A full-solid-waste carbon-negative porous brick and a preparation method thereof

Abstract

The application discloses a kind of full solid waste carbon-negative porous brick and preparation method thereof, belong to solid waste resource and CO2 capture-sequestration-utilization green building material technical field, specifically related to a kind of red mud, steel slag and recycled aggregate as main raw material, by low water-binder ratio semi-dry pressing forming multi-level pore structure, and using cement kiln tail gas CO2 in normal temperature micro-pressure condition is carried out directional carbonation curing, the method for preparing the nationwide waste porous brick with carbon-negative characteristics.The method can realize solid waste high mixing, CO2 efficient sequestration and product performance collaborative promotion.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of green building materials, and particularly relates to a full-solid-waste carbon-negative porous brick using cement kiln tail gas for directional carbon curing and a preparation method thereof. BACKGROUND

[0002] At present, red mud, a high-alkalinity solid waste produced in the production process of alumina, occupies a large amount of land resources in storage, and its free alkali and trace heavy metal components are easy to migrate through rainwater leaching, which poses a potential threat to the soil and groundwater environment. Steel slag, a typical solid waste in the metallurgical industry, is rich in free CaO and active silicates, but due to its poor volume stability and large activity fluctuation, its actual utilization rate in cement and concrete is low. In addition, if the waste concrete aggregate generated by building demolition cannot be used as a high-value-added resource, it will also increase the pressure of solid waste storage.

[0003] Traditional clay sintered bricks are prepared by calcining at a temperature above 900 DEG C, and the carbon dioxide emission per ton of product is more than 0.2 tons; autoclaved aerated concrete avoids the sintering process, but still needs high-pressure steam curing at about 180 DEG C, which has high energy consumption. Some existing low-temperature solid waste brick technologies use solid waste to some extent, but still need to add more than 20% cement or lime as cementitious materials, resulting in a high level of carbon emission in the whole life cycle, which is difficult to meet the requirements of low-carbon development of the building industry.

[0004] Therefore, how to realize high-content collaborative utilization of multi-source solid waste while avoiding high-temperature sintering, high-pressure steam curing and large use of cement, and at the same time realize efficient solidification and storage of carbon dioxide in industrial tail gas, has become a key problem to be solved in this technical field. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a full-solid-waste carbon-negative porous brick using cement kiln tail gas for directional carbon curing and a preparation method thereof, which integrates high-alkali red mud produced in the alumina industry, steel slag discharged in the black metallurgical process, and recycled coarse and fine aggregate generated in the building demolition process in the same cementitious system. The recycled aggregate assumes the dual roles of framework and pore increase, which not only gives the product macroscopic structural strength, but also builds a deep and through gas transmission channel; the steel slag and red mud are filled in the recycled aggregate to adjust the internal multi-element pore structure, and the calcium-containing phase on the surface of the steel slag and the alkaline components in the red mud can react with CO2 to form carbonated products, improving the bonding performance between particles; through this principle, the solid waste incorporation rate is greatly improved, and at the same time, a multi-scale pore structure is formed inside, promoting the transmission and reaction of CO2 in the product during the carbonation curing process, thereby at least one technical problem in the background art can be solved.

[0006] In order to solve the above technical problems, the present application is implemented as follows:

[0007] The embodiment of the present application provides a preparation method of a full-solid waste carbon-negative porous brick, comprising the following steps:

[0008] Step S1, taking red mud, steel metallurgical slag and building demolition recycled aggregate as main raw materials, the total mass of the three accounts for 80-90wt% of the total mass of the ingredients;

[0009] Step S2, adding steel slag powder, recycled micro powder and 3wt%-8wt% of cement activator to the main raw materials, and stirring to form dry mixture;

[0010] Step S3, adding water to the dry mixture, controlling the water-binder ratio to be less than or equal to 0.18, and stirring for 1-3 minutes to obtain semi-dry material;

[0011] Step S4, semi-dry pressing the semi-dry material to form a green body with a four-level pore network structure of through holes, interstitial pores, autogenous pores and gel pores, and the porosity is 20vol%-40vol% under the pressure of 15MPa-40MPa;

[0012] Step S5, pre-drying and curing the green body;

[0013] Step S6, placing the pre-dried green body in a sealed carbonization bin, and introducing cement kiln tail gas with a CO2 volume fraction of 8%-20% at a pressure of 0.05MPa-0.20MPa for carbonization curing for 6-12 hours;

[0014] Step S7, after the carbonization curing is completed, the product is cured in a normal temperature and humidity environment for 3-7 days, and the full-solid waste carbon-negative porous brick is obtained.

[0015] Optionally, in step S1, the content of the red mud is 10wt%-40wt%, the content of the steel slag is 5wt%-20wt%, and the content of the building demolition recycled aggregate is 30wt%-60wt%.

[0016] Optionally, in step S2, the specific surface area of the steel slag powder is not less than 400m 2 ·kg -1 , and the free CaO content is not less than 4wt%.

[0017] Optionally, in step S4, the pore size ranges of the four-level pore network are respectively: through holes 2mm-10mm, interstitial pores 0.1mm-2mm, autogenous pores 10um-100um, and gel pores less than 10um.

[0018] Optionally, in step S6, the cement kiln tail gas is directly used after cyclone dust removal, and the relative humidity in the bin during the carbonization curing process is controlled to be 50%-85%.

[0019] The application also provides a full-solid-waste carbon-negative porous brick prepared by the method, which has a 28d compressive strength of 15 MPa or more, a dry density of 1.50 g·cm -3 ~2.50 g·cm -3 , a CO2 storage amount of 90 kg·t -1 or more, a 24h water absorption of 14% or less, a mass loss of 1.5% or less after 50 freeze-thaw cycles, and a negative value of life cycle carbon emission.

[0020] Optionally, the ratio of porosity to compressive strength is 1vol%:0.4 MPa~1vol%:0.6 MPa.

[0021] Optionally, the total mass of CaCO3, Na2CO3 and calcium carboaluminate phases in the brick body of the full-solid-waste carbon-negative porous brick accounts for 10wt%-18wt% of the solid mass, and CaCO3 is the main crystal phase.

[0022] Optionally, the brick body of the full-solid-waste carbon-negative porous brick has a mass loss of 0.5% or less after 3x10 4 times of wheel load test, and an acoustic damping coefficient increase of 12% or more.

[0023] Optionally, the full-solid-waste carbon-negative porous brick does not need high-temperature baking or high-pressure steam curing in the manufacturing process, and the carbonization heat is completely derived from the cement kiln tail gas waste heat.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] (1) Efficient solid waste utilization and collaborative treatment: taking red mud, steel slag and building demolition recycled aggregate as main raw materials, the total proportion of the three is 80-90 wt%, realizing high-value resource utilization of various industrial solid wastes and significantly reducing environmental load.

[0026] (2) Low-carbon or even carbon-negative emission: using CO2 in the cement kiln tail gas for directional carbonization curing, each ton of product can store CO2 of 90 kg or more, and the whole life cycle carbon accounting shows a negative value of net carbon emission.

[0027] (3) Energy saving and consumption reduction, green process: no high-temperature baking or high-pressure steam curing is needed, only carbonization curing under normal temperature-micro pressure condition is needed, the energy consumption is significantly lower than that of traditional brick material preparation process; the tail gas waste heat is directly used, without additional heating, further reducing energy consumption.

[0028] (4) Excellent product performance: 28-day compressive strength of 15 MPa or more, dry density of 1.3-1.7 g / cm 3 , water absorption, freeze-thaw and salt erosion performance meet the standards of blocks and paving bricks, and have the characteristics of lightweight, high strength, weather resistance and durability.

[0029] (5) Multi-level pore structure synergistic enhancement: Through coarse-fine bimodal grading and low water-binder ratio semi-dry pressing process, four-level pore network of interconnected pores, interstitial pores, autogenous pores and gel pores is constructed in situ, which not only promotes the rapid penetration and reaction of CO2, but also enhances the structural density through carbonation product filling.

[0030] (6) Effective solidification of heavy metals: During carbonation, heavy metals such as Pb and Cd in red mud are converted into stable carbonates or silicates and are coated by CaCO3 crystal shell and silica-aluminum gel, with leaching concentration lower than the limit value of hazardous waste, high environmental safety.

[0031] (7) Strong generalization of process equipment: The used stirring, pressing and carbonation equipment are mature and general equipment, with low investment threshold, great transformation flexibility, easy coupling with existing cement production line and good prospects for large-scale promotion.

[0032] (8) Significant economic benefits: Negative carbon attributes can obtain additional income through carbon trading, while raw material cost is low and energy consumption is less, with overall economic performance better than traditional sintered bricks or autoclaved bricks.

[0033] In summary, the present application has significant advantages in solid waste resource utilization, carbon emission reduction, energy saving and consumption reduction, product performance and industrialization application, with good environmental, economic and social benefits. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 The flow chart of the preparation method of the full-solid waste negative carbon porous brick provided by the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0037] The terms "first", "second", and the like in the description of the application are used to distinguish similar objects, and are not used to describe a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances so that the embodiments of the application can be implemented in an order other than that illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally a class and do not limit the number of objects, for example, the first object can be one or more. In addition, "and / or" in the specification indicates at least one of the connected objects, and the character " / ", generally indicates that the objects before and after are in a "or" relationship.

[0038] Please refer to Figure 1 The embodiment of the application provides a preparation method of a full-solid waste carbon-negative porous brick, comprising the following steps:

[0039] Step S1, taking red mud, steel metallurgical slag and building demolition recycled aggregate as main raw materials, the total mass of the three accounts for 80-90wt% of the total mass of the ingredients;

[0040] Step S2, adding steel slag powder, recycled micro powder and 3wt%-8wt% of cement activator to the main raw materials, and stirring to form dry mixture;

[0041] Step S3, adding water to the dry mixture, controlling the water-binder ratio to be less than or equal to 0.18, and stirring for 1-3 minutes to obtain semi-dry material;

[0042] Step S4, semi-dry pressing the semi-dry material under a pressure of 15MPa-40MPa to form a green body with four-level pore network structure of through holes, interstitial pores, autogenous pores and gel pores, and the porosity is 20vol%-40vol%;

[0043] Step S5, pre-drying and curing the green body;

[0044] Step S6, placing the pre-dried green body in a sealed carbonization chamber, introducing cement kiln tail gas with a CO2 volume fraction of 8%-20%, and performing carbonization curing under a pressure of 0.05MPa-0.20MPa for 6-12 hours;

[0045] Step S7, after the carbonization curing is completed, curing the product in a normal temperature and humidity environment for 3-7 days, and the full-solid waste carbon-negative porous brick is obtained.

[0046] In step S1, the amount of red mud is 10wt%-40wt%, the amount of steel slag is 5wt%-20wt%, and the amount of building demolition recycled aggregate is 30wt%-60wt%.

[0047] In step S2, the specific surface area of the steel slag powder is not less than 400m 2 ·kg -1The free CaO content is not less than 4 wt%.

[0048] In step S3, the slump of the semi-dry material generated after adding water and stirring is less than 30mm, to ensure that the pore network is shaped and does not collapse during subsequent pressing and molding.

[0049] In step S4, the pore sizes of the four-level mesh are as follows: through holes 2mm to 10mm, gap holes 0.1mm to 2mm, self-generated pores 10μm to 100μm, and gel pores less than 10μm.

[0050] Furthermore, the molding time for semi-dry pressing is 3s to 15s.

[0051] In step S5, the pre-drying and curing time is determined based on the sample porosity and drying method, so that the relative humidity in the pores inside the pre-cured body is within the range of 50-70%.

[0052] In step S6, the cement kiln exhaust gas is used directly after being cyclone dust removal. During the carbonization curing process, the relative humidity inside the chamber is controlled at 50% to 85%. The moisture generated during the carbonization process is removed in a timely manner and the internal humidity is adjusted by controlling the wind speed inside the carbonization chamber and setting up drainage ditches.

[0053] During the carbonation stage, CO2 reacts with alkali metals such as CaO, Ca(OH)2, and tricalcium silicate in steel slag powder, steel slag particles, recycled aggregates, and micro powders to generate CaCO3 crystal shells and silica / alumina gel. Among them, the calcium carbonate crystal shells form the main skeleton structure, while the silica / alumina gel fills the spaces between the calcium carbonate crystals and improves the bonding performance, increases the skeleton density, and forms strength.

[0054] Trace amounts of heavy metals such as Pb and Cd in red mud precipitate as carbonates or silicates during the carbonation process and are coated with CaCO3 crystal shells and silica / alumina gel. This results in the leaching concentration of heavy metals in the resulting filter residue, as tested by TCLP, being below the hazardous waste leaching limit of GB5085.3. Simultaneously, the alkaline substances in red mud can undergo carbonization reactions, further increasing carbon sequestration and product strength.

[0055] The heat generated by carbonization in the product exhaust gas comes entirely from the waste heat of the cement kiln exhaust gas, requiring no additional heating; the kiln exhaust gas can be used directly after cyclone dust removal, without the need for deep desulfurization, denitrification and purification.

[0056] This invention also provides a porous brick with negative carbon from solid waste prepared by the method, which has a 28-day compressive strength ≥15MPa and a dry density of 1.50 g·cm³. -3 ~2.50g·cm -3 CO2 solids content ≥90 kg·t -1 It has a 24-hour water absorption rate of ≤14%, a mass loss of ≤1.5% after 50 freeze-thaw cycles, and a negative carbon emission throughout its life cycle.

[0057] Further, the ratio of porosity and compressive strength of the all-solid-waste carbon-negative porous brick is 1vol%:0.4MPa-1vol%:0.6MPa.

[0058] The total mass of CaCO3, Na2CO3 and calcium carboaluminate phases in the brick body of the all-solid-waste carbon-negative porous brick accounts for 10wt%-18wt% of the solid mass, wherein CaCO3 is the main crystal phase.

[0059] The all-solid-waste carbon-negative porous brick has a 3x10 4 The mass loss is less than or equal to 0.5% and the acoustic damping coefficient is increased by more than 12% after the second load test.

[0060] The all-solid-waste carbon-negative porous brick does not need high-temperature baking or high-pressure steam curing in the manufacturing process, and the carbonization heat is completely derived from the cement kiln tail gas waste heat.

[0061] The all-solid-waste carbon-negative porous brick and the preparation method thereof provided by the present application will be described in detail below with specific embodiment 1.

[0062] Embodiment 1

[0063] I. Raw material preparation and pretreatment

[0064] Red mud: The dewatered red mud produced by a Bayer method of an alumina plant in Guangxi has a normal temperature water content of about 18%. A belt filter is used for secondary dewatering, and then hot air circulation drying is performed at 80°C for 4 hours to reduce the water content to less than 8%. After crushing, the particles with a size of 5mm are prepared. The main chemical components (mass fraction) thereof are: Na2O 8.3%, Al2O3 19.6%, Fe2O3 38.7%, SiO2 12.4%, CaO 4.2%, and the 1:10 water immersion pH value is 11.9.

[0065] Steel slag: The converter cooling slag is crushed to a particle size of less than 10mm, and then the metallic iron is removed by magnetic separation. Then, the particles with a particle size of 0.1-4mm are obtained by joint crushing of a jaw crusher and an impact crusher. The main components (mass fraction) thereof are: free CaO 4.9%, total CaO 43.1%, SiO2 14.7%, and iron oxide 18.3%, and the specific surface area is about 380 m² / kg.

[0066] Recycled coarse aggregate: derived from waste C30 concrete members, after being crushed by a jaw crusher, particles with a particle size of 2-10mm are selected by a drum screen, and attached soil is removed by water washing. The surface dry water absorption rate is 4.1%, the needle flake particle content is 9.3%, and the crushing index is 14%, which meets the requirements of the aggregate for blocks.

[0067] Steel slag powder: prepared by ball milling and powder selection of blast furnace water quenched slag, with a specific surface area of 430 m 2 / kg.

[0068] Recycled micro-powder: micro-powder with a particle size of less than 63 μm recovered from construction waste by dry separation, with a total content of active SiO2 and Al2O3 of about 65%.

[0069] Cement activator: P·O 42.5 grade ordinary portland cement.

[0070] Water: normal temperature water.

[0071] II. Proportioning and mixing

[0072] The raw materials were weighed according to the following mass ratio: 25 parts of red mud, 15 parts of steel slag particles, 40 parts of recycled coarse aggregate, 8 parts of steel slag powder, 8 parts of recycled micro-powder, and 4 parts of cement.

[0073] The weighed red mud, steel slag particles, and recycled coarse aggregate were poured into a 300 L planetary forced mixer, and the dry material mode was used for mixing for 30 seconds to preliminarily break the agglomeration of the raw materials.

[0074] Steel slag powder, recycled micro-powder, and cement were added, and dry mixing was continued for 30 seconds to form a uniform dry mixture.

[0075] The dry mixture was added with water (water temperature 25℃) accounting for 16% of the total dry material mass at one time, and the mixer was started at high speed (second gear) for 120 seconds until the material was uniformly mixed, with the particles being wet, no bleeding, and the material being able to be held together and scattered when dropped, at this time the water-binder ratio was 0.16, and the material was in a semi-dry state.

[0076] After mixing, the material was transported to the hopper of the brick press within 10 minutes to prevent excessive evaporation of free water.

[0077] III. Semi-dry pressing forming

[0078] A YQJ-1000 four-column hydraulic brick press was used, and the mold cavity size was 240 mm × 115 mm × 90 mm (standard brick size).

[0079] Each mold was filled with 3.9 kg of semi-dry material. The pressing forming process included 5 seconds of pre-pressing, 3 seconds of main pressing (peak pressure 30 MPa), and 2 seconds of pressure holding at peak pressure before unloading and ejection demolding, resulting in porous brick green bodies.

[0080] According to the monitoring of the thermal imager, the surface temperature of the green body during pressing increased by less than 10℃. The volume porosity of the green body was about 28%, and the multi-level pore network structure was maintained intact.

[0081] IV. Pre-drying and carbonization curing

[0082] The pressed green body was sent into a 12m 3 volume stainless steel sealed carbonation chamber together with the supporting plate.

[0083] The carbonation chamber was sealed, and vacuumized to a pressure of -0.01 MPa, and maintained for 2 hours to pre-dry the green body.

[0084] The carbonation chamber was supplied with cement kiln preheater tail gas after cyclone dust removal. The temperature of the tail gas was 90 ± 5 ℃, and the CO2 volume fraction was 12 ± 0.5%.

[0085] The pressure in the carbonation chamber was adjusted to 0.10 MPa, the gas circulation wind speed was controlled to be 0.8 m / s, and the relative humidity was maintained at about 60%. Continuous carbonation curing was carried out under this condition for 10 hours.

[0086] The monitoring showed that the carbonation reaction rate began to decrease significantly at 6 hours, and the reaction basically reached a steady state at 10 hours. The final CO2 storage amount was 92 kg / t of bricks. The core temperature of the bricks decreased from 32℃ to 28℃.

[0087] Five, late static curing and performance testing

[0088] After the carbonation curing was completed, the bricks were moved to a curing room with a temperature of 25℃ and a relative humidity of 60%, and were closed and statically cured for 5 days.

[0089] The performance of the finished bricks was tested, and the results were as follows:

[0090] Dry density: 1.45 g / cm 3 ;

[0091] 24-hour water absorption: 11.8%;

[0092] 28-day compressive strength: 17 MPa;

[0093] CO2 storage amount (measured by pyrolysis method): 95 kg / t of bricks.

[0094] XRD phase analysis showed that the bricks mainly contained calcite (CaCO3), dicalcium silicate (C2S), calcium-aluminum garnet and other phases.

[0095] SEM-EDS micro-morphology observation showed that calcite clusters were embedded in calcium-aluminum-silicate hydrated gel (C-A-S-H), and heavy metal elements such as lead (Pb) and cadmium (Cd) were uniformly dispersed, and no enrichment was found.

[0096] After 50 freeze-thaw cycles, the mass loss rate was 0.9%; after 30 cycles of sulfate dry-wet cycle, the mass loss rate was 1.3%.

[0097] Six、 Process parameter adjustment verification

[0098] The steel slag powder content is increased to 10wt% (corresponding adjustment of other components), the CO2 storage capacity is increased to 102 kg / t, and the 28-day compressive strength reaches 20.5MPa.

[0099] The carbonization curing time is extended to 12 hours, the CO2 storage capacity can reach 108 kg / t, and the 28-day compressive strength is 18.8MPa.

[0100] The recycled coarse aggregate particle size is adjusted to 4-8 mm, the porosity of the obtained brick body is about 24%, the 28-day compressive strength is increased to 25.2MPa, and the CO2 storage capacity is 91kg / t.

[0101] When the free CaO content in the steel slag used is reduced to 3wt%, the CO2 storage capacity is 88kg / t, and the 28-day compressive strength can still be maintained at 16MPa, indicating that the free CaO content is one of the key factors affecting the carbon sequestration rate.

[0102] Seven、 Environmental and economic benefit evaluation

[0103] The total power consumption during the production of 1 ton of finished brick is about 37kWh, and according to the emission factor of the power grid of 0.55kg CO2 / kWh, the indirect emission of CO2 is about 20.4kg; the power consumption of the tail gas delivery fan is 6kWh, and the emission of CO2 is about 3.3kg; the total emission during the manufacturing stage is about 23.7kg CO2. Since the process sequesters 95kg CO2, the net emission is -71.3kg CO2 / t brick. According to the carbon price of 80yuan / t, the additional income of about 5.6yuan can be obtained through carbon trading for the production of 1 ton of brick.

[0104] The above examples show that the present application can successfully produce negative carbon porous bricks with 28-day compressive strength in the range of 15-25MPa and CO2 storage capacity in the range of 90-110kg / t through the synergistic effect of high-doping of multi-source solid waste, low-water-binder ratio semi-dry pressing forming, and targeted carbonization curing of cement kiln tail gas. Compared with traditional clay sintered bricks, the present process saves more than 60% of energy and reduces more than 120% of carbon dioxide, providing a feasible path for industrialization in the field of building materials.

[0105] It should be noted that in this text, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a…" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0106] Furthermore, it is noted that the scope of the methods and systems of the disclosed embodiments are not limited to what can be presently expected to be a practical implementation, and that the methods and systems can include additional or fewer steps, in different order, or combined steps than those described herein. Also, features described in relation to one example can be combined in other examples.

[0107] The above embodiments of the present application have been described in conjunction with the accompanying drawings, but the present application is not limited to the above described embodiments, and the above described embodiments are merely illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application.

Claims

1. A method for preparing a porous brick with negative carbon from solid waste, characterized in that, Includes the following steps: Step S1: Red mud, steel slag from iron and steel metallurgy, and recycled aggregate from building demolition are used as the main raw materials, with the total mass of the three accounting for 80-90 wt% of the total mass of the ingredients. The amount of red mud is 10 wt% to 40 wt%, the amount of steel slag is 5 wt% to 20 wt%, and the amount of recycled aggregate from building demolition is 30 wt% to 60 wt%. Step S2: Add steel slag powder, recycled micro powder, and 3wt%–8wt% cement activator to the main raw materials, and stir to form a dry mixture. The specific surface area of ​​the steel slag powder is not less than 400 m². 2 ·kg -1 The free CaO content is not less than 4 wt%; Step S3: Add water to the dry mixture, control the water-to-binder ratio to be ≤0.18, and stir for 1-3 minutes to obtain a semi-dry mixture; Step S4: The semi-dry material is semi-dry pressed under a pressure of 15MPa to 40MPa to form a green body with a four-level pore network structure, consisting of through-holes, interstitial pores, self-generated pores, and gel pores. The pore sizes of the four levels are as follows: through-holes 2mm to 10mm, interstitial pores 0.1mm to 2mm, self-generated pores 10μm to 100μm, and gel pores less than 10μm. The porosity of the green body is 20vol% to 40vol%. Step S5: Pre-dry and cure the green body; Step S6: Place the pre-dried green billet in a sealed carbonization chamber, introduce cement kiln exhaust gas with a CO2 volume fraction of 8% to 20%, and perform carbonization curing at a pressure of 0.05 MPa to 0.20 MPa for 6 to 12 hours. During the carbonization curing process, the relative humidity inside the chamber is controlled at 50% to 85%. Step S7: After carbonization and curing, the product is cured in a normal temperature and humid environment for 3 to 7 days to obtain the solid waste negative carbon porous brick.

2. A porous brick containing negative carbon from solid waste, prepared by the method of claim 1, characterized in that, Its 28-day compressive strength is ≥15MPa, and its dry density is 1.50g·cm³. -3 ~2.50g·cm -3 CO2 solids content ≥90 kg·t -1 It has a 24-hour water absorption rate of ≤14%, a mass loss of ≤1.5% after 50 freeze-thaw cycles, and a negative carbon emission throughout its life cycle.

3. The porous brick with negative carbon from solid waste according to claim 2, characterized in that, The ratio of porosity to compressive strength is 1 vol% : 0.4 MPa to 1 vol% : 0.6 MPa.

4. The porous brick with negative carbon from solid waste according to claim 2, characterized in that, The total mass of CaCO3, Na2CO3 and calcium aluminate phase in the porous brick body of solid waste accounts for 10wt% to 18wt% of the solid mass, among which CaCO3 is the main crystalline phase.

5. The porous brick with negative carbon from solid waste according to claim 3, characterized in that, The porous brick containing carbon negative from solid waste has a brick body with a thickness of 3×10. 4 After the second wheel load test, the mass loss is ≤0.5%, and the acoustic damping coefficient is increased by more than 12%.

6. The porous brick with negative carbon from solid waste according to claim 3, characterized in that, The porous brick made entirely of solid waste with negative carbon does not require high-temperature firing or high-pressure steam curing during the manufacturing process; the heat of carbonization comes entirely from the waste heat of cement kiln exhaust gas.

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