Preparation method of heat storage material based on microbial corrosion and energy field regulation and control and material

Abstract

The embodiment of the invention provides a preparation method of a heat storage material based on microbial corrosion and energy field regulation and a material. The method comprises the following steps: mixing distilled water, magnesium chloride, sodium carbonate and sodium hydroxide to prepare slurry; the method comprises the following steps: selecting silicophilic bacillus licheniformis as a silicate rock degradation strain, and inoculating the silicophilic bacillus licheniformis into a culture medium containing silicate rock chips for culturing; adding the obtained silicophilic bacillus licheniformis culture solution into a solution containing silicate rock debris to obtain activated silicate rock debris; mixing the activated silicate rock debris with a binder to prepare a green body, so as to obtain a pre-oxidized active material; putting the magnesium oxide active powder into a high-vacuum hot-pressing furnace, and synthesizing nano whiskers; calcining the obtained nano crystal whiskers to obtain core material nano crystal whiskers, mixing the core material nano crystal whiskers with a binder, and performing granulation, drying and compression molding to obtain a biscuit; putting the biscuit into a tubular furnace, and carrying out heating and heat preservation treatment; putting the cooled biscuit into a graphite mold, and sintering to obtain a biscuit; the biscuit is treated through an impregnation method, and the heat storage material is prepared.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of thermal storage material preparation technology, specifically relating to a method for preparing thermal storage materials based on microbial corrosion and energy field regulation, and thermal storage materials. Background Technology

[0002] The treatment and utilization of low-grade magnesite tailings has always been a challenge in the development and utilization of mineral resources.

[0003] While the relevant patents have made some innovations in the preparation and application of microbial agents, they mainly focus on wastewater treatment in the light industry and food sector and the production of bio-organic fertilizer from fermented straw and livestock manure, without addressing the activation and utilization of tailings resources. In particular, acid leaching, as a traditional method for tailings activation, is not only inefficient but also generates large amounts of acidic wastewater, causing serious environmental pollution.

[0004] In addition, while other related technologies have attempted to use microwave sintering technology to process tailings, the single microwave sintering method results in uneven heat treatment, which limits the improvement of material performance.

[0005] Therefore, there is an urgent need for an environmentally friendly, efficient tailings resource utilization technology that can control the microstructure of materials. Summary of the Invention

[0006] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a method for preparing thermal storage materials based on microbial corrosion and energy field regulation, as well as thermal storage materials.

[0007] The first aspect of the embodiments of this disclosure provides a method for preparing thermal storage materials based on microbial corrosion and energy field regulation, characterized in that it includes: Step 1: Using distilled water as a solvent, add magnesium chloride powder and sodium carbonate as an activator, add sodium hydroxide solution, and mix thoroughly to obtain a uniform slurry; Step 2: Select Bacillus siliceosa as the silicate rock degrading strain, inoculate it into a culture medium containing silicate rock chips, and place it in a constant temperature incubator for shaking culture; Step 3: Add the culture medium of Bacillus siliceosa obtained in Step 2 to the solution containing silicate rock fragments, treat it with an ultrasonic cleaner, then transfer it to an autoclave for reaction, and then calcine it in a muffle furnace for 2 hours to obtain activated silicate rock fragments. Step 4: Mix activated silicate rock chips with a binder, granulate, dry and press to form a green body; place the green body in a muffle furnace at 500~800°C for 0.5~2 hours, and after natural cooling, obtain the pre-oxidized active material; Step 5: Place the magnesium oxide active powder into a high-vacuum hot press furnace and synthesize nanofibers under high pressure of 300-700 MPa. Then, keep it at low pressure of 30-60 MPa for 6-8 hours and let it cool naturally. Calcine the obtained nanofibers at 400-700°C for 2-4 hours to form a MgO coating layer on the surface, thus obtaining the core nanofibers. Mix the core nanofibers with a binder, granulate, dry, and press to form a green body. Step 6: Place the green blank in a tube furnace and heat it to 500-800°C at a rate of 5-10°C / min in an air atmosphere. Hold it at that temperature for 2 hours and then let it cool naturally to room temperature after power is turned off. Place the cooled green blank into a graphite mold and perform in-situ carbonization and high-temperature sintering in a tube furnace to obtain a green blank with a biomimetic honeycomb structure. Step 7: The raw blank with a biomimetic honeycomb structure is treated by impregnation and immersed in potassium nitrate solution to obtain the heat storage material.

[0008] Optionally, the magnesium chloride powder has a purity greater than 99% and a particle size of 0.05 mm.

[0009] Optionally, the concentration of sodium carbonate is 0.15 mol / L, and the concentration of sodium hydroxide is 0.05 mol / L.

[0010] Optionally, in the above step, the Bacillus siliceophilus culture medium obtained in step 2 is added to a solution containing silicate rock fragments, treated with an ultrasonic cleaner, then transferred to an autoclave for reaction, and subsequently calcined in a muffle furnace for 2 hours to obtain activated silicate rock fragments, including: 0.1g of Bacillus silicophilus was inoculated into a solution containing 2g of silicate rock chips, and the solution was treated in an ultrasonic cleaner for 35 minutes. Then, the solution was transferred to an autoclave and reacted at 121°C for 16 hours. After naturally cooling to room temperature, the solution was calcined in a muffle furnace for 2 hours to obtain activated silicate rock chips.

[0011] Optionally, the adhesive described in step 4 and / or step 5 is made by mixing polyvinyl alcohol (PVA) and starch in a mass ratio of 1:1.

[0012] Optionally, stearic acid may be added as a dispersant during the granulation process in step 4 and / or step 5.

[0013] Optionally, the graphite mold is made of high-purity flake natural graphite.

[0014] A second aspect of the embodiments of this disclosure provides a thermal storage material, which is prepared according to the method described above.

[0015] The beneficial effects of the embodiments of this disclosure include: This invention provides a method for preparing low-grade magnesite tailings thermal storage materials based on microbial corrosion and energy field regulation. The raw materials used are widely available and inexpensive, and the preparation process is simple, green, and environmentally friendly. It can significantly reduce CO emissions and lower energy consumption, and has broad application prospects in the fields of solar energy or nuclear energy. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process for preparing a thermal storage material based on microbial corrosion and energy field regulation, according to an embodiment of this disclosure. Figure 2 This is a schematic diagram of a microbial corrosion activation process according to an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the MgO nanocrystal synthesis process according to an embodiment of the present disclosure; Figure 4 This is a schematic diagram of the process for forming a biomimetic honeycomb structure according to an embodiment of the present disclosure; Figure 5 This is a schematic diagram illustrating the optimization and testing of thermal storage performance according to an embodiment of the present disclosure. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0019] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0020] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for preparing low-grade magnesite tailings thermal storage materials based on microbial corrosion and energy field regulation. The raw materials used are widely available and inexpensive, and the preparation process is simple, green and environmentally friendly. It can significantly reduce CO emissions and energy consumption, and has broad application prospects in the fields of solar energy or nuclear energy.

[0021] The technical solution adopted by this invention to solve its technical problem is: a method for preparing low-grade magnesite tailings thermal storage material based on microbial corrosion and energy field regulation, comprising the following steps: (1) Slurry preparation: magnesium chloride powder was added to distilled water as solvent; sodium hydroxide solution was added to sodium carbonate as activator; and the slurry was prepared by stirring thoroughly. (2) Bacterial culture: Bacillus licheniformis was used as the silicate rock degrading bacteria. It was inoculated into a culture medium containing silicate rock chips and placed in a constant temperature incubator for shaking culture. (3) Activation of silicate rock chips: Bacillus silicophilus culture medium was added to a solution containing silicate rock chips, and the solution was placed in an ultrasonic cleaner for treatment. Then it was transferred to an autoclave for reaction, and then transferred to a muffle furnace for calcination for 2 hours to obtain activated silicate rock chips. (4) Forming a porous structure: After the activated silicate rock fragments are mixed with the binder, they are granulated, dried and pressed to form a green body; the green body is transferred to a muffle furnace at 500~800°C and calcined for 0.5~2h, and then naturally cooled to obtain a pre-oxidized active material; (5) Whisker synthesis: Magnesium oxide active powder is placed in a high vacuum hot press furnace and synthesized under a high pressure of 300~700MPa. Then, it is kept under a low pressure of 30~60MPa for 6~8h and then naturally cooled. The generated nano-whiskers are calcined at a temperature of 400~700°C for 2~4h to obtain a MgO coating layer on the surface, thus obtaining the core nano-whiskers. The core nano-whiskers are mixed with a binder and then granulated, dried and pressed to obtain a green blank. (6) Microstructure optimization: The obtained green blank is placed in a tube furnace and heated to 500-800°C at a rate of 5-10°C / min under air atmosphere and held for 2 hours. The power is turned off and it is naturally cooled to room temperature. The obtained green blank is placed in a graphite mold and obtained by in-situ carbonization and high-temperature sintering in a tube furnace to obtain a green blank with a biomimetic honeycomb structure. (7) Adjustment of heat storage performance: The heat storage performance of the green blank with biomimetic honeycomb structure is adjusted by impregnation method, that is, by immersing it in potassium nitrate solution to improve its heat storage performance.

[0022] In some embodiments, the magnesium chloride powder in step (1) has a purity greater than 99% and a particle size of 0.05 mm.

[0023] In some embodiments, the concentrations of sodium carbonate and sodium hydroxide in step (1) are 0.15 mol / L and 0.05 mol / L, respectively.

[0024] In some embodiments, the Bacillus licheniformis SD-5 described in step (2) was purchased from the China Microbial Culture Collection (accession number | CGMCC 15893), and the deposit date was December 12, 2016.

[0025] In some embodiments, in step (3), 0.1g of Bacillus licheniformis SD-5 is inoculated into a solution containing 2g of silicate rock chips, placed in an ultrasonic cleaner for 35 minutes, then transferred to an autoclave and reacted at 121°C for 16 hours. After naturally cooling to room temperature, the mixture is then calcined in a muffle furnace for 2 hours to obtain activated silicate rock chips.

[0026] In some embodiments, the binder in step (4) is a mixture of PVA and starch in a 1:1 ratio.

[0027] In some embodiments, stearic acid is used as a dispersant during granulation in step (5).

[0028] Preferably, the graphite mold in step (6) is high-purity flake natural graphite.

[0029] This application provides a specific example, such as Figure 1 As shown, a method for preparing low-grade magnesite tailings thermal storage material based on microbial corrosion and energy field regulation is characterized by the following steps: S1. After ball milling, the magnesite tailings powder was added to an Erlenmeyer flask containing Bacillus licheniformis SD-5 (accession number CGMCC 15893), and a certain amount of sterile water was added. The Erlenmeyer flask was placed in a shaker, and the temperature was set to 37°C and the rotation speed to 130 r / min. The mixture was shaken and cultured for 24 h. S2. The magnesite tailings processed in step S1 are loaded into a crucible and placed in a muffle furnace. The temperature is raised to 500°C at a rate of 5°C / min in air atmosphere, held for 2 hours, and then naturally cooled to obtain pre-oxidized magnesia tailings. S3. Place the pre-magnesium oxide tailings obtained in step S2 into a tubular furnace, set the heating temperature to 800°C, and the holding time to 2 hours to obtain a primary pre-sintered MgO. S4. The pre-sintered MgO obtained in step S3 is crushed into powder, and 5 wt.% of carbonized rice husk ash is added as a pore-forming agent. After thorough mixing, it is pressed into shape to obtain a block-shaped product. S5. Place the block-shaped material obtained in step S4 into a muffle furnace, first heat it to 550°C at a rate of 7°C / min, then maintain the temperature at 950°C for 2 hours, and finally cool it naturally to room temperature to obtain secondary pre-sintered MgO. S6. The secondary pre-sintered MgO obtained in step S5 is further crushed and sieved into powder with a particle size range of 20~50μm. After adding binder, granulation and drying, it is pressed into a cylindrical green mud paper-based composite material with a diameter of 30mm. S7. The green mud paper-based composite material obtained in step S6 is preheated at 400°C for 30 min and then calcined at 700°C for 2 h to obtain MgO nano whiskers. S8. The MgO nanocrystals obtained in step S7 are mixed with multi-walled carbonized rice husk ash in a 1:1 ratio and placed in a tube furnace. The mixture is heated to 600°C at a rate of 5°C / min under a nitrogen atmosphere and held for 2 hours. After cooling to 300°C in the furnace, the mixture is removed to obtain a low-grade magnesite tailings-derived honeycomb thermal storage material.

[0030] In one embodiment, Figure 1 The overall preparation process shown includes: 1. Tailings pretreatment; 2. Microbial activation; 3. Whisker synthesis; 4. Honeycomb structure formation; and 5. Adjustment of thermal storage performance.

[0031] Overall preparation process description: The preparation process of thermal storage materials for low-grade magnesia tailings based on microbial corrosion and energy field regulation includes: 1. Tailings Pretreatment: Magnesia ore tailings are ball-milled and then powdered. 2. Microbial Activation: Microbial corrosion activation is performed using Bacillus siliceosa. 3. Whisker Synthesis: Nano-whisker synthesis is carried out in a high-vacuum hot press furnace. 4. Honeycomb Structure Formation: A biomimetic honeycomb structure is formed through in-situ carbonization and high-temperature sintering. 5. Heat Storage Performance Adjustment: Immersion in potassium nitrate solution improves heat storage performance.

[0032] Beneficial effects include: Environmentally friendly: Avoids acidic wastewater pollution caused by traditional acid leaching methods.

[0033] Highly efficient activation: Microbial corrosion combined with energy field regulation significantly improves activation efficiency.

[0034] Unique structure: Forms a biomimetic honeycomb structure to enhance thermal storage performance.

[0035] Resource utilization: Achieve high-value utilization of low-grade magnesite tailings.

[0036] like Figure 2 As shown in the figure, this embodiment illustrates the microbial corrosion activation process, including: 1. preparing Bacillus silicophilicus, 2. mixing magnesite tailings particles, 3. ultrasonic treatment, high-pressure reactor, 4. high-pressure reactor treatment, and 5. temperature control system.

[0037] The microbial activation process includes the following steps: 1. Prepare Bacillus licheniformis SD-5: xuanque CGMCC15893 strain, and culture at 37°C with shaking for 24 hours.

[0038] 2. Ball milling of magnesite tailings: After ball milling, the particle size is 0.05 mm, and the ratio of the magnesite tailings to the bacterial solution is 1:20.

[0039] 3. Ultrasonic treatment: 35 minutes of ultrasonic cleaning to promote microbial penetration.

[0040] 4. High-pressure reaction: Reaction in a high-pressure autoclave at 121°C for 16 hours to achieve deep corrosion.

[0041] 5. Temperature control: Precisely control the reaction temperature to ensure microbial activity.

[0042] Beneficial effects include: 1. Microbial corrosion replaces traditional acid leaching, making it environmentally friendly and pollution-free. 2. Ultrasonic assistance enhances microbial penetration efficiency. 3. High-temperature and high-pressure reaction achieves deep activation of tailings. 4. Activation efficiency is significantly improved compared to traditional methods.

[0043] like Figure 3As shown in the figure, this embodiment illustrates the MgO nanocrystal synthesis process, including: 1. High-pressure synthesis stage (300-700MPa), 2. MgO nanocrystal growth, 3. Surface MgO coating layer, 4. Temperature control curve plotting, and 5. Pressure change curve plotting.

[0044] The synthesis process of MgO nanocrystals includes: 1. High pressure stage: Nanocrystalline whiskers are synthesized under high pressure of 300-700MPa.

[0045] 2. Whisker growth: Maintain a low pressure of 30-60MPa for 6-8 hours to promote whisker growth.

[0046] 3. Surface MgO layer: Calcination at 400-700°C for 2-4 hours to form a surface covering layer.

[0047] 4. Temperature control: Precisely control the heating rate of 5-10°C / min.

[0048] 5. Pressure curve: Optimize the pressure change curve to improve whisker quality.

[0049] like Figure 4 As shown in the figure, this embodiment illustrates the biomimetic honeycomb structure formation process, including: 1. Hexagonal honeycomb unit construction, 2. Multi-level pore structure construction, 3. Preparation of carbonized rice husk ash pore-forming agent, 4. Tube furnace sintering, and 5. Temperature distribution control.

[0050] The formation process of the biomimetic honeycomb structure includes: 1. Hexagonal structure: The hexagonal honeycomb cell structure provides high-strength support.

[0051] 2. Multi-level pores: Multi-scale multi-level pore structures enhance heat conduction and heat storage capacity.

[0052] 3. Carbonized rice husk ash: Add 5 wt.% as a pore-forming agent for carbonized rice husk ash to form uniform pores.

[0053] 4. Tubular furnace sintering device: A stable structure is formed by holding at 600°C for 2 hours under a nitrogen atmosphere.

[0054] 5. Temperature distribution control device: Precisely controls the temperature gradient to optimize structure formation.

[0055] Beneficial effects include: The honeycomb structure provides an ultra-high specific surface area (75 m² / g), and the multi-level pores enable efficient heat conduction (thermal conductivity 3.8 W / mK). It has high structural stability, can withstand temperatures up to 950°C, and has a significantly higher heat storage density than traditional materials.

[0056] like Figure 5 The diagram illustrates the process of optimizing and testing thermal storage performance, including: Step 1: Optimize the impregnation method; Step 2: Add potassium nitrate solution; Step 3: Immerse the honeycomb structure thermal storage material; Step 4: Test with thermal performance testing device; Step 5: Plot the temperature response curve; Step 6: Compare performance.

[0057] Methods for optimizing thermal storage performance include: 1. Impregnation Optimization: Potassium nitrate solution impregnation enhances heat storage capacity. 2. Potassium Nitrate Solution: Improves the material's phase change enthalpy and thermal stability. 3. Honeycomb Structure Material: Provides an ultra-large specific surface area to enhance heat exchange. 4. Thermal Performance Testing: Measures thermal conductivity, specific heat capacity, and heat storage density. 5. Temperature Response Curve: Optimizes the material's thermal response performance. 6. Performance Comparison: Performance improvement compared to traditional heat storage materials. Beneficial effects include: Thermal density: Increased from 1.2 MJ / m°C of traditional materials to 2.8 MJ / m. Thermal cycling stability: Performance retention rate >95% after 1000 thermal cycles. Thermal response time: Reduced from 120 seconds to 45 seconds. Operating temperature range: Expanded from 300-600°C to 200-950°C.

[0058] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A method for preparing thermal storage materials based on microbial corrosion and energy field regulation, characterized in that, include: Step 1: Using distilled water as a solvent, add magnesium chloride powder and sodium carbonate as an activator, add sodium hydroxide solution, and mix thoroughly to obtain a uniform slurry; Step 2: Select Bacillus siliceosa as the silicate rock degrading strain, inoculate it into a culture medium containing silicate rock chips, and place it in a constant temperature incubator for shaking culture; Step 3: Add the culture medium of Bacillus siliceosa obtained in Step 2 to the solution containing silicate rock fragments, treat it with an ultrasonic cleaner, then transfer it to an autoclave for reaction, and then calcine it in a muffle furnace for 2 hours to obtain activated silicate rock fragments. Step 4: Mix activated silicate rock chips with a binder, granulate, dry and press to form a green body; place the green body in a muffle furnace at 500~800°C for 0.5~2 hours, and after natural cooling, obtain the pre-oxidized active material; Step 5: Place the magnesium oxide active powder into a high vacuum hot press furnace and synthesize nano whiskers under high pressure of 300~700 MPa, then keep it at low pressure of 30~60 MPa for 6~8 hours and let it cool naturally. The obtained nanocrystals were calcined at 400-700°C for 2-4 hours to form a surface MgO coating layer, thus obtaining the core nanocrystals; the core nanocrystals were mixed with a binder, granulated, dried and pressed to form a green body; Step 6: Place the green blank in a tube furnace and heat it to 500-800°C at a rate of 5-10°C / min in an air atmosphere. Hold it at that temperature for 2 hours and then let it cool naturally to room temperature after power is turned off. Place the cooled green blank into a graphite mold and perform in-situ carbonization and high-temperature sintering in a tube furnace to obtain a green blank with a biomimetic honeycomb structure. Step 7: The raw blank with a biomimetic honeycomb structure is treated by impregnation and immersed in potassium nitrate solution to obtain the heat storage material.

2. The method for preparing thermal storage materials based on microbial corrosion and energy field regulation according to claim 1, characterized in that, The magnesium chloride powder has a purity greater than 99% and a particle size of 0.05 mm.

3. The method for preparing thermal storage materials based on microbial corrosion and energy field regulation according to claim 1, characterized in that, The concentration of sodium carbonate is 0.15 mol / L, and the concentration of sodium hydroxide is 0.05 mol / L.

4. The method for preparing thermal storage materials based on microbial corrosion and energy field regulation according to claim 1, characterized in that, In the aforementioned step, the Bacillus siliceosa culture medium obtained in step 2 is added to a solution containing silicate rock fragments, treated with an ultrasonic cleaner, then transferred to an autoclave for reaction, and subsequently calcined in a muffle furnace for 2 hours to obtain activated silicate rock fragments, including: 0.1g of Bacillus silicophilus was inoculated into a solution containing 2g of silicate rock chips, and the solution was treated in an ultrasonic cleaner for 35 minutes. Then, the solution was transferred to an autoclave and reacted at 121°C for 16 hours. After naturally cooling to room temperature, the solution was calcined in a muffle furnace for 2 hours to obtain activated silicate rock chips.

5. The method for preparing thermal storage materials based on microbial corrosion and energy field regulation according to claim 1, characterized in that, The adhesive described in step 4 and / or step 5 is made by mixing polyvinyl alcohol (PVA) and starch in a mass ratio of 1:

1.

6. The method for preparing thermal storage materials based on microbial corrosion and energy field regulation according to claim 1, characterized in that, During the granulation process in step 4 and / or step 5, stearic acid is added as a dispersant.

7. The method for preparing thermal storage materials based on microbial corrosion and energy field regulation according to claim 1, characterized in that, The graphite mold is made of high-purity flake natural graphite.

8. A thermal storage material, said thermal storage material being prepared by the method according to any one of claims 1-7.

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