Preparation method and application of silica hydrogel forest fire extinguishing agent
By preparing a forest fire extinguishing agent containing silica hydrogel and hypophosphite, the problems of low adhesion to vegetation surfaces and low fire extinguishing efficiency of existing fire extinguishing agents have been solved, achieving efficient and uniform spraying and excellent fire extinguishing effect, which is suitable for coniferous forest fires.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHEAST FORESTRY UNIV
- Filing Date
- 2024-02-23
- Publication Date
- 2026-06-05
Smart Images
Figure CN118079302B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of forest fire extinguishing agents, and more particularly to a method for preparing and applying a silica hydrogel forest fire extinguishing agent. Background Technology
[0002] Forest fires, due to their suddenness and destructiveness, pose a significant threat to human life and property, natural resources, and the natural ecological environment. Furthermore, forest fires often occur in rugged mountainous areas where transportation and communication are often inconvenient, making firefighting extremely difficult. Therefore, effective prevention and suppression of forest fires has become a top priority. Currently, commonly used forest fire extinguishing agents are mainly classified into dry powder extinguishing agents, carbon dioxide extinguishing agents, foam extinguishing agents, halon extinguishing agents, and water-based extinguishing agents. Among these, dry powder, carbon dioxide, and foam extinguishing agents, due to their relatively light weight, are highly susceptible to environmental factors (such as wind direction) during forest fire suppression, resulting in a very limited amount of the extinguishing agent reaching the fire source, making it difficult to effectively control large-scale forest fires. Halon extinguishing agents primarily work by capturing reactive free radicals, thereby interrupting the combustion chain reaction and achieving forest fire suppression. They have high extinguishing efficiency and stable performance; however, the chlorofluorocarbons produced by their decomposition cause serious ozone layer depletion and have been banned in many countries. Therefore, in recent years, environmentally friendly water-based fire extinguishing agents have received widespread attention from researchers, and improving the fire extinguishing efficiency of water-based fire extinguishing agents has become a key research focus worldwide.
[0003] Water is the first material used for fire extinguishing. It has a relatively high specific heat and strong heat absorption, which can significantly reduce the temperature of forest fires. Furthermore, the large amount of water vapor formed during the extinguishing process can isolate combustibles from oxygen, thus inhibiting the spread of the fire. Currently, water has become the most widely used and most important fire extinguishing method for Class A fires. However, directly using water as a forest fire extinguishing agent still presents many problems, such as the difficulty of water remaining on the surface of combustibles for a long time; the large amount of water used during extinguishing leads to waste; and the poor re-ignition resistance of pure water causes it to evaporate before reaching the combustion point, resulting in low extinguishing effectiveness. Therefore, water-based fire extinguishing agents usually need to be supplemented with additives with fire-extinguishing functions during forest fire extinguishing to improve their extinguishing efficiency. Commonly used additives in water-based fire extinguishing agents are mainly phosphates, which exert their fire-extinguishing effect primarily through the inert gas generated by pyrolysis and catalytic carbonization, working together with water. However, water-based fire extinguishing agents often have good fluidity, making it impossible for them to remain effectively on the surface of combustible forest vegetation for a long time. They are also easily affected by the environment, resulting in uneven spraying and serious loss. This leads to a low effective content of these agents on the surface of forest vegetation eroded by fire, poor adhesion and spreadability, and consequently, low fire extinguishing efficiency of traditional forest fire extinguishing agents. Summary of the Invention
[0004] The present invention aims to address the problems of low effective content and low extinguishing efficiency of existing forest fire extinguishing agents on vegetation surfaces, and provides a method for preparing and applying a silica hydrogel forest fire extinguishing agent.
[0005] The preparation method of the silica hydrogel forest fire extinguishing agent of the present invention includes the following steps:
[0006] 1. Add silica aerogel to distilled water, then add emulsifier, and disperse at high speed at room temperature to prepare silica hydrogel emulsion;
[0007] 2. After standing and defoaming, potassium carbonate is added to the silica hydrogel emulsion and dispersed at high speed to prepare a silica micro-crosslinked emulsion;
[0008] Third, ammonium hypophosphate was then added to the silica micro-crosslinked emulsion, dispersed at high speed, and potassium carbonate was neutralized. The pH of the silica micro-crosslinked emulsion was adjusted to 8.5-9.5 to prepare a silica hydrogel forest fire extinguishing agent.
[0009] Furthermore, the mass concentration of silica aerogel in the silica hydrogel emulsion described in step one is 3%-5%.
[0010] Furthermore, the mass concentration of the emulsifier in the silica hydrogel emulsion described in step one is 0.5%-1%.
[0011] Furthermore, the high-speed dispersion described in step one is carried out at a speed of 3500-4500 r / min for a time of 3-5 min.
[0012] Furthermore, the emulsifier mentioned in step one is octadecanoside, dodecyl dimethyl betaine, or sodium dodecyl sulfonate.
[0013] Furthermore, the mass concentration of potassium carbonate in the silica hydrogel emulsion described in step two is 3%-5%.
[0014] Furthermore, the high-speed dispersion in step two is carried out at a speed of 3500-4500 r / min for a time of 5-8 min.
[0015] Furthermore, the mass concentration of ammonium hypophosphite in the silica micro-crosslinked emulsion described in step three is 2% to 6%.
[0016] Furthermore, the high-speed dispersion speed described in step three is 3500-4500 r / min.
[0017] The present invention relates to the application of silica hydrogel forest fire extinguishing agent in the extinguishing of coniferous forest fires.
[0018] The reaction equation for this invention is:
[0019] K₂CO₃ + NH₄H₂PO₂ → KHCO₃ + KH₂PO₂
[0020] The generated potassium hypophosphite, potassium bicarbonate, and ammonium hypophosphite are used as fire extinguishing aids in silica hydrogel forest fire extinguishing agents.
[0021] The beneficial effects of this invention are:
[0022] This invention uses silica aerogel as a water-retaining agent, thickener, and heat-insulating agent, and introduces hypophosphite and potassium salt as synergists to prepare a silica hydrogel forest fire extinguishing agent with high spraying efficiency, excellent vegetation surface adhesion, and superior fire extinguishing performance. The preparation route of this invention is as follows: Figure 1 As shown.
[0023] The fire extinguishing agent prepared by this invention is a white emulsion with a viscosity of approximately 100 Pa·s. Compared to traditional water-based forest fire extinguishing agents, this silica hydrogel fire extinguishing agent has a certain viscosity, resulting in a larger particle size during spraying compared to the fine water mist of traditional water-based fire extinguishing agents. During spraying, it is less affected by environmental factors such as wind and temperature, and its pH value is 8.5–9.5, which meets the pH requirements of GB 17835-2008 "Water-based Fire Extinguishing Agents".
[0024] With the introduction of surfactants, silica hydrogel forest fire extinguishing agents have good wetting properties on the surface of flammable forest vegetation, which is conducive to their uniform spread on flammable vegetation, thereby achieving efficient fire extinguishing performance.
[0025] The silica hydrogel fire extinguishing agent of this invention uses silica aerogel as the main raw material, which is environmentally friendly and poses virtually no harm to the forest environment during spraying. Furthermore, the micro-crosslinking of the silica aerogel surface through potassium carbonate increases the viscosity of the emulsion and improves its adhesion to the surface of combustible vegetation in forests. With the introduction of ammonium hypophosphite, the potassium hypophosphite, potassium bicarbonate, and remaining ammonium hypophosphite formed after neutralization of potassium carbonate can act as synergists for the silica hydrogel fire extinguishing agent. Through the capture of gas-phase free radicals and the catalytic carbonization of the condensed phase, woodpile fires can be quickly extinguished in approximately 2 seconds after spraying, thus improving the fire extinguishing efficiency of the agent. It demonstrates broad application prospects in the prevention and control of forest fires. Attached Figure Description
[0026] Figure 1 Flowchart for the preparation of silica hydrogel forest fire extinguishing agent;
[0027] Figure 2 The adhesion properties of traditional water-based fire extinguishing agents and silica hydrogel fire extinguishing agents;
[0028] Figure 3Infrared spectra of SiO2, K2CO3, NH4H2PO2 and silica hydrogel fire extinguishing agents;
[0029] Figure 4 The effect of the introduction of ammonium hypophosphate on the pH of silica hydrogel forest fire extinguishing agent;
[0030] Figure 5 Schematic diagram of a fire extinguishing model
[0031] Figure 6 Flame morphology changes and extinguishing performance of H2O, Si3K3P2, Si3K3P4 and Si3K3P6 hydrogel forest fire extinguishing agents during the fire extinguishing process.
[0032] Figure 7 Thermal imaging changes during the fire extinguishing process of H2O, Si3K3P2, Si3K3P4 and Si3K3P6 hydrogel forest fire extinguishing agents. Detailed Implementation
[0033] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.
[0034] Specific Implementation Method 1: The preparation method of the silica hydrogel forest fire extinguishing agent in this implementation method includes the following steps:
[0035] 1. Add silica aerogel to distilled water, then add emulsifier, and disperse at high speed at room temperature to prepare silica hydrogel emulsion;
[0036] 2. After standing and defoaming, potassium carbonate is added to the silica hydrogel emulsion and dispersed at high speed to prepare a silica micro-crosslinked emulsion;
[0037] Third, ammonium hypophosphate was then added to the silica micro-crosslinked emulsion, dispersed at high speed, and potassium carbonate was neutralized. The pH of the silica micro-crosslinked emulsion was adjusted to 8.5-9.5 to prepare a silica hydrogel forest fire extinguishing agent.
[0038] The silica hydrogel forest fire extinguishing agent prepared by this method is more suitable for extinguishing forest fires in predominantly coniferous forests. Northern coniferous forest fires are typically characterized by crown fires and coniferous fires, which are medium to high intensity fires with rapid spread and strong destructive power. Traditional water-based forest fire extinguishing agents have low extinguishing efficiency against these fires. Furthermore, traditional forest fire extinguishing agents have poor wetting and adhesion to conifers and tree canopies. Therefore, the silica hydrogel fire extinguishing agent developed in this invention exhibits good adhesion and spreadability in coniferous forest systems, while demonstrating excellent fire extinguishing efficiency through the synergistic effect of the gas and condensed phases.
[0039] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the mass concentration of silica aerogel in the silica hydrogel emulsion described in step one is 3%-5%. Everything else is the same as in Specific Implementation Method One.
[0040] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the mass concentration of the emulsifier in the silica hydrogel emulsion described in step 1 is 0.5%-1%. Everything else is the same as in Specific Implementation Method 1 or 2.
[0041] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the high-speed dispersion speed in step one is 3500-4000 r / min, and the time is 3-5 min. Everything else is the same as in Specific Implementation Methods One to Three.
[0042] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the emulsifier mentioned in step one is octadecanoside glucoside, dodecyl dimethyl betaine, or sodium dodecyl sulfonate. Everything else is the same as in Specific Implementation Methods One to Four.
[0043] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the mass concentration of potassium carbonate in the silica hydrogel emulsion described in step two is 3%-5%. Everything else is the same as in Specific Implementation Methods One to Five.
[0044] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the high-speed dispersion speed in step two is 3500-4000 r / min, and the time is 5-8 min. Everything else is the same as in Specific Implementation Methods One to Six.
[0045] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the mass concentration of ammonium hypophosphite in the silica micro-crosslinked emulsion described in step three is 2% to 6%. Everything else is the same as in Specific Implementation Methods One to Seven.
[0046] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the high-speed dispersion speed in step three is 3500-4000 r / min. Everything else is the same as in Specific Implementation Methods One to Eight.
[0047] Specific Implementation Method 10: Application of silica hydrogel forest fire extinguishing agent in coniferous forest fire extinguishing in this implementation method.
[0048] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.
[0049] Example 1:
[0050] The preparation method of the silica hydrogel forest fire extinguishing agent in this embodiment includes the following steps:
[0051] Step 1: Preparation of silica micro-crosslinked emulsion
[0052] Silica aerogel was weighed and added to a beaker containing distilled water, followed by the emulsifier octadecanoside, to obtain a mixed solution. The mass concentration of silica aerogel in the mixed solution was 3%, and the mass concentration of octadecanoside was 1%. The beaker containing the mixed solution was then placed in a high-speed disperser and dispersed at 4000 rpm for 5 minutes at room temperature to prepare a silica hydrogel emulsion. After standing and defoaming, potassium carbonate was weighed and added to the silica hydrogel emulsion, resulting in a potassium carbonate mass concentration of 3%. High-speed dispersion was continued at 4000 rpm for 5 minutes to allow the silica hydrogel emulsion to undergo micro-crosslinking under alkaline conditions, forming a stable silica micro-crosslinked emulsion, which improved the viscosity and dispersibility of the silica micro-crosslinked emulsion.
[0053] Step 2: Preparation of silica hydrogel forest fire extinguishing agent
[0054] 2 wt% ammonium hypophosphite was added to the silica micro-crosslinked emulsion prepared in step one, and rapidly dispersed at a speed of 4000 r / min. Potassium carbonate was neutralized, and the pH was adjusted to 9.0 to prepare the forest fire extinguishing agent. The specific reaction equation is as follows:
[0055] K₂CO₃ + NH₄H₂PO₂ → KHCO₃ + KH₂PO₂
[0056] Furthermore, the generated potassium hypophosphite, potassium bicarbonate, and ammonium hypophosphite are used as extinguishing aids in the silica hydrogel fire extinguishing agent, thus preparing a silica hydrogel forest fire extinguishing agent. It is then packaged and transported to the fire-fighting area for use. The preparation process of the silica hydrogel forest fire extinguishing agent is as follows: Figure 1 As shown.
[0057] Example 2:
[0058] The difference between this embodiment and Embodiment 1 is that in step two, 4 wt% of ammonium hypophosphite is added to the silica micro-crosslinked emulsion prepared in step one. Other steps and parameters are the same as in Embodiment 1.
[0059] Example 3:
[0060] The difference between this embodiment and Embodiment 1 is that in step two, 6 wt% ammonium hypophosphite is weighed and added to the silica micro-crosslinked emulsion prepared in step one. Other steps and parameters are the same as in Embodiment 1.
[0061] (a) Adhesion performance test of the silica hydrogel forest fire extinguishing agent prepared in Example 1.
[0062] 1. Apply traditional water-based fire extinguishing agent and silica hydrogel fire extinguishing agent to the surface of pine wood chips respectively. Place the wood chips at room temperature and observe their flowability and adhesion at a certain angle.
[0063] 2. Apply traditional water-based fire extinguishing agent and silica hydrogel fire extinguishing agent to the surface of pine wood chips respectively. Place the wood chips in an 80°C forced-air oven and heat for about 10 minutes. After removing them, tilt them at a certain angle to observe their fluidity and adhesion.
[0064] 3. Apply traditional water-based fire extinguishing agent and silica hydrogel fire extinguishing agent to the surface of pine wood chips respectively. Place the wood chips in an 80℃ forced-air drying oven to dry them. After taking them out, tilt them at a certain angle to observe their fluidity and adhesion.
[0065] The adhesion performance test results of traditional water-based fire extinguishing agents and silica hydrogel fire extinguishing agents are as follows: Figure 2 As shown.
[0066] Traditional water-based fire extinguishing agents tend to run off quickly when dripped onto forest vegetation surfaces. In contrast, silica hydrogel fire extinguishing agents exhibit excellent adhesion to forest vegetation surfaces. Furthermore, as the temperature rises, the water in the silica hydrogel fire extinguishing agent evaporates, creating a distinct high-temperature barrier layer on the wood surface. This layer effectively protects the combustibles at the bottom, resulting in superior fire-retardant and extinguishing performance.
[0067] (II) Infrared characterization of silica hydrogel forest fire extinguishing agent
[0068] Figure 3 Infrared spectra of silica hydrogel forest fire extinguishing agents and their extinguishing systems. Analysis of the curves shows that silica aerogel exhibits high activity at 1078 cm⁻¹. -1 There is a distinct spectral absorption band at 1660 cm⁻¹, which is the antisymmetric stretching vibration peak of the Si-O-Si group; potassium carbonate shows a peak at 1660 cm⁻¹. -1 1360cm -1 The characteristic infrared peaks for carbonate ions are observed at 3400-3100 cm⁻¹; ammonium hypophosphate shows peaks at 3400-3100 cm⁻¹. -1 The location is NH4 + The stretching vibration absorption peak is at 1455 cm⁻¹. -1 The infrared characteristic peak of NO is at 1025 cm⁻¹. -1 1138cm -12346cm -1 These are the stretching vibration absorption peaks of PO, P=O, and PH, respectively. Through the construction of the silica hydrogel fire extinguishing agent system, it can be concluded that the Si-O-Si (1078 cm⁻¹) of the raw materials in the hydrogel fire extinguishing agent... -1 C = O (1649cm) -1 NO (1460cm) -1 ), NH4 + (3400-3100cm -1 ), PO (1038cm) -1 P = O (1168cm) -1 ), PH (2303cm) -1 Chemical bonds such as ) are clearly preserved, but due to the reaction of potassium carbonate and ammonium hypophosphite, at 1156 cm⁻¹, -1 The presence of a distinct C-OH bending vibration peak indicates that potassium carbonate and ammonium hypophosphite have undergone a chemical reaction to produce potassium bicarbonate. Therefore, infrared spectral comparison further confirms that the silica hydrogel forest fire extinguishing agent system consists of potassium hypophosphite, potassium bicarbonate, ammonium hypophosphite, and silica aerogel.
[0069] (III) pH Analysis of Silica Hydrogel Forest Fire Extinguishing Agent
[0070] Figure 4 This study shows the pH changes of a silica micro-crosslinked emulsion with the introduction of ammonium hypophosphite into the solution. Analysis clearly shows that as the amount of ammonium hypophosphite added increases, the pH value of the fire extinguishing agent decreases, keeping the pH value of this forest fire extinguishing agent consistently within the range of 8.5 to 9.5, which meets the requirements of GB 17835—2008 "Water-based Fire Extinguishing Agents". Therefore, this fire extinguishing agent has a relatively small impact on the forest environment during use.
[0071] (IV) Performance Analysis of Silica Hydrogel Forest Fire Extinguishing Agent
[0072] 1. Construction of fire extinguishing model
[0073] This experiment was conducted in a 3m × 8m open space, which, compared to a confined space, has a higher oxygen content and wider adaptability. The experimental system consists of three parts: combustion, extinguishing, and collection. The experimental system is as follows: Figure 5As shown. First, for Class A fire, pine strips measuring 2cm × 2cm × 20cm were selected as the combustion material. Three strips were stacked in three layers, forming a 6cm × 20cm stack (5-1). A crystallizing dish (5-2) with a diameter of 15cm and a height of 7cm, containing 10g of alcohol, was used to ignite the stack. An air compressor provided power to the water mist nozzles. A pressure gauge and pressure sensor were installed at the water pump outlet to monitor the pressure in the water pipes in real time. The designed pressure for this experiment was 1.2MPa. Precision atomizing nozzles were used in the experiment, with nozzle (5-3) positioned 45cm from the top surface of the stack. During combustion, data was collected primarily using thermocouples, an infrared imager, and a camera. The thermocouples used in this experiment were high-temperature resistant thermocouple wires with a temperature range of 0–1000℃. Four thermocouples were distributed at the top of the stack, between the first and second layers of strips, between the second and third layers of strips, and at the bottom of the stack. Thermocouples (5-4) were numbered 1# to 4# from top to bottom. Infrared imager 5-5 and camera 5-6 are used to collect temperature changes and flame morphology changes, smoke flow, and record the extinguishing time throughout the process.
[0074] 2. Fire extinguishing performance test of silica hydrogel forest fire extinguishing agent
[0075] Table 1 shows the specific formulation of silica hydrogel forest fire extinguishing agent. According to... Figure 5 The fire extinguishing performance of H2O, Si3K3P2, Si3K3P4, and Si3K3P6 extinguishing agents was analyzed using the constructed fire extinguishing model. The corresponding fire extinguishing test results are as follows: Figure 6 and Figure 7 As shown. Figure 6 The flame morphology changes and extinguishing performance of silica hydrogel forest fire extinguishing agent during the fire extinguishing process are shown in the figure. (a) represents H2O, (b) represents Si3K3P2, (c) represents Si3K3P4, and (d) represents Si3K3P6. Figure 7 The thermal imaging changes during the fire extinguishing process of silica hydrogel forest fire extinguishing agent are shown, where (b1) represents H2O, (b2) represents Si3K3P2, (b3) represents Si3K3P4, and (b4) represents Si3K3P6.
[0076] Table 1 Formulation of silica hydrogel-type forest fire extinguishing agent
[0077]
[0078] It is quite evident that after water and different proportions of silica hydrogel forest fire extinguishing agents were sprayed onto the log fire, the flame area of the log fire continuously shrank, the fire height decreased accordingly, and the temperature of the log surface and surrounding area dropped significantly. However, when using pure H2O for extinguishing, the open flame of the log was extinguished in 12 seconds, and the smoldering time of the log after the open flame was extinguished was as high as 567 seconds. With the introduction of silica aerogel and extinguishing additives, silica hydrogel forest fire extinguishing agents showed superior fire extinguishing efficiency compared to pure H2O. Si3K3P6 hydrogel forest fire extinguishing agent can extinguish an ignited log in just 2 seconds, and the smoldering time of the log is reduced to 405 seconds, which is 162 seconds less than that of pure water. This indicates that silica hydrogel forest fire extinguishing agents have excellent fire extinguishing performance in northern coniferous forest systems.
[0079] Compared with traditional water-based fire extinguishing agents, the advantages of the silica hydrogel forest fire extinguishing agent prepared in this invention are as follows: 1) The main additives of the silica hydrogel forest fire extinguishing agent are silica aerogel, carbonate, and hypophosphite. This formula does not contain halogens and is an environmentally friendly forest fire extinguishing agent; 2) The silica aerogel undergoes micro-crosslinking through the weakly alkaline environment of carbonate, which increases the droplet size of the silica hydrogel forest fire extinguishing agent and reduces the impact of environmental factors such as wind speed and temperature on the spraying process; 3) Silica aerogel acts as a thickener for this hydrogel forest fire extinguishing agent, and the introduction of some emulsifiers significantly improves the adhesion and wetting properties of the fire extinguishing agent to forest vegetation. 4) The silica aerogel in the silica hydrogel fire extinguishing agent has a stable structure during the fire extinguishing process. It can adhere to the surface of flammable vegetation, shielding the transfer of heat, oxygen, and flammable gases, thus providing better fire extinguishing performance and resistance to reignition for forest vegetation. 5) The introduction of fire extinguishing adjuvants potassium hypophosphite, potassium bicarbonate, and ammonium hypophosphite not only generates phosphorus-containing free radicals and potassium-containing compounds during combustion, effectively capturing H·, O·, and H₂O· produced by forest combustibles in the gas phase, but also promotes the carbonization of forest combustibles in the condensed phase, forming a high-quality shielding char layer in synergy with silica, thereby endowing the silica hydrogel forest fire extinguishing agent with excellent fire extinguishing performance. In summary, this silica hydrogel forest fire extinguishing agent solves the problems of low fire extinguishing efficiency, poor spray uniformity, and low wetting adhesion of traditional forest water fire extinguishing agents, and has broad application prospects in the current prevention and control of forest fires.
Claims
1. A method for preparing a silica hydrogel forest fire extinguishing agent, characterized in that, The method includes the following steps:
1. Add silica aerogel to distilled water, then add emulsifier, and disperse at high speed at room temperature to prepare silica hydrogel emulsion; 2. After standing and defoaming, potassium carbonate is added to the silica hydrogel emulsion and dispersed at high speed to prepare a silica micro-crosslinked emulsion; Third, ammonium hypophosphate is then added to the silica micro-crosslinked emulsion, dispersed at high speed, and potassium carbonate is neutralized. The pH of the silica micro-crosslinked emulsion is adjusted to 8.5-9.5 to prepare a silica hydrogel forest fire extinguishing agent.
2. The preparation method of the silica hydrogel forest fire extinguishing agent according to claim 1, characterized in that, The mass concentration of silica aerogel in the silica hydrogel emulsion described in step one is 3%-5%.
3. The method for preparing the silica hydrogel forest fire extinguishing agent according to claim 1 or 2, characterized in that, The mass concentration of the emulsifier in the silica hydrogel emulsion described in step one is 0.5%-1%.
4. The preparation method of the silica hydrogel forest fire extinguishing agent according to claim 3, characterized in that, The high-speed dispersion in step one is carried out at a speed of 3500-4500 r / min for 3-5 min.
5. The preparation method of the silica hydrogel forest fire extinguishing agent according to claim 4, characterized in that, The emulsifier mentioned in step one is octadecanoside, dodecyl dimethyl betaine, or sodium dodecyl sulfonate.
6. The preparation method of the silica hydrogel forest fire extinguishing agent according to claim 5, characterized in that, The mass concentration of potassium carbonate in the silica hydrogel emulsion described in step two is 3%-5%.
7. The preparation method of the silica hydrogel forest fire extinguishing agent according to claim 6, characterized in that, The high-speed dispersion in step two is carried out at a speed of 3500-4500 r / min for 5-8 min.
8. The method for preparing the silica hydrogel forest fire extinguishing agent according to claim 7, characterized in that, The mass concentration of ammonium hypophosphite in the silica micro-crosslinked emulsion described in step three is 2% to 6%.
9. The method for preparing the silica hydrogel forest fire extinguishing agent according to claim 8, characterized in that, The high-speed dispersion speed described in step three is 3500-4500 r / min.
10. The application of the silica hydrogel forest fire extinguishing agent prepared by the method described in claim 1 in the extinguishing of coniferous forest fires.