Carbonized regenerated aerated concrete as well as preparation method and application thereof

Abstract

The invention relates to the technical field of construction waste recycling and heavy metal pollution control, in particular to carbonized regenerated aerated concrete as well as a preparation method and application thereof, and the preparation method comprises the following steps: crushing and grinding waste aerated concrete to obtain waste aerated concrete regenerated particles; carbonizing the waste aerated concrete regenerated particles to obtain carbonized regenerated aerated concrete; during carbonization, the waste aerated concrete regenerated particles are subjected to a carbonization reaction to form nano calcium carbonate and a three-dimensional porous structure amorphous silica gel carbonization product. The preparation method of the carbonized regenerated aerated concrete not only provides a new way for improving the structural performance of the waste aerated concrete, but also indicates that the carbonized regenerated aerated concrete possibly shows excellent adsorption performance in the aspect of heavy metal removal; in addition, the ecological environment problem of high emission of carbon dioxide greenhouse gas is solved to a certain extent, and the problem of recycling of waste aerated concrete construction waste is solved.

Description

Technical Field

[0001] The invention relates to the technical field of construction waste recycling and heavy metal pollution control, and in particular to carbonized regenerated aerated concrete and a preparation method and application thereof. Background Art

[0002] At present, the treatment methods of heavy metal wastewater include chemical precipitation, adsorption, ion exchange, membrane separation technology, ion flotation, electrochemical treatment and photocatalysis. Among these methods, chemical precipitation is favored for its simple operation and low cost, but it is difficult to meet the increasingly stringent environmental protection requirements and may cause secondary pollution and other problems. Although the ion exchange method has a more significant effect on the treatment of low-concentration wastewater, it is costly and easily interfered by other cations. Membrane separation technology is known for its high efficiency, but its high cost and easy clogging problems cannot be ignored. Electrochemical methods are popular for their simple operation and high treatment efficiency, but their high initial investment and energy consumption during operation need to be considered. Photocatalysis technology is still mainly in the laboratory research stage. In addition, biotechnology such as phytoremediation and microbial adsorption are also used for water pollution control, but these methods are somewhat dependent on environmental conditions. Among many treatment technologies, adsorption has been widely used due to its advantages such as convenient operation, high efficiency, low sludge production and economic benefits.

[0003] For the adsorption method, the selection of appropriate adsorbent materials is crucial to improve the treatment efficiency. Currently used adsorbent materials include natural minerals (such as bentonite, diatomaceous earth, zeolite, etc.), natural polymers (such as chitosan, cellulose, etc.), agricultural and forestry wastes (such as sawdust, coconut shells, rice husks, etc.), biosorbents (such as bacteria, algae, etc.), industrial by-products (such as fly ash, red mud, etc.) and synthetic materials (such as activated carbon, biochar, metal oxides, etc.). Although natural materials and wastes are favored due to their abundant resources and low cost, their adsorption performance is relatively weak and the applicable pH range is limited. In contrast, synthetic adsorbents show strong adsorption capacity and wide applicability, but the challenges they face include high cost and insufficient environmental friendliness of the production process, which to some extent limit their popularity in practical applications. Therefore, future research needs to be committed to the development of more efficient, economical and environmentally friendly adsorbent materials to achieve more effective management of heavy metal wastewater.

[0004] Waste aerated concrete, due to its huge stock, low cost, unique porous structure, excellent activity and high specific surface area, has shown great potential to become a low-cost, environmentally friendly heavy metal adsorption material. However, although waste aerated concrete and its modified products have shown certain effects in heavy metal removal, there are still problems such as low adsorption capacity, narrow application pH range, and low removal efficiency of low-concentration heavy metals.

[0005] Therefore, there is an urgent need to develop a new technology and method for modifying waste aerated concrete to improve its removal efficiency for heavy metals, thereby promoting its application in the field of sewage treatment.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a carbonized regenerated aerated concrete and a preparation method and application thereof. The carbonized regenerated aerated concrete prepared by the present invention has a large number of gel pores and a high specific surface area, and exhibits excellent adsorption characteristics.

[0008] In a first aspect, the present invention provides a method for preparing carbonized regenerated aerated concrete, comprising the following steps:

[0009] The waste aerated concrete is crushed and ground to obtain the waste aerated concrete recycled particles;

[0010] Carbonizing the waste aerated concrete regeneration particles to obtain carbonized regenerated aerated concrete;

[0011] During the carbonization, the waste aerated concrete regeneration particles undergo a carbonization reaction to form nano calcium carbonate and amorphous silica gel carbonization products with a three-dimensional porous structure.

[0012] Waste aerated concrete is a porous material prepared by autoclaving cement, lime and fly ash. It contains abundant hydration products such as calcium silicate hydrate (CSH), calcium hydroxide (CH) and ettringite (AFt), which can give it significant carbonization activity. Therefore, during the carbonization process, the chemical components of the recycled particles of waste aerated concrete after crushing and grinding are reconstructed to form carbonization products such as nano calcium carbonate and three-dimensional porous amorphous silica gel. In particular, the silica gel formed after carbonization has a large number of gel pores and a high specific surface area, showing excellent adsorption characteristics.

[0013] The carbonized regenerated aerated concrete prepared by the present invention has significant advantages such as low cost, high adsorption capacity, low carbon and environmental protection, and fully meets the demand for high-efficiency, simple preparation process, low carbon and environmental protection, and low-cost heavy metal adsorption materials.

[0014] As a preferred embodiment of the present technical solution, during the crushing, a hammer crusher is used to crush the waste aerated concrete into pieces of 2mm-10mm.

[0015] As a preferred embodiment of the present technical solution, during the grinding, an agate zirconia ball mill is used to grind at a speed of 150rpm-250rpm for 10min-30min; the particle size of the waste aerated concrete recycled particles is less than 2mm, and the residue on the 10-mesh sieve does not exceed 10%.

[0016] Studies have shown that recycled aerated concrete particles with a particle size of less than 2 mm can carbonize better and absorb more carbon dioxide and generate more silica gel. Silica gel has stable chemical properties, rich pore structure and excellent adsorption performance, and has excellent adsorption capacity for heavy metal ions.

[0017] As a preferred embodiment of the present technical solution, during the carbonization, the concentration of carbon dioxide is controlled to be 17%-23%, the pressure of carbon dioxide is 0.05MPa-0.2MPa, the temperature is 18°C-22°C, the humidity is 65%-75%, and the carbonization age is 5d-12d.

[0018] Studies have shown that the high concentration of carbon dioxide and suitable temperature and humidity can cause carbonization reaction of waste aerated concrete particles, converting CO 2 The waste aerated concrete particles are sealed in the particles in the form of carbonate minerals, and the carbonized waste aerated concrete particles have good heavy metal ion adsorption capacity.

[0019] As a preferred embodiment of the present technical solution, during the carbonization, the purity of the carbon dioxide used is 90%-99%.

[0020] In the second aspect, the present invention also discloses the carbonized regenerated aerated concrete prepared by the above-mentioned preparation method, which should also fall within the protection scope of the present invention.

[0021] On the third aspect, the present invention also discloses the application of the above-mentioned carbonized regenerated aerated concrete in sewage treatment, specifically referring to the application of the carbonized regenerated aerated concrete in the treatment of heavy metal-containing sewage, which should also fall within the protection scope of the present invention.

[0022] As a preferred embodiment of the technical solution, the following steps are included: adding carbonized regenerated aerated concrete to sewage containing heavy metals, and adjusting the pH of the sewage to 2-7. The application pH range is wide, which expands the application scenarios of carbonized regenerated aerated concrete as a heavy metal adsorption material.

[0023] As a preferred embodiment of the present technical solution, in order to improve the adsorption effect, during the heavy metal adsorption process, a constant temperature oscillation box may be used for oscillation treatment.

[0024] As a preferred embodiment of the present technical solution, the heavy metal includes any one or more of nickel, cadmium, lead and cobalt.

[0025] As a preferred embodiment of the present technical solution, when treating sewage, in order to facilitate the recovery of carbonized regenerated aerated concrete after heavy metal adsorption, the carbonized regenerated aerated concrete can be wrapped with a nylon filter of suitable pore size and placed in a suspension ball made of polypropylene with a snap function. The nylon filter and the suspension ball have excellent acid, alkali and corrosion resistance, which not only expands the application scenarios of carbonized regenerated aerated concrete, but also facilitates the recovery and utilization of the adsorption materials of carbonized regenerated aerated concrete.

[0026] As a preferred embodiment of the present technical solution, the carbonized regenerated aerated concrete of the present invention can be further combined with other precipitation, filter pressing, centrifugal separation and wastewater treatment technologies to purify the water body, and the present invention does not make any special limitation thereto.

[0027] The method for preparing carbonized regenerated aerated concrete of the present invention has at least the following beneficial effects:

[0028] 1. In the preparation method of carbonized regenerated aerated concrete of the present invention, the waste aerated concrete is a porous material prepared by autoclaving cement, lime and fly ash, and contains abundant hydration products such as calcium silicate hydrate (CSH), calcium hydroxide (CH) and calcium sulfonate (AFt), which can give it significant carbonization activity. Therefore, during the carbonization process, the chemical components of the recycled particles of the crushed and ground waste aerated concrete are reconstructed to form carbonization products such as nano calcium carbonate and three-dimensional porous amorphous silica gel. In particular, the silica gel formed after carbonization has a large number of gel pores and a high specific surface area, showing excellent adsorption characteristics;

[0029] 2. The preparation method of carbonized regenerated aerated concrete of the present invention not only provides a new way to improve the structural properties of waste aerated concrete, but also indicates that carbonized regenerated aerated concrete may show excellent performance in heavy metal removal;

[0030] 3. The preparation method of carbonized regenerated aerated concrete of the present invention can seal carbon dioxide in the form of carbonate minerals in waste aerated concrete particles, which can solve ecological and environmental problems such as high carbon dioxide greenhouse gas emissions and global warming to a certain extent, as well as the problem of recycling waste aerated concrete construction waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The present invention is a flow chart of the carbonization of waste aerated concrete and its adsorption of heavy metals;

[0033] Figure 2 This is a schematic diagram of the appearance of the concrete carbonization box used in the present invention;

[0034] Figure 3 The microscopic morphology of the waste aerated concrete particles before carbonization under scanning electron microscope imaging of the present invention;

[0035] Figure 4 The microscopic morphology of the waste aerated concrete particles after carbonization under scanning electron microscope imaging of the present invention;

[0036] Figure 5 This is the XRD diagram of the carbonized regenerated aerated concrete particles of the present invention. DETAILED DESCRIPTION

[0037] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] Preparation of Carbonated Regenerated Aerated Concrete

[0042] (1) Raw material pretreatment: The recycled waste aerated concrete is crushed into particles with a particle size of about 5 mm by a hammer crusher, and then placed in an agate zirconia ball mill and set at 200 rpm. After grinding for 20 minutes, relatively smooth particles are obtained. The particle size of the particles after grinding is less than 2 mm, and the residue on a 10-mesh sieve does not exceed 10%;

[0043] (2) Place the waste aerated concrete particles (CP) in a CABR-HTX12 concrete carbonization test chamber ( Figure 2 ) is carbonized to obtain carbonized regenerated aerated concrete (RCP). The conditions adopted in the carbonization test are: temperature of 20±2°C, relative humidity of 70±5%, carbon dioxide concentration of 20±3%, carbon dioxide pressure of 0.1MPa, and carbonization age of 7 days.

[0044] Compared with the waste aerated concrete, the carbonized regenerated aerated concrete obtained after carbonization has a rich pore structure under scanning electron microscope imaging ( Figure 3-4 ).

[0045] Application of Carbonation Regeneration Aerated Concrete in Treatment of Wastewater Containing Heavy Metal Ions

[0046] A heavy metal ion solution with a lead ion concentration of 10 mg / L was prepared in the laboratory. 30 mg of carbonized regenerated aerated concrete was added to 30 mL of the lead ion solution. The pH value of the mixed solution was adjusted with 0.1 mol / L NaOH or HNO 3 Adjust to 2 and shake at 200 rpm in a constant temperature shaking box for 4 h.

[0047] After the oscillation, the lead ion content in the water was detected by inductively coupled plasma emission spectrometry and was 0.254 mg / L.

[0048] Example 2

[0049] Preparation of Carbonated Regenerated Aerated Concrete

[0050] (1) Raw material pretreatment: The recycled waste aerated concrete is crushed into particles with a diameter of about 5 mm by a hammer crusher, and then placed in an agate zirconia ball mill and set at 150 rpm. After grinding for 30 minutes, relatively smooth particles are obtained. The particle size of the particles after grinding is less than 2 mm, and the residue on a 10-mesh sieve does not exceed 10%;

[0051] (2) Place the waste aerated concrete particles (CP) in a CABR-HTX12 concrete carbonization test chamber ( Figure 2) is carbonized to obtain carbonized regenerated aerated concrete (RCP), wherein the conditions adopted in the carbonization test are: temperature of 20±2°C, relative humidity of 70±5%, carbon dioxide concentration of 20±3%, carbon dioxide pressure of 0.1MPa, and carbonization age of 9 days.

[0052] The carbonized regenerated aerated concrete obtained after carbonization has a rich pore structure under scanning electron microscope imaging.

[0053] Application of Carbonation Regeneration Aerated Concrete in Treatment of Wastewater Containing Heavy Metal Ions

[0054] The laboratory prepared a heavy metal ion solution with a cadmium ion concentration of 10 mg / L. 30 mg of carbonized regenerated aerated concrete was added to 30 mL of cadmium ion solution. The pH value of the mixed solution was adjusted with 0.1 mol / L NaOH or HNO 3 Adjust to 5 and shake at 200 rpm in a constant temperature shaking box for 4 h.

[0055] After the oscillation, the cadmium ion content in the water was detected by inductively coupled plasma emission spectrometry and was 0.045 mg / L.

[0056] Example 3

[0057] Preparation of Carbonated Regenerated Aerated Concrete

[0058] (1) Raw material pretreatment: The recycled waste aerated concrete is crushed into particles with a diameter of about 5 mm by a hammer crusher, and then placed in an agate zirconia ball mill and set at 250 rpm. After grinding for 10 minutes, relatively smooth particles are obtained. The particle size of the particles after grinding is less than 2 mm, and the residue on a 10-mesh sieve does not exceed 10%;

[0059] (2) The waste aerated concrete particles (CP) were placed in a CABR-HTX12 concrete carbonation test chamber for carbonization to obtain carbonized regenerated aerated concrete (RCP). The conditions adopted in the carbonization test were: temperature of 20±2°C, relative humidity of 70±5%, carbon dioxide concentration of 20±3%, and carbon dioxide pressure of 0.1MPa, and the carbonization age was 5 days.

[0060] The carbonized regenerated aerated concrete obtained after carbonization has a rich pore structure under scanning electron microscope imaging.

[0061] Application of Carbonation Regeneration Aerated Concrete in Treatment of Wastewater Containing Heavy Metal Ions

[0062] The laboratory prepared a heavy metal ion solution with a lead ion concentration of 10 mg / L. 30 mg of carbonized regenerated aerated concrete was added to 30 mL of the lead ion solution. The pH value of the mixed solution was adjusted with 0.1 mol / L NaOH or HNO 3 Adjust to 7 and shake at 200 rpm in a constant temperature shaking box for 4 h.

[0063] After the oscillation, the lead ion content in the water was detected by inductively coupled plasma emission spectrometry and was 0.137 mg / L.

[0064] Example 4

[0065] Preparation of Carbonated Regenerated Aerated Concrete

[0066] (1) Raw material pretreatment: The recycled waste aerated concrete is crushed into particles with a particle size of about 5 mm by a hammer crusher, and then placed in an agate zirconia ball mill and set at 200 rpm. After grinding for 20 minutes, relatively smooth particles are obtained. The particle size of the particles after grinding is less than 2 mm, and the residue on a 10-mesh sieve does not exceed 10%;

[0067] (2) The waste aerated concrete particles (CP) were placed in a CABR-HTX12 concrete carbonation test chamber for carbonization to obtain carbonized regenerated aerated concrete (RCP). The conditions adopted in the carbonization test were: temperature of 20±2°C, relative humidity of 70±5%, carbon dioxide concentration of 20±3%, and carbon dioxide pressure of 0.1MPa, and the carbonization age was 7 days.

[0068] The carbonized regenerated aerated concrete obtained after carbonization has a rich pore structure under scanning electron microscope imaging.

[0069] Application of Carbonation Regeneration Aerated Concrete in Treatment of Wastewater Containing Heavy Metal Ions

[0070] The laboratory prepared a heavy metal ion solution with a cobalt ion concentration of 10 mg / L. 30 mg of carbonized regenerated aerated concrete was added to 30 mL of the cobalt ion solution. The pH value of the mixed solution was adjusted with 0.1 mol / L NaOH or HNO 3 Adjust to 7 and shake at 200 rpm in a constant temperature shaking box for 4 h.

[0071] After the oscillation, the cobalt ion content in the water was detected by inductively coupled plasma emission spectrometry and the result was 0.0092 mg / L, which met the national first-level standard.

[0072] Example 5

[0073] Preparation of Carbonated Regenerated Aerated Concrete

[0074] (1) Raw material pretreatment: The recycled waste aerated concrete is crushed into particles with a diameter of about 10 mm by a hammer crusher, and then placed in an agate zirconia ball mill and set at 200 rpm. After grinding for 20 minutes, relatively smooth particles are obtained. The particle size of the particles after grinding is less than 2 mm, and the residue on a 10-mesh sieve does not exceed 10%;

[0075] (2) The waste aerated concrete particles (CP) were placed in a CABR-HTX12 concrete carbonation test chamber for carbonization to obtain carbonized regenerated aerated concrete (RCP). The conditions adopted in the carbonization test were: temperature of 20±2°C, relative humidity of 70±5%, carbon dioxide concentration of 20±3%, and carbon dioxide pressure of 0.1MPa, and the carbonization age was 7 days.

[0076] The carbonized regenerated aerated concrete obtained after carbonization has a rich pore structure under scanning electron microscope imaging.

[0077] Application of Carbonation Regeneration Aerated Concrete in Treatment of Wastewater Containing Heavy Metal Ions

[0078] The laboratory prepared a heavy metal ion solution with a cadmium ion concentration of 10 mg / L. 30 mg of carbonized regenerated aerated concrete was added to 30 mL of cadmium ion solution. The pH value of the mixed solution was adjusted with 0.1 mol / L NaOH or HNO 3 Adjust to 7 and shake at 200 rpm in a constant temperature shaking box for 3 h.

[0079] After the oscillation, the cadmium ion content in the water was detected by inductively coupled plasma emission spectrometry and was 0.0313 mg / L.

[0080] Example 6

[0081] Preparation of Carbonated Regenerated Aerated Concrete

[0082] (1) Raw material pretreatment: The recycled waste aerated concrete is crushed into particles with a diameter of about 3 mm by a hammer crusher, and then placed in an agate zirconia ball mill and set at 200 rpm. After grinding for 20 minutes, relatively smooth particles are obtained. The particle size of the particles after grinding is less than 2 mm, and the residue on a 10-mesh sieve does not exceed 10%;

[0083] (2) The waste aerated concrete particles (CP) were placed in a CABR-HTX12 concrete carbonation test chamber for carbonization to obtain carbonized regenerated aerated concrete (RCP). The conditions adopted in the carbonization test were: temperature of 20±2°C, relative humidity of 70±5%, carbon dioxide concentration of 20±3%, and carbon dioxide pressure of 0.1MPa, and the carbonization age was 12 days.

[0084] The carbonized regenerated aerated concrete obtained after carbonization has a rich pore structure under scanning electron microscope imaging.

[0085] Application of Carbonation Regeneration Aerated Concrete in Treatment of Wastewater Containing Heavy Metal Ions

[0086] The laboratory prepared a heavy metal ion solution with a nickel ion concentration of 10 mg / L. 30 mg of carbonized regenerated aerated concrete was added to 30 mL of nickel ion solution. The pH value of the mixed solution was adjusted with 0.1 mol / L NaOH or HNO 3 Adjust to 5 and shake at 200 rpm in a constant temperature shaking box for 2 h.

[0087] After the oscillation, the nickel ion content in the water was detected by inductively coupled plasma emission spectrometry and was 0.0025 mg / L, which met the national first-level standard.

[0088] Figure 1 The present invention is a flow chart of the carbonization of waste aerated concrete and its adsorption of heavy metals.

[0089] Figure 5 This is the XRD diagram of carbonized regenerated aerated concrete particles. It can be seen from the figure that during the carbonization process, the chemical components of the recycled aerated concrete particles after crushing and grinding are reconstructed to form carbonization products such as nano-calcium carbonate and three-dimensional porous amorphous silica gel.

[0090] Comparative Example 1

[0091] This comparative example is basically the same as Example 1, except that the waste aerated concrete is not subjected to carbonization treatment and is directly used for the treatment of wastewater containing heavy metal ions;

[0092] The method and process for treating wastewater containing heavy metal ions are basically the same as those in Example 1.

[0093] After the oscillation, the nickel ion content in the water was detected by inductively coupled plasma emission spectrometry and was 8.96 mg / L.

[0094] Comparative Example 2

[0095] This comparative example is basically the same as Example 1, except that the waste aerated concrete is not crushed or ground, but directly used for carbonization treatment, and then used for the treatment of wastewater containing heavy metal ions after carbonization treatment;

[0096] The method and process for treating wastewater containing heavy metal ions are basically the same as those in Example 1.

[0097] After the oscillation, the nickel ion content in the water was detected by inductively coupled plasma emission spectrometry and was 9.5 mg / L.

[0098] Comparative Example 3

[0099] This comparative example is basically the same as Example 1, except that: waste concrete is used to replace the waste aerated concrete in Example 1;

[0100] The method and process for treating wastewater containing heavy metal ions are basically the same as those in Example 1.

[0101] After the oscillation, the nickel ion content in the water was detected by inductively coupled plasma emission spectrometry and was 6.24 mg / L.

[0102] Table 1 shows the test results of the above-mentioned Examples 1-6 and Comparative Examples 1-3.

[0103] Table 1 Test results

[0104]

[0105]

[0106] As can be seen from Table 1, after the waste gas aerated concrete is crushed, ground and carbonized in Examples 1-6 of the present invention, the obtained carbonized regenerated aerated concrete has a large number of gel pores and a higher specific surface area than the control examples 1-3, and exhibits excellent adsorption characteristics for different heavy metal ions.

[0107] The waste aerated concrete in Comparative Example 1 was not subjected to carbonization treatment and was directly used for the treatment of wastewater containing heavy metal ions. Although the waste aerated concrete has a certain adsorption effect on heavy metal ions, it has problems such as limited adsorption capacity and low removal efficiency of low-concentration heavy metal ions.

[0108] In Control Example 2, the waste aerated concrete was not crushed or ground but directly used for carbonization treatment, which to a certain extent limited the increase in the specific surface area of ​​the carbonized regenerated aerated concrete, resulting in poor adsorption effect of heavy metal ions.

[0109] In Control Example 3, waste concrete is used to replace the waste aerated concrete in Example 1. Although the carbonized waste concrete also has certain cementitious properties, after the waste aerated concrete is carbonized, the calcium carbonate on the surface mainly exists in the form of micrometer level, which is slightly worse than the carbonization products such as nanometer-level calcium carbonate and three-dimensional porous structure amorphous silica gel in the carbonized regenerated aerated concrete of the present application.

[0110] In summary, the preparation method of carbonized regenerated aerated concrete of the present invention not only provides a new approach to improve the structural properties of waste aerated concrete, but also indicates that carbonized regenerated aerated concrete may exhibit excellent performance in heavy metal removal.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing carbonized regenerated aerated concrete, characterized in that: The following steps are involved: The waste aerated concrete is crushed and ground to obtain the waste aerated concrete recycled particles; Carbonizing the waste aerated concrete regeneration particles to obtain carbonized regenerated aerated concrete; During the carbonization, the waste aerated concrete regeneration particles undergo a carbonization reaction to form nano calcium carbonate and three-dimensional porous amorphous silica gel carbonization products.

2. The preparation method according to claim 1, characterized in that: During the crushing, a hammer crusher is used to crush the waste aerated concrete into pieces of 2mm-10mm.

3. The preparation method according to claim 1, characterized in that: During the grinding, an agate zirconia ball mill is used to grind at a speed of 150 rpm to 250 rpm for 10 min to 30 min; The particle size of the waste aerated concrete regeneration particles is less than 2 mm, and the residue on the 10-mesh sieve does not exceed 10%.

4. The preparation method according to claim 1, characterized in that: During the carbonization, the concentration of carbon dioxide is controlled to be 17%-23%, the pressure of carbon dioxide is 0.05MPa-0.2MPa, and the carbonization age is 5d-12d.

5. The preparation method according to claim 1, characterized in that: During the carbonization, the temperature is controlled at 18° C.-22° C. and the humidity is controlled at 65%-75%.

6. The preparation method according to claim 1, characterized in that: During the carbonization, the purity of the carbon dioxide used is 90%-99%.

7. A carbonized regenerated aerated concrete, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 6.

8. Application of the carbonized regenerated aerated concrete according to claim 1 or the carbonized regenerated aerated concrete prepared by the preparation method according to any one of claims 1 to 7 in sewage treatment, characterized in that: The application of the carbonized regenerated aerated concrete in the treatment of sewage containing heavy metal ions.

9. The use according to claim 8, characterized in that: The method comprises the following steps: adding carbonized regenerated aerated concrete into sewage containing heavy metal ions, and adjusting the pH value of the sewage to 2-7.

10. The use according to claim 8, characterized in that: The heavy metals include any one or more of nickel, cadmium, lead and cobalt.

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