Geopolymer as well as preparation method and application thereof
Geopolymers were prepared by gradient temperature curing process, which solved the problem of lack of processability of phosphate-activated geopolymers after curing. This process enabled the controllable transformation of the material from a plastic state to a high-strength state, making it suitable for complex applications such as 3D printing and structural repair.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-27
AI Technical Summary
Existing phosphoric acid-activated geopolymers lack processability after curing, making it difficult to simultaneously meet the requirements of plasticity during processing and high strength during use. In particular, it is difficult to achieve a balance between the plasticity and high strength of materials in 3D printing and structural repair.
A gradient temperature curing process is adopted, in which metakaolin is mixed with phosphoric acid solution and cured in stages at different temperatures to form a plastic and high-strength geopolymer, thus achieving a controllable transformation of the material.
It offers excellent plasticity and shape adaptability during processing, and can be converted into high strength by heating, thus resolving the contradiction between high strength and easy processing, making it suitable for complex applications such as 3D printing and structural repair.
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Figure CN121735565A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of inorganic cementitious materials, in particular to a geopolymer and a preparation method and application thereof. BACKGROUND
[0002] Geopolymer is an inorganic polymer formed by aluminosilicate raw materials under the action of alkaline or acidic activator, which has the advantages of environmental protection, high temperature resistance and good durability. Phosphoric acid activated geopolymer is an important branch of geopolymer, which has attracted attention in recent years due to its unique performance.
[0003] At present, the research on phosphoric acid activated geopolymer mainly focuses on the final mechanical properties, high temperature resistance and curing mechanism. The traditional curing process usually adopts constant temperature curing or one-step temperature rising curing, which aims to obtain as high early and final strength as possible. However, once the material is cured under this process, its shape and state are fixed, and it lacks processability.
[0004] In the application process, for example, in 3D printing, the material needs to have good plasticity during extrusion and can quickly solidify and shape after accumulation; in structural repair, the repair material needs to be able to well fit irregular gaps and surfaces. Most of the existing geopolymer materials cannot meet the contradictory requirements of "plasticity in the process of processing" and "high strength in the process of use".
[0005] Therefore, it is an urgent problem in the field to develop a phosphoric acid activated geopolymer with adjustable performance, especially excellent plasticity at a specific stage, and can be converted into a high-strength solid by simple stimulation (such as temperature rising). SUMMARY
[0006] The purpose of the present application is to provide a geopolymer with adjustable plasticity and high strength.
[0007] In order to achieve the above purpose, the first aspect of the present application provides a method for preparing a geopolymer, which comprises: (1) mixing metakaolin with a phosphoric acid solution to obtain a slurry; (2) gradient temperature curing the slurry to obtain the geopolymer; The operation of the gradient temperature curing comprises: a. first stage curing the slurry at 25-35℃ to obtain intermediate I; b. second stage curing the intermediate I at 38-42℃ to obtain a plastic state geopolymer; Optionally, the method further comprises: c. third stage curing the plastic state geopolymer at 48-55℃ to obtain a high strength state geopolymer.
[0008] The second aspect of the present application provides a geopolymer prepared by the method of the first aspect.
[0009] The third aspect of the present application provides an application of the geopolymer of the second aspect in building 3D printing, structural engineering repair, precision casting mold, customized prefabricated components.
[0010] The technical solution provided by the present application has at least the following advantages: (1) The present application introduces a plastic state in the phosphoric acid activated geopolymer, which can be controlled and stabilized by temperature. This plastic state endows the material with excellent plasticity and shape adaptability during processing. By further heating, a high-strength geopolymer can be obtained, realizing seamless connection from "soft processing" to "hard use" and solving the contradiction between high strength and easy processing.
[0011] (2) The present application provides a "shaping first, then strengthening" processing paradigm, which makes it possible to realize complex 3D printing, accurate repair of irregular defects, and manufacturing of high-precision molds in the field of geopolymer, greatly expanding the application boundary of geopolymer.
[0012] (3) Through the gradient temperature curing process, the geopolymer provided by the present application not only has processing flexibility, but also has excellent final mechanical properties, with compressive strength far exceeding ordinary cement-based materials and many traditional geopolymers, ensuring its reliability as a structural material.
[0013] (4) The geopolymer provided by the present application has simple process, and the preparation process does not need complex equipment or expensive additives, and can be realized only by conventional raw materials and accurate curing system, easy to scale production and application promotion. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 is a plastic geopolymer prepared by Example 1 and Example 4 of the present application. DETAILED DESCRIPTION
[0015] The endpoints of the ranges and any values disclosed in this document are not limited to the precise values stated. The ranges and values should be interpreted as being approximate. Values that fall within the range of values, as well as the values listed, are also intended to be encompassed even if not specifically listed. For values with a range of values, the endpoints of the range are included in the range. The endpoints of the ranges and the values listed are not limited to the precise values stated. The values are intended to be approximate.
[0016] As described above, the first aspect of the present application provides a method for preparing a geopolymer, which comprises: (1) mixing metakaolin and phosphoric acid solution to obtain a slurry; (2) curing the slurry at a gradient temperature to obtain the geopolymer; The operation of the gradient temperature curing comprises: a. first curing the slurry at 25-35℃ in a first stage to obtain intermediate I; b. curing the intermediate I at 38-42℃ in a second stage to obtain a plastic geopolymer; Optionally, the method further comprises: c. curing the plastic geopolymer at 48-55℃ in a third stage to obtain a high-strength geopolymer.
[0017] Preferably, first curing the slurry at 30℃ in a first stage to obtain intermediate I; curing the intermediate I at 40℃ in a second stage to obtain a plastic geopolymer; and curing the plastic geopolymer at 50℃ in a third stage to obtain a high-strength geopolymer.
[0018] Preferably, the curing time of the first stage curing, the second stage curing and the third stage curing is independently 20-28h.
[0019] Further preferably, the curing time of the first stage curing, the second stage curing and the third stage curing is independently 24h.
[0020] Preferably, the operation of the gradient temperature curing further comprises: after injecting the slurry into a mold, placing the mold in a constant temperature and humidity box, and then curing according to a specific temperature and time program.
[0021] Preferably, in the slurry, the molar ratio of the content of aluminum element to silicon element is 0.96-1.27:1; the aluminum element and the silicon element are provided by the metakaolin.
[0022] Further preferably, in the slurry, the molar ratio of the content of phosphorus element to the aluminum element is 0.6-1.0:1; the phosphorus element is provided by the phosphoric acid solution.
[0023] Preferably, in step (1), the concentration of the phosphoric acid solution is 10-15 mol / L.
[0024] Further preferably, the concentration of the phosphoric acid solution is 10-13 mol / L.
[0025] Preferably, the mass ratio of the use amount of the metakaolin to the use amount of the phosphoric acid solution is 0.8-1.5:1.
[0026] Further preferably, the mass ratio of the metakaolin to the phosphoric acid solution is 0.9-1.2:1.
[0027] Preferably, in step (1), the slurry further contains a hydrogen peroxide solution.
[0028] Preferably, the concentration of the hydrogen peroxide solution is 5-10 wt%.
[0029] Further preferably, the amount of the hydrogen peroxide solution is 1-2 wt% based on the total weight of the metakaolin.
[0030] The mixing in step (1) is not particularly limited, and those skilled in the art can select a method known in the art as long as the metakaolin and the phosphoric acid solution are uniformly mixed, which should not be construed as a limitation on the present application.
[0031] Further preferably, in step (2), the temperature gradient curing is performed in an environment with a relative humidity of ≥90 RT%.
[0032] As described above, the second aspect of the present application provides a geopolymer prepared by the method of the first aspect.
[0033] Preferably, the geopolymer is a plastic state geopolymer, and the plastic state geopolymer has an elongation at break of 5-20%.
[0034] Preferably, the plastic state geopolymer of the present application can be bent, compressed, and molded without breaking, and this state can be stably maintained for at least 7 days or more at an ambient temperature of not higher than 40℃.
[0035] Preferably, the geopolymer is a high-strength state geopolymer, and the high-strength state geopolymer has a compressive strength of >80 MPa.
[0036] Further preferably, the geopolymer is a high-strength state geopolymer, and the high-strength state geopolymer has a compressive strength of >100 MPa.
[0037] As described above, the third aspect of the present application provides the use of the geopolymer of the second aspect in building 3D printing, structural engineering repair, precision casting molds, and customized prefabricated components.
[0038] The present application will be described in detail below by way of examples. In the following examples, the raw materials and equipment used are commercially available unless otherwise specified.
[0039] Metakaolin: the content of Al2O3 is 50.232wt%, the content of SiO2 is 46.599wt%, the brand is MK-1100, and it is purchased from Inner Mongolia Chaopai Kaolin Co., Ltd.
[0040] Example 1 (1) 300g of metakaolin was mixed with a phosphoric acid solution by high-speed stirring to obtain a uniform slurry; wherein the concentration of the phosphoric acid solution was 12.5 mol / L; in the obtained slurry, the molar ratio of the content of aluminum element to silicon element was 1.237:1, and the molar ratio of the content of phosphorus element to the aluminum element was 0.8:1; (2) After the slurry obtained in step (1) was injected into a mold, the mold was placed in a constant temperature and humidity box, and gradient temperature curing was carried out according to the following program: a. First stage curing at 30°C to obtain intermediate I; b. Second stage curing by increasing the temperature to 40°C to obtain a plastic state geopolymer; the plastic state geopolymer can be completely taken out of the mold and can be manually bent by more than 90° without cracking; c. Third stage curing of the plastic state geopolymer obtained in step b at 50°C to obtain a high strength state geopolymer.
[0041] In this example, the gradient temperature curing process was carried out under the condition of 90RT% relative humidity; the curing time of the first stage curing, the second stage curing and the third stage curing was 24h respectively; the remaining specific process parameters of this example are shown in Table 1.
[0042] In Table 1, the amount of hydrogen peroxide solution is the mass of hydrogen peroxide solution based on the mass of metakaolin; the Al / Si molar ratio refers to the molar ratio of the content of aluminum element to silicon element in the slurry; the P / Al molar ratio refers to the molar ratio of the content of phosphorus element to aluminum element in the slurry.
[0043] Examples 2-6 Examples 2-6 all used the same process flow as Example 1, the difference is listed in Table 1.
[0044] Comparative Examples 1-2 Comparative Examples 1-2 all used the same process flow as Example 1, the difference is listed in Table 1.
[0045] Table 1
[0046] Test Example The performance test data of the geopolymer prepared in the examples and comparative examples are shown in Table 2.
[0047] In Table 2, the data of 3d refers to the data measured after 3 days of gradient temperature curing (i.e. after the end of the third stage curing); the data of 7d refers to the data measured after 7 days of gradient temperature curing; and the data of 28d refers to the data measured after 28 days of gradient temperature curing.
[0048] The elongation at break was determined according to GB / T 1040.1-2025 'Determination of tensile properties of plastics - Part 1: General principles'.
[0049] The compressive strength was determined according to GB / T 17671-2021 'Methods of testing strength of cement mortar (ISO method)'.
[0050] The porosity was determined according to GB / T 21650.1-2008 'Mercury porosimetry and gas adsorption methods for the determination of pore size distribution and porosity of solid materials - Part 1: Mercury porosimetry'. Table 2
[0051] Figure 1 a-f in Table 1 are plastic state geopolymer prepared in Example 1; Figure 1 g-i in Table 2 are plastic state geopolymer prepared in Example 4, which is prepared by Figure 1 It can be seen that the plastic geopolymer provided by the application has good ductility.
[0052] It can be seen from the above results that the technical scheme provided by the application realizes the controllable transformation of the geopolymer from the plastic state to the high-strength state, has good formability and mechanical properties, and is suitable for 3D printing, structure repair and mold forming, and other application scenarios that have high requirements for material plasticity and strength.
[0053] The above describes the preferred embodiments of the application, but the application is not limited thereto. Within the technical concept of the application, various simple modifications can be made to the technical scheme of the application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the application and fall within the protection scope of the application.
Claims
1. A method for preparing geopolymers, characterized in that, The method includes: (1) Mix metakaolin with phosphoric acid solution to obtain a slurry; (2) The slurry is subjected to gradient temperature curing to obtain the geopolymer; The gradient temperature curing operation includes: a. First, the slurry is cured at 25-35℃ to obtain intermediate I; b. The intermediate I is cured in a second stage at 38-42°C to obtain a plastic geopolymer; Optionally, the method further includes: c) subjecting the plastic geopolymer to a third-stage curing at 48-55°C to obtain a high-strength geopolymer.
2. The method according to claim 1, characterized in that, The curing time for the first stage of curing, the second stage of curing, and the third stage of curing is 20-28 hours each.
3. The method according to claim 1, characterized in that, In the slurry, the molar ratio of aluminum to silicon is 0.96-1.27:1; The aluminum and silicon elements are provided by the metakaolin.
4. The method according to claim 3, characterized in that, In the slurry, the molar ratio of phosphorus to aluminum is 0.6-1.0:1; The phosphorus element is provided by the phosphoric acid solution.
5. The method according to any one of claims 1-4, characterized in that, In step (1), the concentration of the phosphoric acid solution is 10-15 mol / L.
6. The method according to any one of claims 1-4, characterized in that, In step (1), the slurry also contains a hydrogen peroxide solution; And / or, the concentration of the hydrogen peroxide solution is 5-10 wt%; And / or, based on the total weight of the metakaolin, the amount of hydrogen peroxide solution used is 1-2 wt%.
7. The method according to any one of claims 1-4, characterized in that, In step (2), the gradient temperature curing is carried out in an environment with a relative humidity of ≥90 RT%.
8. The geopolymer prepared by the method according to any one of claims 1-7.
9. The geopolymer according to claim 8, characterized in that, The geopolymer is a plastic geopolymer with an elongation at break of 5-20%. And / or, the geopolymer is a high-strength geopolymer, wherein the compressive strength of the high-strength geopolymer is >80MPa.
10. The application of the geopolymer as described in claim 8 or 9 in 3D printing of buildings, structural engineering repair, precision casting molds, and customized prefabricated components.
Citation Information
Patent Citations
In-situ shell-glue type geopolymer porous concrete and preparation method thereof
CN120574021A