Method for preparing heat insulation plate through resource utilization of waste aerogel felt

Abstract

The invention discloses a method for preparing a heat insulation plate by resource utilization of waste aerogel felt. The method comprises the following steps: firstly, crushing the waste aerogel felt into a crushed product containing chopped fibers and aerogel powder; then adding a surfactant and white cement into deionized water, and uniformly stirring and mixing to obtain a mixed solution; slowly adding the obtained crushed products into the obtained mixed solution in batches, and uniformly stirring and mixing, so as to obtain the heat-insulating daub. And finally, pouring and molding the obtained heat-insulating cement in a layered pouring manner, and drying at normal pressure after pouring to obtain the heat-insulating plate. The waste hydrophobic aerogel felt broken material is subjected to surface modification through the surfactant, uniform dispersion of the waste hydrophobic aerogel felt broken material in water is achieved in combination with mechanical strong stirring, then low-mixing-amount white cement is used as a cementing material, and preparation of the heat insulation plate is successfully achieved through the layered pouring and normal-pressure drying technology. The method is simple in process and extremely low in preparation cost, the problem of solid waste disposal is thoroughly solved, and resource utilization of waste materials is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerogel recycling, and particularly relates to a method for preparing a heat insulation board by recycling waste aerogel felt. BACKGROUND

[0002] As a super thermal insulation material, the silica aerogel felt has high efficient thermal insulation performance and high temperature resistance, and thus is widely used in the fields of military, aerospace, metallurgy, chemical industry, building energy saving and the like. With the increasing attention to environmental protection and sustainable development in the world, and the rapid development of new energy and building energy saving, the market demand for the aerogel felt is continuously increasing. However, in the process of capacity expansion, the quantity of waste aerogel felt, including the offcut and by-product generated in the production process, is also increasing.

[0003] The waste aerogel felt is difficult to be treated by incineration as an inorganic high-temperature resistant material. If it is treated by landfill, there are risks of occupying a large amount of land space, high treatment cost and secondary pollution, and also causes waste of valuable resources. How to effectively reduce the treatment cost of the waste aerogel felt, reduce the potential risk of organic modification residues to the environment, and promote the healthy development of circular economy, becomes a key problem to be solved. Therefore, it is particularly important to develop a recycling technology for the waste aerogel felt. SUMMARY

[0004] In view of the above problems in the prior art, the present application provides a method for preparing a heat insulation board by recycling waste aerogel felt, which solves the problems of occupying a large amount of land space, high treatment cost, secondary pollution risk and resource waste in the prior art by landfill treatment of waste aerogel felt.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A method for preparing a heat insulation board by recycling waste aerogel felt, comprising the following steps:

[0007] (1) crushing the waste aerogel felt to obtain a crushed product containing short fibers and aerogel powder;

[0008] (2) adding a surfactant and white cement to deionized water and stirring and mixing uniformly to obtain a mixed solution;

[0009] (3) slowly adding the crushed product obtained in step (1) to the mixed solution obtained in step (2) in batches, and stirring and mixing uniformly to obtain a heat insulation mortar;

[0010] (4) pouring and forming the heat insulation mortar obtained in step (3) by layering, and drying at normal pressure after pouring to obtain a heat insulation board.

[0011] Further, in step (1), the length of the short-cut fiber is 6-12 mm.

[0012] Further, in step (2), the surface active agent is hydroxypropyl methylcellulose or hydroxyethyl cellulose.

[0013] Further, in step (2), in the mixed solution, the amount of each substance added is, by mass percentage: 0.5%-2% of the surface active agent, 2%-5% of the white cement.

[0014] Further, in step (2), in the mixed solution, the mass ratio of deionized water to the sum of the mass of the surface active agent and the white cement is 17-26:1.

[0015] Further, the mass ratio of the waste old aerogel felt to the mixed solution obtained in step (2) is 75:260-350.

[0016] Further, in step (3), the stirring speed is 1500-2000 rpm.

[0017] Further, in step (4), when pouring, the mold used for pouring is kept vibrating continuously or a vibrating rod is used to vibrate the mortar in the mold.

[0018] Further, in step (4), the normal pressure drying is first drying at 50-70℃ for 7-9h, and then drying at 90-110℃ for 1-3h.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. The present application innovatively uses water-soluble organic substances such as hydroxymethyl / hydroxyethyl cellulose to modify the surface of waste old hydrophobic aerogel felt broken material, and combines mechanical stirring to realize its uniform dispersion in water. Then, with low-dosage white cement as a cementing material, without the need for molding, supercritical drying and high-temperature sintering, through the process of layer pouring and normal pressure drying, the efficient resource utilization of waste old aerogel felt is successfully realized. This method not only has a simple process and extremely low preparation cost, but also completely solves the problem of solid waste disposal and realizes the complete recovery and high-value conversion of waste materials.

[0021] 2. The composite board prepared by the present application has excellent heat insulation performance and excellent fire safety: its thermal conductivity is significantly lower than that of traditional rock wool board and polystyrene board, showing excellent heat preservation and insulation effect; at the same time, with the introduction of white cement, the composite board has low calorific value and high fireproof grade, and the low-dosage white cement also does not significantly increase the thermal conductivity, breaking the bottleneck that traditional thermal insulation materials are difficult to balance heat insulation and fireproof performance. It provides a breakthrough solution for the building energy-saving field with low cost, high performance and environmental friendliness. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application will be further described in conjunction with the specific examples.

[0023] The numerical ranges recited herein are inclusive of the recited endpoints and of every integer and fraction within the recited range. All intermediate ranges and subranges between the recited ranges are included herein. The upper and lower limits of these smaller ranges can independently be included or excluded in the smaller ranges.

[0024] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described herein. In case of conflict, the content of the present specification will control. As used herein, the terms “comprises”, “comprising”, “includes”, “including”, “has”, “having”, and the like are open-ended terms that are intended to denote the inclusion of elements or steps without excluding the presence of other elements or steps.

[0025] The experimental methods used in the present application are conventional methods unless otherwise specified.

[0026] The materials, reagents, etc. used in the present application can be purchased or synthesized by known methods unless otherwise specified.

[0027] The quantitative test in the present application is set up with three repeated experiments, and the average value is taken.

[0028] Example 1

[0029] The present embodiment provides a method for preparing a heat insulation board by recycling waste aerogel felt, comprising the following steps:

[0030] (1) 75 g of waste aerogel felt is put into a crusher with a 10 mm screen to be crushed, and a crushed product containing short-cut fibers and aerogel powder is obtained;

[0031] (2) 3 g of hydroxyethyl cellulose and 10 g of white cement are added to 300 g of deionized water, and a mechanical stirrer is used to stir at a speed of 600 r / min for 10 min, so that the solute is uniformly dispersed in the water to form a uniform solution;

[0032] (3) The broken product obtained in step (1) is slowly added to the solution prepared in step (2) in batches, and strong mechanical stirring is carried out at a speed of 2000 r / min until the broken product is uniformly mixed in the solution, and then the stirring is stopped, to obtain the thermal insulation mortar;

[0033] (4) The thermal insulation mortar prepared in step (3) is poured into a mold (200*200*15mm) on a vibrating table in a layered pouring manner, and the vibrating table is vibrated during the pouring process. After pouring is completed, it is dried at 60°C for 8h and then at 100°C for 2h in sequence to obtain the thermal insulation board.

[0034] Example 2

[0035] The embodiment provides a method for preparing a thermal insulation board by recycling waste aerogel felt, comprising the following steps:

[0036] (1) 75g of waste aerogel felt is put into a crusher with a 10mm screen to be broken, to obtain a broken product containing short fibers and aerogel powder;

[0037] (2) 2g of hydroxyethyl cellulose and 8g of white cement are added to 260g of deionized water, and a mechanical stirrer is used to stir at a speed of 600r / min for 10min, so that the solute is uniformly dispersed in the water to form a uniform solution;

[0038] (3) The broken product obtained in step (1) is slowly added to the solution prepared in step (2) in batches, and strong mechanical stirring is carried out at a speed of 2000 r / min until the broken product is uniformly mixed in the solution, and then the stirring is stopped, to obtain the thermal insulation mortar;

[0039] (4) The thermal insulation mortar prepared in step (3) is poured into a mold (200*200*15mm) on a vibrating table in a layered pouring manner, and the vibrating table is vibrated during the pouring process. After pouring is completed, it is dried at 60°C for 8h and then at 100°C for 2h in sequence to obtain the thermal insulation board.

[0040] Example 3

[0041] The embodiment provides a method for preparing a thermal insulation board by recycling waste aerogel felt, comprising the following steps:

[0042] (1) 75g of waste aerogel felt is put into a crusher with a 10mm screen to be broken, to obtain a broken product containing short fibers and aerogel powder;

[0043] (2) 3g of hydroxypropyl methyl cellulose and 10g of white cement are added to 260g of deionized water, and a mechanical stirrer is used to stir at a speed of 600r / min for 10min, so that the solute is uniformly dispersed in the water to form a uniform solution;

[0044] (3) slowly add the broken product obtained in step (1) into the solution prepared in step (2) in batches, and perform strong mechanical stirring at a rotation speed of 2000 r / min until the broken product is uniformly mixed in the solution, and then stop stirring, to obtain the thermal insulation mortar;

[0045] (4) the thermal insulation mortar prepared in step (3) is poured into a mold (200*200*15mm) on a vibrating table in a layered pouring manner, the vibrating table is vibrated during the pouring process, and after the pouring is completed, the thermal insulation board is obtained after being sequentially dried at 60℃ for 8h and dried at 100℃ for 2h.

[0046] The performance comparison table of the thermal insulation boards prepared in examples 1-3 is shown in table 1.

[0047] Table 1 Performance comparison table of the thermal insulation boards prepared in examples 1-3

[0048]

[0049] As can be seen from table 1, the thermal insulation board prepared by the method of the present application not only realizes the resource utilization of waste aerogel felt, but also has excellent thermal insulation performance, and the thermal conductivity coefficient at room temperature is ≤0.033 (W·m -1 ·K -1 ), which is greatly improved compared with the thermal insulation board prepared by the prior art. The heat value of the thermal insulation board is also low, and the fireproof performance is strong.

[0050] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the technical solutions. Those of ordinary skill in the art should understand that those who modify or equivalently replace the technical solutions of the present application without departing from the purpose and scope of the technical solutions should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing heat insulation boards by resource utilization of waste aerogel felt, characterized in that, Includes the following steps: (1) The waste aerogel felt is crushed to obtain a crushed product containing short fibers and aerogel powder. (2) Add the surfactant and white cement to deionized water and stir to mix evenly to obtain a mixed solution; (3) Add the crushed product obtained in step (1) slowly in batches to the mixed solution obtained in step (2) and stir to mix evenly to obtain heat insulation mortar; (4) The heat insulation mortar obtained in step (3) is poured into shape by layering. After pouring, it is dried under normal pressure to obtain the heat insulation board.

2. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, In step (1), the length of the chopped fiber is 6 to 12 mm.

3. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, In step (2), the surfactant is hydroxypropyl methylcellulose or hydroxyethylcellulose.

4. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, In step (2), the amount of each substance added to the mixed solution by mass percentage is: surfactant 0.5% to 2% and white cement 2% to 5%.

5. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 4, characterized in that, In step (2), the mass ratio of deionized water to the sum of the mass of surfactant and white cement in the mixed solution is 17 to 26:

1.

6. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, The mass ratio of the waste aerogel felt to the mixed solution obtained in step (2) is 75:260-350.

7. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, In step (3), the stirring speed is 1500-2000 rpm.

8. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, In step (4), during pouring, the mold used for pouring is kept vibrating continuously or a vibrating rod is used to vibrate the clay in the mold.

9. The method for preparing heat insulation boards by resource utilization of waste aerogel felt according to claim 1, characterized in that, In step (4), the atmospheric pressure drying is first drying at 50-70℃ for 7-9 hours, and then drying at 90-110℃ for 1-3 hours.

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