A silicon-aluminate material, its preparation method and application

Abstract

This invention belongs to the field of building materials technology, specifically relating to a silica-alumina material, its preparation method, and its application. The silica-alumina material comprises 10-65 parts by weight of red mud, 20-60 parts by weight of slag powder, 0-20 parts by weight of silicate cement clinker, 0.1-8 parts by weight of an activator, and 5-15 parts by weight of an expanding agent; wherein, based on the mass of the expanding agent, the expanding agent comprises 0-60 wt% aluminum sulfate, 0-70 wt% carbide slag, 0-70 wt% tricalcium aluminate, 0-60 wt% calcium sulfoaluminate, and 0-60 wt% gypsum, and the content of at least two components in the expanding agent is not zero. The silica-alumina material of this invention, with its specific components and contents, can achieve both high strength and low shrinkage. When used in cement mortar, it can enhance the density of the cement and prevent cracking, enabling the material to be used for a long time.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a silicon-aluminum material, its preparation method, and its application. Background Technology

[0002] With increasing concern about global warming and greenhouse gas emission reduction, the research and development of low-carbon technologies has become an urgent need for the cement industry. Over the past 20 years, researchers have proposed various novel low-carbon cementitious materials. Among them, alkali-activated cementitious materials (also known as AAS composites) have attracted widespread attention due to their outstanding characteristics such as low permeability, high strength, good thermal stability, excellent chemical resistance, and dense microstructure. Furthermore, the precursors or raw materials of alkali-activated materials are mainly industrial solid waste containing aluminosilicate glass, which can effectively reduce greenhouse gas emissions released during the production of ordinary silicate cement (OPC), alleviate energy consumption, and combine economic sustainability with environmental friendliness.

[0003] Compared to traditional cement-based cementitious materials, although alkali-activated cementitious materials exhibit superior mechanical properties in construction, their shrinkage rate is greater than that of ordinary silicate cement slurry. This volumetric instability limits their widespread application in the building materials field. Due to its unique depolymerization-condensation reaction mechanism, aluminosilicate cementitious materials have hydration products and pore structures that differ from OPC. For example, comparing the amorphous hydration products such as sodium aluminosilicate hydrate and calcium aluminosilicate hydrate in aluminosilicate materials with those in OPC hydration products such as calcium silicate hydrate, the sodium aluminosilicate hydrate and calcium aluminosilicate hydrate in aluminosilicate materials have a higher specific surface area, making them more prone to shrinkage and deformation during drying. Furthermore, the hydration products of aluminosilicate cementitious materials lack crystalline phases such as Ca(OH)₂, AFt, and AFm, which have high elastic modulus and good volume stability. These differences result in a higher shrinkage rate and poorer volume stability in aluminosilicate cementitious materials.

[0004] In recent years, although researchers have gradually paid attention to the harm caused by shrinkage and actively studied various expansion agents, such as calcium sulfoaluminate expansion agents, calcium sulfoaluminate-calcium oxide expansion agents and calcium oxide expansion agents, due to the special reaction mechanism, hydration products and pore structure of siliceous alumina cementitious materials, existing expansion agents cannot solve the problems of large shrinkage rate and poor volume stability of siliceous alumina cementitious materials. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of existing aluminosilicate cementitious materials such as large shrinkage rate and poor volume stability, thereby providing an aluminosilicate material, its preparation method and application.

[0006] Therefore, the present invention provides the following technical solution:

[0007] The first aspect of this invention protects a silica-alumina material, wherein the silica-alumina material comprises 10-65 parts by weight of red mud, 20-60 parts by weight of slag powder, 0-20 parts by weight of silicate cement clinker, 0.1-8 parts by weight of activator and 5-15 parts by weight of expansion agent.

[0008] The expanding agent, by mass, comprises 0-60 wt% aluminum sulfate, 0-70 wt% carbide slag, 0-70 wt% tricalcium aluminate, 0-60 wt% calcium sulfoaluminate, and 0-60 wt% gypsum, wherein the content of at least two components in the expanding agent is not 0.

[0009] In this invention, the water content refers to the sum of physically adsorbed water and free water, excluding chemically bound water and crystal water; the water content of the red mud, steel slag, and slag powder is <1wt%.

[0010] In this invention, the water content of the aluminum sulfate, tricalcium aluminate, carbide slag, and calcium sulfoaluminate is <1wt%.

[0011] According to the present invention, the silica-alumina material comprises 30-60 parts by weight of red mud, 35-55 parts by weight of slag powder, 5-15 parts by weight of silicate cement clinker, 3-5 parts by weight of activator and 8-10 parts by weight of expansion agent.

[0012] The expanding agent comprises, by weight, 0-50 wt% aluminum sulfate, 0-60 wt% carbide slag, 0-50 wt% tricalcium aluminate, 0-50 wt% calcium sulfoaluminate, and 0-50 wt% gypsum, and the content of at least two components in the expanding agent is not 0.

[0013] According to the present invention, the expanding agent comprises 50 wt% aluminum sulfate and 50 wt% carbide slag, based on the mass of the expanding agent.

[0014] According to the present invention, the expanding agent comprises 40 wt% aluminum sulfate and 60 wt% carbide slag, based on the mass of the expanding agent.

[0015] According to the present invention, the expanding agent comprises 50 wt% tricalcium aluminate and 50 wt% gypsum, based on the mass of the expanding agent.

[0016] According to the present invention, the expanding agent comprises 50 wt% calcium sulfoaluminate and 50 wt% gypsum, based on the mass of the expanding agent.

[0017] According to the present invention, the expanding agent comprises 30 wt% aluminum sulfate, 30 wt% carbide slag and 40 wt% gypsum, based on the mass of the expanding agent.

[0018] According to the present invention, the activator includes a calcium-containing activator and / or a sodium-containing activator; further, the activator includes at least one selected from calcium formate, calcium lignosulfonate, sodium sulfate, calcium chloride, sodium carbonate, sodium hydroxide, and sodium silicate.

[0019] In this invention, the activator is in solid form, and the water content is mainly water of crystallization and chemically bound water / hydroxyl groups, and the amount used is very low, so there is no need to control the water content.

[0020] According to the present invention, the gypsum includes gypsum for building purposes, and typically, without limitation, the gypsum includes at least one of dihydrate gypsum, desulfurized gypsum, mirabilite gypsum, phosphogypsum, and titanium gypsum.

[0021] In this invention, the gypsum contains water of crystallization in addition to physically adsorbed water and free water (the total water content of the two parts is estimated to be about 10%). However, the amount of gypsum used in the raw materials is small, so the amount of water introduced into the grinding system is also very small and does not require special control.

[0022] In this invention, the red mud includes sintered red mud, which is conventional red mud in the art. Typically, without limitation, the red mud contains Al2O3 content ≥6wt%, SiO2 content ≥10wt%, and 28-day compressive strength activity index higher than 60%.

[0023] In this invention, the slag powder is a conventional slag powder in the art, including water-quenched blast furnace slag powder and / or air-cooled blast furnace slag powder, and the moisture content of the slag powder is <1wt%.

[0024] In this invention, the silicate cement clinker meets the requirements of GB / T 21372 "Silicate Cement Clinker"; the silicate cement clinker is a commercially available dried material, and typically, without limitation, the moisture content of the silicate cement clinker is <1wt%.

[0025] According to the present invention, the water content of the silicon-aluminum material is <1 wt%.

[0026] According to the present invention, the average particle size of the silicon-aluminum material is 30-100 μm.

[0027] The second aspect of this invention protects a method for preparing a silicon-aluminum material, wherein the components of the aforementioned silicon-aluminum material are homogenized, dried, and ground to obtain the silicon-aluminum material.

[0028] A third aspect of this invention protects a cement mortar, wherein the cement mortar comprises the aforementioned aluminosilicate material or the aluminosilicate material prepared by the aforementioned preparation method.

[0029] In this invention, under an environment with a temperature of 20±2℃ and a relative humidity of ≥90%, the flexural strength of the cement mortar after curing in water for 3 days is >7.0MPa and the compressive strength is >30.0MPa.

[0030] And / or, in an environment with a temperature of 20±2℃ and a relative humidity of ≥90%, the flexural strength of the cement mortar after curing in water for 28 days is >9.0MPa and the compressive strength is >50.0MPa;

[0031] And / or, under an environment of temperature of 20±2℃ and relative humidity of 55±5%, the shrinkage rate ×10000 < 800% after curing in water for 28 days.

[0032] The technical solution of this invention has the following advantages:

[0033] 1. This invention provides a silica-alumina material, wherein the silica-alumina material comprises 10-65 parts by weight of red mud, 20-60 parts by weight of slag powder, 0-20 parts by weight of silicate cement clinker, 0.1-8 parts by weight of an activator, and 5-15 parts by weight of an expanding agent; wherein, based on the mass of the expanding agent, the expanding agent comprises 0-60 wt% aluminum sulfate, 0-70 wt% carbide slag, 0-70 wt% tricalcium aluminate, 0-60 wt% calcium sulfoaluminate, and 0-60 wt% gypsum, and the expanding agent contains at least two components... The content is not 0; the silica-alumina material of the present invention with specific components and contents, under the action of activator, red mud, slag powder, silicate cement clinker and part of the activator will form crystalline phases such as ettringite and calcium hydroxide and amorphous phases such as hydrated sodium aluminosilicate and hydrated calcium aluminosilicate. The crystalline phase and amorphous phase synergistically construct the silica-alumina material, wherein the crystals interpenetrate the dense structure of the amorphous gel, improve the pore size distribution, so that when the silica-alumina material is used in cement mortar, the cement mortar can take into account both high strength and low shrinkage, enhance the density of cement and prevent cracking, so that the material can be used for a long time.

[0034] 2. In this invention, the specific content of each component in the silicon-aluminum material increases the crystalline phase content, thereby further reducing the degree of shrinkage and improving mechanical properties.

[0035] 3. In this invention, the specific combination of expansion agents can further reduce the degree of shrinkage, increase the stability of the matrix, and improve the mechanical properties.

[0036] 4. In this invention, each component of the silicon-aluminum material is first homogenized and then ground to ensure that the expansion agent is evenly distributed in the material and to further reduce the degree of shrinkage during subsequent use. Detailed Implementation

[0037] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0038] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0039] To facilitate comparison between data, the sources and compositions of red mud, silicate cement clinker, and slag powder used in the following embodiments and comparative examples of the present invention are the same, and the specific contents of red mud, silicate cement clinker, and slag powder are shown in Table 1.

[0040] Table 1

[0041] Red mud Silicate cement clinker Slag powder <![CDATA[Na2O eq .(wt%)]]> 3.29 0.22 0.46 MgO (wt%) 1.82 3.28 9.11 <![CDATA[Al2O3(wt%)]]> 8.58 4.11 16.32 <![CDATA[SiO2(wt%)]]> 19.73 18.77 30.52 <![CDATA[P2O5(wt%)]]> 0.24 0.08 0.02 <![CDATA[SO3(wt%)]]> 4.38 3.85 2.27 <![CDATA[K2O(wt%)]]> 0.09 0.88 0.4 CaO (wt%) 38.99 62.82 38.44 <![CDATA[TiO2(wt%)]]> 0.94 0.36 0.82 <![CDATA[V2O5(wt%)]]> 3.21 - - MnO (wt%) 0.04 0.06 0.52 <![CDATA[Fe2O3(wt%)]]> 7.78 3.36 0.31 Other (wt%) 0.79 0.24 0.12

[0042] The water content of aluminum sulfate is 0.1 wt%.

[0043] The water content of tricalcium aluminate is 0.1 wt%.

[0044] The moisture content of the carbide slag is 0.1 wt%.

[0045] The water content of calcium sulfoaluminate is 0.1 wt%.

[0046] In the examples and comparative examples, 1 part by weight corresponds to 1g.

[0047] Example 1

[0048] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0049] The aluminosilicate material comprises 60 parts by weight of red mud, 35 parts by weight of slag powder, 5 parts by weight of silicate cement clinker, 5 parts by weight of sodium hydroxide, and 10 parts by weight of expanding agent; the expanding agent comprises 50 wt% aluminum sulfate and 50 wt% carbide slag by mass percentage; all components are homogenized, dried, and ground to obtain the aluminosilicate material.

[0050] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0051] Example 2

[0052] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0053] The aluminosilicate material comprises 30 parts by weight of red mud, 55 parts by weight of slag powder, 15 parts by weight of silicate cement clinker, 4 parts by weight of sodium hydroxide, and 8 parts by weight of expanding agent; the expanding agent comprises 40 wt% aluminum sulfate and 60 wt% carbide slag by mass percentage; all components are homogenized, dried, and ground to obtain the aluminosilicate material.

[0054] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0055] Example 3

[0056] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0057] The method is the same as in Example 1, except that the expanding agent is 50 wt% tricalcium aluminate and 50 wt% gypsum dihydrate.

[0058] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0059] Example 4

[0060] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0061] The method is the same as in Example 1, except that the expanding agent is 50 wt% calcium sulfoaluminate and 50 wt% gypsum dihydrate.

[0062] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0063] Example 5

[0064] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0065] The aluminosilicate material comprises 65 parts by weight of red mud, 30 parts by weight of slag powder, 3 parts by weight of silicate cement clinker, 2 parts by weight of sodium hydroxide, and 7 parts by weight of expanding agent; the expanding agent comprises 50 wt% aluminum sulfate and 50 wt% carbide slag by mass percentage; all components are homogenized, dried, and ground to obtain the aluminosilicate material.

[0066] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0067] Example 6

[0068] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0069] The method is the same as in Example 1, except that the expanding agent is 30 wt% aluminum sulfate, 30 wt% carbide slag and 40 wt% gypsum dihydrate; wherein the water content of the aluminosilicate material is 0.5 wt%; and the average particle size of the aluminosilicate material is 80 μm.

[0070] Example 7

[0071] This embodiment provides a silicon-aluminum material, and the specific preparation method is as follows:

[0072] The aluminosilicate material comprises 65 parts by weight of red mud, 35 parts by weight of slag powder, 5 parts by weight of sodium hydroxide and 10 parts by weight of expanding agent; the expanding agent comprises 50 wt% aluminum sulfate and 50 wt% carbide slag by mass percentage; all components are homogenized, dried and ground to obtain the aluminosilicate material.

[0073] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0074] Comparative Example 1

[0075] This comparative example provides a silicon-aluminum material, and the specific preparation method is as follows:

[0076] The aluminosilicate material comprises 60 parts by weight of red mud, 35 parts by weight of slag powder, 5 parts by weight of silicate cement clinker, and 5 parts by weight of sodium hydroxide. All components are homogenized, dried, and ground to obtain the aluminosilicate material.

[0077] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0078] Comparative Example 2

[0079] This comparative example provides a silicon-aluminum material, and the specific preparation method is as follows:

[0080] The aluminosilicate material comprises 70 parts by weight of red mud, 5 parts by weight of slag powder, 25 parts by weight of silicate cement clinker, 10 parts by weight of sodium hydroxide and 10 parts by weight of expanding agent; the expanding agent comprises 50 wt% aluminum sulfate and 50 wt% carbide slag by mass percentage; all components are homogenized, dried and ground to obtain the aluminosilicate material.

[0081] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0082] Comparative Example 3

[0083] This comparative example provides a silicon-aluminum material, and the specific preparation method is as follows:

[0084] The process is the same as in Example 1, except that the expanding agent is aluminum sulfate; all components are homogenized, dried, and ground to obtain a silicon-aluminum material;

[0085] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0086] Comparative Example 4

[0087] This comparative example provides a silicon-aluminum material, and the specific preparation method is as follows:

[0088] Following the method of Example 1, except that the expanding agent is calcium carbide slag; all components are homogenized, dried, and ground to obtain a silicon-aluminum material;

[0089] The water content of the aluminosilicate material is 0.5 wt%; the average particle size of the aluminosilicate material is 80 μm.

[0090] Test case

[0091] The aluminosilicate materials prepared in the examples and comparative examples were mixed and molded according to GB / T17671-1999 "Test Method for Strength of Cement Mortar (ISO Method)". The specimens were prepared by mixing one part aluminosilicate material and three parts Chinese ISO standard sand with a water-cement ratio of 0.5 by weight, and were made into prism specimens with a width × height × length of 40mm × 40mm × 160mm. They were then cured in water: the mortar specimens were cured in a curing box at 20±2℃ and relative humidity ≥90% for 1 day, and then demolded. The demolded specimens were placed in water at 20±1℃ and cured for 3 days and 28 days, and then the flexural strength and compressive strength were tested.

[0092] Specimens for drying shrinkage testing were prepared according to JC / T 603-2004 "Test Method for Drying Shrinkage of Cement Mortar". The specimens, by mass, consisted of one part silica-alumina material and two parts Chinese ISO standard sand, prepared into mortar specimens with dimensions of 25mm × 25mm × 280mm. After demolding, they were placed directly in an environment with a temperature of 20±2℃ and a relative humidity of 55±5% for curing at the specified 3-day and 28-day curing periods. Taking the 28-day curing period as an example, the drying shrinkage of the cement mortar specimen at 28 days was calculated using the following formula: S 28 =(L0-L 28 )×100 / 250;

[0093] In the formula: S 28 The drying shrinkage rate of cement mortar at 28 days is expressed as a percentage (%).

[0094] L0 is the initial measurement reading, in millimeters (mm);

[0095] L 28 The readings are taken at 28 days of age, and the unit is millimeters (mm).

[0096] 250 represents the effective length of the specimen, in millimeters (mm).

[0097] The specific test results are shown in Table 2.

[0098] Table 2

[0099]

[0100]

[0101] The silica-alumina material prepared by the composition of specific components and dosages of the present invention can achieve both high strength and low shrinkage. When applied in cement mortar, it enhances the density of cement and prevents cracking, enabling the material to be used for a long time.

[0102] A comparison of Examples 1, 3-4, and 6 shows that specific combinations of certain types of expanding agents can reduce shrinkage and increase matrix stability.

[0103] A comparison of Example 1 and Example 5 shows that the specific content of each component in the composition can further reduce the degree of shrinkage and improve the mechanical properties.

[0104] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A silicon-aluminum material, characterized in that, The silica-aluminate material comprises 10-65 parts by weight of red mud, 20-60 parts by weight of slag powder, 0-20 parts by weight of silicate cement clinker, 0.1-8 parts by weight of activator, and 5-15 parts by weight of expansion agent. The expanding agent comprises 50 wt% aluminum sulfate and 50 wt% carbide slag, based on the mass of the expanding agent. Alternatively, the expanding agent comprises 40 wt% aluminum sulfate and 60 wt% carbide slag, based on the mass of the expanding agent. Alternatively, the expanding agent comprises 50 wt% tricalcium aluminate and 50 wt% gypsum, based on the mass of the expanding agent. Alternatively, the expanding agent may comprise 30 wt% aluminum sulfate, 30 wt% carbide slag, and 40 wt% gypsum, based on the mass of the expanding agent.

2. The silicon-aluminum material according to claim 1, characterized in that, The silica-aluminate material comprises 30-60 parts by weight of red mud, 35-55 parts by weight of slag powder, 5-15 parts by weight of silicate cement clinker, 3-5 parts by weight of activator, and 8-10 parts by weight of expansion agent.

3. The aluminosilicate material according to claim 1 or 2, characterized in that, The activator includes calcium-containing activators and / or sodium-containing activators.

4. The aluminosilicate material according to claim 3, characterized in that, The activator includes at least one of calcium formate, calcium lignosulfonate, sodium sulfate, calcium chloride, sodium carbonate, sodium hydroxide, and sodium silicate.

5. The silicon-aluminum material according to claim 1, characterized in that, The gypsum includes at least one of dihydrate gypsum, desulfurized gypsum, mirabilite gypsum, phosphogypsum, and titanium gypsum.

6. The silicon-aluminum material according to claim 1, characterized in that, The water content of the silicon-aluminum material is <1 wt%.

7. The silicon-aluminum material according to claim 1, characterized in that, The average particle size of the silicon-aluminate material is 30-100 μm.

8. A method for preparing a silicon-aluminum material, characterized in that, The components of the aluminosilicate material according to any one of claims 1-4 are homogenized, dried, and ground to obtain the aluminosilicate material.

9. A type of cement mortar, characterized in that, The cement mortar includes the aluminosilicate material as described in any one of claims 1-7 or the aluminosilicate material prepared by the preparation method described in claim 8.

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