Red mud-based polymer and preparation method thereof

Abstract

The present application relates to the technical field of building material preparation, and provides a red mud-based polymer and a preparation method thereof. The preparation method comprises: mixing red mud with a hydrothermal alkaline activator solution and performing a hydrothermal reaction to obtain a modified red mud slurry, wherein the hydrothermal alkaline activator in the hydrothermal alkaline activator solution comprises sodium hydroxide; mixing and stirring the modified red mud slurry with mineral powder and an alkaline activator, and then solidifying and forming the mixture to obtain a red mud-based polymer, thereby providing a method for preparing a high-performance geopolymer using red mud and mineral powder as raw materials, and the prepared geopolymer has high compressive strength and can be well applied in fields such as infrastructure that require high compressive strength, thereby expanding the application range of geopolymers prepared from red mud.

Description

Technical Field

[0001] The present application relates to the technical field of building material preparation, and in particular to a red mud-based polymer and a preparation method thereof. Background Art

[0002] Red mud, the insoluble solid residue produced by dissolving bauxite in a caustic soda solution during the alumina production process, poses a serious environmental pollution risk. To minimize its environmental impact, significant efforts have been made to develop resource-based utilization strategies. Currently, large-scale red mud utilization is possible, with the most promising approach being the production of building materials. Geopolymers are a key building material produced from red mud. Geopolymers are alkali-activated cementitious materials, primarily derived from silicoaluminate. These high-performance cementitious materials are prepared by activating the latent activity of the raw materials with alkali.

[0003] However, existing geopolymers made from red mud (i.e., red mud-based polymers) suffer from low compressive strength, limiting their application in areas such as infrastructure that require high compressive strength. Therefore, there is a need to improve the compressive strength of red mud-based polymers to expand their application range. Summary of the Invention

[0004] The purpose of the present application is to provide a red mud-based polymer and a preparation method thereof, so as to improve the compressive strength of the red mud-based polymer and thus expand the application range of the red mud-based polymer.

[0005] To achieve the above objectives, the present application provides a method for preparing a red mud-based polymer, comprising:

[0006] Mixing red mud with a hydrothermal alkaline activator solution and performing a hydrothermal reaction to obtain a modified red mud slurry, wherein the hydrothermal alkaline activator in the hydrothermal alkaline activator solution includes sodium hydroxide;

[0007] The modified red mud slurry is mixed with mineral powder and an alkali activator and stirred, and then solidified and formed to obtain a red mud-based polymer.

[0008] In one embodiment, the hydrothermal reaction time is 2 to 12 hours, and the concentration of the hydrothermal alkali activator in the hydrothermal alkali activator solution is 1 to 3 mol / L.

[0009] In one embodiment, the red mud is mixed with a hydrothermal alkaline activator solution and subjected to a hydrothermal reaction to obtain a modified red mud slurry, comprising:

[0010] The red mud and the hydrothermal alkaline activator solution are mixed according to a preset water-cement ratio and placed in a hydrothermal reactor, and then the hydrothermal reactor is placed in an oven and reacted at a preset temperature. After the reaction is completed, the hydrothermal reactor is taken out, and the product in the hydrothermal reactor is the modified red mud slurry, wherein the preset value is 0.7~1.3 and the preset temperature is 100~200℃.

[0011] In one embodiment, the red mud-based polymer includes C / N-(A)-SH gel, carbonized calcium hemicarbonate aluminate, magadiite, and layered mica.

[0012] In one embodiment, the modified red mud slurry is mixed with mineral powder and an alkali activator and stirred, and then solidified and formed to obtain a red mud-based polymer, comprising:

[0013] The modified red mud slurry is mixed with mineral powder and an alkali activator, and stirred at a first preset stirring speed for a first preset time and at a second preset stirring speed for a second preset time to obtain a slurry of red mud-based polymer, wherein the alkali activator includes sodium hydroxide, the first preset stirring speed is 1400-1600 rpm, the first preset time is 20-40 seconds, the second preset stirring speed is 2900-3100 rpm, and the second preset time is 80-100 seconds;

[0014] The slurry-like red mud-based polymer is solidified and formed to obtain a solid red mud-based polymer.

[0015] In one embodiment, the solidifying and molding of the slurry red mud-based polymer to obtain a solid red mud-based polymer comprises:

[0016] The slurry-like red mud-based polymer is placed in a mold, vibrated, and sealed, and then the mold is placed in a curing room for curing. After the curing is completed, the mold is demoulded to obtain a solid red mud-based polymer, wherein the curing time is 1 to 30 days.

[0017] In one embodiment, the preparation method further comprises:

[0018] During the process of mixing the modified red mud slurry with the mineral powder and the alkaline activator, the mass fraction of the mineral powder in the mixture formed by the modified red mud slurry, the mineral powder and the alkaline activator is controlled to be 20%~40%, and the sum of the concentrations of the alkaline activator and the hydrothermal alkaline activator in the mixture formed by the modified red mud slurry, the mineral powder and the alkaline activator is controlled to be 2~4 mol / L.

[0019] In one embodiment, the red mud includes Fe2O3, Al2O3, SiO2 and TiO2, and the mass fractions of Fe2O3, Al2O3, SiO2 and TiO2 in the red mud are 43.680%, 22.050%, 12.609% and 8.253%, respectively.

[0020] In one embodiment, the mineral powder includes CaO, SiO2, Al2O3 and MgO, and the mass fractions of CaO, SiO2, Al2O3 and MgO in the mineral powder are 34.261%, 33.104%, 19.159% and 9.182% respectively.

[0021] The present application also provides a red mud-based polymer, which is prepared using the preparation method described above.

[0022] The red mud-based polymer and preparation method provided in the present application are obtained by mixing red mud with a hydrothermal alkaline activator solution and performing a hydrothermal reaction to obtain a modified red mud slurry, wherein the hydrothermal alkaline activator in the hydrothermal alkaline activator solution includes sodium hydroxide. The modified red mud slurry is then mixed and stirred with mineral powder and an alkaline activator, and then solidified and formed to obtain a red mud-based polymer, thereby providing a method for preparing a high-performance geopolymer using red mud and mineral powder as raw materials. The obtained geopolymer has high compressive strength and can be well applied in fields such as infrastructure that require high compressive strength, thereby expanding the application range of geopolymers prepared from red mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0024] Figure 1 1 is a schematic flow chart of a method for preparing a red mud-based polymer provided in an embodiment of the present application;

[0025] Figure 2 is an X-ray diffraction spectrum of red mud and mineral powder provided in the examples of the present application;

[0026] Figure 3a The compressive strength test results of the red mud-based polymers prepared in Examples 1 to 3 and Comparative Example 1 under conditions of different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and different curing times are shown;

[0027] Figure 3b The compressive strength test results of the red mud-based polymers prepared in Examples 4 to 6 and Comparative Example 1 under conditions of different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and different curing times are shown;

[0028] Figure 3c The compressive strength test results of the red mud-based polymers prepared in Examples 7 to 9 and Comparative Example 1 under conditions of different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and different curing times are shown;

[0029] Figure 3d The compressive strength test results of the red mud-based polymers prepared in Examples 10 to 12 and Comparative Example 1 under conditions of different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and different curing times are shown;

[0030] Figure 4a 1 is an X-ray diffraction spectrum of red mud-based polymers prepared in Examples 1 to 3 and Comparative Example 1 under different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and a curing time of 28 days;

[0031] Figure 4b 1 is an X-ray diffraction spectrum of red mud-based polymers prepared in Examples 4 to 6 and Comparative Example 1 under different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and a curing time of 28 days;

[0032] Figure 4c 1 is an X-ray diffraction spectrum of red mud-based polymers prepared in Examples 7 to 9 and Comparative Example 1 under conditions of different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and a curing time of 28 days;

[0033] Figure 4d 10 to 12 and Comparative Example 1 under different hydrothermal reaction times, different hydrothermal alkaline activator solution concentrations, and a curing time of 28 days.

[0034] Figure 5a This is a scanning electron microscope image of the red mud-based polymer prepared in Comparative Example 1 under the condition of a curing time of 28 days;

[0035] Figure 5b is a scanning electron microscope image of the red mud-based polymer obtained in Example 4 under the condition of a curing time of 28 days;

[0036] Figure 5c This is a scanning electron microscope image of the red mud-based polymer obtained in Example 6 under the condition of a curing time of 28 days. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only intended to illustrate the present application and are not intended to limit the scope of the present application. Similarly, the following examples are only some examples of the present application and are not intended to be exhaustive. All other examples obtained by persons of ordinary skill in the art without creative effort are intended to fall within the scope of protection of the present application.

[0038] In the following description of this application, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.

[0039] In the following description of this application, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. In the event of any conflict, the present specification shall prevail. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0041] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0042] The following is a detailed description with reference to specific embodiments. It should be noted that the serial numbers of the following embodiments are not intended to limit the preferred order of the embodiments.

[0043] See also Figure 1 , Figure 1 : is a schematic diagram of a process for preparing a red mud-based polymer provided in an embodiment of the present application. The specific process of the preparation method of the red mud-based polymer can be as follows:

[0044] Step S11. Mixing red mud with a hydrothermal alkali activator solution and performing a hydrothermal reaction to obtain a modified red mud slurry, wherein the hydrothermal alkali activator in the hydrothermal alkali activator solution includes sodium hydroxide.

[0045] Specifically, in step S11, the hydrothermal reaction time can be 2 to 12 hours, for example, 2 hours, 4 hours, 8 hours, or 12 hours, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. By controlling the hydrothermal reaction time within a specific range, effective modification of the red mud raw material can be ensured, thereby ensuring that the properties (e.g., compressive strength) of the geopolymer produced from the red mud modified by the hydrothermal reaction are superior to those of the geopolymer produced from the red mud not modified by the hydrothermal reaction.

[0046] Specifically, in step S11, the concentration of the hydrothermal alkali activator in the hydrothermal alkali activator solution used can be 1 to 3 mol / L, for example, 1 mol / L, 2 mol / L, or 3 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. Thus, by controlling the concentration of the hydrothermal alkali activator solution within a specific range, effective modification of the red mud raw material can be ensured, thereby ensuring that the properties (e.g., compressive strength) of the geopolymer produced from the red mud modified by the hydrothermal reaction are superior to those of the geopolymer produced from the red mud that has not been hydrothermally modified.

[0047] For example, in step S11, the hydrothermal alkali activator in the hydrothermal alkali activator solution used may be sodium hydroxide. That is, in step S11, the hydrothermal alkali activator solution used may be a sodium hydroxide solution, for example, a sodium hydroxide solution with a concentration of 1 mol / L, a sodium hydroxide solution with a concentration of 2 mol / L, or a sodium hydroxide solution with a concentration of 3 mol / L.

[0048] In some embodiments, the above step S11 may specifically include:

[0049] The red mud and the hydrothermal alkaline activator solution are mixed according to a preset water-cement ratio and placed in a hydrothermal reactor. The hydrothermal reactor is then placed in an oven and reacted at a preset temperature. After the reaction is completed, the hydrothermal reactor is taken out, and the product in the hydrothermal reactor is the modified red mud slurry.

[0050] The preset value may be 0.7 to 1.3, for example, specifically 1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. The preset temperature may be 100 to 200°C, for example, specifically 150°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] In addition, during specific implementation, red mud can be mixed with a certain concentration of sodium hydroxide solution (for example, a sodium hydroxide solution with a concentration of 3 mol / L) at a water-cement ratio of 1 and placed in a hydrothermal reactor. The hydrothermal reactor is then placed in a 150°C oven and reacted for a certain period of time (for example, 4 hours or 8 hours). The hydrothermal reactor is then taken out to obtain a product in the hydrothermal reactor, which is the modified red mud slurry.

[0052] Step S12: mixing and stirring the modified red mud slurry with mineral powder and an alkali activator, and then solidifying and forming the mixture to obtain a red mud-based polymer.

[0053] The alkaline activator may include sodium hydroxide, for example, specifically sodium hydroxide.

[0054] In some embodiments, the above step S12 may specifically include:

[0055] Step S121. Mix the modified red mud slurry with the mineral powder and the alkali activator, and stir them at a first preset stirring speed for a first preset time and at a second preset stirring speed for a second preset time to obtain a slurry of red mud-based polymer.

[0056] Among them, the first preset stirring speed can be 1400~1600rpm, for example, specifically 1500rpm, but is not limited to the listed values, and other values ​​not listed in the numerical range are equally applicable. The first preset time can be 20~40 seconds, for example, specifically 30 seconds, but is not limited to the listed values, and other values ​​not listed in the numerical range are equally applicable. The second preset stirring speed can be 2900~3100rpm, for example, specifically 3000rpm, and the second preset time can be specifically 80~100 seconds, for example, specifically 90 seconds, but is not limited to the listed values, and other values ​​not listed in the numerical range are equally applicable.

[0057] Moreover, in a specific implementation, the preparation method of the above-mentioned red mud-based polymer may further include: in the process of mixing the modified red mud slurry with the mineral powder and the alkali activator, controlling the mass fraction of the mineral powder in the mixture formed by the modified red mud slurry, the mineral powder and the alkali activator to be 20%~40%, and controlling the sum of the concentrations of the alkali activator and the hydrothermal alkali activator in the mixture formed by the modified red mud slurry, the mineral powder and the alkali activator to be 2~4 mol / L.

[0058] For example, in the process of mixing the modified red mud slurry with the mineral powder and the alkali activator, the mass fraction of the mineral powder in the mixture formed by the modified red mud slurry, the mineral powder and the alkali activator can be controlled to be 30%, and the sum of the concentrations of the alkali activator and the hydrothermal alkali activator in the mixture formed by the modified red mud slurry, the mineral powder and the alkali activator can be controlled to be 3 mol / L.

[0059] Step S122: solidifying and molding the slurry red mud-based polymer to obtain a solid red mud-based polymer.

[0060] In an embodiment of the present application, the red mud-based polymer obtained in step S12 or after the completion of step S12 is in a solid state and may include C / N-(A)-SH gel, carbonized calcium hemicarbonate aluminate, magadiite and layered mica, wherein the C / N-(A)-SH gel may include C-(A)-SH gel and / or N-(A)-SH gel.

[0061] In some specific embodiments, the above step S122 may include: placing the slurry red mud-based polymer into a mold, vibrating it, sealing it, and then placing the mold in a curing room for curing. After the curing is completed, demolding is performed to obtain a solid red mud-based polymer.

[0062] The mold may specifically be a steel mold of 20mm*20mm*20mm.

[0063] The curing time may be 1 to 30 days, for example, 3 days, 7 days or 28 days, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] In some examples, the curing time can be specifically 3 days, the hydrothermal reaction time in step S11 can be specifically 8 hours, and the hydrothermal alkaline activator solution used in step S11 can be specifically a sodium hydroxide solution with a concentration of 3 mol / L. Thus, by adjusting the curing time, the hydrothermal reaction time, and the concentration of the hydrothermal alkaline activator solution to specific values, the compressive strength of the geopolymer produced from red mud modified by the hydrothermal reaction can be increased by 53% compared to the compressive strength of the geopolymer produced from red mud not modified by the hydrothermal reaction.

[0065] In other examples, the curing time can be specifically 28 days, the hydrothermal reaction time in step S11 can be specifically 4 hours, and the hydrothermal alkaline activator solution used in step S11 can be specifically a sodium hydroxide solution with a concentration of 3 mol / L. Thus, by adjusting the curing time, the hydrothermal reaction time, and the concentration of the hydrothermal alkaline activator solution to specific values, the compressive strength of the geopolymer produced from red mud modified by the hydrothermal reaction can be increased by 34% compared to the compressive strength of the geopolymer produced from red mud not modified by the hydrothermal reaction.

[0066] Moreover, in a specific implementation, after obtaining the above-mentioned modified red mud slurry, the above-mentioned modified red mud slurry can be mixed with mineral powder and an alkali activator (for example, sodium hydroxide), and a high-speed stirrer is first stirred at a first preset stirring speed (for example, 1500 rpm) for a first preset time (for example, 30 seconds), and then stirred at a second preset stirring speed (for example, 3000 rpm) for a second preset time (for example, 90 seconds) to obtain a slurry of red mud-based polymer. The obtained slurry of red mud-based polymer can then be poured into a mold (for example, a 20 mm * 20 mm * 20 mm steel mold) and placed on a vibration table for 60 seconds to ensure that the inside of the slurry is denser. The surface of the slurry is then smoothed, and the surface of the mold is covered with plastic wrap. The mold covered with plastic wrap is then placed in a curing room and removed after curing for a certain period of time (for example, 3 days, 7 days or 28 days) to obtain a solid red mud-based polymer.

[0067] Specifically, the red mud used to prepare the red mud-based polymer in the examples of this application may include Fe2O3, Al2O3, SiO2, and TiO2, with the mass fractions of Fe2O3, Al2O3, SiO2, and TiO2 in the red mud being 43.680%, 22.050%, 12.609%, and 8.253%, respectively. In other words, the red mud used to prepare the red mud-based polymer in the examples of this application is rich in Fe2O3, Al2O3, and SiO2, while also containing a trace amount of TiO2. This ensures that the red mud is a suitable supplement for preparing red mud-based polymers.

[0068] Specifically, the mineral powder used to prepare the red mud-based polymer in the embodiments of the present application may include CaO, SiO2, Al2O3, and MgO, and the mass fractions of CaO, SiO2, Al2O3, and MgO in the mineral powder may be 34.261%, 33.104%, 19.159%, and 9.182%, respectively. In other words, the mineral powder used to prepare the red mud-based polymer in the embodiments of the present application is rich in calcium and silicon, and may include CaO, SiO2, Al2O3, and a trace amount of MgO.

[0069] For example, the mass fractions (wt%) of the chemical components of the red mud and mineral powder used to prepare the red mud-based polymer in the embodiment of the present application can be shown in Table 1 below. The X-ray diffraction (XRD) spectra of the red mud and mineral powder used to prepare the red mud-based polymer in the embodiment of the present application can be shown in Table 1 below. Figure 2 shown.

[0070] Table 1

[0071] CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> MgO <![CDATA[SO3]]> <![CDATA[TiO2]]> MnO <![CDATA[Fe2O3]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> red mud 2.495 12.609 22.050 0.123 0.318 8.253 0.078 43.680 9.297 0.091 Mineral powder 34.261 33.104 19.159 9.182 2.463 0.577 0.264 0.251 0.353 0.247

[0072] Specifically, from Figure 2 It can be seen that the main mineral phases in red mud are hematite, boehmite, gibbsite, goethite, quartz, cancrinite and rutile, while the mineral powder is mainly composed of calcite, dolomite, calcite and a large amount of amorphous phase. Figure 2 The XRD spectra in the lower layer are those of red mud, and those in the upper layer are those of mineral powder. The letter H represents hematite (Fe2O3), the letter B represents boehmite (AlO2), the letter Q represents quartz (SiO2), the letter C represents calcite (CaCO3), the letter O represents goethite (FeO2), the letter R represents rutile (TiO2), and the letter A represents cancrinite (Na 6.02 Ca 1.50 Al 6.00 Si 6.00 C 1.46 O 28.39 ), the letter G represents gibbsite (Al(OH)3), and the letter L represents calcite (Ca 4.00 Mg 2.00 Si 4.00 O 14.00 ), the letter D represents dolomite (Ca 3.00 Mg 3.00 C 6.00 O 18.00 ).

[0073] In some embodiments, before the above-mentioned step S11, the preparation method of the above-mentioned red mud-based polymer may also include: spheroidizing the original red mud in a ball mill for 20 minutes, and then passing it through a 60-mesh sieve to obtain the red mud used to prepare the red mud-based polymer in the embodiment of the present application, so as to ensure the uniformity and fineness of the red mud used to prepare the red mud-based polymer.

[0074] Specifically, the raw red mud can be sourced from Zouping, Shandong, China, and the mineral powder can be sourced from Gongyi Longze Water Purification Materials Co., Ltd. The sodium hydroxide can be granular sodium hydroxide produced by Sinopharm Group.

[0075] Furthermore, for ease of understanding, the present application is further described in detail below through twelve specific examples (ie, Examples 1 to 12), with Comparative Example 1 used as a comparison. Example 1

[0076] In Example 1, the specific process of the preparation method of the red mud-based polymer can be as follows:

[0077] Step S21. Red mud and a 1 mol / L sodium hydroxide solution are mixed at a water-cement ratio of 1 and placed in a hydrothermal reactor. The hydrothermal reactor is then placed in an oven at 150°C and reacted for 2 hours. The reactor is then removed from the oven to obtain a product (i.e., a modified red mud slurry).

[0078] Step S22. The product in the hydrothermal reactor is mixed with mineral powder and sodium hydroxide, and stirred using a high-speed stirrer at 1500 rpm for 30 seconds and then at 3000 rpm for 90 seconds. The mass fraction of the mineral powder in the resulting mixture is 30%, and the total concentration of sodium hydroxide in the resulting mixture is 3 mol / L, thereby obtaining a slurry of red mud-based polymer. The resulting slurry of red mud-based polymer is then poured into a 20 mm*20 mm*20 mm steel mold and vibrated on a vibrating table for 60 seconds to ensure that the slurry is more compact. The surface of the slurry is then smoothed, and the mold surface is covered with plastic wrap. The mold covered with plastic wrap is then placed in a curing chamber and cured for a predetermined period of time (e.g., 3 days, 7 days, or 28 days). After curing, the mold is removed to obtain a solid red mud-based polymer, which is designated as red mud-based polymer X12. Example 2

[0079] The method for preparing the red mud-based polymer provided in Example 2 is essentially the same as that provided in Example 1, with the only difference being that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 2 mol / L sodium hydroxide solution. The solid red mud-based polymer prepared in Example 2 is designated as red mud-based polymer X22. Example 3

[0080] The method for preparing the red mud-based polymer provided in Example 3 is essentially the same as that provided in Example 1, with the only difference being that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 3 mol / L sodium hydroxide solution. The solid red mud-based polymer prepared in Example 3 is designated as red mud-based polymer X32. Example 4

[0081] The method for preparing the red mud-based polymer provided in Example 4 is essentially the same as that provided in Example 1, with the only difference being that the reaction time in step S21 is adjusted from 2 hours to 4 hours. The solid red mud-based polymer prepared in Example 4 is designated as red mud-based polymer X14. Example 5

[0082] The method for preparing a red mud-based polymer provided in Example 5 is essentially the same as that provided in Example 1. The only differences between the two methods are that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 2 mol / L sodium hydroxide solution, and the reaction time in step S21 is adjusted from 2 hours to 4 hours. The solid red mud-based polymer prepared in Example 5 is designated as red mud-based polymer X24. Example 6

[0083] The method for preparing a red mud-based polymer provided in Example 6 is essentially the same as that provided in Example 1. The only differences between the two methods are that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 3 mol / L sodium hydroxide solution, and the reaction time in step S21 is adjusted from 2 hours to 4 hours. The solid red mud-based polymer prepared in Example 5 is designated as red mud-based polymer X34. Example 7

[0084] The method for preparing the red mud-based polymer provided in Example 7 is essentially the same as that provided in Example 1, with the only difference being that the reaction time in step S21 is adjusted from 2 hours to 8 hours. The solid red mud-based polymer prepared in Example 7 is designated as red mud-based polymer X18. Example 8

[0085] The method for preparing the red mud-based polymer provided in Example 8 is essentially the same as that provided in Example 1. The only differences between the two methods are that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 2 mol / L sodium hydroxide solution, and the reaction time in step S21 is adjusted from 2 hours to 8 hours. The solid red mud-based polymer prepared in Example 8 is designated as red mud-based polymer X28. Example 9

[0086] The method for preparing a red mud-based polymer provided in Example 9 is essentially the same as that provided in Example 1. The only differences between the two methods are that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 3 mol / L sodium hydroxide solution, and the reaction time in step S21 is adjusted from 2 hours to 8 hours. The solid red mud-based polymer prepared in Example 9 is designated as red mud-based polymer X38. Example 10

[0087] The method for preparing the red mud-based polymer provided in Example 10 is essentially the same as that provided in Example 1, with the only difference being that the reaction time in step S21 is adjusted from 2 hours to 12 hours. The solid red mud-based polymer prepared in Example 10 is designated as red mud-based polymer X112. Example 11

[0088] The method for preparing the red mud-based polymer provided in Example 11 is essentially the same as the method for preparing the red mud-based polymer provided in Example 1. The only differences between the two methods are that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 2 mol / L sodium hydroxide solution, and the reaction time in step S21 is adjusted from 2 hours to 12 hours. The solid red mud-based polymer prepared in Example 11 is designated as red mud-based polymer X212. Example 12

[0089] The method for preparing the red mud-based polymer provided in Example 12 is essentially the same as the method for preparing the red mud-based polymer provided in Example 1. The only differences between the two methods are that the 1 mol / L sodium hydroxide solution in step S21 is replaced with a 3 mol / L sodium hydroxide solution, and the reaction time in step S21 is adjusted from 2 hours to 12 hours. The solid red mud-based polymer prepared in Example 12 is designated as red mud-based polymer X312.

[0090] Comparative Example 1

[0091] The method for preparing a red mud-based polymer provided in Comparative Example 1 differs from the method for preparing a red mud-based polymer provided in Example 1 in that step S21 is omitted in Comparative Example 1, and the product in the hydrothermal reactor used in step S22 (i.e., the modified red mud slurry) is replaced with the red mud used in step S21. Furthermore, the solid red mud-based polymer prepared in Comparative Example 1 is designated as red mud-based polymer X0.

[0092] Specifically, the compressive strength test of the red mud-based polymers X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 / X0 obtained in Examples 1 to 12 and Comparative Example 1 was performed, and the compressive strength test results of the red mud-based polymers X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 / X0 were obtained as follows: Figure 3a 、 Figure 3b 、 Figure 3c 、 Figure 3d shown.

[0093] Among them, the process of compressive strength testing of the red mud-based polymers X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 / X0 obtained in Examples 1 to 12 and Comparative Example 1 may include: performing compression and flexural tests on the test blocks of the slurry blank group with a curing time of 3 days, 7 days, and 28 days, and testing according to GB / T17671-1999; taking a 20*20*20mm sample out of the curing room, wiping the surface moisture with a rag, and performing a compressive test on a universal testing machine. The compressive strength data result is the average value of six test blocks with the same ratio, and the error value of the compressive strength is taken at the same time.

[0094] And, from Figure 3a 、 Figure 3b 、 Figure 3c 、 Figure 3dIt can be seen that when the hydrothermal reaction time is 2 hours, the compressive strength (Compressive Strength) of the samples prepared in the examples of the present application (i.e., red mud-based polymers X12 / X22 / X32) does not change significantly with the increase in the concentration of the hydrothermal alkaline activator solution (i.e., sodium hydroxide solution) used, and the compressive strength of some samples is even lower than that of the sample prepared in Comparative Example 1 (i.e., red mud-based polymer X0); under the conditions of the hydrothermal reaction time of 4 hours, 8 hours and 12 hours, the curing time (Curing Strength) of the samples prepared in the examples of the present application is 2 hours. The compressive strength of the samples prepared at different curing times (i.e., red mud-based polymers X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312) decreased with increasing concentration of the hydrothermal alkaline activator solution (i.e., sodium hydroxide solution). In particular, when the concentration of the hydrothermal alkaline activator solution (i.e., sodium hydroxide solution) was 3 mol / L, the compressive strength of the samples prepared in all Examples of the present application was not significantly different from that of the sample prepared in Comparative Example 1. Furthermore, as the hydrothermal reaction time increased, the compressive strength of the samples prepared in the Examples of the present application at various curing times first increased and then decreased. Specifically, the early maximum compressive strength of the red mud-based polymer prepared in the embodiment of the present application occurs when the hydrothermal reaction time is 8 hours. At this time, the strength of the sample prepared in the embodiment of the present application with a curing time of 3 days is 53% higher than the compressive strength of the sample prepared in the comparative example with a curing time of 3 days; the late maximum compressive strength of the red mud-based polymer prepared in the embodiment of the present application occurs when the hydrothermal reaction time is 4 hours. At this time, the compressive strength of the sample prepared in the embodiment of the present application with a curing time of 28 days is 34% higher than the compressive strength of the sample prepared in the comparative example with a curing time of 28 days.

[0095] Specifically, by performing X-ray diffraction analysis on the red mud-based polymers X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 / X0 obtained in Examples 1 to 12 and Comparative Example 1 under the condition of a curing time of 28 days, the X-ray diffraction spectra of each red mud-based polymer X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 / X0 were obtained as shown in the following figure: Figure 4a 、 Figure 4b 、 Figure 4c 、 Figure 4d shown.

[0096] The X-ray diffraction analysis of the red mud-based polymers X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 / X0 obtained in Examples 1 to 12 and Comparative Example 1 after a curing period of 28 days may include: taking a small amount of the red mud-based polymer, grinding the hardened slurry, sieving it into a powder with a particle size of less than 80 μm (i.e., passing a 200-mesh sieve), exchanging the solvent with isopropanol, and drying the solvent in a vacuum oven at 50° C. for X-ray diffraction analysis. The X-ray diffraction analysis was performed at a scan rate of 10° / min, a scanning angle range of 5° C. to 80° C., a Cu anode target, an accelerating voltage of 40 kV, a current of 40 mA, a step size of 0.02° / s −1 , a vacuum degree of <0.2 Pa, and a scanning voltage of 20 kV.

[0097] And, in Figure 4a 、 Figure 4b 、 Figure 4c 、 Figure 4d In the text, the letter H represents hematite (Fe2O3), the letter B represents boehmite (AlO2), the letter Q represents quartz (SiO2), the letter A represents calcite (CaCO3), the letter G represents goethite (FeO2), the letter R represents rutile (TiO2), and the letter T represents carbonated hemicarbonate (Ca1 2.00 Al 6.00 O 55.20 C 2.40 ), the letter S represents layered mica (Al 6.33 Ca 6.00 Si 3.33 O 48.75 ), the letter C represents cancrinite (Na 6.02 Ca 1.50 Al 6.00 Si 6.00 C 1.46 O 28.39 ), the letter M represents magadiite (Na2Si 14 O 29 ). Specifically, from Figure 4a 、 Figure 4b 、 Figure 4c 、 Figure 4d It can be clearly seen that the peak at around 29.5° can prove the existence of C / N-(A)-SH gel, and the hydration products of red mud and mineral powder under the stimulation of sodium hydroxide are C / N-(A)-SH gel, carbonized hemicarbonate calcium aluminate, magadiite and layered mica. Figure 4a 、 Figure 4b 、 Figure 4c 、 Figure 4dIt can be clearly seen that compared with the control group (i.e., the red mud-based polymer X0 obtained in Comparative Example 1 under the condition of a curing time of 28 days), in each experimental group (i.e., the red mud-based polymers X12 / X22 / X32 / X14 / X24 / X34 / X18 / X28 / X38 / X112 / X212 / X312 obtained in the above Examples 1 to 12 under the condition of a curing time of 28 days), the peak intensities of magadiite, layered mica and partially carbonized semi-carbonate calcium aluminate at 5°, 6° and 18° decreased sharply or disappeared.

[0098] Specifically, scanning electron microscopy analysis was performed on the red mud-based polymers X14 / X34 / X0 obtained in Example 4, Example 6, and Comparative Example 1 under the condition of a curing time of 28 days, and the scanning electron microscopy images of the red mud-based polymers X14 / X34 / X0 were obtained as follows: Figure 5a 、 Figure 5b 、 Figure 5c shown.

[0099] The SEM images were obtained using a field emission scanning electron microscope (accelerating voltage: 5 kV) equipped with a high-power optical irradiation system. All samples used for SEM observation were fracture-type and gold-sprayed for good conductivity.

[0100] and, Figure 5a 、 Figure 5b 、 Figure 5c Micrographs of red mud-based polymers prepared using red mud, modified red mud hydrothermally treated with 1 mol / L sodium hydroxide solution for 4 hours, and modified red mud hydrothermally treated with 3 mol / L sodium hydroxide solution for 4 hours are shown. Figure 5a It can be seen that the red mud-based polymer prepared using red mud (i.e., the red mud-based polymer X0 prepared in Comparative Example 1 under the condition of a curing time of 28 days) obviously contains many unreacted inert particles. Figure 5b and Figure 5c It can be seen that the red mud-based polymers prepared using the modified red mud hydrothermally treated with 1 mol / L sodium hydroxide solution for 4 hours and the modified red mud hydrothermally treated with 3 mol / L sodium hydroxide solution for 4 hours (i.e., the red mud-based polymers X14 / X34 prepared in Examples 4 and 6 above under the condition of a curing time of 28 days) contain fewer inert particles. Figure 5b In the molten state, a dense gel phase and a flaky N-(A)-SH gel can be seen. Figure 5c A large amount of gel phase can also be found in the hydrated carbon nanotubes, but there are huge cracks in the internal structure.

[0101] As can be seen from the above, the preparation method of the red mud-based polymer provided in this embodiment is to obtain a modified red mud slurry by mixing red mud with a hydrothermal alkaline activator solution and performing a hydrothermal reaction, wherein the hydrothermal alkaline activator in the hydrothermal alkaline activator solution includes sodium hydroxide, and then the modified red mud slurry is mixed and stirred with mineral powder and alkaline activator, and then solidified and formed to obtain a red mud-based polymer, thereby providing a method for preparing high-performance geopolymers using red mud and mineral powder as raw materials, and the prepared geopolymer has high compressive strength and can be well applied in fields such as infrastructure that require higher compressive strength, thereby expanding the application range of geopolymers prepared from red mud.

[0102] In order to better implement the preparation method of the red mud-based polymer provided in the embodiments of the present application, the embodiments of the present application also provide a red mud-based polymer, which is prepared using the preparation method of the red mud-based polymer provided in any of the above embodiments.

[0103] Furthermore, it should be noted that the red mud-based polymer in the embodiments of the present application is prepared by adopting the preparation method of the red mud-based polymer provided in any of the above embodiments, and therefore has all the same beneficial effects, which will not be described in detail in this embodiment.

[0104] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0105] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing a red mud-based polymer, characterized in that: include: Mixing red mud with a hydrothermal alkaline activator solution and performing a hydrothermal reaction to obtain a modified red mud slurry, wherein the hydrothermal alkaline activator in the hydrothermal alkaline activator solution includes sodium hydroxide; The modified red mud slurry is mixed with mineral powder and an alkali activator, stirred, and then solidified to obtain a red mud-based polymer; The hydrothermal reaction time is 2 to 12 hours, and the concentration of the hydrothermal alkali activator in the hydrothermal alkali activator solution is 1 to 2 mol / L; The red mud is mixed with a hydrothermal alkaline activator solution and subjected to a hydrothermal reaction to obtain a modified red mud slurry, comprising: The red mud and the hydrothermal alkaline activator solution are mixed according to a preset water-cement ratio and placed in a hydrothermal reactor, and then the hydrothermal reactor is placed in an oven and reacted at a preset temperature. After the reaction is completed, the hydrothermal reactor is taken out, and the product in the hydrothermal reactor is the modified red mud slurry, wherein the preset value is 0.7-1.3 and the preset temperature is 100-200°C; The modified red mud slurry is mixed with mineral powder and an alkali activator and stirred, and then solidified and formed to obtain a red mud-based polymer, comprising: The modified red mud slurry is mixed with mineral powder and an alkali activator, and stirred at a first preset stirring speed for a first preset time and at a second preset stirring speed for a second preset time to obtain a slurry of red mud-based polymer, wherein the alkali activator includes sodium hydroxide, the first preset stirring speed is 1400-1600 rpm, the first preset time is 20-40 seconds, the second preset stirring speed is 2900-3100 rpm, and the second preset time is 80-100 seconds; solidifying and molding the slurry-like red mud-based polymer to obtain a solid-like red mud-based polymer; The red mud includes CaO, Fe2O3, Al2O3, SiO2 and TiO2, and the mass fractions of CaO, Fe2O3, Al2O3, SiO2 and TiO2 in the red mud are 2.495%, 43.680%, 22.050%, 12.609% and 8.253% respectively.

2. The preparation method according to claim 1, characterized in that The red mud-based polymer comprises C / N-(A)-SH gel, carbonized calcium hemicarbonate aluminate, magadiite and layered mica.

3. The preparation method according to claim 1, characterized in that The solidification and molding of the slurry red mud-based polymer to obtain a solid red mud-based polymer comprises: The slurry-like red mud-based polymer is placed in a mold, vibrated, and sealed, and then the mold is placed in a curing room for curing. After the curing is completed, the mold is demoulded to obtain a solid red mud-based polymer, wherein the curing time is 1 to 30 days.

4. The preparation method according to claim 1, characterized in that The preparation method further comprises: During the process of mixing the modified red mud slurry with the mineral powder and the alkaline activator, the mass fraction of the mineral powder in the mixture formed by the modified red mud slurry, the mineral powder and the alkaline activator is controlled to be 20%~40%, and the sum of the concentrations of the alkaline activator and the hydrothermal alkaline activator in the mixture formed by the modified red mud slurry, the mineral powder and the alkaline activator is controlled to be 2~4 mol / L.

5. The preparation method according to claim 1, characterized in that The mineral powder includes CaO, SiO2, Al2O3 and MgO, and the mass fractions of CaO, SiO2, Al2O3 and MgO in the mineral powder are 34.261%, 33.104%, 19.159% and 9.182% respectively.

6. A red mud-based polymer, characterized in that The method is as described in any one of claims 1 to 5.

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