Method for preparing red-mud-based composite powder explosion suppressant from waste red mud
A red mud-based composite powder explosion suppressant was prepared by combining bio-modified red mud with sodium bicarbonate, which solved the problems of waste red mud treatment and the lack of single powder explosion suppressant materials, and achieved resource utilization and efficient explosion suppression effect.
Patent Information
- Application Number
- CN202511341144.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-19
- Publication Date
- 2026-02-10
Smart Images
Figure CN121495536A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of powder explosion suppressant technology, and in particular to a method for preparing a red mud-based composite powder explosion suppressant using waste red mud. Background Technology
[0002] Currently, the powder processing field, especially the processing of explosive powders, is often accompanied by the risk of explosion disasters. Common prevention and control measures include explosion isolation, explosion suppression, and explosion venting. Among these, explosion suppression measures include powder explosion suppression and inert gas explosion suppression.
[0003] The aluminum production process generates a large amount of waste red mud. In the current technology, the treatment of waste red mud is relatively simple, mainly by stockpiling. This not only occupies a lot of land resources, but may also pollute the surrounding soil, water and other environments due to the alkalinity and other characteristics of red mud, thus wasting resources.
[0004] Early development of powder explosion suppressors focused on single-substance explosion suppression, such as rock powder, NaHCO3, CaCO3, Na2CO3, and Al(OH)3. Research has confirmed that red mud-based composite powder explosion suppressants, composed of multiple substances, can fully utilize the synergistic effect of different components during the explosion suppression process, thus exhibiting superior explosion suppression performance.
[0005] Developing red mud-based composite powder explosion suppressants using industrial solid waste as raw materials can not only efficiently recycle and reuse waste resources, but also provide new technical solutions for the safety protection of industrial dust explosion suppression. Summary of the Invention
[0006] To address the technical problem of the difficulty in recycling waste red mud from aluminum production, this invention discloses a method for preparing red mud-based composite powder anti-explosion agent using waste red mud.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing red mud-based composite powder anti-knock agent using waste red mud includes the following steps: Step a: The waste red mud generated during the aluminum production process is biomodified with Bacillus urealyticum to obtain Bacillus urealyticum modified red mud particles; Step b: Impregnate and crystallize the urea-modified red mud particles with sodium bicarbonate solution to obtain the red mud-based composite powder explosion suppressant.
[0008] Furthermore, the specific process of step a is as follows: a1. The waste red mud is pretreated by screening with vibration and washing with deionized water multiple times. a2. Inoculate the Bacillus urealyticum strain into liquid culture medium and culture it in a constant temperature shaker at a suitable temperature and a certain rotation speed to activate the strain, restore its activity, and allow it to begin to reproduce. a3. Inoculate the activated strain from step a2 into fresh culture medium at a certain ratio and continue to culture under suitable conditions until the bacterial concentration reaches a certain level, which is the Bacillus urealyticum bacterial solution. a4. Mix the pretreated red mud with a certain amount of urea and calcium salt to obtain a mixed system; a5. Inoculate the Bacillus urealyticum bacterial solution into the mixed system at 5%-15% of the red mud mass, and stir thoroughly to ensure that the microorganisms are evenly distributed in the red mud system; place the reaction system in a suitable environment to carry out the reaction, maintain the temperature at 30-37℃, and the reaction time is 3-7 days; a6. After the reaction is completed, solid-liquid separation is performed to obtain modified red mud filter cake, which is then dried. The dried red mud is then pulverized to obtain urea Bacillus modified red mud particles.
[0009] Furthermore, in step a2, the culture medium temperature of Bacillus urealyticum is 30-37℃, and it is cultured in a constant temperature shaker at a speed of 150-200 r / min for 18-24 hours.
[0010] Furthermore, in step a3, the activated Bacillus urealyticum strain is inoculated into a large volume of fresh culture medium at a ratio of 5%-10%, and the OD600 value of the bacterial solution reaches 1.0-1.5.
[0011] Furthermore, in step a4, the amount of urea added is 2%-5% of the mass of red mud, and the concentration of calcium ions in the solution is 0.1-0.5 mol / L.
[0012] Furthermore, the specific process of step b is as follows: b1. Add the modified red mud particles of Bacillus urealyticum to the sodium bicarbonate solution, stir for 30 minutes, and let it stand and soak for 4-8 hours, stirring once every 1 hour. b2. Transfer the mixture to an evaporating dish, heat in a water bath, and slowly evaporate the water at 40-50℃. This allows sodium bicarbonate to gradually crystallize between the red mud layers and in the pores as the water evaporates. Stir continuously to prevent the surface from crystallizing too quickly and forming a coating layer. b3. After the moisture has mostly evaporated, place the sample in a 60℃ oven to dry for 2-4 hours to remove residual moisture; b4. The dry red mud-based composite powder explosion suppressant was ground using a planetary ball mill to obtain a red mud-based composite powder explosion suppressant with a particle size of 50-100um.
[0013] Furthermore, in step b, the mass fraction of the sodium bicarbonate solution is 5%-8%.
[0014] Furthermore, the solid-liquid ratio of Bacillus urealyticum modified red mud particles to sodium bicarbonate solution is 1:5-1:10.
[0015] The beneficial effects of this invention are: (1) This invention addresses the pollution and resource waste caused by the stockpiling of red mud generated in the aluminum industry by utilizing red mud in a biological way. It eliminates harmful impurities in red mud through modification with Bacillus urealyticum and induces the formation of a porous structure with good connectivity, thereby achieving solid waste reduction and functional transformation. (2) This invention utilizes a solution impregnation-crystallization method to prepare red mud-based composite powder explosion suppressant, enabling porous modified red mud to efficiently composite sodium bicarbonate, allowing sodium bicarbonate crystals to be uniformly embedded in the interlayer and pores of red mud, significantly increasing the loading capacity and strengthening the synergistic effect of physical barrier and chemical explosion suppression. (3) The preparation steps of this invention are green and environmentally friendly. It uses industrial solid waste red mud as the main raw material, which is widely available and inexpensive. Through the combination of biological modification and intercalation process, the resulting powder has a uniform particle size distribution and excellent thermal stability and dispersibility. (4) In the explosion suppressant prepared by the present invention, the porous structure of modified red mud and the thermal decomposition characteristics of sodium bicarbonate form a synergistic explosion suppressing effect. It can buffer shock waves and adsorb free radicals through pores, and can also take advantage of the heat absorption and gas dilution effect of sodium bicarbonate decomposition. Its explosion suppressing effect is better than that of red mud or sodium bicarbonate powder alone. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2 This is an electron microscope image of the waste red mud in Embodiment 1 of the present invention; Figure 3 This is an electron micrograph of the fully modified red mud obtained in Example 1 of the present invention; Figure 4 This is an electron microscope image of the red mud-based composite powder explosion suppressant prepared in Example 1 of the present invention. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] Example 1 A method for preparing a red mud-based composite powder anti-explosion agent using red mud generated during aluminum production includes: (1) The red mud was screened by vibration to remove larger particles of impurities. The red mud was washed multiple times with deionized water to complete the pretreatment.
[0019] (2) Inoculate the Bacillus urealyticum strain into a liquid culture medium containing nutrients such as urea, protein, and beef extract, and culture it in a constant temperature shaker at a suitable temperature and a certain rotation speed to activate the strain, so that the strain can regain its activity and begin to reproduce.
[0020] The culture medium for Bacillus urealyticum was 35°C and cultured for 24 hours in a constant temperature shaker at a speed of 160 r / min.
[0021] (3) The activated Bacillus urea strain is inoculated into a large volume of fresh culture medium at a certain ratio and cultured under suitable conditions until the bacterial concentration reaches a certain level. At this time, the number of Bacillus urea in the bacterial solution is considerable and can be used for subsequent red mud modification treatment.
[0022] The activated Bacillus urealyticum strain was inoculated into a large volume of fresh culture medium at a ratio of 10%, and the OD600 value of the bacterial solution reached 1.0-1.5.
[0023] (4) The pretreated red mud is mixed with a certain amount of urea and calcium salt (such as CaCl₂). Urea serves as the substrate for the action of Bacillus urealyticum urease, while calcium salt provides calcium ions for calcium carbonate precipitation.
[0024] The amount of urea added can be controlled at 5% of the mass of red mud, and the amount of calcium salt added should be sufficient to ensure that the calcium ion concentration in the solution is 0.5 mol / L.
[0025] (5) The prepared Bacillus urealyticum bacterial solution was inoculated into the above mixed system at 15% of the red mud mass, and stirred thoroughly to ensure that the microorganisms were evenly distributed in the red mud system and to promote the reaction.
[0026] (6) Place the reaction system in a suitable environment to carry out the reaction, and keep the temperature at 30-37℃. A constant temperature incubator can be used to control the temperature. For aerobic Bacillus urealyticum, a certain oxygen supply must be ensured in the system, which can be achieved by periodic stirring or introducing sterile air. The reaction time is 3-7 days.
[0027] (7) After the reaction is completed, the system after the reaction is separated into solid and liquid by centrifugation, filtration (such as plate and frame filter press) to obtain the modified red mud filter cake. The filter cake is dried at a suitable temperature (such as 60-80℃) to remove the moisture.
[0028] (8) The dried red mud is pulverized to the required particle size by means of air jet pulverization, ball milling, etc., to obtain modified red mud powder.
[0029] (9) Add 30g of sodium bicarbonate to deionized water to obtain a sodium bicarbonate solution with a mass fraction of 8%.
[0030] (10) Add the modified red mud to the sodium bicarbonate solution, with the solid-liquid ratio of red mud to solution controlled at 1:10. Stir for 30 minutes and then let it stand for 4 hours, stirring once every hour to promote full penetration of the solution. After 10 minutes, add 100 mL of H2O to the fully modified red mud alkaline solution and pass 0.5 L of CO2 through it until Al(OH)3 crystals are completely precipitated. Let it stand for 24 hours to obtain the red mud-based composite powder explosion suppressant standing solution.
[0031] (11) Transfer the mixture to an evaporating dish and slowly evaporate the water at a low temperature (40-50℃). Use a water bath for heating so that sodium bicarbonate gradually crystallizes in the red mud layer and pores as the water evaporates. Stir constantly during the evaporation process to prevent the surface from crystallizing too quickly and forming a coating layer that hinders internal penetration.
[0032] (12) After the moisture has basically evaporated, place the sample in a 60℃ oven to dry for 2-4 hours to remove residual moisture.
[0033] (13) The dry red mud-based composite powder explosion suppressant was ground using a planetary ball mill with a ball-to-material ratio of 2:1, a frequency of 40Hz, and a ball milling time of 5min to obtain a red mud-based composite powder explosion suppressant with a particle size of 50-100um.
[0034] Example 2 A method for preparing a red mud-based composite powder anti-explosion agent using red mud generated during aluminum production includes: (1) The red mud was screened by vibration to remove larger particles of impurities. The red mud was washed multiple times with deionized water to complete the pretreatment.
[0035] (2) Inoculate the Bacillus urealyticum strain into a liquid culture medium containing nutrients such as urea, protein, and beef extract, and culture it in a constant temperature shaker at a suitable temperature and a certain rotation speed to activate the strain, so that the strain can regain its activity and begin to reproduce.
[0036] The culture medium for Bacillus urealyticum was 35°C and cultured for 24 hours in a constant temperature shaker at a speed of 160 r / min.
[0037] (3) The activated Bacillus urea strain is inoculated into a large volume of fresh culture medium at a certain ratio and cultured under suitable conditions until the bacterial concentration reaches a certain level. At this time, the number of Bacillus urea in the bacterial solution is considerable and can be used for subsequent red mud modification treatment.
[0038] The activated Bacillus urealyticum strain was inoculated into a large volume of fresh culture medium at a ratio of 10%, and the OD600 value of the bacterial solution reached 1.0-1.5.
[0039] (4) The pretreated red mud is mixed with a certain amount of urea and calcium salt (such as CaCl₂). Urea serves as the substrate for the action of Bacillus urealyticum urease, while calcium salt provides calcium ions for calcium carbonate precipitation.
[0040] The amount of urea added can be controlled at 5% of the mass of red mud, and the amount of calcium salt added should be sufficient to ensure that the calcium ion concentration in the solution is 0.5 mol / L.
[0041] (5) The prepared Bacillus urealyticum bacterial solution was inoculated into the above mixed system at 15% of the red mud mass, and stirred thoroughly to ensure that the microorganisms were evenly distributed in the red mud system and to promote the reaction.
[0042] (6) Place the reaction system in a suitable environment to carry out the reaction, and keep the temperature at 30-37℃. A constant temperature incubator can be used to control the temperature. For aerobic Bacillus urealyticum, a certain oxygen supply must be ensured in the system, which can be achieved by periodic stirring or introducing sterile air. The reaction time is 3-7 days.
[0043] (7) After the reaction is completed, the system after the reaction is separated into solid and liquid by centrifugation, filtration (such as plate and frame filter press) to obtain the modified red mud filter cake. The filter cake is dried at a suitable temperature (such as 60-80℃) to remove the moisture.
[0044] (8) The dried red mud is pulverized to the required particle size by means of air jet pulverization, ball milling, etc., to obtain modified red mud powder.
[0045] (9) Add 10g of sodium bicarbonate to deionized water to obtain a sodium bicarbonate solution with a mass fraction of 5%.
[0046] (10) Add the modified red mud to the sodium bicarbonate solution, with the solid-liquid ratio of red mud to solution controlled at 1:10. Stir for 30 minutes and then let it stand for 4 hours, stirring once every hour to promote full penetration of the solution. After 10 minutes, add 100 mL of H2O to the fully modified red mud alkaline solution and pass 0.5 L of CO2 through it until Al(OH)3 crystals are completely precipitated. Let it stand for 24 hours to obtain the red mud-based composite powder explosion suppressant standing solution.
[0047] (11) Transfer the mixture to an evaporating dish and slowly evaporate the water at a low temperature (40-50℃). Use a water bath for heating so that sodium bicarbonate gradually crystallizes in the red mud layer and pores as the water evaporates. Stir constantly during the evaporation process to prevent the surface from crystallizing too quickly and forming a coating layer that hinders internal penetration.
[0048] (12) After the moisture has basically evaporated, place the sample in a 60℃ oven to dry for 2-4 hours to remove residual moisture.
[0049] (13) The dry red mud-based composite powder explosion suppressant was ground using a planetary ball mill with a ball-to-material ratio of 2:1, a frequency of 40Hz, and a ball milling time of 5min to obtain a red mud-based composite powder explosion suppressant with a particle size of 50-100um.
[0050] Example 3 A method for preparing a red mud-based composite powder anti-explosion agent using red mud generated during aluminum production includes: (1) The red mud was screened by vibration to remove larger particles of impurities. The red mud was washed multiple times with deionized water to complete the pretreatment.
[0051] (2) Inoculate the Bacillus urealyticum strain into a liquid culture medium containing nutrients such as urea, protein, and beef extract, and culture it in a constant temperature shaker at a suitable temperature and a certain rotation speed to activate the strain, so that the strain can regain its activity and begin to reproduce.
[0052] The culture medium for Bacillus urealyticum was 35°C and cultured for 24 hours in a constant temperature shaker at a speed of 160 r / min.
[0053] (3) The activated Bacillus urea strain is inoculated into a large volume of fresh culture medium at a certain ratio and cultured under suitable conditions until the bacterial concentration reaches a certain level. At this time, the number of Bacillus urea in the bacterial solution is considerable and can be used for subsequent red mud modification treatment.
[0054] The activated Bacillus urealyticum strain was inoculated into a large volume of fresh culture medium at a ratio of 10%, and the OD600 value of the bacterial solution reached 1.0-1.5.
[0055] (4) The pretreated red mud is mixed with a certain amount of urea and calcium salt (such as CaCl₂). Urea serves as the substrate for the action of Bacillus urealyticum urease, while calcium salt provides calcium ions for calcium carbonate precipitation.
[0056] The amount of urea added can be controlled at 5% of the mass of red mud, and the amount of calcium salt added should be sufficient to ensure that the calcium ion concentration in the solution is 0.5 mol / L.
[0057] (5) The prepared Bacillus urealyticum bacterial solution was inoculated into the above mixed system at 15% of the red mud mass, and stirred thoroughly to ensure that the microorganisms were evenly distributed in the red mud system and to promote the reaction.
[0058] (6) Place the reaction system in a suitable environment to carry out the reaction, and keep the temperature at 30-37℃. A constant temperature incubator can be used to control the temperature. For aerobic Bacillus urealyticum, a certain oxygen supply must be ensured in the system, which can be achieved by periodic stirring or introducing sterile air. The reaction time is 3-7 days.
[0059] (7) After the reaction is completed, the system after the reaction is separated into solid and liquid by centrifugation, filtration (such as plate and frame filter press) to obtain the modified red mud filter cake. The filter cake is dried at a suitable temperature (such as 60-80℃) to remove the moisture.
[0060] (8) The dried red mud is pulverized to the required particle size by means of air jet pulverization, ball milling, etc., to obtain modified red mud powder.
[0061] (9) Add 5g of sodium bicarbonate to deionized water to obtain a sodium bicarbonate solution with a mass fraction of 3%.
[0062] (10) Add the modified red mud to the sodium bicarbonate solution, with the solid-liquid ratio of red mud to solution controlled at 1:10. Stir for 30 minutes and then let it stand for 4 hours, stirring once every hour to promote full penetration of the solution. After 10 minutes, add 100 mL of H2O to the fully modified red mud alkaline solution and pass 0.5 L of CO2 through it until Al(OH)3 crystals are completely precipitated. Let it stand for 24 hours to obtain the red mud-based composite powder explosion suppressant standing solution.
[0063] (11) Transfer the mixture to an evaporating dish and slowly evaporate the water at a low temperature (40-50℃). Use a water bath for heating so that sodium bicarbonate gradually crystallizes in the red mud layer and pores as the water evaporates. Stir constantly during the evaporation process to prevent the surface from crystallizing too quickly and forming a coating layer that hinders internal penetration.
[0064] (12) After the moisture has basically evaporated, place the sample in a 60℃ oven to dry for 2-4 hours to remove residual moisture.
[0065] (13) The dry red mud-based composite powder explosion suppressant was ground using a planetary ball mill with a ball-to-material ratio of 2:1, a frequency of 40Hz, and a ball milling time of 5min to obtain a red mud-based composite powder explosion suppressant with a particle size of 50-100um.
[0066] The composite powder explosion suppressants obtained in Examples 1-3 of the same mass were used in the explosion suppression test of aluminum powder dust of the same mass, and the effect comparison is shown in Table 1 below.
[0067] Table 1 Results of Explosion Suppression Test As shown in Table 1 above, the maximum explosion pressures of aluminum powder dust in Examples 1-3 were 3.5 MPa, 5.1 MPa, and 3.8 MPa, respectively, and the maximum explosion pressure rise rates were 8 MPa / s, 14 MPa / s, and 19 MPa / s, respectively. Since the sodium bicarbonate content in the red mud-based composite powder explosion suppressants prepared in Examples 1-3 was 30 g, 10 g, and 5 g, respectively, the composite powder explosion suppressant prepared in Example 1 had the best explosion suppression effect.
[0068] The following table (Table 2) compares the effects of different explosion suppressors used in the same aluminum powder dust explosion suppression test.
[0069] Table 2 Comparison of the explosion suppression effects of different explosion suppressants on aluminum powder dust explosions As shown in Table 2, compared with pure sodium bicarbonate, pure fully modified red mud explosion suppressant and composite powder explosion suppressant, the composite powder explosion suppressant has a better explosion suppression effect on aluminum powder dust explosion. This is because the fully modified red mud and sodium bicarbonate in the composite powder explosion suppressant prepared in Example 1 have a synergistic explosion suppression effect.
[0070] The explosion suppressant prepared by this invention can be widely used for dust explosion suppression. By using the explosion suppressor to perform explosion suppression action in the early stage or during the development of a dust explosion, an explosion suppressant mist is formed, which effectively suppresses the dust explosion.
[0071] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.
Claims
1. A method for preparing red mud-based composite powder anti-explosion agent using waste red mud, characterized in that, Includes the following steps: Step a: The waste red mud generated during the aluminum production process is biomodified with Bacillus urealyticum to obtain Bacillus urealyticum modified red mud particles; Step b: Impregnate and crystallize the urea-modified red mud particles with sodium bicarbonate solution to obtain the red mud-based composite powder explosion suppressant.
2. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 1, characterized in that, The specific process of step a is as follows: a1. The waste red mud is pretreated by screening with vibration and washing with deionized water multiple times. a2. Inoculate the Bacillus urealyticum strain into liquid culture medium and culture it in a constant temperature shaker at a suitable temperature and a certain rotation speed to activate the strain, restore its activity, and allow it to begin to reproduce. a3. Inoculate the activated strain from step a2 into fresh culture medium at a certain ratio and continue to culture under suitable conditions until the bacterial concentration reaches a certain level, which is the Bacillus urealyticum bacterial solution. a4. Mix the pretreated red mud with a certain amount of urea and calcium salt to obtain a mixed system; a5. Inoculate the Bacillus urealyticum bacterial solution into the mixed system at 5%-15% of the red mud mass, and stir thoroughly to ensure that the microorganisms are evenly distributed in the red mud system; place the reaction system in a suitable environment to carry out the reaction, maintain the temperature at 30-37℃, and the reaction time is 3-7 days; a6. After the reaction is completed, solid-liquid separation is performed to obtain modified red mud filter cake, which is then dried. The dried red mud is then pulverized to obtain urea Bacillus modified red mud particles.
3. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 2, characterized in that, In step a2, the culture medium temperature of Bacillus urealyticum is 30-37℃, and it is cultured in a constant temperature shaker at a speed of 150-200 r / min for 18-24 hours.
4. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 3, characterized in that, In step a3, the activated Bacillus urealyticum strain is inoculated into a large volume of fresh culture medium at a ratio of 5%-10%, and the OD600 value of the bacterial solution reaches 1.0-1.
5.
5. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 4, characterized in that, In step a4, the amount of urea added is 2%-5% of the mass of red mud, and the concentration of calcium ions in the solution is 0.1-0.5 mol / L.
6. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 1, characterized in that, The specific process of step b is as follows: b1. Add the modified red mud particles of Bacillus urealyticum to the sodium bicarbonate solution, stir for 30 minutes, and let it stand and soak for 4-8 hours, stirring once every 1 hour. b2. Transfer the mixture to an evaporating dish, heat in a water bath, and slowly evaporate the water at 40-50℃. This allows sodium bicarbonate to gradually crystallize between the red mud layers and in the pores as the water evaporates. Stir continuously to prevent the surface from crystallizing too quickly and forming a coating layer. b3. After the moisture has mostly evaporated, place the sample in a 60℃ oven to dry for 2-4 hours to remove residual moisture; b4. The dry red mud-based composite powder explosion suppressant was ground using a planetary ball mill to obtain a red mud-based composite powder explosion suppressant with a particle size of 50-100um.
7. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 5, characterized in that, In step b, the sodium bicarbonate solution has a mass fraction of 10%-20%.
8. The method for preparing red mud-based composite powder anti-explosion agent using waste red mud as described in claim 5, characterized in that, In step b, the solid-liquid ratio of Bacillus urealyticum modified red mud particles to sodium bicarbonate solution is 1:5-1:10.