阅读说明：本技术 一种基于粉煤灰的轻质耐火骨料及其制备方法 (Lightweight refractory aggregate based on fly ash and preparation method thereof ) 是由 桑绍柏 杨启宝 李亚伟 万卓夫 徐义彪 朱天彬 于 2021-09-15 设计创作，主要内容包括：本发明涉及一种基于粉煤灰的轻质耐火骨料及其制备方法。其技术方案是：以73～85wt％的粉煤灰、12～23wt％的生矾土细粉和2～8wt％的锆英石尾矿粉为原料,搅拌；再置于开启的造粒机中,喷洒浓度为10～20wt％的磷酸二氢铝溶液,于110～200℃热处理2～4h,得到轻质骨料素坯；将轻质骨料素坯置于开启的第一圆盘造粒机中,喷洒浆料A,转动10～20min,然后于150～200℃条件下固化0.5～24h,得到封孔高强轻质骨料素坯；将封孔高强轻质骨料素坯置于开启的第二圆盘造粒机中,喷洒溶液B,转动10～20min,室温静置,制得基于粉煤灰的轻质耐火骨料。本发明的粉煤灰使用量大且能实现免烧,所制备的基于粉煤灰的轻质耐火骨料的吸水率低、强度高和成本低。(The invention relates to a lightweight refractory aggregate based on fly ash and a preparation method thereof. The technical scheme is as follows: stirring 73-85 wt% of fly ash, 12-23 wt% of raw alumina fine powder and 2-8 wt% of zirconite tailing powder serving as raw materials; placing the mixture in an opened granulator, spraying 10-20 wt% of aluminum dihydrogen phosphate solution, and carrying out heat treatment at 110-200 ℃ for 2-4 h to obtain a lightweight aggregate biscuit; placing the light aggregate biscuit in an opened first disc granulator, spraying the slurry A, rotating for 10-20 min, and curing at 150-200 ℃ for 0.5-24 h to obtain the hole-sealing high-strength light aggregate biscuit; and placing the hole-sealing high-strength lightweight aggregate biscuit in an opened second disc granulator, spraying the solution B, rotating for 10-20 min, and standing at room temperature to obtain the lightweight refractory aggregate based on the fly ash. The fly ash is large in usage amount and can realize baking-free, and the prepared light refractory aggregate based on the fly ash is low in water absorption, high in strength and low in cost.)

1. A preparation method of a lightweight refractory aggregate based on fly ash is characterized by comprising the following steps:

firstly, putting 73-85 wt% of fly ash, 12-23 wt% of raw alumina fine powder and 2-8 wt% of zircon tailing powder as raw materials into a stirrer, and stirring for 10-25 min to obtain a mixture;

secondly, starting a granulator, placing the mixture in the granulator, spraying a 10-20 wt% aluminum dihydrogen phosphate solution to the granulator, and stopping granulation after the mixture is completely converted into granules to obtain a granular biscuit; carrying out heat treatment on the particle biscuit at the temperature of 110-200 ℃ for 2-4 h to obtain a lightweight aggregate biscuit;

the spraying amount of the aluminum dihydrogen phosphate solution is 14-17 wt% of the mixture;

step three, mixing materials according to the mass ratio of the phenolic resin to the alumina micro powder to the industrial alcohol of 1 to (3-5) to (1-5), and uniformly mixing to obtain slurry A;

step four, starting a first disc granulator, placing the light aggregate biscuit in the first disc granulator, spraying the slurry A into the first disc granulator, rotating for 10-20 min, and curing for 0.5-24 h at the temperature of 150-200 ℃ to obtain the hole-sealing high-strength light aggregate biscuit;

the spraying amount of the slurry A is 12-20 wt% of the lightweight aggregate biscuit;

fifthly, mixing the materials according to the mass ratio of the potassium methylsilicate to the water of 1: 30-100, and stirring the materials uniformly at room temperature to obtain a solution B;

step six, opening a second disc granulator, placing the hole-sealing high-strength lightweight aggregate biscuit in the second disc granulator, spraying the solution B into the second disc granulator, rotating for 10-20 min, and standing for 24-72 h at room temperature to prepare the lightweight refractory aggregate based on the fly ash;

the spraying amount of the solution B is 5-10 wt% of the hole-sealing high-strength lightweight aggregate biscuit.

2. The method for preparing a lightweight refractory aggregate based on fly ash as claimed in claim 1, wherein Al of the fly ash is₂O₃The content is more than or equal to 32wt percent.

3. The method for preparing a lightweight refractory aggregate based on fly ash as claimed in claim 1, wherein said raw alumina fine powder contains Al₂O₃The content is more than or equal to 56 wt%; the particle size of the raw bauxite fine powder is less than or equal to 88 mu m.

4. The method for preparing a fly ash-based lightweight refractory aggregate according to claim 1, wherein ZrO of the zircon tailing powder₂The content is more than or equal to 4 wt%; the content of kyanite phase is more than or equal to 40 percent。

5. The method for preparing a lightweight refractory aggregate based on fly ash as claimed in claim 1, wherein Al of the alumina micropowder₂O₃The content is more than or equal to 99 wt%; the granularity of the alumina micro powder is less than or equal to 2 mu m.

6. A lightweight refractory aggregate based on fly ash, characterized in that the preparation of the lightweight refractory aggregate based on fly ash is the lightweight refractory aggregate based on fly ash prepared by the preparation method of the lightweight refractory aggregate based on fly ash according to any one of claims 1 to 5.

Technical Field

The invention belongs to the technical field of light refractory aggregate. In particular to a lightweight refractory aggregate based on fly ash and a preparation method thereof.

Background

The light refractory aggregate has the characteristics of low volume density, high porosity and low coefficient of thermal conductivity, and has better application in the aspect of kiln energy conservation. There are currently two types of methods for preparing lightweight refractory aggregates: one is that the prepared light refractory material is crushed and screened to prepare light refractory aggregate with specific grain diameter; the other is obtained by directly granulating and then sintering at high temperature. Both methods need a firing link, so that the problem of high energy consumption exists; in addition, the light refractory aggregate has the characteristic of high porosity, so that when the light refractory aggregate is applied to a castable, the water absorption is high, water is not easy to discharge in the drying process, the castable has the problems of microcracks and low strength, and even cracks, so that the safety production is influenced.

Coal-fired power generation at home and abroad is accompanied by the generation of a large amount of fly ash, so that the accumulation of the fly ash can not only cause land waste, but also cause air and water pollution. Therefore, comprehensive and efficient utilization of the fly ash is a problem to be solved urgently.

A novel porous mullite lightweight aggregate and a preparation method thereof (CN103467122A) are disclosed, wherein the technology takes aluminum-silicon fine powder and clay powder as raw materials, and the body density of the novel porous mullite lightweight aggregate is 0.8-1.2 g-cm through mud extrusion molding, drying and high-temperature sintering^-3And lightweight aggregate with compressive strength of 15MPa, wherein the apparent porosity of the lightweight aggregate reaches 45-65%. A light mullite aggregate and its preparing process (CN107089839A) are disclosed, which is prepared from glass powder, sillimanite minerals, kaolin and alpha-Al₂O₃The micro powder is taken as a raw material, and is added with dry coke quenching powder, and the mixture is subjected to dry mixing, granulation, drying and high-temperature firing. The prepared lightweight mullite aggregate has the volume density of only 0.5g cm^-3. Both the two patent technologies need high-temperature sintering, no special hole sealing measures are taken, and the prepared lightweight aggregate has very high water absorption.

Ren yuhua et al (Yuhan Ren, Qiang Ren, Zhenzhe Huo, et al preparation of glass shell flash ash-clay base light weight aggregate with low water absorption by using coal carbonate solution binder [ J ]. Materials Chemistry and Physics,2020(256):1-8.) use fly ash and clay as raw Materials, coke as pore-forming agent and sodium carbonate as binder, and fired at drying and 1200 ℃ to obtain a lightweight aggregate with a water absorption of 2.6%. The patent technology of 'a method for preparing mullite aggregate for high-alumina refractory bricks by using high-alumina fly ash as a single aluminum source' (CN104557094A) is characterized in that high-alumina fly ash is used as a main raw material, is pressed and molded by a semi-dry method, is fired at 1600 ℃, and is crushed to prepare the aggregate with the water absorption rate of 1% and the apparent porosity of 2.3%. Although the two methods can prepare the lightweight aggregate with low water absorption, the high-temperature sintering is required, the energy consumption is high, and the additional mechanical crushing of the preparation method of the lightweight aggregate also needs to increase the working procedure and consume energy.

The preparation of the baking-free lightweight aggregate with the core-shell structure and the performance research [ J ] silicate notice, 2016, 35 (7): 2121-2127 ] of Zhuwanxu et al (Zhuwanxu, Zhangdong, Zhouyangmei, and the like) and Pangtuoming et al (Pangtuoming, Lumeng, Youngang, core-shell structure and baking-free lightweight aggregate) are prepared into the fly ash ceramsite by using cement as a bonding agent, and the prepared fly ash ceramsite has low apparent density and does not need to be sintered independently, but the water absorption rate is more than 17.5%, and the cylinder pressure strength is less than 8.0 MPa.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a light refractory aggregate based on fly ash, which has large usage amount of fly ash and can realize baking-free.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

firstly, using 73-85 wt% of fly ash, 12-23 wt% of raw alumina fine powder and 2-8 wt% of zircon tailing powder as raw materials, and placing the raw materials in a stirrer to stir for 10-25 min to obtain a mixture.

Secondly, starting a granulator, placing the mixture in the granulator, spraying a 10-20 wt% aluminum dihydrogen phosphate solution to the granulator, and stopping granulation after the mixture is completely converted into granules to obtain a granular biscuit; and carrying out heat treatment on the particle biscuit at the temperature of 110-200 ℃ for 2-4 h to obtain the lightweight aggregate biscuit.

The spraying amount of the aluminum dihydrogen phosphate solution is 14-17 wt% of the mixture.

Step three, mixing materials according to the mass ratio of the phenolic resin to the alumina micro powder to the industrial alcohol of 1 to (3-5) to (1-5), and uniformly mixing to obtain the slurry A.

And step four, opening the first disc granulator, placing the light aggregate biscuit in the first disc granulator, spraying the slurry A into the first disc granulator, rotating for 10-20 min, and curing for 0.5-24 h at the temperature of 150-200 ℃ to obtain the hole-sealing high-strength light aggregate biscuit.

The spraying amount of the slurry A is 12-20 wt% of the lightweight aggregate biscuit.

And fifthly, mixing the materials according to the mass ratio of the potassium methylsilicate to the water of 1: 30-100, and stirring the materials uniformly at room temperature to obtain a solution B.

And step six, opening a second disc granulator, placing the hole-sealing high-strength lightweight aggregate biscuit in the second disc granulator, spraying the solution B into the second disc granulator, rotating for 10-20 min, and standing for 24-72 h at room temperature to prepare the lightweight refractory aggregate based on the fly ash.

The spraying amount of the solution B is 5-10 wt% of the hole-sealing high-strength lightweight aggregate biscuit.

Al of the fly ash₂O₃The content is more than or equal to 32wt percent.

Al of the raw alumina fine powder₂O₃The content is more than or equal to 56 wt%; the particle size of the raw bauxite fine powder is less than or equal to 88 mu m.

ZrO of the zircon tailing powder₂The content is more than or equal to 4 wt%; the content of kyanite phase is more than or equal to 40 percent.

Al of the alumina micropowder₂O₃The content is more than or equal to 99 wt%; the granularity of the alumina micro powder is less than or equal to 2 mu m.

The first disk pelletizer is the same as the second disk pelletizer.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following positive effects:

the fly ash and the zircon tailing powder adopted by the invention account for more than 75 wt% of the raw materials, so that the utilization ways of the fly ash and the zircon tailing powder are widened, and the production cost of the light refractory aggregate based on the fly ash is obviously reduced. In addition, the characteristic of large specific surface area of the fly ash also lays a foundation for the light weight of the light refractory aggregate based on the fly ash.

On one hand, the invention adopts the slurry A prepared from phenolic resin, alumina micropowder and industrial alcohol to form a relatively compact layer on the surface of the lightweight aggregate biscuit and seal the air holes on the surface of the lightweight aggregate biscuit; on the other hand, potassium methylsilicate as a water repellent and CO in air₂Or the acidic substance reacts to generate a waterproof film, and the water absorption of the lightweight refractory aggregate based on the fly ash can be obviously reduced under the coupling action of the waterproof film and the cured phenolic resin.

The aluminum dihydrogen phosphate solution with the concentration of 10-20% and the mass of 14-17 wt% of the raw materials is used as a bonding agent, so that the light aggregate biscuit can obtain higher strength; when the slurry A containing the phenolic resin is further sprayed on the surface of the lightweight aggregate biscuit, the phenolic resin can permeate into the lightweight aggregate biscuit and coact with the binding agent aluminum dihydrogen phosphate, so that the strength of the lightweight aggregate biscuit is further improved. More importantly, after being subjected to heat treatment at 110-200 ℃ and curing at 150-200 ℃, the prepared lightweight refractory aggregate based on the fly ash has high strength within the range of room temperature to 1500 ℃.

The preparation method of the lightweight refractory aggregate based on the fly ash does not need high-temperature sintering, has simple preparation process and obviously reduces energy consumption. According to the invention, 2-8 wt% of zircon tailing powder containing a kyanite phase is adopted as the raw material, so that the problem of volume shrinkage caused by impurities in the fly ash can be reduced, the high-temperature liquid phase viscosity of the light refractory aggregate based on the fly ash can be increased, the mullite phase development condition is improved, and the prepared light refractory aggregate based on the fly ash has excellent high-temperature performance.

The lightweight refractory aggregate based on the fly ash prepared by the invention has the structural characteristics of compact appearance and loose and porous interior. Through detection: an apparent density of 1.30-1.92 g-^-3(ii) a The bulk density is 0.90-1.35 g-^-3(ii) a The apparent porosity is 20-35%; the water absorption rate is 2-5% after 1 hour; the barrel pressure strength is 8.0-14.5 MPa; the thermal conductivity is 0.225-0.420W/(m & ltk & gt).

Therefore, the invention has the characteristics of large usage amount of the fly ash and realization of baking-free, and the prepared lightweight refractory aggregate based on the fly ash has low water absorption, high strength and low cost.

Detailed Description

The invention is further described with reference to specific embodiments, without limiting its scope.

In order to avoid repetition, the chemical components and particle sizes of the raw materials in this embodiment are uniformly described as follows, and are not described in detail in the examples:

al of the fly ash₂O₃The content is more than or equal to 32wt percent.

Al of the raw alumina fine powder₂O₃The content is more than or equal to 56 wt%; the particle size of the raw bauxite fine powder is less than or equal to 88 mu m.

ZrO of the zircon tailing powder₂The content is more than or equal to 4 wt%; the content of kyanite phase is more than or equal to 40 percent.

Al of the alumina micropowder₂O₃The content is more than or equal to 99 wt%; the granularity of the alumina micro powder is less than or equal to 2 mu m.

The first disk pelletizer is the same as the second disk pelletizer.

Example 1

A lightweight refractory aggregate based on fly ash and a preparation method thereof. The preparation method in this example is:

firstly, 73-77 wt% of fly ash, 17-23 wt% of raw alumina fine powder and 4-8 wt% of zircon tailing powder are used as raw materials and placed in a stirrer to be stirred for 10-14 min, and then a mixture is obtained.

Secondly, starting a granulator, placing the mixture in the granulator, spraying a 10-12.5 wt% aluminum dihydrogen phosphate solution to the granulator, and stopping granulation after the mixture is completely converted into granules to obtain a granule biscuit; and carrying out heat treatment on the particle biscuit at the temperature of 110-135 ℃ for 2-2.5 h to obtain the lightweight aggregate biscuit.

The spraying amount of the aluminum dihydrogen phosphate solution is 14-15 wt% of the mixture.

Step three, mixing materials according to the mass ratio of the phenolic resin to the alumina micro powder to the industrial alcohol of 1 to (3-4) to (1-3), and uniformly mixing to obtain the slurry A.

And step four, opening the first disc granulator, placing the light aggregate biscuit in the first disc granulator, spraying the slurry A into the first disc granulator, rotating for 10-12.5 min, and curing for 0.5-6.5 h at the temperature of 150-160 ℃ to obtain the hole-sealing high-strength light aggregate biscuit.

The spraying amount of the slurry A is 12-14 wt% of the lightweight aggregate biscuit.

And fifthly, mixing the materials according to the mass ratio of the potassium methylsilicate to the water of 1: 30-45, and stirring the materials uniformly at room temperature to obtain a solution B.

And step six, opening a second disc granulator, placing the hole-sealing high-strength lightweight aggregate biscuit in the second disc granulator, spraying the solution B into the second disc granulator, rotating for 10-12 min, and standing for 24-36 h at room temperature to prepare the lightweight refractory aggregate based on the fly ash.

The spraying amount of the solution B is 5-7 wt% of the hole-sealing high-strength lightweight aggregate biscuit.

The lightweight refractory aggregate based on fly ash prepared in this example was tested: an apparent density of 1.65-1.92 g-^-3(ii) a The bulk density is 1.17-1.35 g-^-3(ii) a The apparent porosity is 20-26%; the water absorption rate is 2.0-3.2% after 1 hour; the barrel pressure strength is 10.8-14.5 MPa; the thermal conductivity is 0.321-0.420W/(m & lt K & gt).

Example 2

A lightweight refractory aggregate based on fly ash and a preparation method thereof. The preparation method in this example is:

step one, 77-81 wt% of fly ash, 15-17 wt% of raw alumina fine powder and 4-7 wt% of zircon tailing powder are used as raw materials and placed in a stirrer to be stirred for 14-18 min, and then a mixture is obtained.

Secondly, starting a granulator, placing the mixture in the granulator, spraying an aluminum dihydrogen phosphate solution with the concentration of 12.5-15 wt% to the granulator, and stopping granulation after the mixture is completely converted into granules to obtain a granule biscuit; and carrying out heat treatment on the particle biscuit at 135-160 ℃ for 2.5-3 h to obtain the lightweight aggregate biscuit.

The spraying amount of the aluminum dihydrogen phosphate solution is 15-15.5 wt% of the mixture.

Step three, mixing materials according to the mass ratio of the phenolic resin to the alumina micro powder to the industrial alcohol of 1 to (3-4) to (3-5), and uniformly mixing to obtain the slurry A.

And step four, opening the first disc granulator, placing the light aggregate biscuit in the first disc granulator, spraying the slurry A into the first disc granulator, rotating for 12.5-15 min, and curing for 6.5-12.5 h at 160-175 ℃ to obtain the hole-sealing high-strength light aggregate biscuit.

The spraying amount of the slurry A is 14-16 wt% of the lightweight aggregate biscuit.

And fifthly, mixing the materials according to the mass ratio of the potassium methylsilicate to the water of 1: 45-60, and stirring the materials uniformly at room temperature to obtain a solution B.

And step six, opening a second disc granulator, placing the hole-sealing high-strength lightweight aggregate biscuit in the second disc granulator, spraying the solution B into the second disc granulator, rotating for 12-14 min, and standing for 36-48 h at room temperature to prepare the lightweight refractory aggregate based on the fly ash.

The spraying amount of the solution B is 7-8 wt% of the hole-sealing high-strength lightweight aggregate biscuit.

The lightweight refractory aggregate based on fly ash prepared in this example was tested: an apparent density of 1.51-1.78 g-^-3(ii) a The bulk density is 1.06-1.25 g-^-3(ii) a The apparent porosity is 23-31%; water absorption rate of 1h2.5 to 3.9 percent; the barrel pressure strength is 9.2-12.0 MPa; the thermal conductivity is 0.271-0.363W/(m &).

Example 3

A lightweight refractory aggregate based on fly ash and a preparation method thereof. The preparation method in this example is:

step one, 81-83 wt% of fly ash, 14-16 wt% of raw alumina fine powder and 3-5 wt% of zircon tailing powder are used as raw materials and placed in a stirrer to be stirred for 18-22 min, and then a mixture is obtained.

Secondly, starting a granulator, placing the mixture in the granulator, spraying an aluminum dihydrogen phosphate solution with the concentration of 15-17.5 wt% to the granulator, and stopping granulation after the mixture is completely converted into granules to obtain a granule biscuit; and carrying out heat treatment on the particle biscuit at 160-185 ℃ for 3-3.5 h to obtain the lightweight aggregate biscuit.

The spraying amount of the aluminum dihydrogen phosphate solution is 15.5-16.5 wt% of the mixture.

Step three, mixing materials according to the mass ratio of the phenolic resin to the alumina micro powder to the industrial alcohol of 1 to (4-5) to (1-3), and uniformly mixing to obtain the slurry A.

And step four, opening the first disc granulator, placing the light aggregate biscuit in the first disc granulator, spraying the slurry A into the first disc granulator, rotating for 15-17.5 min, and curing at 175-190 ℃ for 12.5-18 h to obtain the hole-sealing high-strength light aggregate biscuit.

The spraying amount of the slurry A is 16-18 wt% of the lightweight aggregate biscuit.

And fifthly, mixing the materials according to the mass ratio of the potassium methylsilicate to the water of 1: 60-80, and stirring the materials uniformly at room temperature to obtain a solution B.

And step six, opening a second disc granulator, placing the hole-sealing high-strength lightweight aggregate biscuit in the second disc granulator, spraying the solution B into the second disc granulator, rotating for 14-17 min, and standing for 48-60 h at room temperature to prepare the lightweight refractory aggregate based on the fly ash.

The spraying amount of the solution B is 8-9 wt% of the hole-sealing high-strength lightweight aggregate biscuit.

The lightweight refractory aggregate based on fly ash prepared in this example was tested: an apparent density of 1.43-1.60 g-^-3(ii) a The bulk density is 1.00-1.15 g-^-3(ii) a The apparent porosity is 26-33%; the water absorption rate is 3.1-4.7% after 1 hour; the barrel pressure strength is 8.8-10.5 MPa; the thermal conductivity is 0.243-0.298W/(m & lt K & gt).

Example 4

A lightweight refractory aggregate based on fly ash and a preparation method thereof. The preparation method in this example is:

step one, taking 83-85 wt% of fly ash, 12-15 wt% of raw alumina fine powder and 2-5 wt% of zircon tailing powder as raw materials, and placing the raw materials in a stirrer to stir for 22-25 min to obtain a mixture.

Secondly, starting a granulator, placing the mixture in the granulator, spraying a 17.5-20 wt% aluminum dihydrogen phosphate solution to the granulator, and stopping granulation after the mixture is completely converted into granules to obtain a granule biscuit; and carrying out heat treatment on the particle biscuit at 185-200 ℃ for 3.5-4 h to obtain the lightweight aggregate biscuit.

The spraying amount of the aluminum dihydrogen phosphate solution is 16.5-17 wt% of the mixture.

Step three, mixing materials according to the mass ratio of the phenolic resin to the alumina micro powder to the industrial alcohol of 1 to (4-5) to (3-5), and uniformly mixing to obtain the slurry A.

And step four, opening the first disc granulator, placing the light aggregate biscuit in the first disc granulator, spraying the slurry A into the first disc granulator, rotating for 17.5-20 min, and curing for 18-24 h at 190-200 ℃ to obtain the hole-sealing high-strength light aggregate biscuit.

The spraying amount of the slurry A is 18-20 wt% of the lightweight aggregate biscuit.

And fifthly, mixing the materials according to the mass ratio of the potassium methylsilicate to the water of 1: 80-100, and stirring the materials uniformly at room temperature to obtain a solution B.

And step six, opening a second disc granulator, placing the hole-sealing high-strength lightweight aggregate biscuit in the second disc granulator, spraying the solution B into the second disc granulator, rotating for 17-20 min, and standing for 60-72 h at room temperature to prepare the lightweight refractory aggregate based on the fly ash.

The spraying amount of the solution B is 9-10 wt% of the hole-sealing high-strength lightweight aggregate biscuit.

The lightweight refractory aggregate based on fly ash prepared in this example was tested: an apparent density of 1.30-1.51 g-^-3(ii) a The bulk density is 0.90-1.08 g-^-3(ii) a The apparent porosity is 29-35%; the water absorption rate is 4.2-5.0% after 1 hour; the barrel pressure strength is 8.0-9.5 MPa; the thermal conductivity is 0.225-0.265W/(m & ltk & gt).

Compared with the prior art, the specific implementation mode has the following positive effects:

the usage amount of the fly ash and the zircon tailing powder adopted by the embodiment accounts for more than 75 wt% of the raw materials, so that the utilization ways of the fly ash and the zircon tailing powder are widened, and the production cost of the light refractory aggregate based on the fly ash is obviously reduced. In addition, the characteristic of large specific surface area of the fly ash also lays a foundation for the light weight of the light refractory aggregate based on the fly ash.

On one hand, the concrete embodiment adopts the slurry A prepared from phenolic resin, alumina micro powder and industrial alcohol to form a relatively compact layer on the surface of the lightweight aggregate biscuit and seal the air holes on the surface of the lightweight aggregate biscuit; on the other hand, potassium methylsilicate as a water repellent and CO in air₂Or the acidic substance reacts to generate a waterproof film, and the water absorption of the lightweight refractory aggregate based on the fly ash can be obviously reduced under the coupling action of the waterproof film and the cured phenolic resin.

In the specific embodiment, the aluminum dihydrogen phosphate solution with the raw material mass of 14-17 wt% and the concentration of 10-20% is used as a binding agent, so that the lightweight aggregate biscuit can obtain higher strength; when the slurry A containing the phenolic resin is further sprayed on the surface of the lightweight aggregate biscuit, the phenolic resin can permeate into the lightweight aggregate biscuit and coact with the binding agent aluminum dihydrogen phosphate, so that the strength of the lightweight aggregate biscuit is further improved. More importantly, after being subjected to heat treatment at 110-200 ℃ and curing at 150-200 ℃, the prepared lightweight refractory aggregate based on the fly ash has high strength within the range of room temperature to 1500 ℃.

The preparation method of the light refractory aggregate based on the fly ash does not need high-temperature sintering, has simple preparation process and obviously reduces energy consumption. In the embodiment, 2-8 wt% of zircon tailing powder containing a kyanite phase is adopted as the raw materials, so that the problem of volume shrinkage caused by impurities in the fly ash can be solved, the viscosity of a high-temperature liquid phase in the light refractory aggregate based on the fly ash can be increased, the development condition of a mullite phase is improved, and the prepared light refractory aggregate based on the fly ash has excellent high-temperature performance.

The lightweight refractory aggregate based on fly ash prepared by the specific embodiment has the structural characteristics of compact appearance and loose and porous interior. Through detection: an apparent density of 1.30-1.92 g-^-3(ii) a The bulk density is 0.90-1.35 g-^-3(ii) a The apparent porosity is 20-35%; the water absorption rate is 2-5% after 1 hour; the barrel pressure strength is 8.0-14.5 MPa; the thermal conductivity is 0.225-0.420W/(m & ltk & gt).

Therefore, the specific embodiment has the characteristics of large usage amount of the fly ash and realization of baking-free, and the prepared light refractory aggregate based on the fly ash has low water absorption rate, high strength and low cost.