High-yield active basalt nanosheets and methods of making the same

Abstract

The application provides a high-yield active basalt nanosheet and a preparation method thereof, and the preparation steps comprise the following steps: high-temperature calcination on micron-level basalt flake, etching reaction on acidic oxides and neutral oxides in the basalt flake under hydrothermal reaction conditions by using an alkali solution, and then stripping a nanosheet sandwich structure by ultrasonic treatment to obtain the active basalt nanosheet with nanometer-level thickness. The preparation method has the advantages of simple process, controllable condition, good repeatability and low preparation cost, and the prepared basalt nanosheet has a nanometer-level thickness two-dimensional layered structure, and the unique sheet structure and rich hydroxyl groups on the surface of the basalt nanosheet improve the combination ability and electric breakdown strength in the composite material.

Description

Technical Field

[0001] This invention relates to the fields of inorganic materials and papermaking technology, and in particular to a high-yield active basalt nanosheet and its preparation method. Background Technology

[0002] Basalt scales (BS) are inorganic non-metallic sheet materials formed from natural basalt ore through high-temperature melting and rapid cooling processing. They possess excellent mechanical strength, thermal stability, electrical insulation properties, chemical corrosion resistance, and UV aging resistance, making them a high-potential high-quality insulating material. However, due to limitations in industrial preparation conditions, basalt scales typically have a thickness and diameter in the micrometer range. This large size leads to poor interfacial bonding in composite product preparation. Therefore, reducing the size of basalt scales is an effective way to enhance interfacial bonding and improve the performance of basalt scale composites. To date, research on the preparation process of basalt scale nanosheets (BSNs) is limited, resulting in low yields and poor chemical activity. Therefore, developing a novel basalt nanosheet preparation process to expand the further applications of this material is of great significance. Summary of the Invention

[0003] The purpose of this invention is to provide a low-cost, simple, high-yield, chemically active basalt nanosheet and its preparation method. The basalt nanosheet structure with nanoscale thickness is prepared by high-temperature calcination and alkaline etching. It has a unique sheet structure and abundant hydroxyl groups on the surface, which enhances the bonding ability and electrical breakdown strength in composite materials.

[0004] A method for preparing high-yield active basalt nanosheets, characterized by comprising the following steps:

[0005] (1) Untreated basalt flakes were calcined to obtain expanded basalt flakes;

[0006] (2) Take the expanded basalt flakes from (1) and add them to the prepared sodium hydroxide (NaOH) solution. Stir evenly and carry out a high-temperature hydrothermal reaction. After the reaction is completed, let it cool naturally to room temperature to obtain the etched basalt flakes.

[0007] (3) Wash the etched basalt flakes with deionized water;

[0008] (4) The washed basalt flakes were redispersed in deionized water to obtain a dispersion.

[0009] (5) The dispersion is subjected to ultrasonic treatment and stirred continuously to assist in the peeling of the etched basalt flakes and obtain a redispersible solution.

[0010] (6) The redispersed liquid was allowed to stand and separate into layers. The supernatant after standing and separating was then vacuum dried to obtain basalt nanosheets.

[0011] Furthermore, the untreated basalt flakes in (1) have an average grain size of 20 μm, a calcination temperature of 600–800 °C, and a calcination time of 2–8 h;

[0012] Furthermore, the molar concentration of the sodium hydroxide solution in (2) is 2–13 mol / L;

[0013] Furthermore, the mass ratio of the expanded basalt flakes to the sodium hydroxide solution obtained in (2) is 1-10:100-150;

[0014] Furthermore, in (2), the high-temperature hydrothermal reaction temperature is 50–150°C, and the high-temperature hydrothermal reaction time is 12–36 h;

[0015] Furthermore, in step (3), deionized water is used for repeated washing until the pH value is 6-8;

[0016] Furthermore, the ultrasonic treatment power in (5) is 200-1200W, and the ultrasonic treatment time is 30-60min;

[0017] Furthermore, in step (6), the standing time is 24 hours and the vacuum drying temperature is 80°C.

[0018] An active basalt nanosheet is obtained based on the above-mentioned method for preparing high-yield active basalt nanosheets;

[0019] Furthermore, the basalt nanosheets have a particle size of 0.4–1.5 μm and a thickness of 1.5–2.5 nm, and their surface is modified with hydroxyl groups.

[0020] An application of activated basalt nanosheets in films, paper, coatings, and rubber, using the aforementioned activated basalt nanosheets.

[0021] The above technical solution has the following advantages or beneficial effects:

[0022] This invention provides a high-yield active basalt nanosheet and its preparation method. High-yield, highly active basalt nanosheets with nanoscale thickness are prepared by high-temperature calcination and alkaline etching. These nanosheets have a unique structure and excellent performance. The preparation method is simple, has controllable conditions, good repeatability, and low preparation cost, and has good application prospects.

[0023] Furthermore, the untreated basalt flakes were calcined in a muffle furnace to expand them, in order to change the physical and chemical properties of the basalt flakes in preparation for subsequent processing.

[0024] Furthermore, by preparing a sodium hydroxide solution and mixing it with the expanded basalt flakes, etching is carried out using a hydrothermal reaction. The aim is to remove some of the material from the basalt flakes through a chemical reaction, forming a nanoscale sheet structure.

[0025] Furthermore, the etched basalt flakes were washed with deionized water to remove excess chemicals, then redispersed in deionized water and ultrasonically treated and stirred using an ultrasonic device to aid in the peeling of the basalt flakes.

[0026] Furthermore, the prepared active basalt nanosheets have a two-dimensional layered structure with nanoscale thickness. This unique structure gives them excellent bonding ability and electrical breakdown strength, and they have broad application prospects in composite materials, electronic devices and other fields. Attached Figure Description

[0027] Figure 1 SEM images of the original basalt flakes and the basalt nanosheets obtained in Example 1 are shown below; where (a) to (c) are SEM images of the original basalt flakes, and (d) to (f) are SEM images of the prepared basalt nanosheets.

[0028] Figure 2 The following are particle size distribution diagrams of the original basalt flakes and the basalt nanosheets obtained in Example 1; wherein, (a) is the particle size distribution diagram of the original basalt flakes; and (b) is the particle size distribution diagram of the basalt nanosheets.

[0029] Figure 3 AFM images of the basalt nanosheets obtained in Example 1 are shown; where (a) represents the morphology of the basalt nanosheets and (b) represents the thickness of the basalt nanosheets.

[0030] Figure 4 XRD and FT-IR images of basalt nanosheets after different hydrothermal synthesis reaction times are shown; where (a) is the XRD image and (b) is the FT-IR image.

[0031] Figure 5 The tensile strength and breakdown strength of basalt flake / cellulose nanofiber composite paper and basalt nanosheet / cellulose nanofiber composite paper are given; where (a) is the tensile strength and (b) is the breakdown strength.

[0032] Figure 6 The Tyndall effect pattern is observed when basalt nanosheets are dispersed and then irradiated with a laser. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] A method for preparing high-yield active basalt nanosheets includes the following specific steps:

[0035] (1) Untreated basalt flakes are calcined at a temperature of 600-800℃ for 2-8 hours to obtain expanded basalt flakes; the average particle size of the untreated basalt flakes is 20μm.

[0036] (2) Weigh a certain amount of sodium hydroxide and add it to a deionized aqueous solution. Stir thoroughly to prepare a sodium hydroxide solution with a molar concentration of 2-13 mol / L. Then take the basalt flakes that have expanded in (1) and add them to the prepared sodium hydroxide solution. Stir evenly. The mass ratio of basalt flakes to sodium hydroxide solution is 1-10:100-150. Then carry out a high-temperature hydrothermal reaction. The reaction temperature is 50-150℃ and the reaction time is 12-36h. After the reaction is completed, let it cool naturally to room temperature to obtain etched basalt flakes.

[0037] (3) Wash the etched basalt flakes with deionized water until the pH value is 6-8;

[0038] (4) The washed basalt flakes were redispersed in deionized water to obtain a dispersion.

[0039] (5) The dispersion is subjected to ultrasonic treatment with an ultrasonic power of 200-1200W and an ultrasonic time of 30-60min, and is stirred continuously to assist in the peeling of the etched basalt flakes to obtain a redispersible solution.

[0040] (6) The redispersed liquid was allowed to stand for 24 hours to separate into layers. The supernatant after standing and separation was then vacuum dried at 80°C to obtain basalt nanosheets.

[0041] An active basalt nanosheet is obtained based on the above-mentioned method for preparing high-yield active basalt nanosheets;

[0042] Preferably, the basalt nanosheets have a particle size of 0.4–1.5 μm and a thickness of 1.5–2.5 nm, and their surface is modified with hydroxyl groups.

[0043] An active basalt nanosheet is used in the fields of thin films, paper, coatings, and rubber.

[0044] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0045] Example 1:

[0046] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0047] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0048] (2) Take 1g of expanded basalt flakes and add them into a hydrothermal reactor. Add 100g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, react the solution in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0049] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0050] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0051] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 1000W and an ultrasonic time of 30min to obtain a redispersible solution.

[0052] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets can be obtained.

[0053] like Figure 1 , Figure 2 and Figure 3 The images shown are SEM images of the original basalt flakes and basalt nanosheets, particle size distribution maps of the original basalt flakes and basalt nanosheets, and AFM images of the basalt nanosheets; from Figure 1 As can be seen, the original micron-sized flakes were relatively large, but after calcination and etching, the size of the basalt nanosheets was significantly reduced, and they were successfully exfoliated into a two-dimensional sheet-like structure; from Figure 2 It can be seen that the average particle size of the original basalt flakes was 19.7 μm, while the average particle size of the prepared basalt nanosheets was 0.644 μm, and the Zeta potential also decreased from -1.2 mV to -34.0 mV; from Figure 3 It can be seen that the length of the basalt nanosheets is 0.4-0.8 μm, the average thickness is about 2 nm, and the yield is 27%.

[0054] Example 2:

[0055] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0056] (1) Take 5g of untreated basalt flakes and place them in a crucible. Then, calcine them at 700℃ for 5 hours in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0057] (2) Take 1g of expanded basalt flakes and add them into a polytetrafluoroethylene (PTFE) hydrothermal reactor. Add 120g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into a hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0058] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0059] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0060] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 800W and an ultrasonic time of 60min to obtain a redispersible solution.

[0061] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets can be obtained with a yield of 25%.

[0062] Example 3:

[0063] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0064] (1) Take 5g of untreated basalt flakes and place them in a crucible. Use a high-temperature muffle furnace to calcine them at 800℃ for 5h to obtain expanded basalt flakes.

[0065] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 150g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0066] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0067] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0068] (5) Use an ultrasonic device to ultrasonically treat the dispersion with an ultrasonic power of 400W and an ultrasonic time of 60min to obtain a redispersed solution.

[0069] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets are obtained with a yield of 19%.

[0070] Example 4:

[0071] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0072] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 2 hours in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0073] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 105g of the prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0074] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0075] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0076] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 700W and an ultrasonic time of 50min to obtain a redispersible solution.

[0077] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets can be obtained with a yield of 18%.

[0078] Example 5:

[0079] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0080] (1) Take 5g of untreated basalt flakes and place them in a crucible. Use a high-temperature muffle furnace to calcine them at 600℃ for 8 hours to obtain expanded basalt flakes.

[0081] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0082] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0083] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0084] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 900W and an ultrasonic time of 30min to obtain a redispersible solution.

[0085] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets can be obtained with a yield of 24%.

[0086] Example 6:

[0087] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0088] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0089] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 2mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0090] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0091] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0092] (5) Use an ultrasonic device to sonicate the dispersion. The ultrasonic power is 200W and the ultrasonic time is 60min to obtain a redispersible solution.

[0093] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets are obtained with a yield of 12.6%.

[0094] Example 7:

[0095] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0096] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0097] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of the prepared 5mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0098] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0099] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0100] (5) Use an ultrasonic device to ultrasonically treat the dispersion with an ultrasonic power of 200W and an ultrasonic time of 40min to obtain a redispersed solution.

[0101] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets are obtained with a yield of 16.8%.

[0102] Example 8:

[0103] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0104] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0105] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 2mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 50℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0106] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0107] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0108] (5) Use an ultrasonic device to sonicate the dispersion. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain a redispersible solution.

[0109] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets are obtained with a yield of 4%.

[0110] Example 9:

[0111] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0112] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0113] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 100℃ hot air drying oven for 24h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0114] (3) Transfer the etched basalt flake mixture to the sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0115] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0116] (5) After the dispersion was allowed to stand for 24 hours, the supernatant was taken and dried in a vacuum drying oven to remove moisture, and basalt nanosheets were obtained with a yield of 13%.

[0117] Example 10:

[0118] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0119] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0120] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Then, put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 12h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0121] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0122] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0123] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 1000W and an ultrasonic time of 30min to obtain a redispersible solution.

[0124] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets can be obtained with a yield of 11%.

[0125] Example 11:

[0126] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0127] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0128] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 36h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0129] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0130] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0131] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 1000W and an ultrasonic time of 30min to obtain a redispersible solution.

[0132] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets are obtained with a yield of 13.3%.

[0133] from Figure 4 It can be seen that, compared with the nanosheets prepared by Examples 1, 10 and 11, the basalt nanosheets etched for 24 hours have more alkaline oxide characteristic peaks and a large number of hydroxyl peaks, which is beneficial to their bonding in composite materials.

[0134] Example 12:

[0135] The method for preparing high-yield active basalt nanosheets in this embodiment specifically includes the following steps:

[0136] (1) Take 5g of untreated basalt flakes and place them in a crucible. Calcinate them at 600℃ for 5h in a high-temperature muffle furnace to obtain expanded basalt flakes.

[0137] (2) Take 1g of expanded basalt flakes and add them to the hydrothermal reactor. Add 100g of prepared 13mol / L sodium hydroxide solution and stir thoroughly. Put the stirred solution into the hydrothermal synthesis reactor and react in a 150℃ hot air drying oven for 36h. After the reaction is completed, let it cool to room temperature to obtain etched basalt flakes.

[0138] (3) Transfer the etched basalt flake mixture to a sand core funnel and filter it under a negative pressure of 0.1 MPa to remove excess alkali solution. Add deionized water repeatedly to wash until the pH value is in the range of 6-8.

[0139] (4) The washed basalt flakes were redispersed in 300 mL of deionized water to obtain a dispersion.

[0140] (5) The dispersion was subjected to ultrasonic treatment using an ultrasonic device with an ultrasonic power of 1200W and an ultrasonic time of 30min to obtain a redispersible solution.

[0141] (6) After the redispersed liquid is allowed to stand for 24 hours, the supernatant is taken and placed in a vacuum drying oven to dry thoroughly. After removing the moisture, basalt nanosheets are obtained with a yield of 13.3%.

[0142] Experimental Example 1:

[0143] This experimental example demonstrates the preparation of a composite paper made from basalt nanosheets and cellulose nanofibers (CNF). The specific process is as follows:

[0144] (1) Take 0.162 g of cellulose nanofibers with an absolute dry weight, add deionized water to dilute the concentration to 0.3%, and stir magnetically at 400 rpm for more than 12 hours at room temperature to make it stably dispersed.

[0145] (2) Take 0.108 g of basalt nanosheets obtained in Example 1, add deionized water to dilute the concentration to 0.3%, and mechanically stir under ultrasonic conditions until fully dispersed for 10 min;

[0146] (3) Add the cellulose nanofiber dispersion to the basalt nanosheet dispersion and stir magnetically for 30 min to form a stable mixed solution;

[0147] (4) Pour the mixed solution into the sand core funnel and filter it under negative pressure. After filtration, dry it in the paper forming machine. After drying, basalt nanosheets / cellulose nanofiber composite paper is obtained. The vacuum filtration pressure is 0.1 MPa, the vacuum pressure of the paper forming machine is 2.0 MPa, the drying temperature is 80℃, and the drying time is 3 min.

[0148] (5) Basalt flake / cellulose nanofiber composite paper was prepared using the same method;

[0149] (6) The tensile strength of the prepared composite paper-based material was tested on a servo tensile testing machine, and the breakdown strength was tested on a pressure tester.

[0150] like Figure 5 The figures show the tensile strength and breakdown strength of basalt flake / cellulose nanofiber composite paper and basalt nanosheet / cellulose nanofiber composite paper. It can be seen that after basalt flakes are prepared into basalt nanosheets, the mechanical properties of the composite paper are greatly improved, from 38MPa to 90MPa, and the breakdown strength is also greatly improved, from 15kV / mm to 47kV / mm, indicating that basalt nanosheets have excellent bonding performance and insulation ability.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-yield active basalt nanosheets, characterized in that, Includes the following steps: S1, calcining untreated basalt flakes to obtain expanded basalt flakes; S2, take the expanded basalt flakes from S1, add sodium hydroxide solution and stir evenly, carry out high-temperature hydrothermal reaction, and after the reaction is completed, let it cool naturally to room temperature to obtain etched basalt flakes. S3, wash the etched basalt flakes with deionized water; S4, the washed basalt flakes are redispersed in deionized water to obtain a dispersion; S5, the dispersion is ultrasonically treated and continuously stirred to assist in the peeling of the etched basalt flakes, resulting in a redispersible solution; S6. Allow the redispersed liquid to stand and separate into layers. Take the supernatant after standing and separating into layers and vacuum dry it to obtain basalt nanosheets.

2. The method for preparing high-yield active basalt nanosheets according to claim 1, characterized in that, The untreated basalt flakes in S1 have an average grain size of 20 μm, a calcination temperature of 600–800 °C, and a calcination time of 2–8 h.

3. The method for preparing high-yield active basalt nanosheets according to claim 1, characterized in that, The molar concentration of sodium hydroxide solution in S2 is 2–13 mol / L; the mass ratio of the expanded basalt flakes to sodium hydroxide solution is 1–10:100–150.

4. The method for preparing high-yield active basalt nanosheets according to claim 1, characterized in that, The high-temperature hydrothermal reaction temperature in S2 is 50–150°C, and the high-temperature hydrothermal reaction time is 12–36 h.

5. The method for preparing high-yield active basalt nanosheets according to claim 1, characterized in that, In step S3, deionized water is used for repeated washing until the pH value is 6-8.

6. The method for preparing high-yield active basalt nanosheets according to claim 1, characterized in that, The ultrasonic treatment in S5 has a power of 200-1200W and a treatment time of 30-60min.

7. The method for preparing high-yield active basalt nanosheets according to claim 1, characterized in that, The standing time in S6 is 24 hours, and the vacuum drying temperature is 80°C.

8. An active basalt nanosheet, characterized in that, This method for preparing high-yield active basalt nanosheets is based on any one of claims 1-7.

9. The active basalt nanosheets according to claim 8, characterized in that, The basalt nanosheets have a particle size of 0.4–1.5 μm and a thickness of 1.5–2.5 nm, and their surface is modified with hydroxyl groups.

10. An application of the active basalt nanosheets according to claim 8 in films, paper, coatings, and rubber.

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