Method and apparatus for producing magnesium hydroxide aerogel

Abstract

This invention relates to a method and apparatus for producing magnesium hydroxide aerogel. The method includes: combining the aging stage with its preceding and subsequent stages to form a four-step production method based on the stage characteristics of the magnesium hydroxide aerogel production process and the structural characteristics of the intermediate products at each stage; thereby enabling better utilization of intelligent production control methods, providing a controllable basis for refined production and high product yield and quality; this invention uses intelligent control based on the stage characteristics of the magnesium hydroxide aerogel production process, resulting in lower overall production costs and simpler operation, and the obtained magnesium hydroxide aerogel has a uniform structure, fine pore size, and excellent mechanical properties.

Description

[Technical Field]

[0001] This invention belongs to the field of intelligent manufacturing technology, and in particular relates to a method and apparatus for producing magnesium hydroxide aerogel. [Background Technology]

[0002] Polymer aerogels are considered promising alternative materials in the field of thermal insulation, while magnesium hydroxide is a widely used flame retardant in the polymer industry. Due to their lightweight and porous structure, aerogels have broad application prospects in aerospace, industry, construction, new energy vehicles, electronics, textiles, and environmental protection. Compared to traditional inorganic aerogel materials, plant polysaccharide aerogels also possess advantages such as biodegradability, biocompatibility, and environmental friendliness; introducing flame retardants into the aerogel matrix is ​​a simple and efficient method to improve its flame-retardant properties. Magnesium hydroxide is a widely used environmentally friendly flame retardant in the polymer industry. In the 21st century, polymer materials have become a crucial cornerstone of modern industry and high technology, and are indispensable materials for the basic industries of the national economy and national security.

[0003] Aerogels are uniform, low-density, porous solid materials formed by the aggregation of nanoscale ultrafine particles or polymer molecules. Their unique structure endows aerogels with many excellent properties. These unique properties make aerogels widely used in thermal, optical, electrical, and acoustic fields. Furthermore, aerogels have significant applications in catalysis and adsorption. Their high specific surface area, high porosity, good heat resistance, and excellent selectivity in catalysis processes result in superior activity and selectivity as catalysts, with longer lifespans than ordinary catalysts. Meanwhile, high-temperature resistant aerogel materials have been a research hotspot in recent years. The types of aerogels have become increasingly diverse, including silica aerogels, alumina aerogels, zirconia aerogels, zinc oxide aerogels, iron oxide aerogels, carbon aerogels, polyimide aerogels, polyurethane aerogels, and many more. Introducing magnesium oxide into binary composite aerogels with high-temperature resistance has broad application prospects for aerogels, such as low refractive index, low acoustic impedance, large specific surface area, low Young's modulus, and much less scattering of light and sound than traditional materials.

[0004] As a traditional process, the preparation method of magnesium hydroxide aerogel is already mature, and it is difficult to make breakthroughs in the basic production methods. With the rapid development of the social economy, both people's lives and enterprise production have largely become intelligent and modernized. Simultaneously advancing are artificial intelligence and big data technologies, whose application can drive the production and preparation of traditional products; a window of opportunity for breakthroughs has emerged with the times. How to utilize advanced monitoring methods and intelligent control approaches to optimize traditional processes, improve the efficiency of magnesium hydroxide aerogel production through intelligent control, further optimize the structure and performance of the finished product, and overcome the differences in finished products caused by variations in raw material sources, production environments, and operating methods are the technical problems to be solved. This invention is based on intelligent control of the stage characteristics of the magnesium hydroxide aerogel production process. The overall production cost is low and the operation is simple, resulting in a magnesium hydroxide aerogel with a uniform structure, fine pore size, and excellent mechanical properties. [Summary of the Invention]

[0005] To address the aforementioned problems in the prior art, this invention proposes a method and apparatus for producing magnesium hydroxide aerogel, the method comprising:

[0006] Step S1: Mixing and Preparing Stage; specifically: obtaining a magnesium hydroxide metastable solution based on magnesium-containing raw materials, wherein the metastable solution is a magnesium hydroxide liquid gel with a certain fluidity; wherein: the magnesium-containing raw material is magnesium hydroxide;

[0007] Step S2: Gel-aging step; specifically: placing the metastable solution in a settling container and allowing it to stand relatively still so that the metastable solution gradually loses its fluidity and becomes a solid gel; the relative standing means that the position of the metastable solution relative to the settling container remains unchanged, while the spatial position of the settling container changes.

[0008] Step S2 specifically includes the following steps:

[0009] Step S21: Place the metastable solution in a sealed settling container; the settling container is initially placed on a horizontal surface;

[0010] Step S22: Determine the relative displacement angle α between the stationary container and the horizontal plane; tilt the stationary container so that it reaches the relative displacement angle α; maintain the relative displacement angle until the release condition is met; after the release condition is met, proceed to the next step; continuously collect the center of gravity position of the stationary container during the holding process to obtain a center of gravity position sequence; maintain the relative displacement angle α for a first short time interval; wherein: the release condition is that the center of gravity position of the stationary container no longer changes or changes slightly; set the center position of one end of the stationary container as the axis position, and the center of gravity position of the stationary container is located in the XY plane that is perpendicular to and tangent to the horizontal plane;

[0011] The determination of the relative displacement angle α between the stationary vessel and the horizontal plane specifically involves: recording the angular displacement period t, maintaining one relative displacement angle α and one reverse relative displacement angle -α as one angular displacement period; setting the initial value of the angular displacement period t to 1; and determining the relative displacement angle α between the stationary vessel and the horizontal plane corresponding to the angular displacement period t. t When determining the relative displacement angle in the first angular displacement cycle, the relative displacement angle is set to a preset angle value; when determining the relative displacement angle in subsequent angular displacement cycles t, it is based on the continuously collected centroid position sequence <

[0012] (x t,1 ,y t,1 ),(x t,2 ,y t,2 ),…,(x t,k ,y t,k ),…,(x t,K ,y t,K Update the relative displacement angle; where: K is the total number of consecutive acquisitions at equal intervals; (x t,k ,y t,k ) is the centroid position obtained in the kth sampling;

[0013] The update of the relative displacement angle based on the continuously acquired centroid position sequence is specifically as follows:

[0014] Step S22A1: Calculate the centroid change difference sequence <sr for the t-th and t-1-th angular displacement periods based on the following formula (1). t,k >, <sr t-1,k >, k = 1 to K-1; the current period is the t-th angular displacement cycle, and the calculated sequence of the difference in the center of gravity change is <sr t,k >, the previous angular displacement period, i.e., the (t-1)th angular displacement period.

[0015] The calculated sequence of centroid change differences is <sr t-1,k >, and so on;

[0016]

[0017] Step S22A2: Calculate the entropy value ssr of the centroid change in the t-th and t-1-th periods based on the following formula (2). t and SSR t-1 Determine the periodic change value of entropy, Dssr = ssr t -ssr t-1 If the periodic change value of entropy, Dssr, is less than P1×ssr t If not, the relative displacement angle is not updated; otherwise, proceed to the next step; where: P1 is the comparison coefficient;

[0018]

[0019] Step S22A3: Calculate the update coefficient β1 for period t based on the following formula (3). t The relative displacement angle α is updated using the following formula (4). t Where: β is the preset angular displacement period normalization coefficient; the relative displacement angle α will be updated. t As determined by the relative displacement angle α;

[0020]

[0021] α t =β×β1 t ×α t-1 (4);

[0022] Step S23: Slowly rotate the container and tilt it in the opposite direction so that the container reaches the aforementioned relative displacement angle -α. t Maintain the reverse relative displacement angle until the release condition is met; maintain the reverse relative displacement angle -α t The first shortest time interval;

[0023] Step S24: Determine whether the gel-aging step is complete. If yes, proceed to the next step; otherwise, return to step S22. Specifically, determining whether the gel-aging step is complete means that if the center of gravity of the standing vessel does not change throughout the entire process of step S22 and / or the entire process of step S23, then the gel-aging step is determined to be complete.

[0024] Step S3: Aging and drying steps; specifically: placing the net value container in a horizontal position; keeping it absolutely still so that the solid gel enters a semi-dry state during the condensation process; the absolute stillness means that the position of the solid gel inside and outside relative to the stilling container remains unchanged, and the spatial position of the stilling container does not change.

[0025] Step S4: Deep drying step; specifically: removing the solution from the solid gel and replacing it with air or an inert gas to obtain magnesium hydroxide aerogel.

[0026] Furthermore, the first short time interval is 0.5 to 1 hour.

[0027] Furthermore, the preset angle value is 2 to 15 degrees.

[0028] Furthermore, the comparison coefficient P1 = 0.01.

[0029] Furthermore, deep drying is carried out using atmospheric pressure drying.

[0030] Based on the same inventive concept, the present invention also proposes a magnesium hydroxide aerogel production apparatus for implementing the above method. The apparatus includes a settling vessel and a control module. The control module is used to intelligently control the magnesium hydroxide aerogel production process. The settling vessel is capable of accommodating magnesium hydroxide in various forms and rotating around an axis and a central axis located in a horizontal plane.

[0031] Furthermore, the control module is a computer unit.

[0032] A processor, characterized in that the processor is configured to run a program, wherein the program executes the method for producing magnesium hydroxide aerogel.

[0033] A computer-readable storage medium includes a program that, when run on a computer, causes the computer to perform the method for producing magnesium hydroxide aerogel.

[0034] An intelligent control device includes a processor coupled to a memory, the memory storing program instructions, which, when executed by the processor, implement the method for producing magnesium hydroxide aerogel.

[0035] The beneficial effects of this invention include:

[0036] (1) Based on the stage characteristics of magnesium hydroxide gel production process and the structural characteristics of intermediate products in each stage, the aging stage is combined with its preceding and subsequent stages to form a four-step production method, so as to better utilize intelligent production control methods and provide a controllable basis for refined production and high product yield.

[0037] (2) Based on the center of gravity position data that is easy to collect in real time, the real-time progress of gel aging is accurately obtained. On this basis, intelligent means are used to make adaptive real-time intelligent control of tilt and environmental parameters. This helps the flowing liquid gel to break the unstable capillary structure and scientifically adjust the direction and speed of flow through angular displacement period before the structure is fixed, thereby improving the density and uniformity of the structure.

[0038] (3) By combining a partial aging stage with partial drying, intelligent control based on temperature difference is carried out to avoid irregular structural deformation of the solid support structure of the gel during the polycondensation reaction caused by gravity and liquid flow, thereby rapidly and stably improving the strength of the solid support structure of the gel and forming a regular and uniform internal support structure of the gel; by real-time process monitoring, the critical changes in the structure are detected in time and combined with the environmental parameter stabilization stage, so as to avoid the damage to the formed structure caused by repeated environmental changes.

[0039] (4) After the gel-aging step, as well as the aging and drying steps, a relatively stable magnesium hydroxide solid gel structure with acceptable strength is formed. The possibility of cracking and breakage during the drying process is greatly reduced; the time required for deep drying is also reduced, thus providing a basis for the use of simple drying methods, reducing manufacturing costs and operability. [Attached Image Description]

[0040] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, are not intended to unduly limit the invention. In the drawings:

[0041] Figure 1 This is a schematic diagram of the magnesium hydroxide aerogel production method of the present invention.

[0042] Figure 2 This is a schematic diagram of the angular displacement cycle of the stationary vessel of the present invention.

[0043] Figure 3 This is a schematic diagram of the morphology of magnesium hydroxide aerogel observed under a scanning electron microscope.

Detailed Implementation Methods

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions are merely for explaining the present invention and are not intended to limit the scope of the invention.

[0045] As attached Figure 1 As shown, this invention proposes a method for producing magnesium hydroxide aerogel, the method comprising:

[0046] Step S1: Mixing and Preparing Stage; specifically: obtaining a magnesium hydroxide metastable solution based on magnesium-containing raw materials, wherein the metastable solution is a magnesium hydroxide liquid gel with a certain fluidity; wherein: the magnesium-containing raw materials are magnesium hydroxide and magnesium oxide;

[0047] The method for obtaining a metastable magnesium hydroxide solution based on magnesium-containing raw materials is as follows: magnesium hydroxide is uniformly mixed in an aqueous solution, fully hydrolyzed and undergoes a condensation chemical reaction, the pH value is adjusted by an acid solution to obtain an acidic solution, and then an alkaline solution is slowly added dropwise to control the pH value and maintain the first time length, initiating cross-linking and condensation to form a metastable three-dimensional network structure. The metastable solution has a certain degree of fluidity, meaning that the three-dimensional network structure has not been fully formed.

[0048] The method for obtaining a metastable magnesium hydroxide solution based on magnesium-containing raw materials specifically involves: generating a magnesium hydroxide solution from active magnesium oxide via hydration, wherein the magnesium hydroxide solution is rich in magnesium hydroxide; the magnesium hydroxide-rich solution also includes composite additives; dispersing active magnesium oxide in water and then adding it to an agar or polyvinyl alcohol solution to obtain a magnesium hydroxide-rich solution; adding an anionic polymer dropwise and maintaining it for a first time duration to initiate cross-linking and condensation to form a metastable three-dimensional network structure in the metastable solution; the metastable solution possesses a certain degree of fluidity; of course, other common methods for preparing magnesium hydroxide liquid gels can also be used.

[0049] Preferably, the anionic polymer includes sodium alginate, alginate, etc.

[0050] Preferably, magnesium hydroxide is added to an aqueous solution for complete hydrolysis, wherein the aqueous solution is distilled water, deionized water, or an acidic solution;

[0051] Preferably, the magnesium hydroxide is highly active magnesium hydroxide;

[0052] Preferred: The metastable solution is transparent;

[0053] Preferably, the first time duration is 2-12 hours;

[0054] Preferred method: Heating to approximately 95°C is performed during the process of uniformly mixing magnesium hydroxide in the aqueous solution, which can be supplemented by magnetic stirring;

[0055] Step S2: Gel-aging step; specifically: placing the metastable solution in a settling container and allowing it to stand relatively still so that the metastable solution gradually loses its fluidity and becomes a solid gel; during this process, environmental parameters are adaptively adjusted; the relative standing means that the position of the metastable solution relative to the settling container remains unchanged, while the spatial position of the settling container changes; this step is the key step in forming a stable and uniform structure of the gel to obtain a high-quality aerogel.

[0056] Preferably, the settling container is a rectangular container; of course, the settling container can be customized according to the finished product requirements.

[0057] Step S2 specifically includes the following steps:

[0058] Step S21: Place the metastable solution in a sealed settling container; the settling container is initially placed on a horizontal plane; the horizontal plane is the plane on which the settling container is located;

[0059] Step S22: Determine the relative displacement angle α between the stationary container 2 and the horizontal plane 1; tilt the stationary container so that it reaches the relative displacement angle α; maintain the relative displacement angle until the release condition is met; after the release condition is met, proceed to the next step; continuously collect the center of gravity position of the stationary container during the holding process to obtain a center of gravity position sequence; maintain the relative displacement angle α for a first short time interval; wherein: the release condition is that the center of gravity position of the stationary container no longer changes or undergoes a slight change; as shown in the appendix. Figure 2 As shown, the center position of one end of the container is set as the axis position, and the center of gravity of the container is located in the XY plane that is perpendicular to and tangent to the horizontal plane; subsequently, for ease of calculation, the x and y values ​​of the center of gravity are converted to positive integers.

[0060] Preferably, the first short time interval is 0.5 to 1 hour;

[0061] The determination of the relative displacement angle α between the stationary container 2 and the horizontal plane 1 is specifically as follows: the relative displacement angle α is set to a preset angle value; for example: 2 to 15 degrees.

[0062] The determination of the relative displacement angle α between the stationary container 2 and the horizontal plane 1 specifically involves: recording the angular displacement period t, maintaining one relative displacement angle α and one reverse relative displacement angle -α as one angular displacement period; setting the initial value of the angular displacement period t to 1; and determining the relative displacement angle α between the stationary container and the horizontal plane corresponding to the angular displacement period t. t When determining the relative displacement angle in the first angular displacement cycle, the relative displacement angle is set to a preset angle value; when determining the relative displacement angle in subsequent angular displacement cycles t, it is based on the continuously collected centroid position sequence <(x t,1 ,y t,1 ),(x t,2 ,y t,2 ),…,(x t,k ,y t,k ),…,(x t,K ,y t,K Update the relative displacement angle; where: K is the total number of consecutive acquisitions at equal intervals; (x t,k ,y t,k ) is the centroid position obtained in the kth sampling;

[0063] The update of the relative displacement angle based on the continuously acquired centroid position sequence is specifically as follows:

[0064] Step S22A1: Calculate the centroid change difference sequence <sr for the t-th and t-1-th angular displacement periods based on the following formula (1). t,k >, <sr t-1,k>, k = 1 to K-1; the current period is the t-th angular displacement cycle, and the calculated sequence of the difference in the center of gravity change is <sr t,k >, the previous angular displacement period, i.e., the (t-1)th angular displacement period, the calculated sequence of the difference in the change of the center of gravity is <sr t-1，k >, and so on;

[0065]

[0066] Step S22A2: Calculate the entropy value ssr of the centroid change in the t-th and t-1-th periods based on the following formula (2). t and SSR t-1 Determine the periodic change value of entropy, Dssr = ssr t -ssr t-1 If the periodic change value of entropy, Dssr, is less than P1×ssr t If not, the relative displacement angle is not updated; otherwise, proceed to the next step; where: P1 is the comparison coefficient;

[0067]

[0068] Preferred: P1 = 0.01;

[0069] Step S22A3: Calculate the update coefficient β1 for period t based on the following formula (3). t The relative displacement angle α is updated using the following formula (4). t The angular displacement period normalization coefficient can control the adjustment range within a preset angle range, thus forming a controllable adjustment; it will update the relative displacement angle α. t As determined by the relative displacement angle α;

[0070]

[0071] α t =β×β1 t ×α t-1 (4)

[0072] Alternatively, the relative displacement angle α can be updated using the following formula (5). t This takes into account the reduced flow acceleration caused by the decrease in angle and the reduced flowability caused by the progress of solidification;

[0073] α t =β×β1 t ×α t-1 ×(1-sinα t-1 1 / 2 (5);

[0074] Preferred setting: β is a preset angular displacement period normalization coefficient, which is related to tilting capability and the size of a single adjustment angle; β can be set to 1;

[0075] Step S23: Slowly rotate the container and tilt it in the opposite direction so that the container reaches the aforementioned relative displacement angle -α. t Maintain the reverse relative displacement angle until the release condition is met; maintain the reverse relative displacement angle -α t The first shortest time interval;

[0076] Step S24: Determine whether the gel-aging step is complete. If yes, proceed to the next step; otherwise, return to step S22.

[0077] The determination of whether the gel-aging step is completed is specifically as follows: if the center of gravity of the standing vessel does not change throughout the entire process of step S22 and / or the entire process of step S23, then the gel-aging step is determined to be completed.

[0078] The adaptive adjustment of environmental parameters refers to the intelligent adjustment of environmental parameters based on the gel-aging progress, so that the current environmental parameters are more consistent with the real-time progress of gel-aging.

[0079] Specifically, the steps include the following:

[0080] Step S22B1: Obtain the static vessel parameters and the parameters of the built-in magnesium hydroxide; the static vessel parameters include: length, thickness, and a relative displacement angle sequence <α1, α2, ... αt consisting of the relative displacement angles of the 1st to t periods. t The built-in magnesium hydroxide parameters include weight, mixing ratio, and raw material source; where t is the most recent period.

[0081] Step S22B2: Obtain the centroid position sequence of the first to t-1 periods, and perform sampling interval splitting on the centroid position sequence of the t-1 periods, called k-splitting; to obtain K t-1 element centroid position subsequences.

[0082] <(x) 1,1 ,y 1,1 ),(x 2,1 ,y 2,1 ),…,(x t-1,1 ,y t-1,1 >~<

[0083] (x 1,K ,y 1,K ),(x 2,K ,y 2,K ),…,(x t-1,K ,y t-1,K )>;

[0084] Step S22B2: Input the K t-1 dimensional centroid position subsequences sequentially into the intelligent model to obtain K centroid position prediction values. Sort the K centroid position prediction values ​​according to the angular displacement period to form a centroid position prediction sequence; determine the predicted relative displacement angle α corresponding to the centroid position prediction sequence. p ;

[0085] The intelligent model includes multiple fitting curves of the centroid position and period t; it finds and inputs the closest fitting curve for each position in the t-1 dimension centroid position subsequence as the closest fitting curve, and obtains the predicted centroid position value corresponding to the input t-1 dimension centroid position subsequence based on the closest fitting curve; it then clusters and fits the historical centroid position data obtained under different environmental parameters and built-in magnesium hydroxide parameters to obtain multiple fitting curves.

[0086] Alternative: The intelligent model is an artificial intelligence model; the input parameters include environmental parameters and built-in magnesium hydroxide parameters, and the center of gravity position subsequence; the output is the center of gravity position prediction sequence; the intelligent model is trained by constructing sample data based on historical data; suitable sample data can be selected and constructed by the finished product yield, thereby guiding a suitable environmental parameter adjustment strategy to improve the yield and production efficiency;

[0087] Furthermore: the centroid position subsequence is the data input part of the artificial intelligence model, and the environmental parameters and the built-in magnesium hydroxide parameters are the weight input part of the artificial intelligence model;

[0088] Preferably, the artificial intelligence model includes K first sub-models and 1 second sub-model, with the K first sub-models corresponding to the K acquisition intervals. The input of each first sub-model corresponds to a centroid position sub-sequence, and its output is the precursor value of the predicted centroid position corresponding to the acquisition interval. The input of the second sub-model consists of the precursor values ​​of the K predicted centroid positions output by the K first sub-models, environmental parameters, and a built-in magnesium hydroxide parameter. The second sub-model intelligently adjusts based on the environmental parameters and the built-in magnesium hydroxide parameter to obtain the K predicted centroid positions. This approach significantly reduces the training and computational complexity of the artificial intelligence model, reducing the computational complexity by k dimensions, thus making the implementation of the artificial intelligence model possible. After k-separation, t-1 data obtained at different acquisition intervals can be used to train the multiple first sub-models, expanding the sample size with real data.

[0089] Step S22B3: Compare the predicted relative displacement angle α p and update the relative displacement angle α t To adjust environmental parameters; specifically: based on α p and αt Find the corresponding environmental parameter adjustment strategy and adjust the environmental parameters based on the strategy; for example, adjust the values ​​of environmental parameters such as temperature and pressure; for example, when predicting the relative displacement angle α... p and update the relative displacement angle α t When there is a large difference, the temperature and pressure values ​​can be appropriately increased to accelerate the aging process;

[0090] This invention is based on the center of gravity position data that is easy to collect in real time, accurately obtains the real-time progress of gel aging, and on this basis, uses intelligent means to adaptively control the tilt and environmental parameters in real time. This helps the flowing liquid gel to improve the density and uniformity of the structure by breaking the unstable capillary structure and scientifically and dynamically adjusting the direction and speed of flow through angular displacement period when the structure is not yet fixed.

[0091] Step S3: Aging and drying steps; specifically: placing the solid gel in a horizontal position, controlling the temperature on the upper and lower sides of the solid gel so that the temperatures on the upper and lower sides are different; keeping it absolutely still so that the solid gel enters a semi-dry state during the polycondensation process; the absolute stillness means that the position of the solid gel inside and outside relative to the stilling container remains unchanged, and the spatial position of the stilling container does not change.

[0092] Step S3 specifically includes the following steps:

[0093] Step S31: Place the container in a horizontal position; apply a temperature difference between the upper and lower sides of the container so that the temperature of the upper side is higher than that of the lower side;

[0094] Step S32: Monitor the drying process of the solid gel; when the drying progress meets the stable drying conditions, proceed to step S33; if the stable drying conditions are not met, determine whether the flipping condition is met. If so, rotate the container 360 degrees to exchange the top and bottom sides; otherwise, keep the current state unchanged; wherein: the stable drying condition is that the size or external shape of the solid gel remains unchanged; the flipping condition is that the size or external shape of the solid gel changes and the degree of change reaches a preset level.

[0095] Of course, other methods can be used to determine whether the flipping or drying conditions are met. For example, when the weight of the solid gel in the sliced ​​sample no longer changes, the drying conditions are met, and when the weight reduction ratio reaches a preset ratio, the flipping conditions are met.

[0096] Preferred method: Monitoring the drying process of solid gels by sample slicing;

[0097] Preferred methods include: monitoring changes in the solid gel by observing the changes through the window opening; and monitoring the state of the captured images.

[0098] Step S33: Apply the same temperature and stable environmental parameters to both sides of the standing container to achieve stable drying;

[0099] This step, while allowing the solid gel to undergo internal and external deformation, introduces a temperature difference that causes the liquid solution to flow downwards simultaneously due to gravity and the temperature difference. This allows the interlayer irregularity of the pore structure caused by gravity to occur concurrently with the creation and loosening of the pore structure resulting from the liquid flow. This avoids unidirectional changes in the pore structure caused by the liquid flow, improving the uniformity of the finished product structure. Repeated flipping further enhances the overall vertical uniformity of the finished product. Once the pore structure is stable, the surface tension of the internal liquid can no longer disrupt the internal pore structure. By maintaining stable environmental parameters for stable drying, structural damage caused by repeated environmental changes is avoided.

[0100] Preferably, the temperature difference is 20–80 degrees Celsius;

[0101] In this step, the solid support structure of the solid gel is basically formed, and hydrolysis and condensation reactions continue to occur inside. This invention combines a partial aging stage with partial drying, and uses intelligent temperature difference-based control to avoid irregular structural deformation of the solid support structure caused by gravity and liquid flow during the condensation reaction. This rapidly and stably improves the strength of the solid support structure of the gel, forming a regular and uniform internal support structure. Through real-time process monitoring, it promptly detects and combines critical structural changes to enter the environmental parameter stabilization stage, avoiding possible damage to the formed structure from repeated environmental changes.

[0102] Step S4: Deep drying step; specifically: removing the solution from the solid gel and replacing it with air or an inert gas to obtain magnesium hydroxide aerogel;

[0103] Preferred method: Deep drying is performed using atmospheric pressure drying; atmospheric pressure drying is easier to control; furthermore, deep drying is performed using room temperature and atmospheric pressure drying; the final production process can be carried out simultaneously during transportation, allowing sufficient time for the drying process of the solid gel; after the gel-aging step, as well as the aging and drying steps, a relatively stable magnesium hydroxide solid gel structure with acceptable strength is formed, greatly reducing the possibility of cracking and breakage during the drying process; the time required for deep drying is also reduced, thus making the use of room temperature drying possible, reducing manufacturing costs and operability;

[0104] Of course, freeze-drying can be used for deep drying; first, the temperature value in the environmental parameters is reduced to maintain the solid stability of the solid gel and maintain the environmental vacuum, so that the liquid part in the solid gel is converted into gas and sublimated; thus accelerating the progress of deep drying.

[0105] Example: Magnesium hydroxide and water were stirred in a mixing vessel for 4-8 hours until homogeneous; the mass ratio of the two was 1-1.5:6-10. Complete hydrolysis and condensation chemical reaction occurred. 2% hydrochloric acid was added dropwise to adjust the pH to obtain an acidic solution. Then, an alkaline solution was slowly added dropwise while controlling the pH to around 8 to obtain a metastable solution. The metastable solution was placed in a settling vessel for relative settling for 120 hours to obtain a solid gel. The initial relative displacement angle was set to 10 degrees, with each 12 hours representing one angular displacement. The cycle involves a relative displacement angle decrease of 1-2 degrees per cycle. The solid gel is repeatedly soaked in distilled water, n-hexane, or calcium chloride for 48-72 hours to remove water and ethanol, with the soaking solution being changed 2-3 times. Temperature control is then applied to the upper and lower sides of the solid gel to ensure that the temperatures on the upper and lower sides are different. The temperature difference is gradually reduced from 45 degrees to 20 degrees throughout the process, and the gel is allowed to stand for 8 hours without any temperature difference. The freeze-drying time is 40-50 hours, and the freeze-drying temperature is -60 to -50 degrees Celsius.

[0106] The prepared magnesium hydroxide aerogel product is as follows: Figure 3 As shown, the morphology of the magnesium hydroxide aerogel section was observed using a scanning electron microscope; Figure 3 (a)(b) are SEM images of magnesium hydroxide aerogel produced by traditional process. It can be seen that there is uneven vertical distribution in local areas, and the structural inhomogeneity caused by gas flow has a significant impact. Figure 3 (c)(d) are SEM images of magnesium hydroxide aerogel produced using the embodiments of the present invention. It can be seen that the structure is relatively uniform in both planar and vertical distribution, the three-dimensional spatial structure of the pore size is relatively uniform and smooth, the pore size is relatively balanced, and the three-dimensional network structure has better continuity, density and porosity. The compressive strength reaches 1.12 MPa at 70% strain, which shows excellent mechanical properties.

[0107] Based on the stage characteristics of the magnesium hydroxide gel production process and the characteristics of intermediate products in each stage, this invention combines the aging stage with its preceding and subsequent stages to form a four-step production method. This allows for better utilization of intelligent production control methods, providing a controllable basis for refined production and high product yield and quality.

[0108] Based on the same inventive concept, the present invention also provides a magnesium hydroxide aerogel production apparatus, the apparatus comprising a settling vessel and a control module; the control module is used for intelligent control of the magnesium hydroxide aerogel production process, and the settling vessel is capable of accommodating magnesium hydroxide in various forms and rotating around an axis and a central axis located in a horizontal plane.

[0109] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for producing magnesium hydroxide aerogel, characterized in that, include: Step S1: Mixed prefabrication stage; Specifically, a metastable magnesium hydroxide solution is obtained based on a magnesium-containing raw material, wherein the metastable solution is a magnesium hydroxide liquid gel with a certain degree of fluidity; wherein the magnesium-containing raw material is magnesium hydroxide. Step S2: Gel-aging step; specifically: placing the metastable solution in a settling container and allowing it to stand relatively still so that the metastable solution gradually loses its fluidity and becomes a solid gel; the relative standing means that the position of the metastable solution relative to the settling container remains unchanged, while the spatial position of the settling container changes. Step S2 specifically includes the following steps: Step S21: Place the metastable solution in a sealed settling container; the settling container is initially placed on a horizontal surface; Step S22: Determine the relative displacement angle α between the stationary container and the horizontal plane; tilt the stationary container so that it reaches the relative displacement angle α; maintain the relative displacement angle until the release condition is met; after the release condition is met, proceed to the next step; continuously collect the center of gravity position of the stationary container during the holding process to obtain a center of gravity position sequence; maintain the relative displacement angle α for a first short time interval; wherein: the release condition is that the center of gravity position of the stationary container no longer changes or changes slightly; set the center position of one end of the stationary container as the axis position, and the center of gravity position of the stationary container is located in the XY plane that is perpendicular to and tangent to the horizontal plane; The determination of the relative displacement angle α between the stationary vessel and the horizontal plane specifically involves: recording the angular displacement period t, maintaining one relative displacement angle α and one reverse relative displacement angle -α as one angular displacement period; setting the initial value of the angular displacement period t to 1; and determining the relative displacement angle α between the stationary vessel and the horizontal plane corresponding to the angular displacement period t. t When determining the relative displacement angle in the first angular displacement cycle, the relative displacement angle is set to a preset angle value; when determining the relative displacement angle in subsequent angular displacement cycles t, it is based on the continuously collected centroid position sequence < (x t,1 ,y t,1 ),(x t,2 ,y t,2 ),…,(x t,k ,y t,k ),…,(x t,K ,y t,K Update the relative displacement angle; where: K is the total number of consecutive equally spaced acquisitions; (x t,k ,y t,k ) is the centroid position obtained in the kth sampling; The update of the relative displacement angle based on the continuously acquired centroid position sequence is specifically as follows: Step S22A1: Calculate the centroid change difference sequence <sr for the t-th and t-1-th angular displacement periods based on the following formula (1). t,k >, <sr t-1,k The element values ​​in > are k = 1 to K-1; the current period is the t-th angular displacement cycle, and the calculated sequence of the difference in the center of gravity change is <sr. t,k >, the previous angular displacement period, i.e., the (t-1)th angular displacement period, the calculated sequence of the difference in the change of the center of gravity is <sr t-1,k >, and so on; Step S22A2: Calculate the entropy value ssr of the centroid change in the t-th and t-1-th periods based on the following formula (2). t and SSR t-1 Determine the periodic change value of entropy, Dssr = ssr t -ssr t-1 If the periodic change value of entropy, Dssr, is less than P1×ssr t If not, the relative displacement angle is not updated; otherwise, proceed to the next step; where: P1 is the comparison coefficient; Step S22A3: Calculate the update coefficient β1 for period t based on the following formula (3). t The relative displacement angle α is updated using the following formula (4). t Where: β is the preset angular displacement period normalization coefficient; the relative displacement angle α will be updated. t The determined relative displacement angle α α t ＝β×β1 t ×α t-1 (4)； Step S23: Slowly rotate the container and tilt it in the opposite direction so that the container reaches the aforementioned relative displacement angle -α. t Maintain the reverse relative displacement angle until the release condition is met; maintain the reverse relative displacement angle -α t The first shortest time interval; Step S24: Determine whether the gel-aging step is complete. If yes, proceed to the next step; otherwise, return to step S22. Specifically, determining whether the gel-aging step is complete means that if the center of gravity of the standing vessel does not change throughout the entire process of step S22 and / or the entire process of step S23, then the gel-aging step is determined to be complete. Step S3: Aging and drying steps; specifically: placing the settling container in a horizontal position; maintaining absolute stillness so that the solid gel enters a semi-dry state during the polycondensation process; the absolute stillness means that the position of the solid gel inside and outside relative to the settling container remains unchanged, and the spatial position of the settling container does not change. Step S4: Deep drying step; specifically: removing the solution from the solid gel and replacing it with air or an inert gas to obtain magnesium hydroxide aerogel.

2. The method for producing magnesium hydroxide aerogel according to claim 1, characterized in that, The first short time interval is 0.5 to 1 hour.

3. The method for producing magnesium hydroxide aerogel according to claim 2, characterized in that, The preset angle value is 2 to 15 degrees.

4. The method for producing magnesium hydroxide aerogel according to claim 3, characterized in that, The comparison coefficient P1 = 0.

01.

5. The method for producing magnesium hydroxide aerogel according to claim 4, characterized in that, Deep drying is carried out using atmospheric pressure drying method.

6. An apparatus for producing magnesium hydroxide aerogel for implementing the method according to any one of claims 1-5, characterized in that, The device includes a settling vessel and a control module; the control module is used for intelligent control of the magnesium hydroxide aerogel production process, and the settling vessel can hold magnesium hydroxide in various forms and rotate around an axis and a central axis located in the horizontal plane.

7. The magnesium hydroxide aerogel production apparatus according to claim 6, characterized in that, The control module is a computer unit.

8. A processor, characterized in that, The processor is used to run a program, wherein the program executes the magnesium hydroxide aerogel production method according to any one of claims 1-5.

9. A computer-readable storage medium, characterized in that, Includes a program that, when run on a computer, causes the computer to perform the method for producing magnesium hydroxide aerogel as described in any one of claims 1-5.

10. An intelligent control device, characterized in that, The method includes a processor coupled to a memory, the memory storing program instructions that, when executed by the processor, implement the method for producing magnesium hydroxide aerogel as described in any one of claims 1-5.

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