Geopolymer dry powder material performance regulation method

Abstract

The present application relates to the technical field of geopolymer preparation, and particularly relates to a performance regulation method of geopolymer dry powder material. Firstly, the silicon-aluminum raw material is classified according to high, medium and low silicon-aluminum ratio, and then the classified silicon-aluminum raw material is mixed with alkaline substance and classified again, and then the classified material is subjected to high-temperature calcination, medium-temperature calcination and low-temperature calcination respectively, and finally nine kinds of calcined materials with different silicon-aluminum ratio and calcination temperature are obtained; according to the compressive strength of the geopolymer to be prepared, any one to nine kinds of calcined materials are selected to obtain mixed calcined material; the mixed calcined material is ground with gel active silicon-aluminum raw material to obtain the required geopolymer dry powder material. The present application regulates the silicon-aluminum ratio of the silicon-aluminum raw material and the alkali fusion heat activation temperature, and then regulates the phase of the calcined product, so as to form a regulation method for the reaction process of the geopolymer, and can greatly improve the applicability of the geopolymer in the field of building engineering materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geopolymer preparation, and particularly relates to a performance regulation method of geopolymer dry powder material. BACKGROUND

[0002] Geopolymer is an inorganic cementitious material, which has the advantages of early strength, fast hardening, chemical corrosion resistance, good durability, rich synthetic raw materials, low carbon emission, etc., and is therefore regarded as a new building material after lime and Portland cement. In recent years, geopolymer has attracted widespread attention from countries around the world. Research shows that it has broad application and development prospects in the fields of building materials, sealing materials and solid waste disposal.

[0003] The large-scale application of geopolymer needs to meet the requirements of various projects, so the performance regulation of geopolymer is one of the keys to its popularization and application. In view of the optimization of the preparation method of geopolymer and the performance regulation, the applicant's previous patent CN113003968A discloses a geopolymer dry powder material and a preparation method thereof, which uses the mixing of alkali fusion material and active material to realize the water preparation of geopolymer, and can solve the problem of liquid alkali activation preparation in the prior art to a certain extent; patent CN116514426A further discloses a preparation method of homogenized geopolymer dry powder, which controls the chemical homogeneity of the material to improve the performance of geopolymer.

[0004] However, the above two patents mainly focus on the adjustment of materials fired at the same temperature. In order to better regulate the performance of geopolymer such as setting time and strength, the coupling of firing temperature and raw material properties needs to be considered in actual preparation, so it is necessary to further improve the existing preparation method. SUMMARY

[0005] In order to solve the above problems, the present application first provides a performance regulation method of geopolymer dry powder material.

[0006] The present application adopts the following technical solutions:

[0007] A performance regulation method of geopolymer dry powder material, comprising the following steps:

[0008] S1. Preparing fired material

[0009] S11. Confirming the classification of silicon-aluminum raw material: the silicon-aluminum raw material includes high silicon-aluminum ratio, medium silicon-aluminum ratio and low silicon-aluminum ratio, the silicon-aluminum ratio of the high silicon-aluminum ratio is greater than or equal to 15, the silicon-aluminum ratio of the medium silicon-aluminum ratio is 6-10, and the silicon-aluminum ratio of the low silicon-aluminum ratio is 1-6;

[0010] S12. The silicon-aluminum raw material is mixed with the alkaline substance in a set ratio, and the mixture is divided into three parts in a set ratio, and is subjected to high-temperature calcination, medium-temperature calcination and low-temperature calcination, respectively, wherein the high-temperature calcination is performed at a temperature of 600-700℃, the medium-temperature calcination is performed at a temperature of 400-600℃, and the low-temperature calcination is performed at a temperature of 250-400℃;

[0011] Thus, nine kinds of calcined materials are obtained, i.e. high-silicon-aluminum ratio-high-temperature material, high-silicon-aluminum ratio-medium-temperature material, high-silicon-aluminum ratio-low-temperature material, medium-silicon-aluminum ratio-high-temperature material, medium-silicon-aluminum ratio-medium-temperature material, medium-silicon-aluminum ratio-low-temperature material, low-silicon-aluminum ratio-high-temperature material, low-silicon-aluminum ratio-medium-temperature material and low-silicon-aluminum ratio-low-temperature material.

[0012] S2. Preparation of geopolymer

[0013] S21. According to the compressive strength of the geopolymer to be prepared, any 1-9 kinds of the nine kinds of calcined materials are selected for mixing to obtain mixed calcined materials.

[0014] S22. The mixed calcined materials are mixed with the gel-active silicon-aluminum raw material in a mass ratio of (0.10-0.25):1 to obtain a mixture, and the silicon-aluminum ratio of the mixture is controlled to be 2-5 by controlling the silicon-aluminum ratio of the gel-active silicon-aluminum raw material. After the mixture is ground, the dry powder material of the geopolymer is obtained.

[0015] Preferably, the mixing strategy of the nine kinds of calcined materials is as follows: according to the influence weight on the compressive strength, the order is medium-silicon-aluminum ratio-medium-temperature material, medium-silicon-aluminum ratio-low-temperature material, medium-silicon-aluminum ratio-high-temperature material, high-silicon-aluminum ratio-medium-temperature material, high-silicon-aluminum ratio-low-temperature material, high-silicon-aluminum ratio-high-temperature material, low-silicon-aluminum ratio-medium-temperature material, low-silicon-aluminum ratio-low-temperature material and low-silicon-aluminum ratio-high-temperature material, and the enhancement of the medium-silicon-aluminum ratio-medium-temperature material on the compressive strength is a positive condition, the reduction of the low-silicon-aluminum ratio-high-temperature material on the compressive strength is a positive condition, and with the decrease of the silicon-aluminum ratio of the calcined material, the setting time of the slurry is shortened.

[0016] Preferably, the silicon-aluminum raw material is one or more of coal gangue, fly ash, quartz or silica ash, and the alkaline substance is sodium hydroxide.

[0017] Preferably, the silicon-aluminum raw material and the alkaline substance are mixed in a mass ratio of 1:(0.8-1.0), and then subjected to one-time ore grinding, and the one-time ore grinding is performed to a particle size of less than 0.5mm.

[0018] Preferably, the gel-active silicon-aluminum raw material is any one or a combination of several of metakaolin, fly ash, coal gasification slag and silica ash.

[0019] Preferably, in the step S22, the proportion of the grinding to below 0.045 mm particle size is more than 75%.

[0020] The application further provides a geopolymer prepared from the geopolymer dry powder material prepared according to the regulation method.

[0021] The application further provides a preparation method of the geopolymer, wherein the geopolymer dry powder material is prepared into a geopolymer slurry according to a water-cement ratio of 0.2-0.5, and the geopolymer is obtained by curing and drying the geopolymer slurry.

[0022] Preferably, the curing specifically includes: placing the slurry into a required mold to shake off air bubbles, demolding after sealed curing for 24 hours, and continuing to cure in a humidity of 93% RH for at least 28 days.

[0023] The application has the following beneficial effects:

[0024] By adjusting the silicon-aluminum ratio and the alkali fusion and heat activation temperature of the silicon-aluminum raw material, the phase of the calcined product can be adjusted, the forms and speeds of releasing alkali after the calcined products with different phase structures are contacted with water are different, and the reaction processes of the calcined products and the cementitious active silicon-aluminum are also different, thereby forming the regulation method for the reaction process of the geopolymer.

[0025] Under the condition of high silicon-aluminum ratio material, the alkali fusion and heat activation product mainly contains sodium silicate phase, and with the increase of temperature, the reaction is more complete, while under the condition of low silicon-aluminum ratio material, the alkali fusion and heat activation product contains sodium silicate and sodium aluminosilicate crystal substances, and with the decrease of the silicon-aluminum ratio and the increase of the temperature, the content of the sodium aluminosilicate crystal increases and the structure is more stable, and the reaction with water is weaker than that of sodium silicate, and the dissolution rate is slow, thereby the later strength of the geopolymer can be regulated.

[0026] Therefore, under the action of the raw material with different silicon-aluminum ratios and the alkali fusion and heat activation temperature, the calcined product can regularly regulate the performance of the geopolymer.

[0027] For a certain geopolymer, by classifying and adjusting the raw material for preparing the geopolymer, the silicon-aluminum ratio and / or the calcination temperature of the raw material can be increased or decreased according to the method, so as to adjust the performance of the prepared geopolymer dry powder, and the method can greatly improve the application of the geopolymer in the field of building engineering materials. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the preparation method of the application.

[0029] Figure 2 The compressive strength of the sample prepared in Example 1.

[0030] Figure 3 Setting time of the sample prepared for Example 1.

[0031] Figure 4 Compressive strength of the sample prepared for Example 1.

[0032] Figure 5 Compressive strength of the sample prepared for Example 1.

[0033] Figure 6 Compressive strength of the sample prepared for Examples 1-3 at the 28th day of curing.

[0034] Figure 7 Compressive strength of the sample prepared for Examples 1-3 at the 56th day of curing. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described in more detail below in combination with examples.

[0036] Example 1

[0037] The preparation process of the geopolymer includes the following steps:

[0038] S1. Quartz and alumina are mixed in a certain proportion to obtain silica-alumina raw materials with different silica-alumina ratios (1.5, 2, 6, 8, 12, 20);

[0039] S2. The silica-alumina raw materials are mixed with sodium hydroxide at a mass ratio of 1.2, and then ground. Then, low-temperature (350℃) calcination is performed, and the calcined material is ground to 0.074mm to obtain low-temperature calcined materials with different silica-alumina ratios;

[0040] S3. The coal gangue rich in kaolin is converted into metakaolin by high-temperature calcination at 700℃ for 8h, which is used as a cementitious active silica-alumina raw material;

[0041] S4. The low-temperature calcined material is mixed with the cementitious active silica-alumina raw material, and the mass of the low-temperature calcined material accounts for 15% of the total mass of the cementitious active silica-alumina raw material and the low-temperature calcined material. The silica-alumina ratio of the mixture is 2.5, and then all the powders are ground to a particle size of less than 0.045mm to obtain the required dry geopolymer powder.

[0042] The prepared homogeneous geopolymer dry powder is used to prepare a geopolymer slurry with a water-cement ratio of 0.33. After sufficient stirring, the slurry is placed in a square mold with a side length of 100mm. After shaking to remove air bubbles in the slurry, the slurry is sealed and cured at room temperature for 24h, and then demolded and placed in a curing box with a humidity of 93% for further curing.

[0043] As Figure 2The sample (low-temperature calcined material preparation) different curing age compressive strength statistical chart is shown, it can be seen that the compressive strength of the geopolymer block 3 days gradually decreases with the high, medium and low silicon aluminum ratio calcined material, but the compressive strength of the geopolymer block 7, 28, 56 days increases first and then decreases with the high, medium and low silicon aluminum ratio calcined material. The early strength (3 days) of the geopolymer sample prepared by high silicon aluminum ratio material is higher, but the late strength grows slowly, and the mid-late strength of the sample grows obviously with the decrease of the silicon aluminum ratio of the material. However, when the aluminum silicon ratio of the calcined material is too low (<6), the compressive strength of the sample decreases obviously, which is mainly due to the formation of a large amount of crystalline aluminum silicate in the calcined material, which restricts the release of active silicon aluminum in the calcined material. In addition, with the decrease of the silicon aluminum ratio of the calcined material, the setting time of the sample gradually shortens, such as Figure 3 Therefore, when the calcination temperature is constant, the adjustment based on the silicon aluminum ratio can realize the adjustment of the properties of the geopolymer dry powder (such as the compressive strength under long curing time).

[0044] Example 2

[0045] The preparation process of the geopolymer includes the following steps:

[0046] S1. Quartz and alumina are mixed in a certain proportion to obtain silicon aluminum raw materials with different silicon aluminum ratios (1.5, 2, 6, 8, 12, 20);

[0047] S2. The silicon aluminum raw material is mixed and ground with sodium hydroxide according to a mass ratio of 1.2, and then is subjected to medium-temperature (500℃) calcination. After calcination, the material is ground to 0.074mm to obtain high-temperature calcined material;

[0048] S3. The coal gangue rich in kaolin is converted into metakaolin by high-temperature calcination at 700℃ for 8h, which is used as a cementitious active silicon aluminum raw material;

[0049] S4. The medium-temperature calcined material is mixed with the cementitious active silicon aluminum raw material, and the mass of the medium-temperature calcined material accounts for 15% of the total mass of the cementitious active silicon aluminum raw material and the medium-temperature calcined material. The silicon aluminum ratio of the mixture is 2.5, and then the mixture is ground to all powder particle sizes below 0.045mm to obtain the required geopolymer dry powder.

[0050] The prepared homogeneous geopolymer dry powder is used to prepare geopolymer slurry according to a water-cement ratio of 0.33. After sufficient stirring, the slurry is placed in a square mold with a side length of 100mm. After shaking to remove air bubbles in the slurry, the slurry is sealed and cured at room temperature for 24h, and then demolded and placed in a curing box with a humidity of 93% for further curing.

[0051] As Figure 4The statistical chart of compressive strength of samples (prepared from medium-temperature roasted materials) at different curing ages shows that, within the same curing age, the compressive strength of geopolymers prepared from materials roasted at 500℃ is higher than that of samples prepared from materials roasted at 350℃. Appropriate temperature increases the activity of roasted materials, which is beneficial to the growth of geopolymer strength.

[0052] Example 3

[0053] The geopolymer preparation process includes the following steps:

[0054] S1. Quartz and alumina are mixed in a certain proportion to obtain silicon-aluminum raw materials with different silicon-aluminum ratios (1.5, 2, 6, 8, 12, 20);

[0055] S2. Silicon-aluminum raw materials and sodium hydroxide are mixed and ground at a mass ratio of 1.2, and then roasted at high temperature (700℃). After roasting, the material is ground to 0.074mm to obtain high-temperature roasted material; S3. Coal gangue rich in kaolin is calcined at 700℃ for 8 hours to transform into metakaolin, which is used as a cementing active silicon-aluminum raw material.

[0056] S4. The high-temperature roasted material is mixed with the gelling active silica-alumina raw material. The mass of the high-temperature roasted material accounts for 15% of the total mass of the active silica-alumina raw material and the medium-temperature roasted material. The silica-alumina ratio of the mixture is 2.5. Then, they are ground together until all powder particles are below 0.045 mm to obtain the required geopolymer dry powder.

[0057] The homogenized geopolymer dry powder was prepared into a geopolymer slurry with a water-cement ratio of 0.33. After thorough stirring, the slurry was placed in a cube mold with a side length of 100 mm. After shaking to remove air bubbles from the slurry, it was sealed and cured at room temperature for 24 hours. Then, it was demolded and placed in a curing box with a humidity of 93% for further curing.

[0058] like Figure 5 The statistical chart of compressive strength of samples (prepared from high-temperature roasted materials) at different curing ages shows that, within the same curing age, the compressive strength of geopolymers prepared from materials roasted at 700℃ is generally lower than that of samples prepared from materials roasted at 350℃ and 500℃, but the variation pattern is basically the same. This phenomenon can be attributed to the decrease in activity of roasted materials due to the increase in roasting temperature, which in turn restricts the growth rate of geopolymer strength.

[0059] The compressive strength data of samples from Examples 1-3 on day 28 were collected, and the results are shown below. Figure 6 The compressive strength data of samples from Examples 1-3 on day 56 were collected, and the results are shown in [the original text]. Figure 7Starting from day 28, the strength of the prepared geopolymers conformed to the following criteria: 1) Compressive strength of calcined materials prepared at the same temperature: medium silicon-aluminum ratio > high silicon-aluminum ratio > low silicon-aluminum ratio; 2) Compressive strength of calcined materials prepared with the same silicon-aluminum ratio: medium temperature > low temperature > high temperature. Ultimately, the compressive strength of the geopolymers prepared from the nine calcined materials decreased in the following order: medium silicon-aluminum ratio - medium temperature material, medium silicon-aluminum ratio - low temperature material, medium silicon-aluminum ratio - high temperature material, high silicon-aluminum ratio - medium temperature material, high silicon-aluminum ratio - low temperature material, high silicon-aluminum ratio - high temperature material, low silicon-aluminum ratio - medium temperature material, low silicon-aluminum ratio - low temperature material, and low silicon-aluminum ratio - high temperature material. That is, a medium silicon-aluminum ratio - medium temperature material is a positive condition for increasing compressive strength, while a low silicon-aluminum ratio - high temperature material is a positive condition for decreasing compressive strength. Therefore, for a specific geopolymer, by classifying and adjusting the raw materials used in its preparation, and adaptively increasing or decreasing the silicon-aluminum ratio and / or calcination temperature according to this method, the properties of the prepared geopolymer dry powder can be adjusted.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating the properties of geopolymer dry powder materials, characterized in that, Includes the following steps: S1. Preparation of calcining materials S11. Confirm the classification of silicon-aluminum raw materials: The silicon-aluminum raw materials include high silicon-aluminum ratio, medium silicon-aluminum ratio, and low silicon-aluminum ratio. The silicon-aluminum ratio of the high silicon-aluminum ratio is greater than or equal to 15; the silicon-aluminum ratio of the medium silicon-aluminum ratio is 6-10, excluding 6; and the silicon-aluminum ratio of the low silicon-aluminum ratio is 1-6. S12. The silicon-aluminum raw material and the alkaline substance are mixed in a set ratio. The mixture is divided into three parts in the set ratio and subjected to high-temperature calcination, medium-temperature calcination and low-temperature calcination respectively. The high-temperature calcination temperature is 600~700℃, excluding 600℃; the medium-temperature calcination temperature is 400~600℃, excluding 400℃; and the low-temperature calcination temperature is 250~400℃. Thus, nine types of roasting materials were obtained, namely, high silicon-aluminum ratio-high temperature material, high silicon-aluminum ratio-medium temperature material, high silicon-aluminum ratio-low temperature material, medium silicon-aluminum ratio-high temperature material, medium silicon-aluminum ratio-medium temperature material, medium silicon-aluminum ratio-low temperature material, low silicon-aluminum ratio-high temperature material, low silicon-aluminum ratio-medium temperature material, and low silicon-aluminum ratio-low temperature material. S2. Preparation of geopolymers S21. Based on the compressive strength of the geopolymer to be prepared, select any 1 to 9 of the 9 roasting materials and mix them to obtain the first roasting material; S22. The first calcined material and the gel-active silica-alumina raw material are mixed at a mass ratio of (0.10~0.25):1 to obtain a mixture. By controlling the silica-alumina ratio of the gel-active silica-alumina raw material, the silica-alumina ratio of the mixture is made to be between 2 and 5. The mixture is then ground to obtain the desired geopolymer dry powder material.

2. The method for controlling the performance of geopolymer dry powder materials as described in claim 1, characterized in that, The mixing strategy for the nine roasted materials is as follows: ranked according to their influence on compressive strength, the order is: medium silicon-aluminum ratio - medium temperature material, medium silicon-aluminum ratio - low temperature material, medium silicon-aluminum ratio - high temperature material, high silicon-aluminum ratio - medium temperature material, high silicon-aluminum ratio - low temperature material, high silicon-aluminum ratio - high temperature material, low silicon-aluminum ratio - medium temperature material, low silicon-aluminum ratio - low temperature material, and low silicon-aluminum ratio - high temperature material. The medium silicon-aluminum ratio - medium temperature material is a positive condition for the enhancement of compressive strength, while the low silicon-aluminum ratio - high temperature material is a positive condition for the reduction of compressive strength. Furthermore, as the silicon-aluminum ratio of the roasted materials decreases, the solidification time of the slurry shortens.

3. The method for controlling the performance of geopolymer dry powder materials as described in claim 1, characterized in that, The silicon-aluminum raw material is one or more of coal gangue, fly ash, quartz or silica fume; the alkaline substance is sodium hydroxide.

4. The method for controlling the performance of geopolymer dry powder materials as described in claim 3, characterized in that, The silicon-aluminum raw material and the alkaline substance are mixed at a mass ratio of 1:(0.8~1.0) and then ground once until the particle size is below 0.5mm.

5. The method for performance control of geopolymer dry powder materials as described in claim 1, characterized in that, The gel-activated silica-alumina raw material is any one or a combination of several of metakaolin, fly ash, coal gasification slag, and silica fume.

6. The method for performance control of geopolymer dry powder materials as described in claim 1, characterized in that, In step S22, the proportion of particles ground to a size of 0.045 mm or smaller is more than 75%.

7. A geopolymer, characterized in that, The geopolymer dry powder material prepared by the control method according to any one of claims 1-6 is obtained.

8. A method for preparing the geopolymer as described in claim 7, characterized in that, The geological polymer dry powder material is prepared into a geological polymer slurry with a water-cement ratio of 0.2 to 0.5, and the slurry is cured and dried to obtain the desired geological polymer.

9. The preparation method according to claim 8, characterized in that, The curing process specifically involves: placing the slurry into the required mold, shaking to remove air bubbles, sealing and curing for 24 hours, demolding, and then placing it in an environment with a humidity of 93%RH for at least 28 days for further curing.

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