Coal-based low-carbon solid waste cementing material suitable for 3D printing as well as preparation method and application of coal-based low-carbon solid waste cementing material
By replacing cement clinker, the preparation of coal-based low-carbon solid waste gelling materials has been solved, and the high carbon emission and solid waste utilization problems of traditional 3D printing materials have been achieved, which has achieved low-carbon and environmentally friendly 3D printing materials performance improvement, meeting the requirements of complex structures and high-precision printing.
Patent Information
- Application Number
- CN202510598371.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2025-07-18
AI Technical Summary
The high content of cement clinker in traditional 3D printed concrete materials leads to large carbon emissions, and solid waste such as coal gangue and fly ash cannot be effectively utilized, which affects the material performance and printability, making it difficult to meet the requirements of complex structures and high-precision printing.
Coal gangue, fly ash, phosphogypsum and limestone powder are used to replace cement clinker by about 50%. By optimizing raw material ratio and process flow, low-carbon solid waste gelling materials suitable for 3D printing are prepared, and admixtures are added to adjust rheology performance and settling time.
Significantly reduce carbon emissions, realize the resource utilization of solid waste, have good 3D printing performance and engineering structure mechanical properties, and meet the needs of complex structures and high-precision printing.
Abstract
Description
Technical Field
[0001] The present invention provides a coal-based low-carbon solid waste cementitious material applicable to 3D printing, its preparation method and application, belonging to the technical field of cementitious materials. Background Art
[0002] Traditional 3D printing concrete materials mostly use ordinary Portland cement as the main raw material, with a high content of cement clinker. The carbon emissions during the production process are relatively large, and the environmental burden is heavy. In traditional 3D printing mortar, the proportion of cement clinker is as high as 60% - 80%. And about 0.8 tons of CO2 are emitted during the production of one ton of Portland cement clinker. Therefore, the conventional concrete 3D printing process will lead to an increase in carbon emissions.
[0003] With the exploitation and utilization of coal resources, a large amount of solid waste such as coal gangue, fly ash, phosphogypsum and limestone powder is generated, causing serious environmental pollution and resource waste. The existing technologies have poor treatment and utilization effects on these wastes and fail to fully exert their resource potential. The stacking of industrial solid wastes such as coal gangue, fly ash and phosphogypsum not only occupies land, but also causes serious environmental pollution. Replacing part of ordinary Portland cement with solid wastes generated during coal mining to prepare a low-carbon gel material suitable for building 3D printing has important economic value.
[0004] At the same time, with the increasing application demand of the construction industry for 3D printing technology, traditional cement-based materials have problems such as too fast curing time and insufficient mechanical properties in 3D printing, and cannot meet the requirements of complex structures and high-precision printing. The application of existing low-carbon and environmentally friendly materials in 3D printing still has technical bottlenecks in terms of material properties and printability.
[0005] Therefore, making full use of the wastes generated during coal development and processing them into cementitious materials that can be used for 3D printing is a current research hotspot. Summary of the Invention
[0006] In view of this, the purpose of the present invention is to provide a coal-based low-carbon solid waste cementitious material applicable to 3D printing, its preparation method and application. The present invention uses coal gangue, fly ash, phosphogypsum and limestone powder to replace about 50% of cement clinker to prepare a coal-based solid waste low-carbon cementitious material. By reasonably optimizing the raw material ratio and process flow, the material can reduce carbon emissions, realize the resource utilization of solid waste, and at the same time have good 3D printing performance and meet the mechanical property requirements of engineering structures.
[0007] The coal-based low-carbon solid waste cementitious material applicable to 3D printing of the present invention includes cementitious materials, admixtures, aggregates and water; the cementitious materials are composed of raw materials with the following mass percentages:
[0008] Cement clinker: 40% - 50%;
[0009] Activated coal gangue powder: 20% - 30%;
[0010] Fly ash: 5% - 15%;
[0011] Phosphogypsum: 3% - 8%;
[0012] Limestone powder: 5% - 15%.
[0013] Preferably, the activated coal gangue powder is obtained by crushing coal gangue, calcining it at 700 - 800 °C for 1.5 - 2.5 hours, then quenching it with water and finally ball - milling it to a specific surface area ≥ 450 m 2 / kg, D 50 ≤ 20 μm.
[0014] Preferably, the fly ash is Class I fly ash; the aggregate is quartz sand with a continuous gradation of particle size 0.15 - 1.18 mm; the mass ratio of the aggregate to the binder is 1:2.
[0015] Preferably, the admixture includes at least one of a retarder, a water - reducing agent, an air - entraining agent, a rheology modifier and an early - strength agent;
[0016] The admixture accounts for 0.1% - 2% of the total mass of the coal - based low - carbon solid waste cementitious material.
[0017] Preferably, the water - binder ratio of the coal - based low - carbon solid waste cementitious material is 0.28 - 0.35.
[0018] The preparation method of the coal - based low - carbon solid waste cementitious material applicable to 3D printing according to the present invention includes the following steps:
[0019] Put the cement clinker, activated coal gangue powder, fly ash, phosphogypsum, limestone powder and admixture into a mixer for stirring and mixing; then add water in proportion for uniform stirring, and then add the aggregate for uniform stirring; finally, carry out static curing treatment.
[0020] The application of the coal - based low - carbon solid waste cementitious material applicable to 3D printing according to the present invention in 3D printing is to inject the coal - based low - carbon solid waste cementitious material into a 3D printer, set the printing temperature at 20 - 35 °C, the extrusion rate at 10 - 30 mm / s, and print layer by layer to obtain a 3D - printed building structure.
[0021] Preferably, during the 3D printing process, the initial setting time is 30 - 40 minutes and the final setting time is 1 - 2 hours.
[0022] Preferably, the fluidity of the coal - based low - carbon solid waste cementitious material is controlled to be 150 - 220 mm by slump test.
[0023] The present invention also provides a 3D printed building structure, which is prepared by injecting the coal-based low-carbon solid waste cementitious material into a 3D printer, setting the printing temperature at 20-35°C and the extrusion rate at 10-30 mm / s, and printing layer by layer.
[0024] The compressive strength of the 3D printed building structure prepared by the present invention is ≥30 MPa, the mass loss rate of frost resistance in 28 days is ≤5%, and the carbon emission is reduced by 40%-50% compared with traditional cement-based materials.
[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0026] The coal-based low-carbon solid waste cementitious material of the present invention uses coal mining waste to replace 50% of cement clinker, significantly reducing carbon dioxide emissions. Solid wastes such as coal gangue, fly ash, phosphogypsum and limestone powder in the present invention are effectively utilized, reducing environmental pollution. The excellent rheological properties and appropriate hardening characteristics of the coal-based low-carbon solid waste cementitious material of the present invention enable it to be widely applied to 3D printing technology, meeting the requirements of the modern construction industry for complex structures and high precision.
[0027] The present invention not only solves the technical problems of resource utilization of coal-based solid wastes, but also provides a new direction for the development of low-carbon building materials, and at the same time promotes the application of 3D printing technology in the construction field. Detailed implementation manners
[0028] To make the purpose, technical solutions and advantages of the present invention clearer, the preferred implementation manners of the present invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0029] Embodiment 1
[0030] A coal-based low-carbon solid waste cementitious material suitable for 3D printing is prepared by using cementitious materials, admixtures, aggregates and water; the cementitious materials are composed of the following raw materials in mass percentages:
[0031] Cement clinker: 50%; activated coal gangue powder: 25%; Class I fly ash (ash content ≤15%): 10%; phosphogypsum: 5%; limestone powder: 10%.
[0032] Among them, the activated coal gangue powder is obtained by crushing coal gangue to a particle size ≤5 mm, then calcining at 750°C for 2 hours, quenching and cooling with water, and then ball milling to a specific surface area of 480 m 2 / kg, D 50 is 12 μm.
[0033] The aggregate is continuously graded quartz sand with a particle size of 0.15 - 1.18 mm, and the mass ratio of quartz sand to binder is 1:2.
[0034] The admixture is a polycarboxylate superplasticizer, which accounts for 0.5 wt% of the coal-based low-carbon solid waste binder; the particle size of limestone powder is ≤ 50 μm.
[0035] The water-binder ratio of the coal-based low-carbon solid waste binder is 0.32.
[0036] The preparation method of the coal-based low-carbon solid waste binder in this example is as follows: Put cement clinker, activated coal gangue powder, Class I fly ash, phosphogypsum, limestone powder and superplasticizer into a mixer and mix at 30 r / min for 5 minutes; then add water in proportion and stir for 3 minutes, then add the aggregate and stir for 5 minutes; finally, let it stand and cure for 10 minutes.
[0037] Example 2
[0038] A coal-based low-carbon solid waste binder suitable for 3D printing is prepared by using binder, admixture, aggregate and water; the binder is composed of raw materials with the following mass percentages:
[0039] Cement clinker: 45%; Activated coal gangue powder: 30%; Class I fly ash (ash content ≤ 15%): 12%; Phosphogypsum: 5%; Limestone powder: 8%.
[0040] Among them, the activated coal gangue powder is obtained by crushing coal gangue to a particle size of ≤ 5 mm, then calcining at 800 °C for 2 hours, quenching and cooling with water, and then ball milling to a specific surface area of 500 m 2 / kg, D 50 is 12 μm.
[0041] The aggregate is continuously graded quartz sand with a particle size of 0.15 - 1.18 mm, and the mass ratio of quartz sand to binder is 1:2.
[0042] The admixture is a polycarboxylate superplasticizer, which accounts for 0.8 wt% of the coal-based low-carbon solid waste binder; the particle size of limestone powder is ≤ 50 μm.
[0043] The water-binder ratio of the coal-based low-carbon solid waste binder is 0.35.
[0044] The preparation method of the coal-based low-carbon solid waste binder in this example is as follows: Put cement clinker, activated coal gangue powder, Class I fly ash, phosphogypsum, limestone powder and superplasticizer into a mixer and mix at 30 r / min for 5 minutes; then add water in proportion and stir for 3 minutes, then add the aggregate and stir for 5 minutes; finally, let it stand and cure for 10 minutes.
[0045] Comparative Example 1
[0046] A traditional cementitious material is prepared from cementitious materials, admixtures, aggregates and water; among which the cementitious materials are composed of raw materials with the following mass percentages:
[0047] Cement clinker: 80%
[0048] Class I fly ash (ash content ≤ 15%): 20%.
[0049] Among them, the aggregate is continuously graded quartz sand with a particle size of 0.15 - 1.18 mm, and the mass ratio of quartz sand to cementitious materials is 1:2.
[0050] The admixture is a polycarboxylate water reducer, which accounts for 0.5 wt% of the coal-based low-carbon solid waste cementitious material. The water-cement ratio of this traditional cementitious material is 0.32.
[0051] The cementitious materials of Example 1, Example 2 and Comparative Example 1 are respectively 3D printed to form a 3D printed building structure, and the steps are as follows:
[0052] Inject the cementitious material into a 3D printer, set the printing temperature at 25 °C, the extrusion rate at 20 mm / s, and print layer by layer to obtain a 3D printed building structure. Among them, during the 3D printing process, the initial setting time is 50 minutes and the final setting time is 3.5 hours.
[0053] For the 3D printed building structure made of the cementitious material of Example 1, its 28-day compressive strength is 48.5 MPa, the interlayer bond strength is 2.3 MPa, and the CO2 emission is 298 kg / t of cementitious material. Among them, the initial fluidity of the cementitious material of Example 1 is 185 mm.
[0054] For the 3D printed building structure made of the cementitious material of Example 2, its 28-day compressive strength is 43.2 MPa, the interlayer bond strength is 2.0 MPa, and the CO2 emission is 275 kg / t of cementitious material. Among them, the initial fluidity of the cementitious material of Example 2 is 175 mm.
[0055] For the 3D printed building structure made of the cementitious material of Comparative Example 1, its 28-day compressive strength is 52 MPa, the interlayer bond strength is 1.6 MPa, and the CO2 emission is 460 kg / t of cementitious material. Among them, the initial fluidity of the cementitious material of Comparative Example 1 is 170 mm.
[0056] By synergistically utilizing industrial solid wastes such as coal gangue, fly ash, and phosphogypsum, the present invention not only effectively solves the environmental pollution problems caused by the accumulation of solid wastes, but also reduces the carbon emissions resulting from the consumption of cement clinker. At the same time, the gel material prepared by the present invention has good rheological properties, controllable setting time, and mechanical properties, which can meet the strict requirements of 3D printing technology for comprehensive properties such as material extrudability, interlayer adhesion, and shape stability. Therefore, the technical solution of the present invention has important economic, environmental, and social benefits in promoting the green and low-carbon transformation of the construction industry and expanding the application field of 3D printing building materials.
[0057] The embodiments described above are some embodiments of the present invention, rather than all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.
Claims
1. A coal-based low-carbon solid waste cementitious material applicable to 3D printing, characterized in that, It includes binder materials, admixtures, aggregates and water; the binder materials are composed of raw materials with the following mass percentages: Cement clinker: 40% - 50%; Activated coal gangue powder: 20% - 30%; Fly ash: 5% - 15%; Phosphogypsum: 3% - 8%; Limestone powder: 5% - 15%.
2. The coal-based low-carbon solid waste cementitious material applicable to 3D printing according to claim 1, wherein The activated coal gangue powder is obtained by crushing coal gangue, calcining it at 700 - 800 °C for 1.5 - 2.5 hours, then quenching it with water for cooling, and finally ball-milling it to a specific surface area of ≥ 450 m 2 / kg, D 50 ≤ 20 μm; The fly ash is Class I fly ash; The aggregates are quartz sands with a continuous gradation of particle sizes from 0.15 to 1.18 mm; The mass ratio of the aggregates to the binder materials is 1:
2.
3. The coal-based low-carbon solid waste cementitious material applicable to 3D printing according to claim 1, wherein, The admixtures include at least one of a retarder, a water reducer, an air-entraining agent, a rheology agent and an early strength agent; The admixtures account for 0.1% - 2% of the total mass of the coal-based low-carbon solid waste cementitious material.
4. The coal-based low-carbon solid waste cementitious material applicable to 3D printing according to claim 1, wherein The water-binder ratio of the coal-based low-carbon solid waste cementitious material is 0.28 - 0.
35.
5. The preparation method of the coal-based low-carbon solid waste cementitious material applicable to 3D printing according to any one of claims 1 to 4, characterized in that, It includes the following steps: Put the cement clinker, activated coal gangue powder, fly ash, phosphogypsum, limestone powder and admixtures into a mixer for stirring and mixing; then add water in proportion and stir evenly, and then add the aggregates and stir evenly; finally, carry out static curing treatment.
6. Application of the coal-based low-carbon solid waste cementitious material applicable to 3D printing according to any one of claims 1 to 4 in 3D printing, characterized in that, Inject the coal-based low-carbon solid waste cementitious material into a 3D printer, set the printing temperature at 20 - 35 °C, the extrusion rate at 10 - 30 mm / s, and print layer by layer to obtain a 3D printed building structure.
7. The application of the coal-based low-carbon solid waste cementitious material applicable to 3D printing as described in claim 6 in 3D printing is characterized in that, During the 3D printing process, the initial setting time is 30 - 40 minutes, and the final setting time is 1 - 2 hours.
8. The application of the coal-based low-carbon solid waste cementitious material applicable to 3D printing according to claim 6 in 3D printing is characterized in that, The fluidity of the coal-based low-carbon solid waste cementitious material is controlled to be 150 - 220 mm through slump test.
9. A 3D printed building structure, characterized in that, It is prepared by injecting the coal-based low-carbon solid waste cementitious material according to any one of claims 1 - 4 into a 3D printer, setting the printing temperature at 20 - 35 °C, the extrusion rate at 10 - 30 mm / s, and printing layer by layer.
10. The 3D printed building structure according to claim 9, characterized in that, The compressive strength of the 3D printed building structure ≥ 30 MPa, the mass loss rate of 28-day frost resistance ≤ 5%, and the carbon emission is reduced by 40% - 50% compared with traditional cement-based materials.