A carbonization reinforced material based on secondary aluminum ash and a carbonized aerated concrete prepared by using the same

Abstract

The present invention discloses a carbonization reinforcing material based on secondary aluminum ash. The components and their respective weight parts include: 14-18 parts of modified aluminum ash slurry, 5-10 parts of mixed ammonium solution, and 35-45 parts of gypsum. The modified aluminum ash slurry is obtained by modifying aluminum ash slurry with alkali metal carbonate. The mixed ammonium solution is obtained by mixing the hydrolysis gas of secondary aluminum ash and carbon-containing gas and then introducing them into water for reaction. Among them, the aluminum ash slurry is obtained by stirring and hydrolyzing secondary aluminum ash and then standing and stratifying. The hydrolysis gas is collected in the stirring and hydrolysis step. The carbonization reinforcing material of the present invention can effectively improve the skeleton structure of carbonization products, significantly enhance the compressive strength, splitting tensile strength, etc. of aerated concrete, and can cooperate with ammonium salts, gypsum, etc. to effectively shorten the carbonization curing time and demolding time, improve the degree of carbonization reaction, and has significant economic and environmental benefits. The carbonized aerated blocks prepared by using it can take into account good strength, bulk density, dry shrinkage, thermal conductivity, etc., and are suitable for popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and particularly relates to a carbonation strengthening material based on secondary aluminum ash and a carbonated aerated concrete prepared by using the same. Background Art

[0002] Aerated concrete has excellent properties such as light weight, heat insulation, fire resistance, etc., and is widely used in high-rise, seismic and cold-region buildings. Conventional autoclaved aerated concrete consumes a large amount of cement, lime, high-silica sand and steam, and there is still relatively large energy consumption and carbon emissions in the production process. Carbonated aerated concrete is completely different from autoclaved aerated concrete. The raw materials for its preparation are mainly steel slag, magnesium slag and other materials with carbonation activity. After carbon dioxide curing, calcite and silica gel are generated to provide strength. Although carbonated aerated concrete can absorb a large amount of carbon dioxide during the curing process, there are mainly three problems that are difficult to solve: 1) Without using lime, the temperature rise during static curing is small, and more hydraulic materials need to be added to control the demolding time; 2) The size of aerated concrete is large, and as the carbonation reaction proceeds, the carbonation products reduce the surface porosity, and it is difficult for carbon dioxide to diffuse into the interior, resulting in incomplete carbonation inside; 3) The carbonation product calcite has good crystallinity, and the adhesion strength between carbonation products is low, resulting in low carbonation strength.

[0003] Secondary aluminum ash is a waste generated during the process of adding a salt flux during the recycling of aluminum ash slag, and contains components such as a large amount of salt flux and aluminum nitride. The salt flux will gradually leach out in a humid state, polluting the soil and groundwater. Aluminum nitride will slowly react with water to generate ammonia, polluting the environment. Secondary aluminum ash also contains a small amount of low-activity elemental aluminum, which can generate hydrogen under acidic or alkaline conditions, and may cause destructive expansion. Further exploring the efficient application of secondary aluminum ash in concrete has important research and application significance. Summary of the Invention

[0004] The main purpose of the present invention is to provide, in view of the problems and deficiencies existing in the prior art, a carbonation strengthening material for aerated concrete prepared by using secondary aluminum ash, which can effectively improve the skeleton structure of carbonation products, significantly enhance the compressive strength, splitting tensile strength, etc. of aerated concrete, and can cooperate with ammonium salts, gypsum, etc. to effectively shorten the carbonation curing time and demolding time, improve the degree of carbonation reaction, and have significant economic and environmental benefits; the carbonated aerated block prepared by using this carbonation strengthening material can take into account good strength, bulk density, dry shrinkage and thermal conductivity, etc., and is suitable for popularization and application.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A carbonization reinforcing material based on secondary aluminum ash, and its components and the weight parts thereof include: 14-18 parts of modified aluminum ash slurry, 5-10 parts of mixed ammonium solution, and 35-45 parts of gypsum; the modified aluminum ash slurry is obtained by stirring and modifying the aluminum ash slurry obtained by stirring and hydrolyzing secondary aluminum ash and then standing and stratifying; the mixed ammonium solution is obtained by mixing the hydrolysis gas obtained by stirring and hydrolyzing secondary aluminum ash with a carbon-containing gas and then reacting it in water.

[0007] In the above solution, the main chemical components in the secondary aluminum ash and their mass percentages include: 30-50% of Al2O3, 15-30% of AlN, 5-10% of elemental Al, 10-20% of SiO2, and 5-15% of NaCl + KCl.

[0008] In the above solution, the temperature of the water used in the hydrolysis step is 50-80 °C.

[0009] In the above solution, the stirring rate used in the stirring hydrolysis is 10-20 r / min, and the time is 30-60 min.

[0010] In the above solution, the standing and stratifying time is 1-2 h; wait for natural precipitation and stratification to obtain the upper clear liquid and aluminum ash slurry.

[0011] In the above solution, in the preparation process of the modified aluminum ash slurry, the main raw materials and their weight fractions include: 10 parts of secondary aluminum ash, 15-25 parts of water, and 1-2 parts of alkali metal carbonate.

[0012] Furthermore, the alkali metal carbonate can be selected from one or more of sodium carbonate, potassium carbonate, lithium carbonate, etc.

[0013] In the above solution, the water content in the obtained aluminum ash slurry is controlled at 30-40 wt%, and the content of NaCl + KCl is controlled below 2 wt%.

[0014] In the above solution, the temperature used in the stirring and modifying step is 50-70 °C, the stirring rate is 60-120 r / min, and the time is 30-60 min; there is no strict limit on the heating method, such as using high-temperature steam heating, using high-temperature industrial waste gas heating, etc.

[0015] In the above solution, the volume ratio of the secondary aluminum ash hydrolysis gas to the carbon-containing gas is 1:0.5-3.

[0016] In the above solution, the concentration of ammonia in the secondary aluminum ash hydrolysis gas is 30-50 vol%, and the temperature is 20-40 °C.

[0017] Furthermore, the main remaining gases in the secondary aluminum ash hydrolysis gas are air and hydrogen, among which the hydrogen content is 1-5 vol%, and the air content is 45-69 vol%.

[0018] In the above solution, the concentration of carbon dioxide in the carbon-containing gas is 15-100%, and the temperature is 20-50°C; there is no strict restriction on the carbon-containing gas. For example, industrial tail gas with a carbon dioxide concentration above 15% or high-purity industrial carbon dioxide can be used. Among them, the content of nitrogen oxides and sulfur dioxide does not exceed 100 mg / m 3 .

[0019] In the above solution, the reaction time of the gas introduced into water is 20-40 min.

[0020] In the above solution, the concentration of NH4 + in the obtained mixed ammonium solution is 5-10 mol / L, and the concentration of CO3 2- +HCO3 - is 3-6 mol / L; the temperature is 20-45°C.

[0021] In the above solution, the gypsum is one of desulfurized gypsum, phosphogypsum, etc. The content of calcium sulfate dihydrate is not less than 90 wt%, the pH value is 5.5-8, and the moisture content does not exceed 10 wt%.

[0022] The preparation method of the above-mentioned aerated concrete carbonation strengthening material based on secondary aluminum ash includes the following steps: uniformly stirring the weighed modified aluminum ash, mixed ammonium solution, and gypsum to obtain the aerated concrete carbonation strengthening material.

[0023] A carbonated aerated concrete prepared by using the above-mentioned carbonation strengthening material based on secondary aluminum ash, each component and its weight fraction include: 55-70 parts of steel slag, 0-10 parts of cement, 0.1-0.5 parts of water reducing agent, 15-25 parts of carbonation strengthening material based on secondary aluminum ash, 15-20 parts of water, and 0.1-0.2 parts of foaming agent.

[0024] In the above solution, the main chemical composition and its mass percentage in the steel slag include: 20-40% of C2S, 10-20% of C3S, 10-20% of Ca(OH)2, 10-30% of Ca2Fe2O5, 0-10% of CaCO3, and 0-20% of SiO2.

[0025] In the above solution, the cement can be selected as ordinary Portland cement, etc.

[0026] In the above solution, the water reducing agent is preferably a polycarboxylate water reducing agent, and its water reducing rate is 30-40%.

[0027] In the above solution, the foaming agent is a physical foaming agent, and specifically, a protein-based foaming agent can be selected, and the foaming multiple is 40-60.

[0028] The above preparation method of carbonated aerated concrete comprises the following steps: weighing steel slag, cement, water reducing agent, carbonation strengthening material and water, and uniformly stirring to prepare a mixed slurry; preparing foam with a foaming agent, and uniformly stirring the foam and the mixed slurry to obtain a finished slurry; pouring the finished slurry into a mold frame, demolding and cutting after the blank hardens, and carbonating and curing the cut blank in a kettle with industrial tail gas.

[0029] In the above solution, the hardening and demolding time is 2.5 - 3.5 h.

[0030] In the above solution, the concentration of carbon dioxide in the gas used for carbonation curing is 20 - 100%, the temperature is 20 - 50 °C; the carbonation pressure is 0.2 - 0.5 MPa, and the carbonation time is 5 - 24 h.

[0031] Preferably, the carbonation time is 5 - 10 h.

[0032] More preferably, the carbonation time is 7 - 8 h.

[0033] The carbonated aerated concrete prepared according to the above solution has a compressive strength of more than 3.7 MPa after 8 h of carbonation curing, a bulk density of 629 - 643 kg / m 3 , a drying shrinkage not exceeding 0.3 mm / m, a splitting tensile strength of 0.9 - 0.97 MPa, a thermal conductivity not exceeding 0.14 W / (m·K), and a carbonation weight gain rate reaching 18 - 20.5%.

[0034] The performance optimization mechanism of the carbonation strengthening material for aerated concrete in the present invention includes:

[0035] 1) After aluminum nitride in secondary aluminum ash hydrolyzes, aluminum hydroxide and ammonia gas are generated. The ammonia gas in the hydrolysis gas reacts with carbon dioxide in the carbon-containing gas to generate ammonium carbonate and ammonium bicarbonate; at the same time, using alkali metal carbonates such as sodium carbonate to modify the aluminum ash slurry can effectively remove the low-activity elemental aluminum wrapped in the secondary aluminum ash (if strong alkali is used, excessive meta-aluminate will be produced, causing flash setting and resulting in performance degradation), preventing hydrogen from being generated by the later reaction of aluminum and damaging the hardened blank structure; in addition, the alkaline conditions of the introduced alkali metal carbonate can promote the breaking of silicon-oxygen bonds and calcium-oxygen bonds in the glass body of the steel slag, and alkali activation causes the glass body to disintegrate, and the generated hydration products further fill the pores, promoting strength growth;

[0036] 2) During the early curing process of the finished pulp, ammonium carbonate / ammonium bicarbonate in the mixed ammonium solution reacts with gypsum to form nano-calcium carbonate and highly soluble ammonium sulfate; meanwhile, aluminum in the aluminum ash pulp reacts with cement, steel slag, gypsum, and ammonium sulfate under alkaline conditions to form needle-like ettringite, which combines with nano-calcium carbonate, etc. to form an initial skeleton structure with better overall performance, facilitating the accumulation of reaction products in the pores of the skeleton structure during the subsequent carbonation curing process, and thus effectively increasing the compressive strength, splitting tensile strength, etc. of the obtained aerated concrete;

[0037] 3) The obtained carbonation-enhanced material contains a certain amount of alkaline components. During the carbonation curing process, the pore solution is more likely to absorb carbon dioxide, which is beneficial to increasing the carbonation rate; in addition, the concentration of carbonate ions in the pore solution increases, increasing the supersaturation of calcium carbonate, and it is easier to generate calcium carbonate with finer grains during the carbonation process, improving the morphology of the carbonation products, which is beneficial to improving the properties of carbonated aerated concrete;

[0038] 4) During the early curing process of the finished pulp, gypsum reacts with ammonium carbonate to form nano-calcium carbonate and highly soluble ammonium sulfate; the increase of SO4 in the liquid phase also promotes the reaction with the modified aluminum ash pulp to form ettringite; when gypsum, the mixed ammonium solution, and the aluminum ash pulp are used in combination, the process of forming ettringite continuously consumes SO4 in the liquid phase, which can effectively avoid the reaction of high-concentration sulfate with calcium ions released from cement and steel slag to form gypsum in the later stage, thereby causing volume expansion and performance deterioration. 2- 2-

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1) There are a large amount of aluminum oxide and aluminum hydroxide in the aluminum ash pulp, which can react with calcium ions and sulfate ions under alkaline conditions to quickly coagulate and harden, and can avoid the structural deterioration caused by the floating and merging of pores, effectively shortening the demolding time.

[0041] 2) The raw materials are low-carbon and environmentally friendly; the main raw materials used, secondary aluminum ash and gypsum, are both solid wastes; when using the carbonation-enhanced material to prepare carbonated aerated concrete, the cement dosage does not exceed 10%, far lower than the total dosage of autoclaved aerated cement and lime of 30-40%.

[0042] 3) It has significant economic and environmental benefits; the main raw materials of carbonated aerated concrete are steel slag, secondary aluminum ash, and waste gypsum. Taking a 300,000 m³ / year B06-grade carbonated aerated concrete production line as an example, it can absorb 25,000-35,000 tons of carbon dioxide per year and co-dispose more than 20,000 tons of secondary aluminum ash and gypsum.

[0043] 4) The obtained carbonated aerated concrete has excellent performance, and the product quality meets the requirements of A3.5B06 grade, and the performance indicators such as appearance quality and drying shrinkage all meet the standard requirements. ​​Description of the Drawings

[0044] Figure 1 It is a process flow diagram for preparing a carbonation-enhanced material for aerated concrete from secondary aluminum ash. Detailed Embodiments

[0045] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] In the following specific implementation solutions, the secondary aluminum ash used mainly includes the following chemical components and their mass percentages: Al2O3 42%, AlN 18%, elemental Al 8%, SiO2 16%, NaCl + KCl 10%. Phosphogypsum is used as the gypsum, with a content of 92% of calcium sulfate dihydrate, a pH value of 5.5, and a moisture content of 6.8%. The main chemical components and their mass percentages in the steel slag are: C2S 32%, C3S 14%, Ca(OH)2 16%, Ca2Fe2O5 16%, CaCO3 6%, SiO2 7%.

[0047] P·O42.5 ordinary Portland cement is used as the cement. A polycarboxylate superplasticizer is used as the water reducer, with a water reduction rate of 35%. A protein-based foaming agent provided by Henan Huatai New Material Technology Co., Ltd. is used as the physical foaming agent. It is diluted 40 times with water to prepare a dilution solution. The foam bleeding amount of the prepared foam is 38 ml, the sedimentation distance is 5 mm, and the density is 38 kg / m 3 。

[0048] Example 1

[0049] A carbonation-enhanced material based on secondary aluminum ash, and its preparation method includes the following steps:

[0050] 1) Take 10 parts (by weight, the same below) of secondary aluminum ash and 20 parts of water, stir evenly, and collect the obtained aluminum ash liquid and hydrolysis gas; among them, the water temperature is controlled at 65°C; the stirring time is controlled at 40 min, and the stirring rate is controlled at 15 r / min;

[0051] 2) Let the aluminum ash liquid stand for 2 h, wait for it to naturally precipitate and layer, and obtain the upper clear liquid and aluminum ash slurry; the water content in the aluminum ash slurry is controlled at 35%; the content of NaCl + KCl is controlled at 1.5%;

[0052] 3) Take 2 parts of sodium carbonate and stir it evenly with the obtained aluminum ash slurry to obtain a modified aluminum ash slurry. The stirring time is controlled at 45 min, and the stirring rate is controlled at 90 r / min; the temperature of the modified aluminum ash slurry is controlled at 60°C;

[0053] 4) Mix the obtained hydrolyzed gas and industrial carbon dioxide gas in a volume ratio of 1:0.5 to obtain a mixed gas, and then pass the mixed gas into 6 parts of water and react for 30 min to prepare a mixed ammonium solution; among them, the ammonia concentration in the hydrolyzed gas is 35 vol% (the hydrogen content is 2.7 vol%, and the rest is air), and the temperature is 28 °C; the NH4 + concentration in the obtained mixed ammonium solution is 8 mol / L, and the sum of the concentrations of CO3 2- +HCO3 - is 5.5 mol / L, and the temperature is 43 °C; the purity of the industrial carbon dioxide gas is 99%;

[0054] 5) Take 16 parts of modified aluminum ash slurry, 8 parts of mixed ammonium solution, and 40 parts of gypsum, and stir evenly to obtain a carbonization reinforcing material.

[0055] Example 2

[0056] A carbonization reinforcing material based on secondary aluminum ash, and its preparation method includes the following steps:

[0057] 1) Take 10 parts of secondary aluminum ash (parts by weight, the same below), 25 parts of water, stir evenly, and collect the obtained aluminum ash liquid and hydrolyzed gas; among them, the water temperature is controlled at 60 °C; the stirring time is controlled at 60 min, and the stirring rate is controlled at 10 r / min;

[0058] 2) Let the aluminum ash liquid stand for 1.5 h, wait for it to naturally precipitate and layer, and obtain the supernatant and aluminum ash slurry; the water content in the aluminum ash slurry is controlled at 36.7%; the content of NaCl + KCl is controlled at 0.9%;

[0059] 3) Take 1.5 parts of sodium carbonate and stir it evenly with the obtained aluminum ash slurry to obtain a modified aluminum ash slurry. The stirring time is controlled at 30 min, and the stirring rate is controlled at 120 r / min; the temperature of the modified aluminum ash slurry is controlled at 65 °C;

[0060] 4) Mix the obtained hydrolyzed gas and industrial tail gas in a volume ratio of 1:2.5 to obtain a mixed gas, and then pass the mixed gas into 6 parts of water and react for 40 min to prepare a mixed ammonium solution; among them, the ammonia concentration in the hydrolyzed gas is 33 vol% (the hydrogen content is 2.9 vol%, and the rest is air), and the temperature is 25 °C; the NH4 + concentration in the obtained mixed ammonium solution is 9 mol / L, and the sum of the concentrations of CO3 2- +HCO3 - is 5.2 mol / L, and the temperature is 41 °C; the carbon dioxide concentration in the industrial tail gas is 18%, and the total content of nitrogen oxides and sulfur dioxide is 79 mg / m 3 , and the rest is nitrogen and oxygen;

[0061] 5) Take 18 parts of modified aluminum ash slurry, 6 parts of mixed ammonium solution, and 42 parts of gypsum, and stir evenly to obtain a carbonization reinforcing material.

[0062] Application Example 1

[0063] Take 60 parts of steel slag, 7 parts of cement, 0.4 parts of water reducing agent, 16 parts of the carbonation enhanced material based on secondary aluminum ash obtained in Example 1, and 17 parts of water. After stirring evenly, prepare a mixed slurry; stir the mixed slurry evenly with foam (obtained by mechanically foaming with 0.15 parts of protein-based foaming agent) to obtain a finished slurry. Pour the finished slurry into a mold frame, and after the blank hardens, demold and cut it. The cut blank is put into a autoclave and carbonated and cured with industrial waste gas; among them, the demolding time is 3.1 h; the carbon dioxide concentration in the industrial waste gas is 23%, the temperature is 42 °C, the air pressure during the carbonation curing process is controlled at 0.3 MPa without change, and the curing duration is 8 h (#1), 16 h (#2), 24 h (#3).

[0064] Detect according to the reference aerated concrete standard GB / T11969-2008, and the performance is as follows.

[0065] Table 1 Performance test results of the carbonated aerated concrete obtained in Application Example 1

[0066]

[0067] As can be seen from Table 1, the comprehensive performance of the #1 carbonated aerated concrete obtained by curing for 8 h is comparable to the performance of the #2 and #3 carbonated aerated concretes obtained by curing for 16 h and 24 h respectively. Using the concrete body described in the present invention, carbonation can be basically completed after curing for 8 h, which can significantly reduce the curing cost and shorten the curing cycle, and is suitable for popularization and application.

[0068] Application Example 2

[0069] A kind of carbonated aerated concrete, its preparation process is roughly the same as that of Application Example 1, the difference is that the carbonation enhanced material obtained in Example 2 is used, and the demolding time is 3.3 h. Detect according to the reference aerated concrete standard GB / T11969-2008, and the performance is as follows, where the carbonation curing times corresponding to the #4, #5 and #6 carbonated aerated concretes are 8 h, 16 h and 24 h respectively.

[0070] Table 2 Performance test results of the carbonated aerated concrete obtained in Application Example 2

[0071]

[0072] Application Example 3

[0073] A kind of carbonated aerated concrete, its preparation process is roughly the same as that of Application Example 1, the difference is that: take 63 parts of steel slag, 0.4 parts of water reducing agent, 20 parts of carbonation enhanced material, and 17 parts of water. After stirring evenly, prepare a mixed slurry; the demolding time is 3.1 h; the carbonation curing duration is 8 h.

[0074] Testing was carried out in accordance with the aerated concrete standard GB / T 11969-2008, and the performance is as follows.

[0075] Table 3 Performance test results of the carbonated aerated concrete obtained in Application Example 3

[0076]

[0077] Application Example 4

[0078] A kind of carbonated aerated concrete, its preparation process is roughly the same as that of Application Example 1, the differences are as follows:

[0079] Take 56 parts of steel slag, 7 parts of cement, 0.4 parts of water reducing agent, 20 parts of carbonation strengthening material, and 17 parts of water, stir evenly and then prepare a mixed slurry; the demolding time is 2.9 h; the carbonation curing duration is 8 h.

[0080] Testing was carried out in accordance with the aerated concrete standard GB / T 11969-2008, and the performance is as follows.

[0081] Table 4 Performance test results of the carbonated aerated concrete obtained in Application Example 4

[0082]

[0083] Comparative Example 1

[0084] A kind of carbonated aerated concrete, its preparation process is roughly the same as that of Application Example 1, the differences are as follows: Take 73 parts of steel slag, 7 parts of cement, 0.4 parts of water reducing agent, and 20 parts of water, stir evenly and then prepare a mixed slurry; the demolding time is 7.3 h.

[0085] Testing was carried out in accordance with the aerated concrete standard GB / T 11969-2008, and the performance is as follows.

[0086] Table 5 Performance test results of the carbonated aerated concrete obtained in Comparative Example 1

[0087]

[0088] Comparative Example 2

[0089] A kind of carbonated aerated concrete, its preparation process is roughly the same as that of Application Example 1, the differences are as follows:

[0090] Take 60 parts of steel slag, 7 parts of cement, 0.4 parts of water reducing agent, 16 parts of the modified aluminum ash slurry described in Example 1, and 17 parts of water, stir evenly and then prepare a mixed slurry; the demolding time is 3.9 h.

[0091] Testing was carried out in accordance with the aerated concrete standard GB / T 11969-2008, and the performance is as follows.

[0092] Table 6 Performance test results of the carbonated aerated concrete obtained in Comparative Example 2

[0093]

[0094] Comparative Example 3

[0095] A carbonated aerated concrete, the preparation process of which is substantially the same as that of Application Example 1, except that 60 parts of steel slag, 7 parts of cement, 0.3 parts of water reducing agent, 2.7 parts of the mixed ammonium solution described in Example 1, 13.3 parts of gypsum and 17 parts of water are taken and stirred evenly to prepare a mixed slurry; the demoulding time is 3.7 h.

[0096] Testing was carried out in accordance with the reference aerated concrete standard GB / T11969-2008, and the performance is as follows.

[0097] Table 7 Performance test results of the carbonated aerated concrete obtained in Comparative Example 3

[0098]

[0099] Comparative Example 4

[0100] A carbonated aerated concrete, the preparation process of which is substantially the same as that of Application Example 1, except that: the modified aluminium ash slurry is obtained by modifying the aluminium ash slurry with water glass (modulus 1.5) substituting the modifier (modifier) equally; 60 parts of steel slag, 7 parts of cement, 0.6 parts of water reducing agent, 16 parts of carbonation strengthening material and 23 parts of water are taken and stirred evenly to prepare a mixed slurry; the demoulding time is 3.4 h and the carbonation curing duration is 24 h. Testing was carried out in accordance with the reference aerated concrete standard GB / T11969-2008, and the performance is as follows.

[0101] Table 8 Performance test results of the carbonated aerated concrete obtained in Comparative Example 4

[0102]

[0103] The present invention is not limited to the above embodiments. For those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and retouches can also be made, and these improvements and retouches are also regarded as within the protection scope of the present invention. The content not described in detail in this specification belongs to the prior art well-known to those of ordinary skill in the art.

Claims

1. A carbonized aerated concrete prepared from a carbonized reinforced material based on secondary aluminum ash, characterized in that: The components and their weight percentages include: 55-70 parts of steel slag, 0-10 parts of cement, 0.1-0.5 parts of water reducer, 15-25 parts of carbonized reinforcing material, 15-20 parts of water, and 0.1-0.2 parts of foaming agent; The carbonized reinforced material based on secondary aluminum ash comprises the following components and their weight percentages: 14-18 parts of modified aluminum ash slurry, 5-10 parts of mixed ammonium liquid, and 35-45 parts of gypsum; the modified aluminum slurry is obtained by stirring and modifying aluminum ash slurry with alkali metal carbonate; the mixed ammonium liquid secondary aluminum ash hydrolysis gas is mixed with carbon-containing gas and then introduced into water for reaction; the aluminum slurry is obtained by stirring and hydrolyzing secondary aluminum ash and allowing it to stand for stratification, and the secondary aluminum ash hydrolysis gas is collected during the stirring and hydrolysis step; In the preparation process of the modified aluminum ash slurry, the main raw materials and their weight fractions include: 10 parts of secondary aluminum ash, 15-25 parts of water, and 1-2 parts of alkali metal carbonate; The temperature used in the stirring modification step is 50-70°C; the stirring rate used is 60-120 r / min, and the time is 30-60 min; The standing time for stratification is 1~2h.

2. The carbonized aerated concrete according to claim 1, characterized in that The main chemical components of the secondary aluminum ash and their mass percentages include: Al2O3 30-50%, AlN 15-30%, elemental Al 5-10%, SiO2 10-20%, and NaCl+KCl 5-15%.

3. The carbonized aerated concrete according to claim 1, characterized in that The water content in the aluminum slurry is controlled at 30-40%, and the NaCl+KCl content is controlled below 2%.

4. The carbonized aerated concrete according to claim 1, characterized in that The volume ratio of the secondary aluminum ash hydrolysis gas to the carbon-containing gas is 1:0.5~3.

5. The carbonized aerated concrete according to claim 1, characterized in that The concentration of ammonia in the secondary aluminum ash hydrolysis gas is 30-50 vol%, and the temperature is 20-40°C; the concentration of carbon dioxide in the carbon-containing gas is 15-100%, and the temperature is 20-50°C.

6. The carbonized aerated concrete according to claim 1, characterized in that NH4 in the mixed ammonium solution + The concentration of CO3 is 5~10mol / L, 2- +HCO3 - The concentration is 3~6mol / L; the temperature is 20~45℃.

7. The carbonized aerated concrete according to claim 1, characterized in that The content of calcium sulfate dihydrate in the gypsum is not less than 90wt%, the pH value is 5.5-8, and the moisture content is less than 10%.

8. The carbonized aerated concrete according to claim 1, characterized in that The carbonization curing adopts a carbon dioxide concentration of 20~100% in the gas, a temperature of 20~50℃; a carbonization pressure of 0.2~0.5MPa, and a carbonization time of 5~24h.

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