Sludge-based geopolymer carbonized artificial aggregate as well as preparation method and application thereof

Abstract

The invention provides a sludge-based geopolymer carbonized artificial aggregate as well as a preparation method and application thereof, and relates to the technical field of solid waste resource utilization. The method comprises the following steps: sequentially drying and grinding sludge to obtain sludge ash; calcining the sludge ash, and mixing the calcined sludge ash with slag, steel slag, an alkali activator, water and a water reducer to obtain slurry; the slurry is sequentially subjected to forming, pre-curing and carbonization curing, and a carbonized artificial aggregate inner blank is obtained; and immersing the carbonized artificial aggregate inner blank in cement mortar for packaging, and then performing maintenance to obtain the sludge-based geopolymer carbonized artificial aggregate. According to the invention, wastes such as sludge, steel slag and mineral slag are converted into building aggregates, so that cooperative treatment of various solid wastes is realized, environmental pollution caused by landfill and stacking is reduced, and land occupation is reduced; and the prepared artificial aggregate has high strength, can be used for building and municipal engineering instead of natural aggregate, meets the engineering requirements and promotes the development of green building materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid waste resource utilization, and particularly relates to a sludge-based polymer carbonized artificial aggregate as well as a preparation method and application thereof. BACKGROUND

[0002] With the development of marine resource development and marine engineering, the amount of deep-sea sludge is gradually increasing. Deep-sea sludge is rich in various minerals, but may also contain harmful substances such as heavy metals. If it is randomly discharged or improperly treated, it will cause serious pollution to the marine ecological environment. Therefore, it is necessary to find an effective treatment method to realize the harmless and resource utilization of deep-sea sludge.

[0003] The steel industry and the mining industry will produce a large amount of steel slag and slag in the production process. The accumulation of a large amount of steel slag and slag not only occupies a large amount of land, but also may cause pollution to the surrounding environment, and it is urgent to reasonably utilize these industrial wastes.

[0004] In building engineering, natural aggregate is an important component of materials such as concrete and mortar. However, with the continuous advancement of infrastructure construction, the demand for natural aggregate continues to grow, leading to a growing shortage of resources. At the same time, overexploitation of natural aggregate will damage the natural environment such as mountains and rivers, causing a series of ecological problems. Therefore, it is of great practical significance to develop artificial aggregate that can replace natural aggregate. SUMMARY

[0005] Therefore, the present application aims to provide a sludge-based polymer carbonized artificial aggregate as well as a preparation method and application thereof. The present application uses sludge, steel slag and slag to prepare carbonized artificial aggregate, realizes effective recycling of solid waste, and the prepared carbonized artificial aggregate has high strength and is expected to replace natural aggregate.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The present application provides a preparation method of a sludge-based polymer carbonized artificial aggregate, comprising the following steps:

[0008] (1) drying, grinding and calcining the sludge in sequence to obtain sludge ash;

[0009] (2) mixing the sludge ash with slag, steel slag, alkali activator, water and water reducing agent to obtain a slurry;

[0010] (3) sequentially forming, pre-curing and carbonation curing the slurry to obtain a carbonized artificial aggregate inner embryo; the carbonation curing is carried out in a carbon dioxide-containing atmosphere;

[0011] (4) encapsulating the carbonized artificial aggregate by immersing the carbonized artificial aggregate in cement mortar, and curing to obtain the sludge-based geopolymer carbonized artificial aggregate; the cement mortar comprises silica fume, fly ash, slag, cement, sand, water and water reducing agent.

[0012] Preferably, the sludge is deep-sea sludge; after the grinding treatment, the obtained powder is sieved, and the undersize is taken; the sieving is sieving through a 200-mesh sieve.

[0013] Preferably, the calcination temperature is 700-900 DEG C, and the time is 1-3 h.

[0014] Preferably, the alkali activator is water glass, and the modulus of the water glass is 2.0.

[0015] Preferably, in the step (2), the mass fractions of the sludge ash, slag and steel slag are 40-80%, 10-40% and 0-30% respectively, and the mass fraction of the steel slag is not 0; the ratio of the mass of sodium oxide in the alkali activator to the total mass of the sludge ash, slag and steel slag is 0.05-0.07:1; the ratio of the mass of water to the total mass of the sludge ash, slag and steel slag is 0.18-0.23:1; and the mass of the water reducing agent is 1-2% of the total mass of the sludge ash, slag and steel slag.

[0016] Preferably, the forming method is extruding and cutting the slurry.

[0017] Preferably, the humidity of the pre-curing is 90%, the temperature is 25-40 DEG C, and the time is 12-24 h; the volume fraction of carbon dioxide in the carbon dioxide-containing atmosphere is 30-60%, the pressure of the carbonation curing is 0.5 MPa, the temperature is 30-50 DEG C, the humidity is 40-60%, and the time is 12-24 h.

[0018] Preferably, in the step (4), the cement is P·O52.5 cement; in terms of mass parts, the silica fume in the cement mortar is 100 parts, the fly ash is 70 parts, the slag is 60 parts, the cement is 920 parts, the sand is 1050 parts, the water is 207 parts, and the water reducing agent is 23 parts.

[0019] The application provides a sludge-based geopolymer carbonized artificial aggregate prepared by the preparation method.

[0020] The application provides application of the sludge-based geopolymer carbonized artificial aggregate in building materials.

[0021] The application provides a preparation method of a sludge-based geopolymer carbonized artificial aggregate.

[0022] The present application mixes the calcined activated sludge ash, slag, steel slag, alkali activator, water and water reducing agent, and then puts the mixture into a carbon dioxide containing atmosphere for carbonization curing after molding and pre-curing, in this process, the alkali activator can effectively activate the silicon aluminum components in the slag and sludge ash, promote the formation of hydrated calcium silicate and hydrated calcium aluminate silicate, make the aggregate density higher, and be beneficial to the preliminary molding and further carbonization, the calcium hydroxide and dicalcium silicate, calcium hydroxide and calcium hydroxide generated by the reaction of calcium hydroxide and dicalcium silicate in the steel slag, and the part of hydrated calcium silicate which has been hydrated and generated, react with carbon dioxide to generate calcium carbonate, and enhance the strength and density of the aggregate;

[0023] The present application realizes carbon dioxide fixation by adopting carbonization curing process, can avoid high temperature firing, and greatly reduces energy consumption and carbon emission;

[0024] The present application adopts the cement mortar composed of silica ash, fly ash, slag, cement, sand, water and water reducing agent for packaging, wherein the slag has potential hydraulicity, has higher reactivity, can occur secondary hydration reaction under alkaline conditions (calcium hydroxide generated by cement hydration), further generates C-S-H gel, enhances the structural density, and improves the strength of the artificial aggregate;

[0025] The present application converts the waste such as sludge, steel slag and slag into building aggregate, realizes the collaborative treatment of multiple types of solid waste, reduces the pollution to the environment caused by landfill and stacking, and reduces land occupation; and the prepared artificial aggregate has high strength, can replace natural aggregate for building and municipal engineering, meets the engineering requirement, and promotes the development of green building materials. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a process schematic diagram for packaging in the present application;

[0027] Figure 2 It is a proportioning design diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0028] The present application provides a preparation method of sludge-based polymer carbonized artificial aggregate, comprising the following steps:

[0029] (1) drying, grinding treatment and calcining the sludge in sequence to obtain sludge ash;

[0030] (2) mixing the sludge ash with slag, steel slag, alkali activator, water and water reducing agent to obtain a slurry;

[0031] (3) sequentially molding, pre-curing and carbonization curing the slurry to obtain a carbonized artificial aggregate inner embryo; the carbonization curing is carried out in a carbon dioxide containing atmosphere;

[0032] (4) encapsulating the carbonized artificial aggregate by immersing the carbonized artificial aggregate in cement mortar, and curing to obtain the sludge-based geopolymer carbonized artificial aggregate; the cement mortar comprises silica fume, fly ash, slag, cement, sand, water and water reducing agent.

[0033] In the present application, the raw materials involved are all commercially available products well known in the art, unless otherwise specified.

[0034] In the present application, the sludge is sequentially dried, ground and calcined to obtain sludge ash.

[0035] In the present application, the sludge is preferably deep-sea sludge, which has a low content of organic matter, and is beneficial to reduce the influence on the strength of the artificial aggregate.

[0036] In the present application, the drying can be drying; the grinding can be performed by using a grinder. In the present application, after the grinding, the obtained powder is preferably sieved, and the undersize is taken; the sieving is preferably sieving through a 200-mesh sieve.

[0037] In the present application, the calcination is preferably performed at a temperature of 700-900℃, which can be 700℃, 800℃ or 900℃, and for a time of 1-3h, which can be 1h, 2h or 3h; the calcination is preferably performed in a fluidized bed incinerator. In the present application, the sludge ash is activated by calcination to remove impurities such as organic matter, and improve the activation efficiency. After the calcination, the sludge ash is preferably cooled to room temperature.

[0038] In the present application, the main components of the sludge ash are silicon dioxide and aluminum oxide. In the embodiments of the present application, the mass fraction of silicon dioxide in the sludge ash is 60-70%, and the mass fraction of aluminum oxide is 10-15%.

[0039] After obtaining the sludge ash, the sludge ash is mixed with slag, steel slag, alkali activator, water and water reducing agent to obtain a slurry.

[0040] In the present application, the steel slag can be specifically converter slag, and the steel slag is preferably steel slag powder (undersize of a 200-mesh sieve). In the present application, the slag is preferably granulated blast furnace slag powder (S95 grade slag).

[0041] In the present application, the alkali activator is preferably water glass, and the modulus of the water glass is preferably 2.0. In the embodiments of the present application, the water glass with a modulus of 2.0 is obtained by adding sodium hydroxide to water glass with a modulus of 2.4 to adjust the modulus.

[0042] In the present application, the mass fractions of the sludge ash, the slag and the steel slag are preferably 40-80%, 10-40% and 0-30% respectively, and the mass fraction of the steel slag is not 0, based on the total mass of the sludge ash, the slag and the steel slag; wherein the mass fraction of the sludge ash can be 40%, 50%, 60%, 70% or 80%, the mass fraction of the slag can be 10%, 20%, 30% or 40%, and the mass fraction of the steel slag can be 10%, 20% or 30%. The present application controls the amounts of the sludge ash, the slag and the steel slag in the above proportions, which can take into account the characteristics of raw materials and the performance of products. In the present application, the ratio of the mass of sodium oxide in the alkali activator (i.e. the alkali activator is converted into sodium oxide) to the total mass of the sludge ash, the slag and the steel slag is preferably 0.05-0.07:1, and can be 0.05:1, 0.06:1 or 0.07:1. In the present application, the ratio of the mass of water to the total mass of the sludge ash, the slag and the steel slag (i.e. the water-cement ratio) is preferably 0.18-0.23:1, and can be 0.20:1, 0.21:1, 0.22:1 or 0.23:1. In the present application, the water reducing agent is preferably a polycarboxylic acid water reducing agent, and the mass of the water reducing agent is preferably 1-2% of the total mass of the sludge ash, the slag and the steel slag.

[0043] In the present application, the method for mixing the sludge ash with the slag, the steel slag, the alkali activator, water and the water reducing agent is preferably as follows:

[0044] The sludge ash is first mixed with the slag and the steel slag to obtain a mixed powder;

[0045] After water is added to the mixed powder for second mixing, the alkali activator is added to the obtained mixture for third mixing, and then the water reducing agent is added for fourth mixing to obtain the slurry.

[0046] In the present application, the first mixing is preferably carried out in a mortar mixing pot; the first mixing is preferably low-speed stirring for 3 min, followed by medium-speed stirring for 2 min to obtain a mixed powder with uniform mixing. In the present application, the second mixing and the fourth mixing are both preferably low-speed stirring for 3 min, followed by medium-speed stirring for 3 min; the third mixing is preferably low-speed stirring for 3 min. In the present application, the stirring speed of the low-speed stirring is preferably 60 rpm, and the stirring speed of the medium-speed stirring is preferably 120 rpm.

[0047] After the slurry is obtained, the slurry is sequentially subjected to shaping, pre-curing and carbonation curing in the present application to obtain a carbonated artificial aggregate inner embryo.

[0048] In the present application, the forming method is preferably: the slurry is sequentially extruded and cut. In the present application, the extrusion and cutting are preferably performed by a double-screw material cutting machine (i.e. cutting while extruding), and in an embodiment of the present application, the cutting is cutting the extruded material into small cylinders. In an embodiment of the present application, after the cutting, the obtained cutting material (i.e. small cylinders) is preferably subjected to shape optimization, which is preferably performed in a coating machine, and specifically, the shape of the cutting material is converted into a spherical shape by rotating the coating machine. The present application adopts an integrated process of extrusion-cutting-coating machine shape optimization to form the aggregate, which can greatly reduce the porosity inside the embryo in the aggregate, and the aggregate is more compact after carbonization, thereby greatly improving the performance of the aggregate.

[0049] In the present application, the humidity (RH) of the pre-curing is preferably 90%, the temperature is preferably 25-40℃, which can be 25, 30 or 35℃, and the time is preferably 12-24h, which can be 12, 15 or 20h. In the present application, the pre-curing is wet curing, which preliminarily hardens the particles.

[0050] In the present application, the carbonization curing is performed in a carbon dioxide-containing atmosphere, the volume fraction of carbon dioxide in the carbon dioxide-containing atmosphere is preferably 30-60%, which can be 30%, 40%, 50% or 60%, and the carbonization curing is preferably performed in a carbonization box, which adjusts the concentration of carbon dioxide. In the present application, the pressure of the carbonization curing (i.e. the pressure of the carbon dioxide-containing atmosphere) is preferably 0.5MPa, the temperature is preferably 30-50℃, which can be 30, 40 or 50℃, the humidity (RH) is preferably 40-60%, which can be 40%, 50% or 60%, and the time is preferably 12-24h. In order to improve the strength of the aggregate, the present application uses pressurized curing during the carbonization curing stage of the aggregate to improve the carbonization efficiency; in a high carbon dioxide concentration environment, the calcium-containing mineral phase in the material can absorb carbon dioxide to convert into calcium carbonate with high strength, thereby accelerating the development of the strength of the aggregate.

[0051] The steel slag contains potential active components such as dicalcium silicate and tricalcium silicate, but also contains free calcium oxide and free magnesium oxide which leads to poor volume stability. The slag is also rich in elements such as silicon, aluminum and calcium, and has certain cementitious properties. The present application uses carbonation process to make the alkaline substances in the raw materials absorb carbon dioxide to generate carbonates with high strength (for example, calcium-containing mineral phases (including free calcium oxide) can absorb carbon dioxide to convert into calcium carbonate with high strength, and free magnesium oxide is also carbonated), thereby accelerating the strength development of the aggregate and solving the problem of poor volume stability of the steel slag. Moreover, carbonation of the material with carbon dioxide can fix carbon dioxide in the aggregate, realize carbon dioxide capture and utilization, help to reduce the concentration of carbon dioxide in the atmosphere, and reduce greenhouse gas emissions. In addition, the carbonation process avoids high-temperature firing, which can greatly reduce energy consumption and carbon emissions.

[0052] After obtaining the carbonated artificial aggregate inner embryo, the carbonated artificial aggregate inner embryo is encapsulated in cement mortar for curing to obtain the sludge-based polymer carbonated artificial aggregate.

[0053] In the present application, the cement mortar comprises silica fume, fly ash, slag, cement, sand, water and water reducing agent; the cement is preferably P·O52.5 cement; the sand is preferably machine-made sand, and the particle size of the machine-made sand is preferably 300 μm or less; and the water reducing agent is preferably a polycarboxylic acid water reducing agent. In terms of mass fraction, the silica fume in the cement mortar is 100 parts, the fly ash is 70 parts, the slag is 60 parts, the cement is 920 parts, the sand is 1050 parts, the water is 207 parts, and the water reducing agent is 23 parts. In the present application, the cement mortar is UHPC mortar; wherein the slag has potential hydraulicity, has high reactivity, can undergo secondary hydration reaction under the action of an alkaline activator (calcium hydroxide generated by cement hydration, etc.), further generates C-S-H gel, enhances structural density, and improves strength; the cement, especially P·O52.5 cement, has high strength grade, and can provide basic strength guarantee for the UHPC mortar; the fly ash and silica fume have pozzolanic activity, can generate gel, and fill pores; the fly ash, silica fume and slag are all industrial waste residues, which are used as raw materials for the preparation of UHPC mortar, realize the resource utilization of industrial waste residues, reduce the discharge of waste residues, have good environmental protection benefits, and also reduce the cost of raw materials.

[0054] In the present application, the components of the cement mortar can be mixed uniformly, specifically, the silica fume, fly ash, slag, cement and sand can be mixed and stirred uniformly, then water is added and stirred by a mortar stirrer, and then the water reducing agent is added after uniform stirring.

[0055] In the present application, the specific operation of the encapsulation is preferably that the carbonized artificial aggregate inner embryo is immersed in the cement mortar, and fully stirred to make the aggregate fully wrapped by the cement mortar slurry. Figure 1 The process schematic diagram of the encapsulation is that the carbonized artificial aggregate inner embryo is prepared in advance, and then encapsulated by using the cement mortar shell.

[0056] In the present application, the curing is preferably carried out in a standard curing room, that is, the encapsulated aggregate is taken out and placed in the standard curing room for curing.

[0057] The present application uses sludge, steel slag and slag as main raw materials to prepare carbonized artificial aggregate, cooperatively processes multiple types of solid waste, realizes effective recycling of solid waste, reduces pollution to the environment caused by landfill and stacking, reduces land occupation, achieves the purpose of resource recycling, reduces the dependence on natural resources, and meets the concept of sustainable development.

[0058] The present application provides a sludge-based polymer carbonized artificial aggregate prepared by the preparation method.

[0059] The present application provides an application of the sludge-based polymer carbonized artificial aggregate in building materials.

[0060] The present application solves the environmental management problem of sludge and industrial waste slag through the integrated technology of multiple waste cooperative utilization, carbonization and carbon sequestration, and performance optimization, simultaneously creates high-value low-carbon building material products, realizes multiple benefits of environmental protection, resource recycling and engineering performance improvement, provides an innovative solution for solid waste management and carbon emission reduction.

[0061] In order to further illustrate the present application, the sludge-based polymer carbonized artificial aggregate, the preparation method and the application thereof provided by the present application are described in detail below with reference to examples, but they should not be understood as limiting the scope of protection of the present application.

[0062] Examples 1-10

[0063] 1 Raw materials

[0064] 1.1 Sludge ash

[0065] The sludge originated from the Dongjiakou Port Area of ​​Qingdao Port, specifically from the Gangtou Wanbang Ore Terminal Project (300,000-ton berth and approach bridge area). Deep-sea dredging sludge excavated from the port basin was dried, ground, and then sieved through a 200-mesh screen. The undersize material was then calcined (in a fluidized bed incinerator at 800℃ for 1 hour, followed by cooling) to obtain sludge ash. The sludge ash has a specific surface area of ​​420 m². 2 / kg, the main components are shown in Table 1.

[0066] Table 1. Chemical composition (wt%) of sludge ash (SSA)

[0067] Chemical composition SiO2 CaO Al2O3 K2O Fe2O3 LOI (loss on ignition) Mass fraction 69.02 6.10 12.40 3.17 2.81 6.50

[0068] 1.2 Blast furnace slag powder

[0069] The selected granulated blast furnace slag powder (GBFS, S95 grade slag) came from the Qingdao Jimo Plant of China Construction Western Construction, with a specific surface area of ​​410 m². 2 / kg, and its main chemical components are shown in Table 2.

[0070] Table 2 Chemical composition (wt%) of blast furnace slag powder

[0071] Chemical composition CaO SiO2 Al2O3 MgO TiO2 MnO Fe2O3 Mass fraction 36.23 32.35 14.87 5.18 0.87 0.31 1.76

[0072] 1.3 Steel Slag

[0073] The steel slag used comes from converter slag powder (SS) produced by Hebei Jingye Steel Plant, with a specific surface area of ​​390 m². 2 / kg, the main components are shown in Table 3.

[0074] Table 3. Main chemical composition of steel slag (wt%)

[0075] Chemical composition CaO SiO2 Al2O3 Fe2O3 MgO MnO SO3 Na2O Mass fraction 34.25 22.27 12.33 15.09 9.11 2.05 1.01 0.38

[0076] 2. Mixing ratio

[0077] Examples of specimen fit in Examples 1-10 Figure 2 As shown in Table 4, the water-cement ratio is the ratio of the mass of water to the total mass of sludge ash, slag, and steel slag; the alkali content is the ratio of the mass of sodium oxide in the alkali activator to the total mass of sludge ash, slag, and steel slag; and the mass fraction of the water-reducing agent is the percentage of the water-reducing agent in the total mass of sludge ash, slag, and steel slag. The specimens in Examples 1-10 are sequentially designated as G30-SA40-S30, G30-SA50-S20, G30-SA60-S10, G20-SA70-S10, G10-SA80-S10, G40-SA40-S20, G40-SA50-S10, G10-SA60-S30, G10-SA70-S20, and G20-SA80-S0.

[0078] 3. Preparation of sludge-based polymer carbonized artificial aggregate

[0079] The specific steps are as follows:

[0080] (1) Weighing: according to the design ratio in Table 4, use an electronic balance to weigh the required blast furnace slag powder, sludge ash, and steel slag; use a measuring cup to weigh the required water and polycarboxylic acid water reducer for standby; add sodium hydroxide to the water glass with a modulus of 2.4 to adjust the modulus to 2.0 as an alkali activator;

[0081] (2) Powder mixing: pour all the weighed powders into the mortar mixer, first stir at low speed for 3 min, then stir at medium speed for 2 min, so that the powders are fully mixed and evenly distributed;

[0082] (3) Inner embryo slurry preparation: pour the water reserved in step (1) into the mortar mixer of (2), stir at low speed for 3 min, then stir at medium speed for 3 min, add the pre-prepared alkali activator, stir at low speed for 3 min, then pour in the polycarboxylic acid water reducer, stir at low speed for 3 min, then stir at medium speed for 3 min, to obtain the slurry; the stirring speed at low speed is 60 rpm, and the stirring speed at medium speed is 120 rpm;

[0083] (4) Inner embryo shaping and pre-curing: pour the slurry prepared in step (3) into a double-screw material cutting machine for extrusion and cutting to obtain several small cylinders; then pour the small cylinders into a coating machine in multiple times for shape optimization to be converted into spherical shape, and then perform wet curing (humidity RH is 90%, temperature is 25°C, and time is 12h) to preliminarily harden the particles;

[0084] (5) Carbonization curing: use a carbonization box to adjust the CO2 concentration to 30% (volume fraction); the pressure is 0.5 MPa, the inner embryo after curing in step (4) is accelerated for carbonization, the temperature is 50°C, the humidity RH is 60%, and the carbonization time is 12h, to obtain the carbonized artificial aggregate embryo;

[0085] (6) Preparation of UHPC mortar: according to the UHPC mortar mixing ratio shown in Table 5, mix and stir the weighed cement and admixture uniformly, use a mortar mixer to add water and stir, and put the prepared cement mortar into a beaker;

[0086] (7) Packaging aggregate and curing: put the carbonized artificial aggregate embryo after carbonization curing in step (5) into the cement mortar in step (6), stir with a glass rod to fully wrap the aggregate with the slurry; take out the packaged coarse aggregate and place it in a standard curing room for 7 days.

[0087] (8) Performance test: the compressive strength test was carried out by using a pressure testing machine, including the compressive strength test of the carbonized artificial aggregate (i.e. the pre-encapsulation compressive strength) obtained after carbonization and curing, and the compressive strength test of the test piece (i.e. the post-encapsulation compressive strength) obtained after encapsulation and curing. Each proportion was tested six times to obtain an average value, and the results are shown in Table 4.

[0088] Table 4: Raw material mixing ratio and compressive strength of the test piece obtained before and after encapsulation of Examples 1-10

[0089]

[0090] As can be seen from Comparative Examples 1-10, the strength of the aggregate reaches a higher level when the sludge ash content is 40%, and the strength decreases with the increase of the sludge ash content. In addition, the carbonization effect of steel slag and slag is compared, and when the sludge ash content is certain, the higher the steel slag content, the better the performance of the test piece, which further indicates that the carbonization is more sufficient and the carbon sequestration effect is better.

[0091] Table 5: Mixing ratio of UHPC mortar shell of artificial aggregate

[0092]

[0093] Note: The slag in Table 5 is the same as the blast furnace slag powder shown in Table 2, and the particle size of the machine-made sand is below 300 μm.

[0094] The above description is only the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for producing a sludge-based polymer carbonized artificial aggregate, characterized by, The preparation method comprises the following steps: (1) drying, grinding and calcining sludge in sequence to obtain sludge ash; (2) mixing the sludge ash with slag, steel slag, alkali activator, water and water reducing agent to obtain a slurry; (3) sequentially performing molding, pre-curing and carbonation curing on the slurry to obtain a carbonated artificial aggregate inner embryo; the carbonation curing is performed in a carbon dioxide-containing atmosphere; (4) encapsulating the carbonated artificial aggregate inner embryo in cement mortar, and curing to obtain the sludge-based polymer carbonated artificial aggregate; the cement mortar comprises silica fume, fly ash, slag, cement, sand, water and water reducing agent.

2. The production method according to claim 1, characterized by, The sludge is deep-sea sludge; after the grinding, the obtained powder is sieved, and undersize is taken; the sieving is performed through a 200-mesh sieve.

3. The preparation method according to claim 1, characterized in that, The calcination temperature is 700-900 DEG C, and the time is 1-3 h.

4. The method of claim 1, wherein, The alkali activator is water glass, and the modulus of the water glass is 2.

0.

5. The preparation method according to claim 4, characterized in that, In step (2), the mass fractions of the sludge ash, slag and steel slag are 40-80%, 10-40% and 0-30% respectively based on the total mass of the sludge ash, slag and steel slag, and the mass fraction of the steel slag is not 0; the mass ratio of sodium oxide in the alkali activator to the total mass of the sludge ash, slag and steel slag is 0.05-0.07:1; the mass ratio of water to the total mass of the sludge ash, slag and steel slag is 0.18-0.23:1; and the mass of the water reducing agent is 1-2% of the total mass of the sludge ash, slag and steel slag.

6. The method of claim 1, wherein, The molding method is extruding and cutting the slurry.

7. The preparation method according to claim 1, characterized in that, The pre-curing humidity is 90%, the temperature is 25-40 DEG C, and the time is 12-24 h; the volume fraction of carbon dioxide in the carbon dioxide-containing atmosphere is 30-60%, the pressure of the carbonation curing is 0.5 MPa, the temperature is 30-50 DEG C, the humidity is 40-60%, and the time is 12-24 h.

8. The method of claim 1, wherein, In step (4), the cement is P·O52.5 cement; in terms of mass fraction, the silica fume in the cement mortar is 100 parts, the fly ash is 70 parts, the slag is 60 parts, the cement is 920 parts, the sand is 1050 parts, the water is 207 parts, and the water reducing agent is 23 parts.

9. The sludge-based polymer carbonated artificial aggregate prepared by the preparation method in any one of claims 1-8.

10. The application of the sludge-based polymer carbonated artificial aggregate in claim 9 in building materials.

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