast components, or between refractory bricks and precast components, forming a complete refractory masonry. Currently, refractory mortar is generally supplied in dry powder form, requiring on-site mixing with water or other liquids to create a paste-like slurry before application. This method has the following significant drawbacks: 1) Significant limitations on construction conditions: Specialized mixing equipment and site sheds are required. The equipment must be thoroughly cleaned before use to prevent impurities from entering. The mixed slurry must be manually or mechanically transported to the construction area inside the kiln, making the operation cumbersome.

[0003] 2) Environmental pollution and health risks: A large amount of dust is generated during the mixing process, which pollutes the environment and endangers the health of construction workers.

[0004] 3) Material waste problem: In areas with low usage and long construction intervals, dry powder mixing is prone to excessive waste due to improper measurement.

[0005] 4) Unstable construction quality: It is significantly affected by site conditions. For example, using groundwater or kiln circulating water for mixing may cause the slurry to swell or harden too quickly; deviations in the amount of liquid added may cause drying cracks (too much liquid added) or poor plasticity (insufficient liquid added), resulting in low density of the masonry joints and insufficient bonding strength; the masonry construction skills of workers vary, and manually kneading the slurry to control the size of the masonry joints may lead to large deviations in the size of the brick joints, etc. All these factors affect the airtightness and structural stability of the kiln masonry, creating hidden dangers for the safe operation of high-temperature kilns. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a refractory mortar sheet precast body, its preparation method, and its construction method. This refractory mortar sheet precast body possesses a rich microporous structure, balancing thermal insulation and moisture permeability. It also exhibits good molding strength, excellent plasticity after wetting, and high-temperature performance, enabling a "ready-to-use on-site" construction mode. This eliminates a series of problems caused by secondary on-site mixing and is suitable for the efficient construction of industrial kiln masonry.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A refractory mortar sheet preform is provided, comprising, by weight percentage: The composition consists of 70-80% porous bauxite clinker, 5-10% quartz powder, 5-10% silica fume, 0.5-1.0% isothiazolinone derivative, 3-6% passivated aluminum powder, 0.1-0.3% tricalcium aluminate (C3A), 3-5% dextrin, and 10-15% polyvinyl alcohol solution. The mass ratio of polyvinyl alcohol (PVA) to water in the polyvinyl alcohol solution is 1:18-20; The refractory slurry sheet preform is obtained by mixing the above raw materials evenly, pressing them into thin sheets, and then curing them.

[0008] According to the above scheme, the thickness of the refractory mortar sheet prefabricated body is 5-10mm, and the size matches the refractory bricks or prefabricated parts to be laid.

[0009] According to the above scheme, the particle size of the porous bauxite clinker is 1.0–0 mm.

[0010] According to the above scheme, the porous bauxite clinker contains Al2O3 ≥ 55wt% and has a loose bulk density of 0.55-1.2 g / cm³. 3 .

[0011] According to the above scheme, the porous bauxite clinker is obtained by grinding hard clay or bauxite into powder, adding ignition loss, then using aluminum sulfate as a binder, forming pellets, calcining at 1350-1460℃, and finally crushing into 1.0-0mm particles. Preferably, the ignition loss is sawdust.

[0012] According to the above scheme, the particle size of the quartz powder is 0.074-0 mm.

[0013] According to the above scheme, in the silicon micro powder, SiO2 ≥ 92wt% and d90 ≤ 2.5μm.

[0014] According to the above scheme, the isothiazolinone derivative is at least one of MIT (2-methyl-4-isothiazolin-3-one) and BIT (1,2-benzisothiazolin-3-one).

[0015] According to the above scheme, the passivated aluminum powder has a particle size of 0.5-0.25mm.

[0016] According to the above scheme, the passivated aluminum powder is aluminum powder whose surface is passivated by being coated with aluminum oxide, wherein the elemental Al content is between 85-95 wt% and the Al2O3 content is between 5-15 wt%. Preferably, the passivated aluminum powder is prepared by passivating aluminum powder by blowing it with a mixed gas containing water vapor and CO2, or by placing it in air for a long time, and then coating its surface with aluminum oxide.

[0017] According to the above scheme, the polyvinyl alcohol solution is a mixed solution obtained by mixing cold water-soluble polyvinyl alcohol (PVA) powder and water at a mass ratio of 1:18-20 and then stirring at high speed.

[0018] A method for preparing the above-mentioned refractory slurry sheet-like preform is provided, comprising the following steps: 1) Raw material mixing: Weigh each solid raw material according to the mass ratio, mix them evenly, and then add polyvinyl alcohol solution while stirring. Stir until a viscous slurry is formed, and control the stirring time within 30 minutes. 2) Pressing and shaping: Press the slurry obtained in step 1) into thin sheets and cut them into sizes that match the refractory bricks or precast parts to be laid on site; 3) Curing and delivery: The sheet-like slurry obtained in step 2) is cured for 1-3 hours. During this period, C3A reacts with aluminum powder to hydrate and release heat, which promotes the evaporation of water and forms strength. After curing, the sheet-like precast refractory slurry is obtained.

[0019] According to the above scheme, in step 1), the consistency of the viscous slurry reaches between 100 and 110. The viscosity is measured by the penetration test, with units of 0.1 mm. Here, 0.1 mm means that, using the penetration test, the depth to which a pointed cone is inserted into the slurry; for a consistency of 110, the insertion depth is 0.1 mm. 110 = 11mm.

[0020] According to the above scheme, in step 2), the thickness of the sheet is 5-10mm.

[0021] A construction method for the above-mentioned refractory mortar sheet precast body is provided, comprising the following steps: During on-site construction, water mist is first sprayed onto the surface of the refractory bricks or precast components. Then, refractory mortar sheet precast bodies of corresponding sizes are laid down. Water mist is sprayed onto the surface of the refractory mortar sheet precast bodies to wet the surface. The water quickly penetrates into the interior through the pores, softening the upper and lower surfaces of the refractory mortar sheet precast bodies. The upper layer of refractory bricks or precast components is then placed and gently tapped to adjust the position and ensure that the refractory bricks or precast components are in close contact with the refractory mortar sheet precast bodies, thus completing the masonry work.

[0022] This invention provides a sheet-like preform of refractory slurry, comprising porous bauxite clinker, quartz powder, silica powder, isothiazolinone derivatives, passivated aluminum powder, tricalcium aluminate (C3A), dextrin, and an added polyvinyl alcohol solution. The raw materials are mixed, pressed into thin sheets, and cured. Wherein: Porous bauxite clinker, quartz powder, and silica powder are used as the main components to provide the physicochemical properties required for flaky slurry at various temperature ranges, meeting the requirements for use in high-temperature industrial kilns.

[0023] When raw materials such as polyvinyl alcohol, dextrin, and isothiazolinone derivatives are mixed, they generate fine bubbles, which work synergistically with the porous structure of porous bauxite clinker to form a large number of micropores, ensuring rapid water penetration during construction to achieve softening of the sheet-like mud.

[0024] When combined with appropriate proportions and concentrations of polyvinyl alcohol, polyvinyl alcohol can form a network-like colloidal structure, which acts as a skeleton to bind the powder. By controlling the amount of water, a suitable viscosity can be maintained so that it can be pressed into sheets without dissolving when water is added. This provides a sustained high strength. Together with dextrin, it provides early strength for the sheet-like slurry molding process, ensuring the integrity of the sheet-like structure of the slurry during storage, transportation, and laying.

[0025] The synergistic use of passivated aluminum powder and tricalcium aluminate (C3A) serves two purposes. First, the alumina passivation film on the surface of the passivated aluminum powder prevents the aluminum powder from reacting during the raw material mixing process. Second, during the curing process, the alkaline environment formed by the hydrolysis of tricalcium aluminate gradually destroys the alumina passivation film on the surface of the aluminum powder, promoting vigorous hydration and exothermic reaction of the aluminum powder, accelerating the drying and solidification of the slurry to form strength, and further ensuring the stability of the sheet-like structure. At the same time, the hydrogen gas generated by the reaction escapes and forms interconnected micropores, which facilitates water penetration during construction.

[0026] The sheet-like slurry obtained by this invention differs from conventional powders in that it cannot be completely dried. By adding isothiazolinone derivatives, mold spots caused by moisture during storage can be effectively prevented.

[0027] When constructing the obtained refractory mortar sheet precast body on site, it is only necessary to spray water mist on the surface of the refractory bricks and the surface of the refractory mortar sheet precast body. Because the refractory mortar sheet precast body has a large number of pores, water can quickly penetrate into the refractory mortar sheet precast body. Yellow dextrin is easily soluble in water, and after spraying water, it dissolves quickly, making the mortar surface soften into a viscous paste, ensuring a tight bond with the refractory bricks during construction.

[0028] The beneficial effects of this invention are as follows: 1. This invention provides a refractory mortar sheet preform, which uses porous bauxite clinker, quartz powder and silica powder as the main components, synergistically passivated aluminum powder, tricalcium aluminate (C3A) and dextrin, combined with isothiazolinone derivatives, and then adds a polyvinyl alcohol solution of appropriate ratio and concentration. The raw materials are mixed to form sheets and then cured. The resulting refractory mortar sheet preform has a rich microporous structure, which takes into account both heat insulation and water permeability, and at the same time has good molding strength, good plasticity after wetting and high temperature performance, and is suitable for efficient masonry of industrial kilns.

[0029] 2. The refractory slurry sheet preform obtained by the present invention realizes "ready to use on site after unpacking", completely avoiding on-site mixing and reducing labor and equipment costs.

[0030] 3. The present invention also provides a method for preparing the above-mentioned refractory slurry sheet preform. First, the mixing and stirring time of the raw materials is controlled to avoid the failure of the alumina passivation film of the passivated aluminum powder. Then, during the curing process, the alumina passivation film on the surface of the aluminum powder gradually fails in the alkaline environment generated by C3A, and violent hydration and exothermic reaction occur, realizing self-heating drying in the curing stage, which significantly shortens the molding cycle. The preparation method is simple, has high production efficiency, and has prospects for industrial application.

[0031] 4. During construction, this invention only requires water spraying to soften the material before laying, which significantly simplifies the operation, reduces quality fluctuations, and improves the airtightness and structural reliability of the masonry. Moreover, there is no dust pollution during the construction process, the material waste rate is less than 1%, the equipment investment is minimal, and the overall cost is significantly lower than that of traditional processes, resulting in outstanding environmental and economic benefits. Detailed Implementation

[0032] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0033] The raw materials used in the following embodiments and comparative examples of the present invention meet the following standards: The porous bauxite clinker has a particle size of 1.0-0 mm, an alumina content of 56 wt%, and a bulk density of 1.05 g / cm³. 3 The porous bauxite clinker is obtained by grinding bauxite into powder, adding ignition waste wood chips, using aluminum sulfate as a binder, forming balls on a pelletizing disc, and then calcining the balls with a certain strength in a high-temperature kiln at 1400℃. The calcined porous clinker is then crushed into 1-0mm particles for use.

[0034] The particle size of the quartz powder is 0.074-0 mm.

[0035] The passivated aluminum powder has a particle size of 0.5-0.25 mm, with a content of 87.7 wt% elemental aluminum and 12.3 wt% alumina. It is a composite material that has been passivated by a mixture of CO2 and water vapor, resulting in a surface coating of alumina.

[0036] Yellow dextrin is an industrial-grade, room-temperature, water-soluble yellow dextrin.

[0037] Polyvinyl alcohol solution: Cold water-soluble polyvinyl alcohol powder (particle size ≤ 0.088 mm, degree of hydrolysis about 88%) is mixed with water at a mass ratio of 1:20. During the mixing process, water is added while stirring to completely dissolve the powder into a solution. Silica powder: SiO2 content 95.15wt%, particle size d90: 2.37um.

[0038] Tricalcium aluminate (C3A): Industrial grade; Isothiazolinone derivatives: MIT and BIT, model: M95, sourced from Guangzhou Runhong Chemical Co., Ltd.

[0039] Example 1 A refractory mortar sheet preform is provided, wherein the raw material composition, by mass percentage, is: Porous bauxite clinker 1.0-0mm 70%; Quartz powder 0.074-0mm 10%; silica powder 8%; thiazolinone derivatives 0.7%; passivated aluminum powder 0.5-0.25mm 6%; Tricalcium aluminate (C3A) 0.3%; 5% dextrin; 10.5 wt% polyvinyl alcohol solution added.

[0040] The above-mentioned method for preparing refractory slurry sheet-like preforms includes the following steps: 1) Raw material mixing: Weigh each solid raw material according to the mass ratio, mix them evenly, and then add polyvinyl alcohol solution while stirring. Continue stirring until the slurry consistency reaches 106 (0.1 mm) for 25 minutes. 2) Pressing and molding: The above slurry is pressed into 5.5mm thick sheets in a roller press and cut into sizes that match the refractory bricks to be laid on site; 3) Curing and shipping: Place the sheet mud on a horizontal surface of an indoor curing rack for 2 hours. During this time, C3A reacts with aluminum powder to hydrate and release heat, promoting moisture evaporation and strength formation. Then it can be packaged and shipped.

[0041] Example 2 A refractory mortar sheet preform is provided, wherein the raw material composition, by mass percentage, is: Porous bauxite clinker 1.0-0mm 80%; Quartz powder 0.074-0mm 5%; silica powder 5%; thiazolinone derivatives 0.7%; Passivating aluminum powder 0.5-0.25mm 6%; Tricalcium aluminate (C3A) 0.3%; Yellow dextrin 3%; plus 13wt% polyvinyl alcohol solution.

[0042] The above-mentioned method for preparing refractory slurry sheet-like preforms includes the following steps: 1) Raw material mixing: Weigh each solid raw material according to the mass ratio, mix them evenly, and then add polyvinyl alcohol solution while stirring. Continue stirring until the slurry consistency reaches 107 (0.1 mm) for 25 minutes. 2) Pressing and molding: The above slurry is pressed into 5.5mm thick sheets in a roller press and cut into sizes that match the refractory bricks to be laid on site; 3) Curing and shipping: Place the sheet mud on a horizontal surface of an indoor curing rack and cure for 2 hours and 20 minutes. During this period, C3A reacts with aluminum powder to hydrate and release heat, which promotes the evaporation of moisture and the formation of strength. Then it can be packaged and shipped.

[0043] Example 3 A refractory mortar sheet preform is provided, wherein the raw material composition, by mass percentage, is: Porous bauxite clinker 1.0-0mm 70.8%; Quartz powder 0.074-0mm 10%; 10% silica powder; 1.0% thiazolinone derivative; 0.5-0.25mm passivated aluminum powder. 3%; tricalcium aluminate (C3A) 0.2%; dextrin 5%; added polyvinyl alcohol solution 11 wt%.

[0044] The above-mentioned method for preparing refractory slurry sheet-like preforms includes the following steps: 1) Raw material mixing: Weigh each solid raw material according to the mass ratio, mix them evenly, and then add polyvinyl alcohol solution while stirring. Continue stirring until the slurry consistency reaches 105 (0.1 mm) for 20 minutes. 2) Pressing and molding: The above slurry is pressed into 5.5mm thick sheets in a roller press and cut into sizes that match the refractory bricks to be laid on site; 3) Curing and shipping: Place the sheet mud on a horizontal surface of an indoor curing rack and cure for 2 hours and 40 minutes. During this period, C3A reacts with aluminum powder to hydrate and release heat, which promotes the evaporation of moisture and the formation of strength. Then it can be packaged and shipped.

[0045] Example 4 A refractory mortar sheet preform is provided, wherein the raw material composition, by mass percentage, is: Porous bauxite clinker 1.0-0mm 76%; Quartz powder 0.074-0mm 8%; Silica powder 7%; thiazolinone derivatives 0.6%; passivated aluminum powder 0.5-0.25mm 5.0%; Tricalcium aluminate (C3A) 0.1%; 3.3% dextrin; 11.8 wt% added polyvinyl alcohol solution.

[0046] The above-mentioned method for preparing refractory slurry sheet-like preforms includes the following steps: 1) Raw material mixing: Weigh each solid raw material according to the mass ratio, mix them evenly, and then add polyvinyl alcohol solution while stirring. Continue stirring until the slurry consistency reaches 104 (0.1 mm) for 20 minutes. 2) Pressing and molding: The above slurry is pressed into 5.5mm thick sheets in a roller press and cut into sizes that match the refractory bricks to be laid on site; 3) Curing and shipping: Place the sheet mud on a horizontal surface of an indoor curing rack and cure for 2 hours and 10 minutes. During this period, C3A reacts with aluminum powder to hydrate and release heat, which promotes the evaporation of moisture and the formation of strength. Then it can be packaged and shipped.

[0047] A construction method for the above-mentioned refractory mortar sheet precast body is provided, comprising the following steps: During on-site construction, water mist is first sprayed onto the surface of the refractory bricks, and then refractory mortar sheet precast bodies of corresponding sizes are laid. Water mist is sprayed onto the surface of the refractory mortar sheet precast bodies to wet the surface. The water quickly penetrates into the interior through the pores, softening the upper and lower surfaces of the refractory mortar sheet precast bodies. Then, the upper layer of refractory bricks is laid, and the upper layer of bricks is gently tapped with a rubber mallet to adjust the position and ensure that the bricks are in close contact with the refractory mortar, thus completing the masonry.

[0048] Comparative example: A refractory slurry prepared by a conventional process is provided, with the following raw material components by mass percentage: Porous bauxite clinker 1.0-0mm 76%; Quartz powder 0.074-0mm 8%; clay 5.5% silica powder 7%; Yellow dextrin 3%; Carboxymethyl cellulose 0.5%; plus purified water 29%.

[0049] The preparation and construction methods are as follows: After the above powder is dry-mixed evenly in a mixer, it is packaged and shipped out of the factory. At the construction site, the powder and clean water are evenly mixed in a mass ratio of 100:29 to form a paste with a consistency of 350 (0.1mm) that meets the requirements for masonry construction. Then, it is applied for masonry.

[0050] The refractory slurry sheet-like preforms obtained in Examples 1, 2, 3, and 4, and the performance parameters of the comparative slurry are shown in Table 1.

[0051] Table 1 Performance parameters of the embodiments and comparative examples

[0052] As shown in Table 1, the refractory mortar sheet precast body of the present invention is superior to the comparative example in terms of construction efficiency, construction quality, and bond flexural strength. Furthermore, because the refractory mortar sheet precast body of the present invention significantly simplifies the construction process and improves construction efficiency, it represents a novel type of refractory mortar and a novel construction method.

[0053] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A refractory mortar sheet precast body, characterized in that, The raw materials of the refractory mortar sheet preform, by weight percentage, include: The composition consists of 70-80% porous bauxite clinker, 5-10% quartz powder, 5-10% silica fume, 0.5-1.0% isothiazolinone derivative, 3-6% passivated aluminum powder, 0.1-0.3% tricalcium aluminate, 3-5% dextrin, and 10-15% polyvinyl alcohol solution. The mass ratio of polyvinyl alcohol to water in the polyvinyl alcohol solution is 1:18-20; The refractory slurry sheet preform is obtained by mixing the above raw materials evenly, pressing them into thin sheets, and then curing them.

2. The refractory mortar sheet preform according to claim 1, characterized in that, The thickness of the refractory mortar sheet prefabrication is 5-10mm, and its size matches the refractory bricks or prefabricated components to be laid.

3. The refractory mortar sheet preform according to claim 1, characterized in that, The porous bauxite clinker has a particle size of 1.0-0 mm, Al2O3 ≥ 55 wt%, and a bulk density of 0.55-1.2 g / cm³. 3 .

4. The refractory mortar sheet preform according to claim 1, characterized in that, The porous bauxite clinker is obtained by grinding hard clay or bauxite into powder, adding loss on ignition, using aluminum sulfate as a binder, forming pellets, calcining at 1350-1460℃, and finally crushing into 1.0-0mm pieces.

5. The refractory mortar sheet preform according to claim 1, characterized in that, The quartz powder has a particle size of 0.074-0 mm; the silica powder has SiO2 ≥ 92 wt% and d90 ≤ 2.5 μm; the isothiazolinone derivative is at least one of 2-methyl-4-isothiazolin-3-one and 1,2-benzisothiazolin-3-one.

6. The refractory mortar sheet preform according to claim 1, characterized in that, The passivated aluminum powder has a particle size of 0.5-0.25 mm.

7. The refractory mortar sheet preform according to claim 1, characterized in that, The passivated aluminum powder is aluminum powder whose surface is passivated by aluminum oxide coating, wherein the elemental Al content is between 85-95 wt% and the Al2O3 content is between 5-15 wt%.

8. The refractory slurry sheet-like precast body according to claim 7, characterized in that, Passivated aluminum powder is prepared by passing aluminum powder through a mixture of CO2 gas containing water vapor and passivation, or by placing it in air for a long time and then coating its surface with aluminum oxide.

9. A method for preparing a refractory slurry sheet-like preform according to any one of claims 1-8, characterized in that, Includes the following steps: 1) Weigh each solid raw material according to the mass ratio, mix them evenly, and add polyvinyl alcohol solution while stirring. Stir until a viscous slurry is formed. The stirring time should be controlled within 30 minutes. 2) Press the slurry obtained in step 1) into thin sheets and cut them to the size that matches the refractory bricks or precast parts to be laid on site; 3) Curing the sheet-like slurry obtained in step 2) for 1-3 hours yields the refractory slurry sheet-like precast body.

10. A construction method for a refractory mortar sheet precast body according to any one of claims 1-8, characterized in that, Includes the following steps: During on-site construction, water mist is first sprayed onto the surface of the refractory bricks or precast components. Then, refractory mortar sheet precast bodies of corresponding sizes are laid down. Water mist is sprayed onto the surface of the refractory mortar sheet precast bodies to wet the surface. The water quickly penetrates into the interior through the pores, softening the upper and lower surfaces of the refractory mortar sheet precast bodies. The upper layer of refractory bricks or precast components is then placed, and the upper layer of refractory bricks or precast components are gently tapped to adjust their position and ensure close contact with the mortar, thus completing the masonry work.

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