A waste incineration by-product carbon sequestration filling material and a preparation method thereof

Abstract

The application provides a waste incineration by-product carbon sequestration filling material and a preparation method thereof. The method comprises the following steps: mixing waste incineration fly ash, high-aluminum ore powder, L-proline and water according to a specific ratio to form a uniform fly ash slurry, and introducing carbon dioxide gas to perform a carbonation reaction to obtain slurry A. Then, the slurry A, waste incineration bottom slag, sulphoaluminate cement and L-histidine and other raw materials are mixed to form filling material B. The filling material B is filled into a goaf to further complete a carbon sequestration reaction, and the carbon sequestration filling material is obtained. The carbon sequestration filling material prepared by the method has excellent compressive strength and long-term stability, and also has high carbon dioxide capture capacity and heavy metal solidification capacity. The technology provides a feasible path for resource utilization of waste incineration by-products, and also provides an economic and environmentally-friendly solution for mining filling operations, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of solid waste resource utilization, and particularly relates to a carbon fixation filling material and a preparation method thereof. BACKGROUND

[0002] Waste incineration process produces fly ash and bottom ash. These by-products cannot be directly utilized due to their high concentration of chloride ions and heavy metals, and have high environmental risks. The harmful substances rich in waste incineration fly ash make it face great challenges in direct recycling and utilization. At present, waste incineration fly ash has been applied to some building materials, but due to its potential environmental pollution risk and unstable performance, its practical application is still limited. Similarly, waste incineration bottom ash has also been applied to a certain extent, especially in some engineering fields, such as roadbed materials in infrastructure construction, building fillers, etc. However, the high density and instability of the bottom ash still limit its application potential in wider fields. Therefore, it is urgent and important to develop safe, feasible and efficient, high-value utilization of waste incineration waste resource technology.

[0003] Under this background, mining filling material as a new type of resource utilization material, with its low demand for raw materials and certain advantages in performance, has become a potential field of application of waste incineration waste. Mining filling material not only can reduce waste accumulation, but also can effectively fill the mine and improve the environment of the mining area, so it has great development space. Waste incineration products, especially fly ash and bottom ash, as raw materials for filling materials, have great application potential. SUMMARY

[0004] The present application is directed to the technical problems of low resource utilization rate of waste incineration by-products and high environmental risk, and proposes a waste incineration by-product carbon fixation filling material and its method. Through the innovative design of front-end carbon fixation reconstruction of fly ash particles and rear-end carbon fixation structure refinement, the method successfully realizes efficient carbonization of waste incineration fly ash and its application in filling materials. Specifically, first, waste incineration fly ash, high-aluminum mineral powder, L-proline and water are mixed in a specific mass ratio to form a uniform fly ash slurry. Then, by introducing CO2 gas, a carbonation reaction is carried out to promote the reaction of alkaline substances in the fly ash with CO2 to generate stable carbonates, thereby achieving effective carbon fixation of the fly ash. Next, the treated fly ash slurry, waste incineration bottom ash, sulphoaluminate cement and L-histidine are mixed by stirring to form a filling material, which is finally filled into the goaf to further realize carbon fixation reaction in the goaf, completing the two-stage carbonation and carbon fixation process. The obtained filling material not only has good compressive strength and long-term stability, but also exhibits high carbon dioxide capture capacity, effectively reducing greenhouse gas emissions and having significant environmental benefits. This technology not only effectively replaces traditional mineral resources to provide an economic and environmentally friendly solution for mining filling operations, but also provides a feasible path for the resource utilization of waste incineration fly ash, with wide application prospects.

[0005] The present application is directed to the technical problems of low resource utilization rate of waste incineration by-products and high environmental risk, and proposes a waste incineration by-product carbon fixation filling material and its method. Through the innovative design of front-end carbon fixation reconstruction of fly ash particles and rear-end carbon fixation structure refinement, the method successfully realizes efficient carbonization of waste incineration fly ash and its application in filling materials. Specifically, first, waste incineration fly ash, high-aluminum mineral powder, L-proline and water are mixed in a specific mass ratio to form a uniform fly ash slurry. Then, by introducing CO2 gas, a carbonation reaction is carried out to promote the reaction of alkaline substances in the fly ash with CO2 to generate stable carbonates, thereby achieving effective carbon fixation of the fly ash. Next, the treated fly ash slurry, waste incineration bottom ash, sulphoaluminate cement and L-histidine are mixed by stirring to form a filling material, which is finally filled into the goaf to further realize carbon fixation reaction in the goaf, completing the two-stage carbonation and carbon fixation process. The obtained filling material not only has good compressive strength and long-term stability, but also exhibits high carbon dioxide capture capacity, effectively reducing greenhouse gas emissions and having significant environmental benefits. This technology not only effectively replaces traditional mineral resources to provide an economic and environmentally friendly solution for mining filling operations, but also provides a feasible path for the resource utilization of waste incineration fly ash, with wide application prospects.

[0006] The present application is directed to the technical problems of low resource utilization rate of waste incineration by-products and high environmental risk, and proposes a waste incineration by-product carbon fixation filling material and its method. Through the innovative design of front-end carbon fixation reconstruction of fly ash particles and rear-end carbon fixation structure refinement, the method successfully realizes efficient carbonization of waste incineration fly ash and its application in filling materials. Specifically, first, waste incineration fly ash, high-aluminum mineral powder, L-proline and water are mixed in a specific mass ratio to form a uniform fly ash slurry. Then, by introducing CO2 gas, a carbonation reaction is carried out to promote the reaction of alkaline substances in the fly ash with CO2 to generate stable carbonates, thereby achieving effective carbon fixation of the fly ash. Next, the treated fly ash slurry, waste incineration bottom ash, sulphoaluminate cement and L-histidine are mixed by stirring to form a filling material, which is finally filled into the goaf to further realize carbon fixation reaction in the goaf, completing the two-stage carbonation and carbon fixation process. The obtained filling material not only has good compressive strength and long-term stability, but also exhibits high carbon dioxide capture capacity, effectively reducing greenhouse gas emissions and having significant environmental benefits. This technology not only effectively replaces traditional mineral resources to provide an economic and environmentally friendly solution for mining filling operations, but also provides a feasible path for the resource utilization of waste incineration fly ash, with wide application prospects.

[0007] The present application is directed to the technical problems of low resource utilization rate of waste incineration by-products and high environmental risk, and proposes a waste incineration by-product carbon fixation filling material and its method. Through the innovative design of front-end carbon fixation reconstruction of fly ash particles and rear-end carbon fixation structure refinement, the method successfully realizes efficient carbonization of waste incineration fly ash and its application in filling materials. Specifically, first, waste incineration fly ash, high-aluminum mineral powder, L-proline and water are mixed in a specific mass ratio to form a uniform fly ash slurry. Then, by introducing CO2 gas, a carbonation reaction is carried out to promote the reaction of alkaline substances in the fly ash with CO2 to generate stable carbonates, thereby achieving effective carbon fixation of the fly ash. Next, the treated fly ash slurry, waste incineration bottom ash, sulphoaluminate cement and L-histidine are mixed by stirring to form a filling material, which is finally filled into the goaf to further realize carbon fixation reaction in the goaf, completing the two-stage carbonation and carbon fixation process. The obtained filling material not only has good compressive strength and long-term stability, but also exhibits high carbon dioxide capture capacity, effectively reducing greenhouse gas emissions and having significant environmental benefits. This technology not only effectively replaces traditional mineral resources to provide an economic and environmentally friendly solution for mining filling operations, but also provides a feasible path for the resource utilization of waste incineration fly ash, with wide application prospects.

[0008] (1) The waste incineration fly ash, high-aluminum mineral powder, L-proline and water are mixed in a specific mass ratio to form a uniform fly ash slurry, and the stirring speed is set to 500 r / min, and the slurry is stored in stirring tank A;

[0009] (2) CO2 gas with a concentration of 20% Vol is introduced into stirring tank A to maintain the carbonation reaction for 5 min, and then the CO2 flow rate is maintained to continue the carbonation reaction for another 5 min, finally obtaining slurry A;

[0010] (3) The sulphoaluminate cement, waste incineration bottom ash, slurry A in stirring tank A and L-histidine are transported to stirring tank B in a specific ratio, the stirring speed is set to 300 r / min, and the stirring time is 10 min to obtain filling material B;

[0011] (4) the filling material B prepared in the stirring tank B is transported to a goaf, a CO2 pipeline is arranged at the bottom of the goaf, and industrial flue gas with a CO2 concentration of 20% Vol is continuously introduced into the goaf through the CO2 pipeline during the solidification of the filling material, so that the carbon fixation filling material is obtained.

[0012] In the technical scheme of the present application: in step (1), the proportions of the waste incineration fly ash, the high-aluminum ore powder, the L-proline and the water are 10-40 parts by mass, 10-40 parts by mass, 0.5-1.2 parts by mass and 50 parts by mass, respectively.

[0013] In the technical scheme of the present application: in step (2), the initial flow rate of CO2 is set to 0.2-1.0 Nm 3 / h; subsequently, the flow rate is increased to 0.5-1.5 Nm 3 / h.

[0014] In the technical scheme of the present application: in step (3), the proportions of the sulphoaluminate cement, the waste incineration bottom ash, the slurry A in the stirring tank A and the L-histidine are 5-10 parts by mass, 30-50 parts by mass, 45-70 parts by mass and 0.5-1.0 parts by mass, respectively.

[0015] In the technical scheme of the present application: in step (3), the particle size of the waste incineration bottom ash is 0.5-1 mm.

[0016] In the technical scheme of the present application: in step (4), the injection flow rate of CO2 is set to 0.8-1.5 Nm 3 / h.

[0017] In the technical scheme of the present application: in step (4), the injection time of CO2 is set to 30-120 min.

[0018] In the technical scheme of the present application: in step (4), the CO2 pipeline is made of PVC and has an inner diameter of 100-150 mm.

[0019] The beneficial effects of the present application are as follows:

[0020] (1) The present application utilizes the synergistic effect of carbon dioxide gas and L-proline to accurately regulate the mineral structure of waste incineration fly ash, successfully realizes the reconstruction thereof, and generates a reconstructed material mainly composed of amorphous calcium carbonate. Carbon dioxide plays a key role in the process, can react with the calcium-rich minerals in the fly ash, and is converted into amorphous calcium carbonate with high reactivity, significantly improving the physical and chemical activity of the fly ash.

[0021] (2) The present application ingeniously regulates the dynamic chemical equilibrium between the aluminum phase and the carbonate ions by introducing high-aluminum mineral powder as an auxiliary material and using waste incineration bottom ash as aggregate, thereby effectively regulating the formation process of the difficult-to-dissolve double salt mineral. This regulation of the reaction mechanism enhances the reactivity of the reconstructed fly ash and other materials. A small amount of sulphoaluminate cement plays a catalytic role in this system, promoting the formation of ettringite mineral phase in a lower alkalinity environment, further accelerating the progress of the hydration and cementation reaction, and significantly improving the mechanical strength and structural stability of the filling material.

[0022] (3) After the filling material is pumped into the goaf, the L-histidine acts as a carbonation crystal type regulator in the second step of the carbonation reaction, promoting the further carbonation conversion of the residual calcium-containing mineral phase in the high-flow filling material to generate nano-sized calcium carbonate mainly in the form of aragonite. This reaction not only optimizes the microstructure of the material, significantly filling the voids, but also greatly improves the compactness and density of the filling material, thereby enhancing its mechanical stability and impermeability.

[0023] (4) Compared with the traditional filling material processing method, the filling material prepared by the present application has the following advantages: first, the material has excellent mechanical properties, especially in the development of early strength, which provides reliable bearing capacity guarantee for the construction process; second, through the dual action of gel adsorption and carbonate solidification mechanism, the material can effectively reduce the heavy metal leaching and improve the environmental friendliness, meeting the strict environmental standards. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Production process flow of waste incineration by-product carbon sequestration filling material.

[0025] Figure 2 X-ray diffraction analysis comparison of the filling material in some examples.

[0026] Figure 3 Infrared spectrum analysis of the filling material in some comparative examples and examples. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with the drawings and specific examples, but the scope of protection of the present application is not limited thereto:

[0028] Example 1

[0029] (1) First, mix the waste incineration fly ash, high-aluminum mineral powder, L-proline and water according to a mass ratio of 40:10:0.5:50 to form a uniform waste incineration fly ash slurry, and store it in stirring tank A.

[0030] (2) Set the stirring speed of the stirring tank A to 500 r / min, and introduce lime kiln flue gas with a CO2 concentration of 20% Vol. In the initial stage, the flow rate of CO2 is set to 0.5 Nm 3 / h, and the carbonation reaction is maintained for 5 min; then, the flow rate is increased to 1.0 Nm 3 / h, and the carbonation reaction is maintained for 5 min, and finally slurry A is obtained.

[0031] (3) The sulphoaluminate cement, the waste incineration bottom ash, the slurry A in the stirring tank A and L-histidine are transported into the stirring tank B according to a mass ratio of 5:30:65:0.5, and the stirring speed is set to 300 r / min, and the stirring time is 10 min, and filling material B is prepared.

[0032] (4) The filling material B prepared in the stirring tank B is transported to the filling device and is transported to the underground goaf by pumping. A small CO2 pipeline is installed at the bottom of the goaf filling system, and industrial flue gas with a CO2 concentration of 20% Vol is continuously introduced during the solidification of the filling material, and the injection flow rate of CO2 is set to 0.8 Nm 3 / h, and is maintained for 60 min, and a carbon sequestration filling material is obtained.

[0033] Example 2

[0034] The raw materials and test methods used in this example are the same as those in Example 1.

[0035] The steps for preparing the filling material in this example are different from those in Example 1, and in step (1), the waste incineration fly ash, the high-aluminum mineral powder, L-proline and water are mixed according to a mass ratio of 30:20:1.2:50.

[0036] Example 3

[0037] The raw materials and test methods used in this example are the same as those in Example 1.

[0038] The steps for preparing the filling material in this example are different from those in Example 1, and in step (2), the flow rate of CO2 is set to 1 Nm 3 / h, and the carbonation reaction is maintained for 5 min; then, the flow rate is increased to 1.5 Nm 3 / h, and the carbonation reaction is maintained for 5 min, and finally slurry A is obtained.

[0039] Example 4

[0040] The raw materials and test methods used in this example are the same as those in Example 1.

[0041] The difference between the preparation of the filling material in this example and Example 1 is that in step (2), the flow rate of CO2 is set to 0.2 Nm 3 / h, and the carbonization reaction is maintained for 5 min; then, the flow rate is increased to 0.5 Nm 3 / h, and the carbonization reaction is maintained for 5 min, and finally slurry A is obtained.

[0042] Example 5

[0043] The raw materials and test methods used in this example are the same as those in Example 1.

[0044] The difference between the preparation of the filling material in this example and Example 1 is that in step (3), the sulphoaluminate cement, the bottom ash of waste incineration, the slurry A in the stirring tank A, and the L-histidine are transported into the stirring tank B according to a mass ratio of 5:20:75:0.5.

[0045] Example 6

[0046] The raw materials and test methods used in this example are the same as those in Example 1.

[0047] The difference between the preparation of the filling material in this example and Example 1 is that in step (3), the sulphoaluminate cement, the bottom ash of waste incineration, the slurry A in the stirring tank A, and the L-histidine are transported into the stirring tank B according to a mass ratio of 10:50:40:1.

[0048] Example 7

[0049] The raw materials and test methods used in this example are the same as those in Example 1.

[0050] The difference between the preparation of the filling material in this example and Example 1 is that in step (4), the industrial flue gas with a CO2 concentration of 20% Vol is continuously introduced, the injection flow rate of CO2 is set to 1.5 Nm 3 / h, and the process is continued for 30 min.

[0051] Example 8

[0052] The raw materials and test methods used in this example are the same as those in Example 7.

[0053] The difference between the preparation of the filling material in this example and Example 7 is that in step (4), the lime kiln flue gas with a CO2 concentration of 20% Vol is continuously introduced, the injection flow rate of CO2 is set to 1.5 Nm 3 / h, and the process is continued for 120 min.

[0054] Comparative Example 1

[0055] (1) First, the fly ash from waste incineration and water are mixed in a mass ratio of 50:50 to form a uniform fly ash slurry from waste incineration, and then stored in mixing tank A.

[0056] (2) Sulphoaluminate cement, natural aggregate, and slurry A in mixing tank A are transported to mixing tank B in a mass ratio of 5:30:65. The mixing speed is set to 300 r / min and the mixing time is 10 min to obtain the filling material.

[0057] Comparative Example 2

[0058] (1) First, the waste incineration fly ash, high-alumina mineral powder, L-proline and water are mixed in a mass ratio of 40:10:0.5:50 to form a uniform waste incineration fly ash slurry, and then stored in a mixing tank A.

[0059] (2) The agitator speed of mixing tank A is set to 450 r / min, and lime kiln flue gas with a carbon dioxide concentration of 20% Vol is simultaneously introduced. Initially, the CO2 flow rate is set to 0.5 Nm³. 3 The flow rate was maintained at 1.0 Nm³ / h for 5 minutes to sustain the carbonization reaction; subsequently, the flow rate was increased to 1.0 Nm³ / h. 3 Continue the carbonization reaction for 5 minutes at a time, and finally obtain slurry A.

[0060] (3) Sulfoaluminate cement, natural aggregate, slurry A in mixing tank A and L-histidine are transported to mixing tank B in a mass ratio of 5:30:65:0.5. The mixing speed is set to 300 r / min and the mixing time is 10 min to obtain the filling material.

[0061] Comparative Example 3

[0062] (1) First, the waste incineration fly ash, high-alumina mineral powder, L-proline and water are mixed in a mass ratio of 40:10:0.5:50 to form a uniform waste incineration fly ash slurry, and then stored in mixing tank A.

[0063] (3) Sulfoaluminate cement, waste incineration bottom ash, slurry A in mixing tank A and L-histidine are transported to mixing tank B in a mass ratio of 5:30:65:0.5. The mixing speed is set to 300 r / min and the mixing time is 10 min to obtain filling material B.

[0064] (4) The filling material prepared in mixing tank B is transported to the filling device and then pumped to the underground goaf. A thin carbon dioxide pipeline is installed at the bottom of the goaf filling system. During the solidification process of the filling material, lime kiln flue gas with a carbon dioxide concentration of 20% Vol is continuously introduced, and the CO2 injection flow rate is set at 0.8 Nm. 3 / h, and lasted for 60 min, to obtain the filling material.

[0065] The X-ray diffraction patterns of the filling materials prepared in the partial examples and comparative examples are shown in Figure 2 From the results of the patterns, it can be seen that the main alkaline components such as Ca(OH)2and Ca(Cl)O in the waste incineration fly ash treated by the method have undergone significant chemical conversion, and are converted into various crystal forms of calcium carbonate, including amorphous calcium carbonate, calcite, villiaumite and aragonite. With the change of the additive content, Figure 2 It can be observed that the generation amount of aragonite crystal form with high specific surface area, high surface roughness and high reactivity is significantly improved. This phenomenon shows that the additive plays a key role in regulating the morphology and performance of calcium carbonate crystals, and can effectively promote the formation of aragonite crystal form, and enhance the reactivity of the material through its unique crystal structure.

[0066] The infrared spectrum results of the filling materials prepared in the partial examples and comparative examples are shown in Figure 3 According to the analysis, Figure 3 The C-O stretching vibration characteristic peaks (about 1400 cm -1 nearby) of amorphous calcium carbonate and aragonite calcium carbonate in the filling material treated by the method are significantly enhanced. This change shows that the absorption amount of carbon dioxide in the system is significantly improved during the treatment process, and the morphology of calcium carbonate has changed significantly. Especially in the conversion process of calcium carbonate, the generation amount of aragonite crystal form is further enhanced, which shows that the method can efficiently promote the carbonation reaction of alkaline components and control the morphology of calcium carbonate crystals.

[0067] The mechanical properties of the filling materials prepared in each embodiment and comparative examples are listed in Table 1. From the test data, it can be seen that the unconfined compressive strengths of the filling materials prepared in Comparative Examples 1-3 are all lower than 0.5 MPa, while the unconfined compressive strengths of the filling materials treated by the method are significantly improved. In the first step of carbonization, the alkaline minerals of the municipal solid waste incineration fly ash react to form mineral phases mainly composed of amorphous calcium carbonate. This process not only improves the physical and chemical activity of the material, but also provides a stable matrix for subsequent reactions. In this stage, although the high-aluminum mineral powder does not directly participate in the reaction, it plays a role in uniform dispersion through sufficient mixing, creating favorable conditions for subsequent multiphase reactions. In the mixing stage, the high-aluminum mineral powder reacts with the municipal solid waste incineration bottom ash to release active silicon-aluminum sources, providing the necessary chemical basis for the formation of the initial structure of the material. Subsequently, the small amount of introduced sulphoaluminate cement catalyzes the formation of ettringite mineral phases in a low alkalinity environment, which fill the initial pore structure, effectively improving the compactness of the material and accelerating the hydration and cementation reaction. In addition, L-histidine acts as a surfactant in the system, not only promoting the further carbonation conversion of residual calcium-based minerals, but also helping to generate nano-sized calcium carbonate mainly in the form of aragonite. These nano-sized particles further fill and strengthen the microstructure of the material, significantly improving the compactness and mechanical properties of the material. However, the results also show that the CO2 flux is not the higher the better, and excessive CO2 will destroy the structural integrity of the initial hydration gel, leading to a decrease in material strength.

[0068] Table 1 Mechanical properties of filling materials (MPa)

[0069]

[0070] After curing for 7 days, the heavy metal leaching test of the prepared filling materials was carried out using the Toxicity Characteristic Leaching Procedure (TCLP), and the test results are shown in Table 2. From the data, it can be seen that the heavy metal leaching concentrations of the filling materials prepared in Comparative Examples 1-3 are all higher than the national standard limit value, indicating that the materials without optimized treatment have a high environmental risk. In contrast, the filling materials treated by the method exhibit a significant heavy metal solidification effect, with their heavy metal leaching concentrations all lower than the national standard limit value, meeting the requirements for safe use. This improvement is mainly due to the optimized design of the material components and microstructure in the method. During the reaction process, the calcium carbonate generated by the carbonation reaction not only provides higher material compactness, but also significantly reduces the migration channels of heavy metals through physical blocking. At the same time, the introduction of alkaline environment and active silicon-aluminum sources induces the formation of ettringite and other secondary mineral phases, which effectively fix the heavy metal ions in the system through chemical coordination and ion exchange. In addition, the generation of aragonite-type nano-sized calcium carbonate further fills the material micropores, enhancing the long-term stability of the solidification system to heavy metals.

[0071] Table 2 Heavy metal leaching content (mg / L) of filling material

[0072]

[0073] The preparation method of the filling material provided by the present application realizes large-scale application of waste incineration fly ash, and ensures that the obtained filling material exhibits excellent performance in mechanical properties and heavy metal leaching control, thereby meeting the strict requirements of actual engineering application.

[0074] Finally, the above specific embodiments are only used to illustrate the technical solutions of the present application rather than limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A method for producing a waste incineration by-product carbon sequestration filling material, characterized by, The method comprises the following steps: (1) mixing waste incineration fly ash, high-aluminum ore powder, L-proline and water in proportion, setting the stirring speed at 500 r / min, forming a uniform waste incineration fly ash slurry, and storing it in stirring tank A; (2) introducing lime kiln flue gas with a CO2 concentration of 20% Vol into stirring tank A, maintaining the carbonation reaction for 5 min at the initial CO2 flow rate, then maintaining the carbonation reaction for another 5 min at the maintained CO2 flow rate, and finally obtaining slurry A; (3) feeding sulfoaluminate cement, waste incineration bottom ash, slurry A in stirring tank A and L-histidine into stirring tank B in proportion, setting the stirring speed at 300 r / min, and stirring for 10 min to obtain filling material B; in step (3), the proportions of sulfoaluminate cement, waste incineration bottom ash, slurry A in stirring tank A and L-histidine are 5-10 parts by mass, 30-50 parts by mass, 45-70 parts by mass and 0.5-1.0 parts by mass, respectively; (4) delivering the filling material B prepared in the stirring tank B to a goaf, the bottom of the goaf being provided with a CO2 pipeline, and continuously introducing industrial flue gas with a CO2 concentration of 20% Vol into the goaf through the CO2 pipeline during the solidification of the filling material, to obtain the carbon fixation filling material; in step (4), the flow rate of the introduction of the lime kiln flue gas with a CO2 concentration of 20% Vol into the goaf is 0.8-1.5 Nm 3 After the second carbonization reaction, L-histidine acts as a carbonization crystal form regulator in the process, promoting the further carbonization conversion of residual calcium-containing mineral phases in the high-fluidity filling material to generate nano-sized calcium carbonate mainly in the form of aragonite.

2. The method of claim 1, wherein, In step (1), the proportions of the waste incineration fly ash, the high-aluminum ore powder, the L-proline and water are 10-40 parts by mass, 10-40 parts by mass, 0.5-1.2 parts by mass and 50 parts by mass, respectively.

3. The method of claim 1, wherein, In step (2), the initial flow rate of CO2 is in the range of 0.2 - 1.0 Nm 3 / h; the maintained flow rate of CO2 is in the range of 0.5 - 1.5 Nm 3 / h.

4. The method of claim 1, wherein, In step (3), the particle size of the waste incineration bottom ash is 0.5-1 mm.

5. The method of claim 1, wherein, In step (4), the introduction time of lime kiln flue gas with a CO2 concentration of 20% Vol into the goaf is 30-120 min.

6. The method of claim 1, wherein, In step (4), the CO2 pipeline is made of PVC with an inner diameter of 100-150 mm.

7. A waste incineration by-product carbon sequestering fill material, characterized by: The filling material is prepared by the method of any one of claims 1 to 6.

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