A construction waste sintered brick for thermal insulation and a preparation method thereof

Abstract

The application discloses a construction waste sintered brick for heat preservation and a preparation method thereof, and relates to the technical field of sintered bricks. The modified fly ash is wrapped by aerogel, so that the fine coal gangue and construction waste can be embedded in the surface mesopore of the modified flyash, and then the sintered brick is prepared from the starch, the modified fly ash and the sludge. In the sintering process, the aerogel is carbonized to form a fixed structure, the sintering shrinkage deformation of the fly ash is inhibited, the starch forms carbon microspheres, and the carbon aerogel is connected. Then, the brick body is wetted by a sodium hydroxide solution, and the second sintering is carried out, so that the solid network support structure is formed in the brick body, the mechanical properties and the heat preservation performance of the sintered brick are improved, the internal pores of the sintered brick are regulated, and the high water absorption of the sintered brick is prevented.

Description

Technical Field

[0001] This invention relates to the field of sintered brick technology, specifically to a thermal insulation sintered brick made from construction waste and its preparation method. Background Technology

[0002] Construction waste refers to the debris generated after the demolition of man-made buildings and structures. It is generally produced during the construction process or the repair and demolition of old buildings, and is a significant type of urban solid waste. The amount of construction waste is increasing daily. Each demolished building generates hundreds or even thousands of tons of construction waste. Construction waste not only occupies space, pollutes groundwater and air, but is also difficult to decompose.

[0003] Building energy conservation is one of the requirements for sustainable development in my country. Ordinary sintered insulating bricks have high thermal conductivity and high bulk density, and use a large amount of arable clay, which does not meet environmental protection requirements. Solid lightweight inorganic porous insulation materials have high water absorption, and their moisture retention performance is easily affected by humidity, resulting in a significant reduction. Organic porous insulation materials are flammable, prone to aging, and have poor durability. Summary of the Invention

[0004] The purpose of this invention is to provide a thermal insulation sintered brick made from construction waste and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a sintered brick made from construction waste for thermal insulation, wherein the sintered brick made from construction waste for thermal insulation comprises coal gangue, starch, construction waste, modified fly ash, and sludge.

[0006] Furthermore, the modified fly ash is prepared by first grinding the fly ash in alkaline mist, then grinding it a second time in quaternization modifier mist, and then polymerizing it with resorcinol to form an aerogel-encapsulated modified fly ash.

[0007] Furthermore, the quaternization modifier is prepared from dimethylaminoacetaldehyde and bromoethane.

[0008] Furthermore, the sludge is sludge from a wastewater treatment plant.

[0009] Furthermore, a method for preparing sintered bricks from construction waste for thermal insulation includes the following preparation steps:

[0010] (1) Mix 1-5 parts of dimethylaminoacetaldehyde, 2-6 parts of bromoethane and 18-22 parts of anhydrous ethanol, heat to 80°C, stir for 8 hours, distill at -0.07 MPa and 48°C for 4 hours, wash with ether 5 times, and dry at 50°C for 12 hours to obtain quaternization modifier.

[0011] (2) Place fly ash in a ball mill and ball mill for 20 min. Then turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 3-8 L / min. Continue grinding for 40-60 min. Turn off the atomizer and stop ball milling. Heat at 95°C for 100-200 min, then raise the temperature to 120°C and dry for 2-4 h. Turn on the atomizer and pass in a quaternizing modifier aqueous solution with a mass fraction of 0.3-2.2% at 10-15 L / min. Continue grinding for 3-6 h to obtain quaternized fly ash.

[0012] (3) Mix 10-20 parts of resorcinol, 4-12 parts of quaternized fly ash, and 0.1-0.6 parts of sodium hydroxide, add anhydrous ethanol until the solid content is 15-30%, stir at 100-300 rpm for 2-3 hours, seal, age at 90℃ for 72 hours, cut into blocks with a length and width of 0.5 cm, freeze to obtain modified fly ash;

[0013] (4) Place 30-56 parts of construction waste and 6-20 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill for 10-30 minutes. Then add 24-30 parts of modified fly ash, 11-27 parts of sludge, and 5-15 parts of starch, and add water to a moisture content of 8-15%. Extrude the mixture at 15-25 MPa, dry it at 150-200℃ for 60-100 minutes, then heat it to 950-1000℃ and calcine it for 2-3 hours to obtain bricks. Cool the bricks to 180-200℃, spray them with a sodium hydroxide aqueous solution of 0.5-2.2 times the weight of the bricks, keep them warm for 3-5 hours, then heat them to 950-1000℃ and calcine them for 100-150 minutes to obtain sintered bricks made from construction waste for insulation.

[0014] Furthermore, the stirring speed in step (1) is 40 to 80 rpm.

[0015] Furthermore, the grinding medium in step (2) is a zirconia ball.

[0016] Furthermore, the ball milling conditions described in steps (2) and (3) are: a speed of 400 rpm and a ball-to-material ratio of 5:1.

[0017] Furthermore, the specific freezing process in step (3) is as follows: after pre-freezing in a refrigerator for 5 to 7 hours, it is placed in a freeze dryer with a cold trap temperature of -65°C and a vacuum degree of 1 Pa and dried for 24 to 40 hours.

[0018] Furthermore, the mass concentration of the sodium hydroxide aqueous solution in step (4) is 30 g / L.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0020] This invention first crushes coal gangue and construction waste, then mixes them with starch, modified fly ash, sludge, and other raw materials. During the mixing process, the fine coal gangue and construction waste are embedded into the mesopores on the surface of the modified fly ash by mechanical force. At the same time, starch and sludge form a binder to connect the modified fly ash. Then, a first sintering is performed. At high temperature, the modified fly ash and the starch between the fly ash particles carbonize, and the starch forms carbon microspheres that connect to the carbon aerogel. Next, the brick blank is moistened with sodium hydroxide solution and a second sintering is performed. At high temperature, the coal gangue reacts with alkali to form calcium silicate, and adjacent coal gangue powders form loose fragments during the sintering process, further connecting the carbon aerogel to form a solid network support structure. This reduces the deformation of the sintered brick, improves the mechanical and thermal insulation properties of the sintered brick, and simultaneously regulates the internal porosity of the sintered brick to prevent excessive water absorption.

[0021] This invention involves a first grinding of fly ash in an alkaline mist. Mechanical grinding enhances the adsorption effect of the fly ash, thereby adsorbing alkaline solutions from the surrounding environment and activating the potential activity of the fly ash, resulting in a negative charge on its surface. A second grinding process is then performed using a quaternization modifier, generated from the reaction of dimethylaminoacetaldehyde and bromoethane, as the mist. The positively charged quaternization modifier interacts electrostatically with the negative charge on the fly ash surface. This modifier is then used as a raw material to polymerize with resorcinol, forming an aerogel-encapsulated modified fly ash. During sintering, the modified fly ash undergoes surface carbonization, forming a fixed structure that inhibits sintering shrinkage and deformation, thereby improving the mechanical properties of the sintered bricks. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] (1) Mix 1 part dimethylaminoacetaldehyde, 2 parts bromoethane and 18 parts anhydrous ethanol, heat to 80°C, stir at 40 rpm for 8 h, distill at -0.07 MPa and 48°C for 4 h, wash with ether 5 times, dry at 50°C for 12 h to obtain quaternization modifier.

[0025] (2) Place fly ash in a ball mill and use zirconia balls as the grinding medium. After ball milling for 20 minutes at 400 rpm and a ball-to-material ratio of 5:1, turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 3 L / min. Continue grinding for 40 minutes, turn off the atomizer, stop ball milling, heat at 95℃ for 100 minutes, then raise the temperature to 120℃ and dry for 2 hours. Turn on the atomizer and pass in a 0.3% quaternization modifier aqueous solution at 10 L / min. Continue grinding for 3 hours to obtain quaternized fly ash.

[0026] (3) Mix 10 parts resorcinol, 4 parts quaternized fly ash, and 0.1 parts sodium hydroxide, add anhydrous ethanol until the solid content is 15%, stir at 100 rpm for 2 hours, seal, age at 90°C for 72 hours, cut into blocks with a length and width of 0.5 cm, pre-freeze in a refrigerator for 5 hours, and then put them into a freeze dryer with a cold trap temperature of -65°C and a vacuum degree of 1 Pa for 24 hours to obtain modified fly ash;

[0027] (4) Place 30 parts of construction waste and 6 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill at 400 rpm and a ball-to-material ratio of 5:1 for 10 min. Then add 24 parts of modified fly ash, 11 parts of sludge, and 5 parts of starch, and add water to a moisture content of 8%. Extrude and mold at 15 MPa, dry at 150℃ for 60 min, then heat to 950℃ and calcine for 2 h to obtain bricks. Cool to 180℃, spray with 0.5 times the mass of the bricks of a sodium hydroxide aqueous solution with a mass concentration of 30 g / L, keep warm for 3 h, then heat to 950℃ and calcine for 100 min to obtain sintered bricks made from construction waste for insulation.

[0028] Example 2

[0029] (1) Mix 3 parts of dimethylaminoacetaldehyde, 4 parts of bromoethane and 20 parts of anhydrous ethanol, heat to 80°C, stir at 60 rpm for 8 hours, distill at -0.07 MPa and 48°C for 4 hours, wash with ether 5 times, and dry at 50°C for 12 hours to obtain quaternization modifier.

[0030] (2) Place fly ash in a ball mill and use zirconia balls as the grinding medium. After ball milling for 20 minutes at 400 rpm and a ball-to-material ratio of 5:1, turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 5 L / min. Continue grinding for 50 minutes, turn off the atomizer, stop ball milling, heat at 95℃ for 150 minutes, then raise the temperature to 120℃ and dry for 3 hours. Turn on the atomizer and pass in a 1.3% quaternization modifier aqueous solution at 12 L / min. Continue grinding for 4.5 hours to obtain quaternized fly ash.

[0031] (3) Mix 15 parts resorcinol, 8 parts quaternized fly ash, and 0.3 parts sodium hydroxide, add anhydrous ethanol until the solid content is 20%, stir at 200 rpm for 2.5 h, seal, age at 90℃ for 72 h, cut into blocks with a length and width of 0.5 cm, pre-freeze in a refrigerator for 6 h, and then put into a freeze dryer with a cold trap temperature of -65℃ and a vacuum degree of 1 Pa for 28 h to obtain modified fly ash;

[0032] (4) Place 48 parts of construction waste and 13 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill at 400 rpm and a ball-to-material ratio of 5:1 for 20 min. Then add 26 parts of modified fly ash, 20 parts of sludge, and 10 parts of starch, and add water to a moisture content of 11%. Extrude and mold at 20 MPa, dry at 175℃ for 80 min, then heat to 975℃ and calcine for 2.5 h to obtain bricks. Cool to 190℃, spray with a sodium hydroxide aqueous solution with a mass concentration of 30 g / L at 1.4 times the mass of the bricks, keep warm for 4 h, then heat to 960℃ and calcine for 120 min to obtain sintered bricks made from construction waste for insulation.

[0033] Example 3

[0034] (1) Mix 5 parts of dimethylaminoacetaldehyde, 6 parts of bromoethane and 22 parts of anhydrous ethanol, heat to 80°C, stir at 80 rpm for 8 h, distill at -0.07 MPa and 48°C for 4 h, wash with ether 5 times, dry at 50°C for 12 h to obtain quaternization modifier.

[0035] (2) Place fly ash in a ball mill and use zirconia balls as the grinding medium. After grinding for 20 minutes at 400 rpm and a ball-to-material ratio of 5:1, turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 8 L / min. Continue grinding for 60 minutes, turn off the atomizer, stop grinding, heat at 95℃ for 200 minutes, then raise the temperature to 120℃ and dry for 4 hours. Turn on the atomizer and pass in a 2.2% quaternization modifier aqueous solution at 15 L / min. Continue grinding for 6 hours to obtain quaternized fly ash.

[0036] (3) Mix 20 parts resorcinol, 12 parts quaternized fly ash, and 0.6 parts sodium hydroxide, add anhydrous ethanol until the solid content is 30%, stir at 300 rpm for 3 hours, seal, age at 90°C for 72 hours, cut into blocks with a length and width of 0.5 cm, pre-freeze in a refrigerator for 7 hours, and then put them into a freeze dryer with a cold trap temperature of -65°C and a vacuum degree of 1 Pa for 40 hours to obtain modified fly ash;

[0037] (4) Place 56 parts of construction waste and 20 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill at 400 rpm and a ball-to-material ratio of 5:1 for 30 min. Then add 30 parts of modified fly ash, 27 parts of sludge, and 15 parts of starch, and add water to a moisture content of 15%. Extrude the bricks at 25 MPa, dry them at 200℃ for 100 min, then heat them to 1000℃ and calcine them for 3 h to obtain bricks. Cool them to 200℃, spray them with a sodium hydroxide aqueous solution with a mass concentration of 30 g / L at 2.2 times the mass of the bricks, keep them warm for 5 h, then heat them to 1000℃ and calcine them for 150 min to obtain sintered bricks made from construction waste for insulation.

[0038] Comparative Example 1

[0039] (1) Place fly ash in a ball mill, use zirconia balls as the grinding medium, and ball mill at 400 rpm and a ball-to-material ratio of 5:1 for 20 min. Then turn on the atomizer and pass in 4 mol / L sodium hydroxide solution at 5 L / min. Continue grinding for 50 min, turn off the atomizer, stop ball milling, heat at 95℃ for 150 min, then raise the temperature to 120℃ and dry for 3 h to obtain pre-modified fly ash.

[0040] (2) Mix 15 parts resorcinol, 8 parts pre-modified fly ash and 0.3 parts sodium hydroxide, add anhydrous ethanol to the solid content to 20%, stir at 200 rpm for 2.5 h, seal, age at 90℃ for 72 h, cut into blocks with a length and width of 0.5 cm, pre-freeze in a refrigerator for 6 h, and then put into a freeze dryer with a cold trap temperature of -65℃ and a vacuum degree of 1 Pa for 28 h to obtain modified fly ash;

[0041] (3) 48 parts of construction waste and 13 parts of coal gangue were placed in a ball mill and ball milled at 400 rpm and a ball-to-material ratio of 5:1 for 20 min using steel balls as the medium. Then, 26 parts of modified fly ash, 20 parts of sludge, and 10 parts of starch were added, and water was added until the moisture content was 11%. The mixture was extruded and shaped at 20 MPa and dried at 175℃ for 80 min. The temperature was then raised to 975℃ and calcined for 2.5 h to obtain bricks. The bricks were cooled to 190℃ and sprayed with a sodium hydroxide aqueous solution with a mass concentration of 30 g / L at 1.4 times the mass of the bricks. After keeping the temperature for 4 h, the temperature was raised to 960℃ and calcined for 120 min to obtain sintered bricks made from construction waste for insulation.

[0042] Comparative Example 2

[0043] Forty-eight parts of construction waste and 13 parts of coal gangue were placed in a ball mill and milled for 20 minutes at 400 rpm and a ball-to-material ratio of 5:1 using steel balls as the medium. Then, 26 parts of fly ash, 20 parts of sludge, and 10 parts of starch were added, and water was added until the moisture content was 11%. The mixture was extruded and shaped at 20 MPa, dried at 175°C for 80 minutes, heated to 975°C, and fired for 2.5 hours to obtain bricks. The bricks were cooled to 190°C and sprayed with a sodium hydroxide aqueous solution with a mass concentration of 30 g / L, which was 1.4 times the mass of the bricks. After holding at this temperature for 4 hours, the temperature was raised to 960°C and fired for 120 minutes to obtain sintered bricks made from construction waste for thermal insulation.

[0044] Comparative Example 3

[0045] (1) Mix 3 parts of dimethylaminoacetaldehyde, 4 parts of bromoethane and 20 parts of anhydrous ethanol, heat to 80°C, stir at 60 rpm for 8 hours, distill at -0.07 MPa and 48°C for 4 hours, wash with ether 5 times, and dry at 50°C for 12 hours to obtain quaternization modifier.

[0046] (2) Place fly ash in a ball mill and use zirconia balls as the grinding medium. After ball milling for 20 minutes at 400 rpm and a ball-to-material ratio of 5:1, turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 5 L / min. Continue grinding for 50 minutes, turn off the atomizer, stop ball milling, heat at 95℃ for 150 minutes, then raise the temperature to 120℃ and dry for 3 hours. Turn on the atomizer and pass in a 1.3% quaternization modifier aqueous solution at 12 L / min. Continue grinding for 4.5 hours to obtain quaternized fly ash.

[0047] (3) Mix 15 parts resorcinol, 8 parts quaternized fly ash, and 0.3 parts sodium hydroxide, add anhydrous ethanol until the solid content is 20%, stir at 200 rpm for 2.5 h, seal, age at 90℃ for 72 h, cut into blocks with a length and width of 0.5 cm, pre-freeze in a refrigerator for 6 h, and then put into a freeze dryer with a cold trap temperature of -65℃ and a vacuum degree of 1 Pa for 28 h to obtain modified fly ash;

[0048] (4) Place 48 parts of construction waste and 13 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill at 400 rpm and a ball-to-material ratio of 5:1 for 20 min. Then add 26 parts of modified fly ash and 20 parts of sludge, and add water to a moisture content of 11%. Extrude and mold at 20 MPa, dry at 175℃ for 80 min, then heat to 975℃ and calcine for 2.5 h to obtain bricks. Cool to 190℃, spray with a sodium hydroxide aqueous solution with a mass concentration of 30 g / L at 1.4 times the mass of the bricks, keep warm for 4 h, then heat to 960℃ and calcine for 120 min to obtain sintered bricks made from construction waste for insulation.

[0049] Comparative Example 4

[0050] (1) Mix 3 parts of dimethylaminoacetaldehyde, 4 parts of bromoethane and 20 parts of anhydrous ethanol, heat to 80°C, stir at 60 rpm for 8 hours, distill at -0.07 MPa and 48°C for 4 hours, wash with ether 5 times, and dry at 50°C for 12 hours to obtain quaternization modifier.

[0051] (2) Place fly ash in a ball mill and use zirconia balls as the grinding medium. After ball milling for 20 minutes at 400 rpm and a ball-to-material ratio of 5:1, turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 5 L / min. Continue grinding for 50 minutes, turn off the atomizer, stop ball milling, heat at 95℃ for 150 minutes, then raise the temperature to 120℃ and dry for 3 hours. Turn on the atomizer and pass in a 1.3% quaternization modifier aqueous solution at 12 L / min. Continue grinding for 4.5 hours to obtain quaternized fly ash.

[0052] (3) Mix 15 parts resorcinol, 8 parts quaternized fly ash, and 0.3 parts sodium hydroxide, add anhydrous ethanol until the solid content is 20%, stir at 200 rpm for 2.5 h, seal, age at 90℃ for 72 h, cut into blocks with a length and width of 0.5 cm, pre-freeze in a refrigerator for 6 h, and then put into a freeze dryer with a cold trap temperature of -65℃ and a vacuum degree of 1 Pa for 28 h to obtain modified fly ash;

[0053] (4) Place 48 parts of construction waste and 13 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill at 400 rpm and a ball-to-material ratio of 5:1 for 20 minutes. Then add 26 parts of modified fly ash, 20 parts of sludge, and 10 parts of starch, and add water to a moisture content of 11%. Extrude and mold at 20 MPa, dry at 175°C for 80 minutes, then heat to 975°C and calcine for 2.5 hours to obtain sintered bricks made from construction waste for thermal insulation.

[0054] Example of effect

[0055] Table 1 below shows the performance analysis results of the thermal insulation sintered bricks made from construction waste using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0056] Table 1

[0057] Compressive strength (MPa) Water absorption rate (%) Thermal conductivity (W / (m·K)) Example 1 25.8 12.0 0.19 Example 2 26.2 12.5 0.18 Example 3 25.5 11.7 0.19 Comparative Example 1 14.4 11.5 0.24 Comparative Example 2 14.0 11.3 0.25 Comparative Example 3 15.3 11.4 0.20 Comparative Example 4 15.0 14.6 0.19

[0058] A comparison of experimental data from the examples and comparative examples reveals that this invention utilizes aerogel to encapsulate modified fly ash, which is then sintered with coal gangue, construction waste, starch, modified fly ash, and sludge to form bricks. Fine coal gangue and construction waste are embedded in the mesopores on the surface of the modified fly ash. During sintering, the aerogel carbonizes, forming a fixed structure that inhibits the shrinkage and deformation of the fly ash during sintering. The starch forms carbon microspheres that connect the carbon aerogel. The brick blank is then wetted with sodium hydroxide solution for a second sintering, further connecting the carbon aerogel and forming a solid network support structure. This reduces the deformation of the sintered bricks, improves their mechanical and thermal insulation properties, and regulates the internal porosity of the sintered bricks, preventing excessive water absorption.

[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing sintered bricks from construction waste for thermal insulation, characterized in that, The preparation steps include the following: (1) Mix 1-5 parts of dimethylaminoacetaldehyde, 2-6 parts of bromoethane and 18-22 parts of anhydrous ethanol, heat to 80°C, stir for 8 hours, distill at -0.07 MPa and 48°C for 4 hours, wash with ether 5 times, and dry at 50°C for 12 hours to obtain quaternization modifier. (2) Place the fly ash in a ball mill and ball mill for 20 min. Then turn on the atomizer and pass in a 4 mol / L sodium hydroxide solution at 3-8 L / min. Continue grinding for 40-60 min. Turn off the atomizer and stop ball milling. Heat at 95°C for 100-200 min, then raise the temperature to 120°C and dry for 2-4 h. Turn on the atomizer and pass in a quaternization modifier aqueous solution with a mass fraction of 0.3-2.2% at 10-15 L / min. Continue grinding for 3-6 h to obtain quaternized fly ash. (3) Mix 10-20 parts of resorcinol, 4-12 parts of quaternized fly ash, and 0.1-0.6 parts of sodium hydroxide, add anhydrous ethanol until the solid content is 15-30%, stir at 100-300 rpm for 2-3 hours, seal, age at 90℃ for 72 hours, cut into blocks with a length and width of 0.5 cm, freeze to obtain modified fly ash; (4) Place 30-56 parts of construction waste and 6-20 parts of coal gangue in a ball mill, use steel balls as the medium, and ball mill for 10-30 minutes. Then add 24-30 parts of modified fly ash, 11-27 parts of sludge, and 5-15 parts of starch, and add water to make the moisture content 8-15%. Extrude and mold at 15-25 MPa, dry at 150-200℃ for 60-100 minutes, then heat to 950-1000℃ and calcine for 2-3 hours to obtain bricks. Cool to 180-200℃, spray with 0.5-2.2 times the weight of the bricks of sodium hydroxide aqueous solution, keep warm for 3-5 hours, then heat to 950-1000℃ and calcine for 100-150 minutes to obtain sintered bricks made from construction waste for insulation.

2. The method for preparing thermal insulation sintered bricks from construction waste according to claim 1, characterized in that, The stirring speed in step (1) is 40~80 rpm.

3. The method for preparing thermal insulation sintered bricks from construction waste according to claim 1, characterized in that, The grinding medium in step (2) is a zirconia ball.

4. The method for preparing thermal insulation sintered bricks from construction waste according to claim 1, characterized in that, The ball milling conditions described in steps (2) and (4) are: a speed of 400 rpm and a ball-to-material ratio of 5:

1.

5. The method for preparing thermal insulation sintered bricks from construction waste according to claim 1, characterized in that, The specific freezing process in step (3) is as follows: after pre-freezing in the refrigerator for 5 to 7 hours, it is placed in a freeze dryer with a cold trap temperature of -65°C and a vacuum degree of 1 Pa and dried for 24 to 40 hours.

6. The method for preparing thermal insulation sintered bricks from construction waste according to claim 1, characterized in that, The mass concentration of the sodium hydroxide aqueous solution in step (4) is 30 g / L.