Ammonium phosphate ABC type ultrafine dry powder fire extinguishing agent and preparation method thereof

Abstract

The invention discloses an ammonium phosphate ABC type ultrafine dry powder fire extinguishing agent and a preparation method thereof. The ultrafine dry powder fire extinguishing agent comprises raw material components by weight percentage: 40-50% of ammonium polyphosphate, 15-30% of industrial-grade monoammonium phosphate, 15-20% of fire-fighting-grade monoammonium phosphate, 1-3% of white carbon black, 3-5% of hydrophobic white carbon black, 1-3% of catalyst, 0.5-1% of surface modifier and 3-6% of inert filler. The ammonium phosphate dry powder fire extinguishing agent has a high content of effective fire-extinguishing ingredients and strong fire-extinguishing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of fire protection equipment technology, specifically relating to an ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent and its preparation method. Background Technology

[0002] Both surface fires and mine fires cause numerous casualties and significant losses of property and natural resources. Statistics show that between 2021 and 2022, approximately 88,000 fires occurred annually, resulting in about 2,300 deaths and property losses exceeding 6 billion yuan each year. Therefore, developing and preparing highly efficient and cost-effective fire extinguishing agents to quickly and effectively extinguish fires and reduce losses is of great significance.

[0003] For a long time, the fire extinguishing agents commonly used both domestically and internationally have mainly included foam fire extinguishing agents, dry powder fire extinguishing agents, inert gas fire extinguishing agents, water fire extinguishing agents, and halon fire extinguishing agents. In terms of overall fire extinguishing performance, halon fire extinguishing agents are widely used due to their high fire extinguishing efficiency, low cost, low toxicity and no residue, low corrosivity, easy storage, and wide applicability. However, research in the 1980s showed that the release of large amounts of halon substances into the atmosphere would damage the ozone layer, creating huge holes and posing a significant threat to the health of the Earth and humanity. To protect the human environment, my country joined the Montreal Protocol on Substances that Deplete the Ozone Layer in 1991 and formulated a Chinese plan to reduce ozone-depleting substances, deciding to gradually reduce the production of halon fire extinguishing agents and the consumption of halon fire extinguishing systems and fire extinguishers each year until their complete elimination by 2010. After the phase-out of halon fire extinguishing agents, suitable substitutes are necessary to ensure that my country's fire-fighting capabilities are not reduced. As a substitute for halon fire extinguishing agents, it must possess high fire extinguishing efficiency and low production costs, while also considering environmental factors. Ammonium phosphate dry powder fire extinguishing agents, with their environmental friendliness, high fire extinguishing efficiency, and wide fire extinguishing range, can extinguish Class A (flammable solids), Class B (flammable liquids), and Class C (flammable gases) fires, making them one of the most ideal substitutes for halon fire extinguishing agents. Moreover, my country has abundant phosphate rock resources, resulting in low production costs.

[0004] Currently, the development trend of dry powder fire extinguishing agents both domestically and internationally is towards optimized formulations and ultrafine refining. Because ultrafine refining results in smaller particle sizes, significantly increased specific surface area, and high surface activity, dry powder can be stably and uniformly suspended in the air for several minutes, forming a relatively stable aerosol. Upon heating, it can rapidly decompose and capture active free radicals in the flame. Therefore, it not only has high fire extinguishing efficiency but also a completely different application method compared to traditional dry powder fire extinguishing agents; it is similar to halon-based fire extinguishing. Ultrafine dry powder fire extinguishing agents combine chemical and physical fire extinguishing effects, effectively inhibiting flame combustion and extinguishing flames through covering, cooling, and suffocation, while also blocking heat radiation, exhibiting excellent fire extinguishing performance. Summary of the Invention

[0005] The purpose of this invention is to provide an ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent and its preparation method. This fire extinguishing agent has high fire extinguishing efficiency and high purity of the main fire extinguishing components (main fire extinguishing components are 80-90%), good dispersion performance, and can remain suspended in the air for a long time to form an aerosol-like structure.

[0006] To achieve the objectives of this invention, the following implementation scheme is provided.

[0007] In one embodiment, the ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent of the present invention comprises the following raw material components by weight percentage: ① ammonium polyphosphate 40-50%, ② industrial grade monoammonium phosphate 15-30%, ③ fire-fighting grade monoammonium phosphate 15-20%, ④ silica 1-3%, ⑤ catalyst 1-3%, ⑥ inert filler 3-6%, ⑦ surface modifier 0.5-1%, and ⑧ hydrophobic silica 3-5%.

[0008] In the above embodiments, preferably, the ultrafine dry powder fire extinguishing agent of the present invention comprises the following raw material components by weight percentage: ① 40-50% ammonium polyphosphate, ② 20-30% industrial grade monoammonium phosphate, ③ 15-20% fire-fighting grade monoammonium phosphate, ④ 1-2% silica, ⑤ 2-3% catalyst, ⑥ 5-6% inert filler, ⑦ 0.8-1% surface modifier, and ⑧ 3-4% hydrophobic silica, wherein the moisture content of the fire extinguishing agent is below 0.12% (inclusive).

[0009] Preferably, in the above-mentioned ultrafine dry powder fire extinguishing agent, the particle size D90 of the raw materials ①-⑥ is 6-10 μm.

[0010] Preferably, in the above-mentioned ultrafine dry powder fire extinguishing agent, the hydrophobic silica particle size D90 is 1-3 μm.

[0011] Preferably, in the ultrafine dry powder fire extinguishing agent of the present invention, the catalyst is selected from one or more of bentonite and organometallic salts.

[0012] More preferably, in the ultrafine dry powder fire extinguishing agent of the present invention, the bentonite is activated clay, and the organometallic salt is selected from zinc acetate.

[0013] Preferably, in the ultrafine dry powder fire extinguishing agent of the present invention, the filler is selected from one or more of talc powder, zeolite powder, or mica powder. More preferably, the filler is 2% talc powder, 2% zeolite powder, and 2% mica powder, based on the total weight of the fire extinguishing agent.

[0014] Preferably, the ultrafine dry powder fire extinguishing agent of the present invention, ammonium polyphosphate, has a phosphorus pentoxide content ≥70%, a moisture content ≤0.5%, a particle size D50 of 10-12 μm, and a degree of polymerization of 500-800; industrial-grade monoammonium phosphate has an NH4H2PO4 content of 96-98% and a moisture content ≤0.5%; fire-fighting grade monoammonium phosphate has an NH4H2PO4 content of 96-98% and a moisture content ≤1.5%.

[0015] Preferably, in the ultrafine dry powder fire extinguishing agent of the present invention, the catalyst is an organometallic salt or bentonite.

[0016] More preferably, the bentonite is acid-treated bentonite (i.e., activated clay) with an activity >150H+mmol / kg. Its surface and interior are porous. During the powder surface modification process, when water comes into contact with it, the catalyst releases protons into the water, and the water-carried protons hydrolyze and purify with the surface modifier.

[0017] More preferably, the organometallic salt is zinc acetate, which enables the surface modifier to form a good film on the powder surface at low temperature.

[0018] More preferably, the inert filler is talc powder, mica powder, zeolite powder, etc., with the following weight percentages (based on the total weight of the extinguishing agent): talc powder 1-2%, mica powder 1-2%, zeolite powder 1-2%. The inert filler can adjust the bulk density of the ultrafine dry powder extinguishing agent, prevent agglomeration, increase insulation and vibration resistance, improve its dispersibility, and can also be used as a pulverizing aid.

[0019] More preferably, the surface modifier is methyl hydrogen silicone oil with a hydrogen content ≥1.5% and a viscosity (at 25°C) <20 mm / s.

[0020] More preferably, the silica is precipitated silica, which is pulverized to 150-200 mesh by air jet milling and has a silica content of ≥90%.

[0021] More preferably, the hydrophobic silica is fumed silica that has undergone hydrophobic modification treatment, with a silica content of ≥98% and a mesh size of 5000 mesh, which increases the flowability and hydrophobicity of the ultrafine dry powder.

[0022] In another embodiment, a method for preparing the ammonium phosphate ABC type ultrafine dry powder fire extinguishing agent of the present invention is provided.

[0023] Includes the following steps:

[0024] a) The surface modifier is completely dissolved in gasoline, water is added, and the mixture is stirred and emulsified to obtain an emulsion;

[0025] b) Crush the raw materials ①-⑥ to a D90 of 6-10 μm, add the crushed raw materials to a vacuum siliconizer, stir, heat to 50-60°C, pressurize and inject the emulsion from step a), and form atomization. After the addition is complete, continue stirring.

[0026] c) Raise the temperature to 100-105℃ to evaporate the moisture and obtain ultrafine dry powder fire extinguishing agent A;

[0027] d) The temperature was lowered to 70℃, and hydrophobic silica was added to ultrafine dry powder extinguishing agent A. The mixture was stirred continuously and dried to obtain ultrafine dry powder extinguishing agent B.

[0028] e) Sieve the ultrafine dry powder extinguishing agent B to obtain ultrafine dry powder extinguishing agent C. The finished product is ABC ultrafine dry powder extinguishing agent.

[0029] Preferably, in the preparation method of the present invention described above, the mass ratio of surface modifier, gasoline and water in step a) is 1:2-3:0.5-0.8.

[0030] Preferably, in the above-mentioned method for preparing an ammonium phosphate ABC type ultrafine dry powder fire extinguishing agent, in step a), the stirring rate is 1000 r / min and the emulsification time is 10-15 min.

[0031] In step b), before the vacuum siliconizer system temperature reaches 50-60℃, the stirring plow speed is 50-65 r / min, the flying knife speed is 400-600 r / min, the vacuum degree is -0.01 MPa, and the time is 20-30 min; after the vacuum siliconizer system temperature reaches 50-60℃, the stirring plow speed is 70-80 r / min, the flying knife speed is 1300-1400 r / min, the vacuum pressure is -0.04 MPa, and the time is 20-30 min.

[0032] In step c), the temperature of the vacuum siliconizer system is set to 100-105℃, the speed of the stirring plow blade is 50-65 r / min, the speed of the flying blade is 800-1000 r / min, the vacuum pressure is -0.02 MPa, and the time is 90 min.

[0033] In step d), the temperature of the vacuum siliconizer system is set to 80℃-90℃, the speed of the stirring plow blade is 70-80 r / min, the speed of the flying blade is 1300-1400 r / min, the vacuum degree is -0.01 MPa, and the time is 30 min.

[0034] In one specific embodiment, a method for preparing an ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent according to the present invention includes the following steps:

[0035] a) Mix and dry the raw materials (hereinafter referred to as "raw materials") 50-60% ammonium polyphosphate, 15-30% industrial grade monoammonium phosphate, 15-20% fire-fighting grade monoammonium phosphate, 1-3% silica, 1-3% catalyst, and 3-6% inert filler at 80-90℃.

[0036] b) After the dried raw material is naturally cooled for 30 minutes, it is pulverized. The D90 particle size after pulverization is 6-10 μm.

[0037] c) Dissolve 0.5-1% of the surface modifier in gasoline to obtain a solution. After adding water to the solution, stir and emulsify to obtain an emulsion.

[0038] d) Add the pulverized raw material into the vacuum siliconizer, heat the system temperature inside the siliconizer to 50-60℃ while stirring, and inject the emulsion into the siliconizer under pressure while stirring to form an atomization effect. Continue stirring after injection is complete.

[0039] e) Under stirring, the temperature of the vacuum siliconization system is raised to 100-105℃. Stirring is continued to evaporate the moisture and obtain ultrafine dry powder fire extinguishing agent A.

[0040] f) Under stirring, the temperature of the vacuum siliconization machine system is reduced to 70°C. 3-5% hydrophobic silica is added to the ultrafine dry powder fire extinguishing agent A, and the mixture is continuously stirred and dried to obtain ultrafine dry powder fire extinguishing agent B.

[0041] g) Ultrafine dry powder extinguishing agent B is ultrasonically sieved to obtain ultrafine dry powder extinguishing agent C, which is the finished product ABC ultrafine dry powder extinguishing agent.

[0042] As a preferred option, in step a, because the silica is light, it is added to the stirring 5-10 minutes before the raw material mixing and drying is finished, and the dust removal and pneumatic fan is turned off to reduce the silica being sucked away, while still being mixed into the material.

[0043] Preferably, in step b, the frequency of the classifier and the flow rate of the secondary air inlet are adjusted to control the particle size and particle diameter distribution after pulverization.

[0044] Preferably, in step c, the gasoline is 98# gasoline. After the surface modifier is fully mixed with the gasoline, water is added and stirred at high speed to form an emulsion.

[0045] Preferably, in step d, the working pressure of the atomizing nozzle is 1.4-1.6 MPa. The atomization degree of the atomizing nozzle has a great influence on the surface modification effect. Low atomization degree leads to uneven dispersion of the surface modifier in the powder.

[0046] Preferably, in step e, the vacuum pressure is maintained at -0.04 MPa, and this stage lasts for 90-120 minutes.

[0047] Preferably, in step f, the vacuum pressure is maintained at -0.01 MPa, and after adding hydrophobic silica, the mixture is stirred for 30-40 minutes.

[0048] Preferably, in step g, the three-dimensional vibrating screen and the ultrasonic device have a screen mesh size of 500 mesh.

[0049] The ultrafine dry powder fire extinguishing agent of the present invention has the following advantages:

[0050] 1. Because ammonium polyphosphate is relatively fine, it takes a long time to grind alone. However, the addition of industrial-grade monoammonium phosphate and fire-fighting-grade monoammonium phosphate, which are coarser, greatly shortens the grinding time when the three are mixed together and ground, and also balances the particle size of the powder well.

[0051] 2. Ammonium polyphosphate mainly extinguishes fires by asphyxiation through thermal expansion and carbonization, and by isolating air, while monoammonium phosphate mainly extinguishes fires by chemical inhibition through thermal decomposition and heat absorption. Therefore, this invention combines the fire extinguishing advantages of both.

[0052] 3. In addition, since this invention uses high-polymerization-degree ammonium polyphosphate, which has a better low moisture absorption rate, the addition of fire-fighting grade monoammonium phosphate also reduces production costs.

[0053] 4. Adding silica increases the fluidity of the pulverized raw material, allowing the surface modifier to be evenly dispersed in the powder; the main extinguishing components are high, with good dispersibility and long suspension time in the air. Detailed Implementation

[0054] The following examples are representative and are intended to further understand and illustrate the essence of the present invention, but do not limit the scope of the present invention in any way.

[0055] Example 1: Ammonium phosphate ABC ultrafine dry powder fire extinguishing agent

[0056] Weigh 500 kg of raw materials according to the following formula:

[0057] ① Ammonium polyphosphate 50%; ② Industrial grade monoammonium phosphate 20%; ③ Fire-fighting grade monoammonium phosphate 15.2%; ④ Activated clay 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 0.8%; ⑩ Hydrophobic Silica 3%;

[0058] Preparation process:

[0059] 1. Put the above ingredients ①-⑦ into a mixing and drying mixer, and dry them at 80-90℃ until the moisture content is below 0.1%. Add ingredient ⑧ 5-10 minutes before the end of mixing and drying. After the mixing and drying is completed, let the material cool naturally for 30 minutes.

[0060] 2. Crush the cooled raw material to the specified particle size, D90 particle size is 6-10um;

[0061] 3. Put the crushed material into the siliconizer, continue heating and stirring for 30 minutes, control the temperature at 55℃, and maintain the vacuum negative pressure at -0.01Mpa.

[0062] 4. Mix ⑨ with gasoline and water at a mass ratio of 1:2:0.5, stir at a stirring speed of 1000 r / min, and emulsify for 10-15 min to form a mixed emulsion.

[0063] 5. The mixed emulsion is injected into the siliconizer under pressure. Before the temperature of the medium vacuum siliconizer system reaches 50-60℃ (preferably 60℃), the stirring speed of the plow blade is controlled at 50-65 r / min, the flying blade speed is controlled at 400-600 r / min, the vacuum degree is -0.01 MPa, and the time is 20-30 min (preferably 20 min). After the temperature of the vacuum siliconizer system reaches 60℃, the stirring speed of the plow blade is controlled at 70-80 r / min, the flying blade speed is controlled at 1300-1400 r / min, the vacuum pressure is -0.04 MPa, and the time is 20-30 min (preferably 20 min).

[0064] 6. Control the temperature at 105℃, the speed of the flying knife at 800-1000 r / min, and the vacuum pressure at -0.02Mpa to -0.04Mpa for 90 min to obtain ultrafine dry powder A.

[0065] 7. Add hydrophobic silica to ultrafine dry powder A, control the temperature of the medium vacuum siliconization system in the range of 80℃-90℃, control the speed of the stirring plow blade in the range of 70-80r / min, control the speed of the flying knife in the range of 1300-1400r / min, the vacuum degree is -0.01Mpa, and the time is 30min to obtain ultrafine dry powder B.

[0066] 8. Sieve through a 500-mesh sieve to obtain ultrafine dry powder C, package it, and the finished product is the fire extinguishing agent in the title.

[0067] Example 2: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0068] Weigh 500 kg of raw materials according to the following formula:

[0069] ① Ammonium polyphosphate 40%; ② Industrial grade monoammonium phosphate 30%; ③ Fire-fighting grade monoammonium phosphate 15.2%; ④ Activated clay 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 0.8%; ⑩ Hydrophobic Silica 3%.

[0070] The preparation process is the same as in Example 1.

[0071] Example 3: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0072] Weigh 500 kg of raw materials according to the following formula:

[0073] ① Ammonium polyphosphate 50%; ② Industrial grade monoammonium phosphate 20%; ③ Fire-fighting grade monoammonium phosphate 15%; ④ Activated clay 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 1%; ⑩ Hydrophobic Silica 3%.

[0074] The preparation process is the same as in Example 1.

[0075] Example 4: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0076] Weigh 500 kg of raw materials according to the following formula:

[0077] ① Ammonium polyphosphate 40%; ② Industrial grade monoammonium phosphate 30%; ③ Fire-fighting grade monoammonium phosphate 15%; ④ Activated clay 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 1%; ⑩ Hydrophobic silica 3%.

[0078] The preparation process is the same as in Example 1.

[0079] Example 5: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0080] Weigh 500 kg of raw materials according to the following formula:

[0081] ① Ammonium polyphosphate 50%; ② Industrial grade monoammonium phosphate 15.2%; ③ Fire-fighting grade monoammonium phosphate 20%; ④ Zinc acetate 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 0.8%; ⑩ Hydrophobic silica 3%.

[0082] The preparation process is the same as in Example 1.

[0083] Example 6: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0084] Weigh 500 kg of raw materials according to the following formula:

[0085] ① Ammonium polyphosphate 40%; ② Industrial grade monoammonium phosphate 30%; ③ Fire-fighting grade monoammonium phosphate 15.2%; ④ Zinc acetate 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 0.8%; ⑩ Hydrophobic silica 3%.

[0086] The preparation process is the same as in Example 1.

[0087] Example 7: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0088] Weigh 500 kg of raw materials according to the following formula:

[0089] ① Ammonium polyphosphate 40%; ② Industrial grade monoammonium phosphate 30%; ③ Fire-fighting grade monoammonium phosphate 15%; ④ Zinc acetate 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 1%; ⑩ Hydrophobic silica 3%.

[0090] The preparation process is the same as in Example 1.

[0091] Example 8: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0092] Weigh 500 kg of raw materials according to the following formula:

[0093] ① Ammonium polyphosphate 50%; ② Industrial grade monoammonium phosphate 20%; ③ Fire-fighting grade monoammonium phosphate 15%; ④ Zinc acetate 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 1%; ⑩ Hydrophobic silica 3%.

[0094] The preparation process is the same as in Example 1.

[0095] Example 9: Ammonium phosphate salt ABC type ultrafine dry powder fire extinguishing agent

[0096] Weigh 500 kg of raw materials according to the following formula:

[0097] ① Ammonium polyphosphate 50%; ② Industrial grade monoammonium phosphate 20%; ③ Fire-fighting grade monoammonium phosphate 15.2%; ④ Zinc acetate 3%; ⑤ Talc powder 2%; ⑥ Zeolite powder 2%; ⑦ Mica powder 2%; ⑧ Silica 2%; ⑨ Surface modifier 0.8%; ⑩ Hydrophobic silica 3%;

[0098] The preparation process is the same as in Example 1.

[0099] Comparative Example 1: Ammonium Phosphate Class ABC Ultrafine Dry Powder Fire Extinguishing Agent

[0100] Weigh 500 kg of raw materials according to the following formula:

[0101] ① 85% industrial grade monoammonium phosphate; ② 3% activated clay; ③ 2% talc; ④ 2% zeolite powder; ⑤ 2% mica powder; ⑥ 2% silica; ⑦ 1% surface modifier; ⑧ 3% hydrophobic silica.

[0102] The preparation process is the same as in Example 1.

[0103] Comparative Example 2: Ammonium Phosphate Salt Class ABC Ultrafine Dry Powder Fire Extinguishing Agent

[0104] Weigh 500 kg of raw materials according to the following formula:

[0105] ① Fire-grade monoammonium phosphate 85%; ② Activated clay 3%; ③ Talc powder 2%; ④ Zeolite powder 2%; ⑤ Mica powder 2%; ⑥ Silica 2%; ⑦ Surface modifier 1%; ⑧ Hydrophobic silica 3%.

[0106] The preparation process is the same as in Example 1.

[0107] Comparative Example 3: Ammonium Phosphate Class ABC Ultrafine Dry Powder Fire Extinguishing Agent

[0108] Weigh 500 kg of raw materials according to the following formula:

[0109] ① Ammonium polyphosphate 50% ② Fire-grade monoammonium phosphate 35% ③ Activated clay 3% ④ Talc powder 2% ⑤ Zeolite powder 2% ⑥ Mica powder 2% ⑦ Silica 2% ⑧ Surface modifier 1% ⑨ Hydrophobic silica 3%

[0110] The preparation process is the same as in Example 1.

[0111] Extinguishing agent performance testing and fire extinguishing effectiveness testing

[0112] The performance of ammonium phosphate ABC type ultrafine dry powder fire extinguishing agents in Examples 1-8 and Comparative Examples 1-3 was tested. The bulk density, moisture content, hygroscopicity, water repellency, anti-caking property (penetration), low temperature resistance, 90% particle size, and electrical insulation were tested according to the test methods in the standard "GA578-2005 Ultrafine Dry Powder Fire Extinguishing Agent". The test results are shown in Table 1.

[0113] Table 1. Performance Test Results of Ammonium Phosphate Types ABC Ultrafine Dry Powder Fire Extinguishing Agents

[0114]

[0115]

[0116] Fire extinguishing performance test

[0117] The extinguishing efficacy of ammonium phosphate ABC class ultrafine dry powder fire extinguishing agents in Examples 1-8 and Comparative Examples 1-3 was tested according to the test methods in the standard "GA578-2005 Ultrafine Dry Powder Fire Extinguishing Agents". The extinguishing efficacy for Class B and C fires and Class A fires was tested. The test results are shown in Table 2.

[0118] Table 2. Performance Test Results of Ammonium Phosphate Types ABC Ultrafine Dry Powder Fire Extinguishing Agents

[0119]

[0120]

[0121] Table 1 shows the overall powder performance, and Table 2 shows the fire extinguishing characteristics, indicating that the ammonium phosphate ABC type ultrafine dry powder fire extinguishing agents prepared in Examples 1-8 have superior dispersion performance and fire extinguishing efficiency compared to Comparative Examples 1-3. In Table 1, the overall powder performance of Examples 1-4 and 6-9 shows that the ultrafine dry powder fire extinguishing agent with a polyphosphate specific gravity of 50% has better moisture absorption and anti-caking properties than the ultrafine dry powder fire extinguishing agent with a polyphosphate specific gravity of 40%. Furthermore, in Table 2, the fire extinguishing characteristics of Examples 1-4 and 6-9 also show that the fire extinguishing efficiency is better when the polyphosphate specific gravity is 50% than when it is 40%. In Table 1, the hydrophobicity is better when the surface modifier addition is 1% than when it is 0.8%. In Table 1, the fire-grade monoammonium phosphate in Example 5 has a higher specific gravity than the industrial-grade monoammonium phosphate in Example 3. Because the content of fire-grade monoammonium phosphate is lower than that of industrial-grade monoammonium phosphate, the fire extinguishing efficiency of Example 3 in Table 2 is better than that of Example 5. Tables 1 and 2, Examples 1-4 and 6-9, show that the effects of using zinc acetate as a catalyst and activated clay as a catalyst are not significantly different. However, activated clay is relatively cheaper and more suitable for large-scale production. Comparative Examples 1-2 are the main raw materials of commonly used ultrafine dry powder fire extinguishing agents on the market. The addition of ammonium polyphosphate to Tables 1 and 2 results in superior overall powder performance and fire extinguishing performance compared to Comparative Examples 1-2. Surprisingly, although Comparative Example 3 contains ammonium polyphosphate, it lacks industrial-grade monoammonium phosphate, yet its fire extinguishing efficiency is lower than that of Examples 1-8. Experiments show that the ammonium phosphate ultrafine dry powder fire extinguishing agent of this invention can effectively extinguish Class A, B, and C fires. After being sprayed with compressed gas, it forms an aerosol, and the powder can be stably suspended in the air. It also possesses characteristics similar to compressible, fluid, and dispersible gaseous fire extinguishing agents, enabling total flooding fire extinguishing. When sprayed into a confined space to reach the extinguishing concentration, the flame can be extinguished in a very short time.

Claims

1. An ammonium phosphate ABC type ultrafine dry powder fire extinguishing agent, comprising the following raw material components by weight percentage: ① ammonium polyphosphate 40-50%, ② industrial grade monoammonium phosphate 15-30%, ③ fire grade monoammonium phosphate 15-20%, ④ white carbon black 1-3%, ⑤ catalyst 1-3%, ⑥ inert filler 3-6%, ⑦ surface modifier 0.5-1% and ⑧ hydrophobic white carbon black 3-5%.

2. The ultrafine dry powder fire extinguishing agent according to claim 1, comprising the following raw material components by weight: ① ammonium polyphosphate 40-50%, ② industrial grade monoammonium phosphate 20-30%, ③ fire grade monoammonium phosphate 15-20%, ④ white carbon black 1-2%, ⑤ catalyst 2-3%, ⑥ inert filler 5-6%, ⑦ surface modifier 0.8-1% and ⑧ hydrophobic white carbon black 3-4%, wherein: The water content of the fire extinguishing agent is 0.12% or less.

3. The ultrafine dry powder fire extinguishing agent according to claim 1 or 2, wherein the particle size D90 of the raw materials ①-⑥ is 6-10 um.

4. The ultrafine dry powder fire extinguishing agent according to claim 1 or 2, wherein the particle size D90 of the hydrophobic silica is 1-3 μm.

5. The ultrafine dry powder fire extinguishing agent according to claim 1 or 2, wherein the catalyst is selected from one or more of bentonite and organic metal salts, and the surface modifier is methyl hydrogen silicone oil.

6. The ultrafine dry powder fire extinguishing agent according to claim 5, wherein the bentonite is activated white clay, and the organic metal salt is selected from zinc acetate.

7. The ultrafine dry powder fire extinguishing agent according to claim 1, wherein the inert filler is selected from one or more of talcum powder, zeolite powder or mica powder.

8. The ultrafine dry powder fire extinguishing agent according to claim 7, wherein the inert filler is 1-2% talcum powder, 1-2% zeolite powder and 1-2% mica powder, based on the total weight of the fire extinguishing agent.

9. A method for preparing the ultrafine dry powder fire extinguishing agent according to any one of claims 1 to 8, The following steps are involved: a) dissolving the surface modifier (7) completely in gasoline, adding water and stirring to emulsify to obtain an emulsion; b) crushing raw materials ①-⑥, adding them into a vacuum siliconizing machine, stirring, heating to 50-60°C, injecting the emulsion of step a) under pressure, and forming atomization, and stirring continuously after addition; c) Raise the temperature to 100-105°C to evaporate the water and obtain ultrafine dry powder fire extinguishing agent A; d) lowering the temperature to 70° C., adding the hydrophobic white carbon black (⑧) to the ultrafine dry powder fire extinguishing agent A, continuously stirring, and drying to obtain an ultrafine dry powder fire extinguishing agent B; e) The ultrafine dry powder fire extinguishing agent B is sieved to obtain ultrafine dry powder fire extinguishing agent C. The finished product is ultrafine dry powder fire extinguishing agent ABC, wherein the sieve mesh is 500 mesh.

10. The preparation method according to claim 9, wherein in step a), the mass ratio of the surface modifier, gasoline and water is 1:2-3:0.5-0.8.

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