Fire extinguishing material prepared from calcium sulfate dihydrate, fire extinguishing agent comprising it and use

Abstract

This invention belongs to the field of fire extinguishing material preparation technology, and relates to a fire extinguishing material prepared from calcium sulfate dihydrate, a fire extinguishing agent containing it, and its applications. The key technical points are as follows: Solid waste containing calcium sulfate dihydrate is processed into powder with a particle diameter of less than 250 μm at 50–70°C, which is used as the first fire extinguishing material. The calcium sulfate content is ≥80%. The solid waste is one or more of natural gypsum ore, phosphate tailings, or phosphogypsum or desulfurization gypsum produced during coal desulfurization. This invention uses calcium sulfate dihydrate as the main ingredient, adds appropriate moisture content regulators, additives, and fire extinguishing performance enhancers, and undergoes surface modification treatment to produce a novel dry powder fire extinguishing agent. It mainly extinguishes fires through physical action and can effectively suppress the generation of toxic fumes. It has significant cost advantages, a wide range of applications, and can also expand the reuse value of solid waste.

Description

Technical Field

[0001] This invention belongs to the field of fire extinguishing material preparation technology, and relates to a fire extinguishing material prepared from calcium sulfate dihydrate, a fire extinguishing agent containing it, and its application. Background Technology

[0002] Currently, phosphate mine tailings and coal desulfurization both generate a large amount of solid waste, the main component of which is calcium sulfate dihydrate, commonly known as phosphogypsum and desulfurization gypsum. It is usually used as building material. However, with the construction market remaining sluggish for a considerable period of time in the future, the consumption of building materials will plummet, which will inevitably lead to a large accumulation of such waste, which will be difficult to handle, occupy land, affect the environment, and may cause secondary disasters such as landslides and mudslides.

[0003] Currently, the most widely used fire extinguishing agent is dry powder, with a domestic market size of 50 million tons per year. It mainly consists of BC and ABC types. The former is primarily composed of sodium bicarbonate, priced at around 3,000 yuan per ton, while the latter is primarily composed of ammonium dihydrogen phosphate / ammonium sulfate, priced at around 6,000 yuan per ton. These two types of dry powder fire extinguishing agents have dominated the market for nearly a century, with long-term homogeneous competition among manufacturers resulting in a product qualification rate of less than 40%. BC type fire extinguishing agents are suitable for extinguishing liquid and gaseous fires; ABC type fire extinguishing agents are suitable for extinguishing solid, liquid, and gaseous fires, but their cooling effect during extinguishing is poor, making reignition easy. Besides dry powder, existing fire extinguishing agents include water-based, foam, gaseous, liquid, and aerosol types, but these are all designed for initial fires in small indoor spaces and are ineffective against large-scale outdoor fires. Currently, there are no suitable fire extinguishing agents for typical forest fires and new energy battery fires. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the existing technology and provide a fire extinguishing material prepared from calcium sulfate dihydrate, as well as the fire extinguishing agent containing it and its application. It uses solid waste gypsum, including phosphogypsum and desulfurized gypsum, and gypsum produced from the recycling of other wastes as the main raw material, adds appropriate ingredients, and goes through a series of processes to make a series of products suitable for different needs. This solves the problems of high cost and unsuitability for large-area fire extinguishing of current fire extinguishing agents, as well as the problem that solid fires extinguished by current dry powder fire extinguishing agents are prone to reignition.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0006] The present invention provides a fire extinguishing material prepared from calcium sulfate dihydrate, wherein solid waste containing calcium sulfate dihydrate is processed into powder with a particle diameter of less than 250 μm at 50-70°C, and used as the first fire extinguishing material, wherein the content of calcium sulfate is ≥80%.

[0007] Solid waste is one or more of the following: natural gypsum mine, phosphate mine tailings, phosphogypsum or desulfurization gypsum produced during coal desulfurization.

[0008] Furthermore, when the moisture content of the first extinguishing material is less than the set threshold, a moisture content regulator is used to mix the first extinguishing material so that the moisture content of the mixture is greater than or equal to the threshold, and the resulting mixture is the second extinguishing material.

[0009] Note: The water content mentioned here mainly refers to the water of crystallization content, and also includes a small amount of adsorbed water content; the water content regulator is one or more of magnesium sulfate heptahydrate, calcium chloride hexahydrate, or aluminum sulfate. These three compounds have a higher proportion of water of crystallization in their molecular structure, and adding them can increase the water of crystallization content. However, if one or more of these three are used alone as fire extinguishing materials, they are prone to clumping and cannot maintain a dry and loose state for a long time, so they cannot be sprayed for fire extinguishing.

[0010] Furthermore, the first or second fire extinguishing material is sieved into five components with different particle sizes: ① below 20 μm; ② 20–40 μm; ③ 40–63 μm; ④ 63–125 μm; and ⑤ 125–250 μm. Each component with a different particle size is a third fire extinguishing material.

[0011] Furthermore, the third fire extinguishing material with different particle sizes is mixed according to the gradation to obtain the fourth fire extinguishing material.

[0012] Furthermore, ingredients with a particle diameter of <20μm are added to the fourth fire extinguishing material and mixed evenly to obtain the fifth fire extinguishing material; the raw materials are one or more of fly ash, wood ash or soil from the old course of the Yellow River.

[0013] Note: Adding this ingredient helps the fire extinguishing material remain dry and loose for a longer period of time, preventing it from clumping and thus improving its fire extinguishing effect.

[0014] The present invention also provides a method for preparing a fire extinguishing agent using calcium sulfate dihydrate as the main material, wherein the fifth fire extinguishing material is surface modified with a surfactant to obtain a first fire extinguishing agent.

[0015] The surfactant here refers to one or more of methylated silicone oil, hydrogen-containing silicone oil, or fluorocarbon silicone oil, and the amount added is 0.5% to 2.5%.

[0016] The surface modification method mainly involves controlling the temperature at 50–70°C and high-speed stirring.

[0017] Furthermore, the fire extinguishing performance of the first fire extinguishing agent is enhanced by using a fire extinguishing performance enhancer to obtain a second fire extinguishing agent.

[0018] The fire extinguishing performance enhancer here is one or both of magnesium acetate hydrate or carbamide.

[0019] The present invention also provides the application of the above-mentioned fire extinguishing materials and fire extinguishing agents, wherein the first fire extinguishing agent and the second fire extinguishing agent are used in portable dry powder fire extinguishers, automatic dry powder fire extinguishing systems or in the manufacture of fire extinguishing bombs;

[0020] The third, fourth, and fifth fire extinguishing materials are used in large fire extinguishing equipment such as dry powder fire trucks, fireboats, fire helicopters, and drones.

[0021] The first and second fire extinguishing materials are used to replace dry sand for fire extinguishing, such as in laboratories, gas stations, oil depots, and docks.

[0022] Note: From the perspective of fire extinguishing performance, the first and second extinguishing agents are more suitable for fire extinguishing equipment; those suitable for fire extinguishing equipment are also more suitable for replacing dry sand extinguishing. The above-mentioned graded combination is mainly based on a comprehensive consideration of factors such as fire extinguishing cost.

[0023] In summary, the present invention has the following beneficial effects:

[0024] This invention provides a fire extinguishing material prepared from calcium sulfate dihydrate, a fire extinguishing agent containing it, and its application. It uses solid waste gypsum, including phosphogypsum and desulfurized gypsum, and gypsum produced from the recycling of other wastes as the main raw material, adds appropriate ingredients, and goes through a series of processes to make a series of products suitable for different needs. (1) It solves the problem that the current fire extinguishing agents are expensive and not suitable for large-area fire fighting; (2) It solves the problem that the current dry powder fire extinguishing agents are easy to reignite after extinguishing solid fires; (3) The fire extinguishing process is mainly physical and does not produce toxic chemical components, and has high environmental protection performance; (4) It can inhibit the generation of toxic smoke from fires and reduce asphyxiation deaths caused by fire smoke. Attached Figure Description

[0025] Figure 1 A flowchart illustrating the preparation process of the fire extinguishing agent provided by this invention;

[0026] Figure 2 This is a DSC curve of the raw material in step S1 of Example 1;

[0027] Figure 3 Thermogravimetric analysis diagram of the raw material in step S1 of Example 1;

[0028] Figure 4 This is the woodpile fire model used in Example 2.

[0029] Figure Labels

[0030] 1. Ignition plate; 2. Support frame; 3. Weighing platform; 4. Angle iron. Detailed Implementation

[0031] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific implementation methods, features and effects of a fire extinguishing material prepared from calcium sulfate dihydrate according to the present invention, as well as the fire extinguishing agent containing it and its application, are described in detail below.

[0032] This specific embodiment first provides a fire extinguishing material prepared from calcium sulfate dihydrate according to the present invention. Solid waste containing calcium sulfate dihydrate is processed into powder with a particle diameter of less than 250μm at 50-70°C, which is used as the first fire extinguishing material. The content of calcium sulfate is ≥80%.

[0033] Solid waste is one or more of the following: natural gypsum mine, phosphate mine tailings, or phosphogypsum or desulfurization gypsum produced during coal desulfurization.

[0034] As a preferred embodiment of the above, when the moisture content of the first fire extinguishing material is less than a set threshold, a moisture content regulator is used to mix and pulverize the first fire extinguishing material so that the moisture content of the mixture is greater than or equal to the threshold, and the resulting mixture is the second fire extinguishing material.

[0035] The moisture content testing and adjustment includes taking the first fire extinguishing material and testing its weight loss ratio at 200℃. If the weight loss at 200℃ is less than 15±1%, which is less than 15%, the moisture content is adjusted by adding a moisture content regulator. The proportion of moisture content regulator added can be determined by theoretical calculation or by experimental curves until the second fire extinguishing material is obtained after testing again and the water loss at 200℃ reaches 20%.

[0036] As a preferred embodiment of the above, the first or second fire extinguishing material is sieved into five components with different particle sizes: ① below 20 μm; ② 20–40 μm; ③ 40–63 μm; ④ 63–125 μm; and ⑤ 125–250 μm. Each component with a different particle size is a third fire extinguishing material.

[0037] As a preferred embodiment of the above, the moisture content regulator is one or more of magnesium sulfate heptahydrate, calcium chloride hexahydrate, or aluminum sulfate.

[0038] As a preferred embodiment of the above, the third fire extinguishing material with different particle sizes is mixed to obtain the fourth fire extinguishing material.

[0039] As a preferred embodiment of the above, an ingredient with a particle diameter of <20μm is added to the fourth fire extinguishing material and mixed evenly to obtain the fifth fire extinguishing material.

[0040] The raw materials for the ingredients are one or more of fly ash, soil from the old course of the Yellow River, or wood ash, and the addition amount is the fourth fire extinguishing material: ingredients (mass ratio) 90-98: 2-10.

[0041] As a preferred embodiment of the above, the ingredients are processed into powder with a particle diameter of less than 50 μm by a grinding mill. Several of the following can be selected: fly ash, soil from the old course of the Yellow River, or wood ash. They are pre-mixed and then processed together by a grinding mill into powder with a particle diameter of less than 50 μm. The sample is tested and its weight loss at 200℃ reaches 1 ± 0.5%, which is then used as the ingredients.

[0042] The present invention also provides a fire extinguishing agent for a fire extinguishing material prepared from calcium sulfate dihydrate, wherein the fifth fire extinguishing material is surface modified with a surfactant to obtain a first fire extinguishing agent.

[0043] Furthermore, the surfactant is one or more of methoxy silicone oil, hydrogen-containing silicone oil, or fluorocarbon silicone oil, and the amount added is 0.5% to 2.5%.

[0044] The specific method for surface modification is as follows: Add the fifth extinguishing material to a high-speed mixer, adjust the speed to 240 rpm, mix for 5 to 10 minutes, add 0.5 to 2.5% (by weight) of surfactant of the fifth extinguishing material in 3 portions, control the temperature to 40 to 70°C, adjust the speed to 480 rpm, continue mixing for 10 to 30 minutes, and stop mixing for 30 minutes after the temperature naturally drops below 30°C to produce the first extinguishing agent, which can be used as a type A dry powder extinguishing agent, suitable for extinguishing Class A fires, and can be packaged and sealed.

[0045] As a preferred embodiment of the above, the fire extinguishing performance of the first fire extinguishing agent is enhanced by using a fire extinguishing performance enhancer to obtain a second fire extinguishing agent.

[0046] As a preferred embodiment of the above, the fire extinguishing performance enhancer is one or both of magnesium acetate hydrate or carbamide.

[0047] The method to enhance fire extinguishing performance is as follows: Start the high-speed mixer, add the first extinguishing agent and the fire extinguishing performance enhancer, the amount added is 5-15% of the first extinguishing agent (by weight), gradually adjust the speed to 800-1200 rpm, continue for 1-5 minutes, and then discharge the material, package and seal it to obtain the second extinguishing agent, which can be used as an ABC type dry powder extinguishing agent and is suitable for extinguishing ABC class fires.

[0048] The order of mixing and the speed of the high-speed mixer can be changed according to actual production needs. In addition to mixing the materials, the rotation of the high-speed mixer can also raise the temperature, and the temperature change can change the speed of the surface modification reaction.

[0049] In some preferred embodiments, the formulation and preparation method of the extinguishing agent include the following processes, the flowchart of which is shown below. Figure 1 :

[0050] 1. Preparation of main ingredient powder:

[0051] 1) Raw material selection: Select desulfurized gypsum or phosphogypsum as the main raw material (natural dihydrate gypsum can also be used);

[0052] 2) Sampling and analysis: Sampling and analyzing its chemical composition, analyzing the content of various components, and selecting it when the content of calcium sulfate reaches the set value or above and there are no other toxic or radioactive substances;

[0053] 3) Processing: The raw materials are processed into powder with a particle diameter of less than 250μm by controlling the temperature at 50~70℃. This powder is called the main material powder (first fire extinguishing material).

[0054] 4) Moisture content testing and adjustment: Take a powder sample processed in the previous step and test its weight loss ratio at 200℃. When it reaches 20±1%, it is called qualified main material powder. If the weight loss at 200℃ is small and does not reach 19%, the moisture content of the main material powder can be adjusted by adding a moisture content regulator. One or more of magnesium sulfate heptahydrate, calcium chloride hexahydrate, and aluminum sulfate can be selected as the moisture content regulator. The proportion of moisture content regulator added can be determined by theoretical calculation or by experimental curve until the water loss at 200℃ reaches 20% in the next test, and qualified main material powder (secondary fire extinguishing material) is obtained.

[0055] 5) Screening: According to different application scenarios and to adapt to different types of fire extinguishing equipment, qualified main material powder is screened into five different particle sizes: ① below 20μm; ② 20~40μm; ③ 40~63μm; ④ 63~125μm; ⑤ 125~250μm. These are collectively referred to as qualified main material powder (third fire extinguishing material).

[0056] 2. Preparation of ingredient powder:

[0057] 1) Selection of raw materials: Select one or more of the following: fly ash, soil from the old course of the Yellow River, and wood ash;

[0058] 2) Processing: The selected ingredients are processed into powder with a particle diameter of less than 50μm through a grinding mill. If several ingredients are selected, they are pre-mixed and then processed together into powder with a particle diameter of less than 50μm through a grinding mill. The weight loss at 200℃ is tested and it reaches 1±0.2%, which is called qualified ingredient powder.

[0059] 3. Fire extinguishing material mixing: According to the needs of extinguishing different types of fires, the need to adapt to different fire extinguishing equipment and appliances, and the need for different shelf life, the qualified main powder and qualified auxiliary powder are mixed in a certain proportion to make different grades of formulated fire extinguishing materials (fifth fire extinguishing materials).

[0060] 4. Preparation of extinguishing agent:

[0061] 1) Selection of compliant main material powder: Select four types of compliant main material powder with particle diameters: ① below 20μm; ② 20~40μm; ③ 40~63μm; ④ 63~125μm. Mix them in a certain proportion and they are called fire extinguishing agent main material powder (fourth fire extinguishing material).

[0062] 2) Selection of qualified ingredient powder: Qualified ingredient powder with a particle diameter of less than 20μm is called fire extinguishing agent ingredient powder;

[0063] 3) Preparation of pre-formed extinguishing agent powder: The main extinguishing agent powder and the auxiliary extinguishing agent powder are thoroughly mixed at a ratio of 90-98%: 2-10% to obtain pre-formed extinguishing agent powder;

[0064] 4) Surfactant selection: One or more of the following can be selected as surfactants: methoxy silicone oil, hydrogen-containing silicone oil, and fluorocarbon silicone oil, with an addition amount of 0.5-2.5%;

[0065] 5) Selection of fire extinguishing performance enhancer: It can be one or both of magnesium acetate hydrate or carbamide;

[0066] 6) Surface modification treatment: Add the pre-made extinguishing agent powder to a high-speed mixer, adjust the speed to 240 rpm, mix for 5-10 minutes, add surfactant in 3 batches (by weight) 0.5-2.5% of the total amount of pre-made extinguishing agent powder, and control the temperature to 40-80℃. Adjust the speed to 480 rpm and continue mixing for 10-30 minutes. After the temperature naturally drops below 30℃, stop mixing for 30 minutes to produce Type A dry powder extinguishing agent (first extinguishing agent), suitable for extinguishing Class A fires, and can be packaged and sealed.

[0067] 7) Fire extinguishing performance enhancement treatment: Following the previous step, restart the high-speed mixer, add fire extinguishing performance enhancer, add 5-15% and gradually adjust the speed to 800-1200 rpm, continue for 1-5 minutes, then discharge the material, package and seal it to make ABC type dry powder fire extinguishing agent (second fire extinguishing agent), which is suitable for extinguishing ABC class fires.

[0068] Steps 6) and 7) here can be changed in order and the speed of the high-speed mixer can be adjusted according to actual production needs. In addition to mixing the materials, the rotation of the high-speed mixer can also raise the temperature. Temperature changes can change the speed of the surface modification reaction.

[0069] This specific embodiment also provides the application of the above-mentioned fire extinguishing materials and fire extinguishing agents, wherein the first fire extinguishing agent and the second fire extinguishing agent are used for filling portable dry powder fire extinguishers, automatic dry powder fire extinguishing systems, or preparing fire extinguishing bombs;

[0070] The third, fourth, and fifth fire extinguishing materials are used in large fire-fighting equipment such as dry powder fire trucks, fireboats, drones, and helicopters.

[0071] The first and second fire extinguishing materials are used to replace dry sand for fire extinguishing, such as in laboratories, gas stations, oil depots, and docks.

[0072] From the perspective of fire extinguishing performance, the first and second extinguishing agents are more suitable for fire extinguishing equipment; those suitable for fire extinguishing equipment are also more suitable for replacing dry sand fire extinguishing. If factors such as fire extinguishing cost are taken into account, the above-mentioned graded combination is adopted.

[0073] Example 1

[0074] After preliminary selection of sources, the environmental protection department's test report on the desulfurization gypsum of a certain thermal power plant revealed that the calcium sulfate content of the coal-fired desulfurization gypsum produced by the thermal power plant was >93% (dry weight), and that it was free of radioactivity and other harmful substances, thus confirming that it could be used as a raw material.

[0075] By sampling and measuring the crystallization water content of desulfurized gypsum, it was found that since desulfurized gypsum in general thermal power plants is mostly stored in the open air, the crystallization water content varies between different manufacturers, and the water content differs between the surface and deep layers. This water content is divided into adsorbed water and crystallized water, with the deeper layer containing more adsorbed water. Therefore, a small Luoyang shovel was used to select 5 different points from both the surface and deep layers, and after mixing, 200g of the sample was weighed out. The sample was then dried at 50-70℃ under a negative pressure of 0.05Mpa for 30-60 minutes, and the weight G was measured using a 0.2g balance. The sample was then placed in an electric drying oven at 200-250℃ for 50-60 minutes, and the weight G1 was measured again. The weight loss G2 was then calculated.

[0076] G2 = G - G1, where the weight loss is considered as the water of crystallization content;

[0077] Calculate the percentage of water of crystallization: H2O% = G2 / G·100%;

[0078] With a water of crystallization (H2O) content of 15±0.2%, it can be determined that the desulfurized gypsum from this plant can be processed according to the following steps.

[0079] S1. Using a horizontal impact mill or air jet mill, the temperature is controlled at 60℃, and magnesium sulfate heptahydrate (1 / 5 to 1 / 6 of the raw material weight) is added to the raw material to process it into powder with a particle diameter of less than 125μm to obtain the second fire extinguishing material. The powder is then sieved into four different particle sizes: less than 20μm; 20-40μm; 40-63μm; and 63-125μm to obtain the third fire extinguishing material.

[0080] S2. Add the powder of the above fineness to the mixer in a ratio of 2:3:3:2 to obtain the fourth fire extinguishing material;

[0081] S3. Select fly ash and wood ash as raw materials, and process the selected raw materials into powder with a particle diameter of less than 40μm through an impact mill to obtain the raw material powder.

[0082] S4. Add the fourth extinguishing material to the high-speed mixer at a ratio of 90:10 (by mass), gradually adjust the speed to 1200 rpm, and control the temperature to not exceed 70℃ during the process. Mix for 15 minutes, stop the mixer, and allow it to cool naturally to obtain the first extinguishing agent.

[0083] S5. Packaging and sealing: Once the temperature drops below 30℃, unload the material and package it.

[0084] The above describes the preparation of a dry powder extinguishing agent suitable for extinguishing Class A fires, which is also applicable to Class C and E fires.

[0085] The raw materials used in step S1 were subjected to DSC and TG tests. The test results are shown in [the table below]. Figure 2 and Figure 3 .

[0086] in, Figure 2 The horizontal axis represents temperature (°C), and the vertical axis represents heat flux (mW); Onset (initial temperature): 136.95°C; Peak (peak temperature): 151.41°C; Endset (end temperature): 161.28°C; Integra1 (integral value): -1441.29mJ (representing the total energy of the thermal effect). As shown in the figure, the raw material loses water around 156.41°C with a strong endothermic effect, indicating that it can absorb heat from the flame and lower the surrounding temperature; the formation of gaseous water molecules during the water loss process can isolate oxygen, and no heat release was observed in the figure.

[0087] Figure 3 The horizontal axis represents temperature (°C), and the vertical axis represents mass (mg). (Comparison) Figure 2 It can be seen that the corresponding temperature range before and after its weight loss (decomposition and loss of water of crystallization) is as follows. It can also be seen that the raw material has high thermal stability and is more suitable as a base material for fire extinguishing agents because it only loses water of crystallization without producing other complex chemical reactions and releasing water of crystallization and absorbing heat.

[0088] Example 2

[0089] (1) Two 3kg dry powder fire extinguishers were selected, numbered 1# and 2#. Other specifications were uniformly as follows: nozzle diameter φ4mm, nozzle inner diameter φ10mm, nozzle length 400mm, cylinder diameter φ127.4mm, cylinder volume 3.8L, siphon inner diameter φ12mm, siphon distance from cylinder bottom 13mm~16mm, and materials and strength conforming to the provisions of GB 4351-2023.

[0090] (2) Fire extinguisher filling: Weigh 3.0±0.1 kg of the first extinguishing agent prepared in Example 1 and add it to the selected No. 1 and No. 2 fire extinguishers in the previous step. Fill with nitrogen gas and the initial pressure is (1.2±0.1) MPa (gauge pressure).

[0091] (3) Experimental model preparation

[0092] Larch wood is selected and treated to achieve a moisture content of 10%–14% (by mass) and a density of 0.5 g / cm³. 3 The wooden strips have a square cross-section with a side length of 39mm ± 1mm ​​and a length of 635 ± 10mm. There are 7 strips per layer in 16 layers (e.g., ...). Figure 4 ).

[0093] (4) Test procedures (see GB4066-2017):

[0094] To ignite the wood, pour 500mL of decorative paint thinner into an ignition pan directly under the woodpile and ignite it. Once the wood has burned out, remove the ignition pan.

[0095] To extinguish the fire, begin extinguishing the fire when the woodpile has burned down to 53-55% of its original mass. Position yourself 3 meters directly in front of the woodpile, quickly activate the prepared fire extinguisher, and spray rapidly towards the top, bottom, front, and both sides of the woodpile.

[0096] (5) Test Results

[0097] The experiment was conducted in an open, windy environment, which increased the difficulty of extinguishing the fire compared to national standards, but the fire was still extinguished within 4-6 seconds. The data is shown in the table below:

[0098] fire extinguisher Specification Fire extinguishing agent Firefighting time (s) Continuous spray duration (s) Has it reignited? 1# 3Kg First extinguishing agent 5.48 23.87 none 2# 3Kg First extinguishing agent 4.91 23.45 none

[0099] (6) Comparison with the currently dominant national standard ABC dry powder fire extinguishing agent

[0100] To demonstrate the effectiveness of the first extinguishing agent of this invention, a comparative experiment was conducted simultaneously with this experiment using national standard ABC dry powder (model specification: ABC-NH4H2PO4 (75%) + (NH4)2SO4 (15%); measured values: NH4H2PO4 content 76.8%, (NH4)2SO4 content 13.9%). Three 3kg dry powder fire extinguishers, labeled #3, #4, and #5, were filled under the same experimental conditions. The results are as follows:

[0101] fire extinguisher Specification Fire extinguishing agent Firefighting time (s) Continuous spray duration (s) Has it reignited? 3# 3kg National Standard ABC 8.43 21.73 have 4# 3kg National Standard ABC 7.69 22.36 none 5# 3kg National Standard ABC 9.86 21.11 have

[0102] The data shows that the national standard fire extinguishing agent has a slightly shorter continuous spray time, indicating that it has better fluidity. Due to its surface modification treatment, it has a higher spray intensity. In contrast, the first fire extinguishing agent of this invention has not undergone surface modification treatment and has slightly poorer fluidity. The national standard ABC dry powder used in the comparative experiment produced obvious smoke throughout the fire extinguishing process. After the flames were extinguished, the woodpile continued to smoke, and both #3 and #5 experienced reignition, indicating that its cooling effect was poor.

[0103] Example 3

[0104] In an open, sheltered, and windless location, open the valve of a 10 kg LPG cylinder to its maximum position, allowing the LPG to spray out. Ignite the gas from the side and rear of the direction from which it is sprayed out using an igniter. Quickly open the 3 kg portable dry powder fire extinguisher prepared in Example 2 and spray it from the side and rear of the direction from which the flame is sprayed out. The flame will be extinguished in 1-2 seconds.

[0105] Example 4

[0106] The first extinguishing agent prepared in Example 1 uses methoxysilicone oil as the surfactant, which is added at 2.5% of the first extinguishing agent (by weight); the extinguishing performance enhancer is magnesium acetate hydrate or carbamide.

[0107] S1. Add 50 kg of the first extinguishing agent prepared in Example 1 to a high-speed mixer, adjust the speed to 240 rpm, mix for 10 minutes, add 5 kg of surfactant in 3 portions, and control the temperature to 60°C.

[0108] S2. Adjust the rotation speed to 480 rpm, then add 50 kg of the first extinguishing agent and continue mixing for 15 minutes, while controlling the temperature at 60°C;

[0109] S3. Adjust the speed to 800-1200 rpm, then add 120 kg of the first extinguishing agent and continue mixing for 15 minutes. Control the temperature at 60℃, add 30 kg of extinguishing performance enhancer, continue mixing for 5 minutes, and then stop the machine.

[0110] S4. Once the temperature naturally drops below 30℃, the material can be discharged to obtain the second extinguishing agent. It is then packaged and sealed to produce ABC type dry powder extinguishing agent.

[0111] Example 5

[0112] In this embodiment, the smallest model of a spray riveting machine produced by a certain factory was selected for testing. The total weight of the spray riveting machine is 350 kg. It is equipped with a 50-type spray nozzle, a 5.5 kW feeding motor, a 50 mm nozzle diameter, a spray pressure of 0.8 MPa, a horizontal distance of 200 meters for spraying cement mortar, a vertical height of 20 meters, and a spray volume of 3 cubic meters per hour.

[0113] The type A dry powder fire extinguishing agent prepared in Example 1 was used for a spray test, and the data were compared with those of cement mortar spraying. The results are as follows:

[0114] materials Injection pressure Horizontal distance Vertical height Injection volume Conversion of water gun measurement units cement mortar 0.8Mpa 202m 21m <![CDATA[3M 3 / h]]> 0.833L / s Second extinguishing agent 0.8 MPa 226m 58m <![CDATA[6.6M 3 / h]]> 1.83L / s

[0115] Data comparison shows that using this type of engineering equipment, the vertical spray height of the second extinguishing agent of this invention can be increased by 2.5 times, but some larger powder particles accumulate in the pipeline; the spray volume increases several times, the horizontal spray distance increases by about 10%, and the vertical spray height, horizontal distance, and spray volume reach 226 meters, 58 meters, and 1.83 liters / second, respectively. In terms of spray volume, the dry powder is 1.83 liters / second. Subsequently, by enhancing the fluidity of the powder, increasing the pressure, and adding water guns, the spray distance, height, and spray volume can be further increased.

[0116] Therefore, the dry powder fire extinguishing agent of the present invention can be used in conjunction with such equipment to extinguish fires covering large areas.

[0117] The fire extinguishing agent provided by this invention utilizes the properties of crystalline hydrates such as calcium sulfate dihydrate to achieve a combination of liquid water and solid dry powder, exhibiting superior properties compared to existing dry powder fire extinguishing products.

[0118] 1. When heated, it releases water molecules, which can absorb heat and play a cooling role, effectively preventing the phenomenon of resurgence;

[0119] 2. When the extinguishing agent is sprayed onto the surface of the burning object, it rapidly decomposes into gaseous water molecules upon heating, isolating the burning object from oxygen and diffusing at high speed, diluting flammable gases, combustion-supporting gases, and toxic gases in the fire scene, thereby playing a role in suppressing combustion, explosion, and poisoning.

[0120] The fire extinguishing material with calcium sulfate dihydrate as the main ingredient and the fire extinguishing agent made from it have significant cost advantages and a wide range of applications. They can be used to extinguish Class A, B, C, E and F fires, as well as forest fires and hazardous chemical fires. They are especially suitable for extinguishing Class A fires (such as fires involving clothing and fabrics). At the same time, they can expand the reuse value of solid waste.

[0121] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been shown above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a fire extinguishing agent, characterized in that, Solid waste containing calcium sulfate dihydrate is processed into powder with a particle diameter of less than 250 μm at 50-70°C and used as the first fire extinguishing material, wherein the calcium sulfate content is ≥80%; the solid waste is one or more of natural gypsum ore, phosphate mine tailings, or phosphogypsum or desulfurization gypsum produced in the desulfurization process of coal combustion. When the moisture content of the first fire extinguishing material is less than a set threshold, a moisture content regulator is used to mix the first fire extinguishing material so that the moisture content of the mixture is greater than or equal to the threshold, and the resulting mixture is the second fire extinguishing material. The moisture content regulator is one or more of magnesium sulfate heptahydrate, calcium chloride hexahydrate, or aluminum sulfate. The moisture content testing and adjustment includes taking the first fire extinguishing material and testing its weight loss ratio at 200°C. If the weight loss at 200°C is less than 15±1%, which is less than 15%, the moisture content is adjusted by adding a moisture content regulator until the test is repeated and the water loss at 200°C reaches 20%, thus obtaining the second fire extinguishing material. The second fire extinguishing material is sieved into components comprising a first particle size, a second particle size, a third particle size, a fourth particle size, and a fifth particle size. Each component of a particle size constitutes a third fire extinguishing material. Specifically, the first particle size is less than 20 μm, the second particle size is 20–40 μm, the third particle size is 40–63 μm, the fourth particle size is 63–125 μm, and the fifth particle size is 125–250 μm. The third fire extinguishing material with different particle sizes is mixed to obtain the fourth fire extinguishing material; Adding an ingredient with a particle diameter <20μm to the fourth fire extinguishing material and mixing it evenly yields the fifth fire extinguishing material; the ingredient is one or more of fly ash, wood ash, or soil from the old course of the Yellow River; the mass ratio of the fourth fire extinguishing material to the ingredient is 90-98:2-10; the preparation method of the ingredient includes: processing the ingredient into powder with a particle diameter of less than 50μm using a grinding mill, or pre-mixing and then processing them together into powder with a particle diameter of less than 50μm using a grinding mill, and taking samples to test that the weight loss at 200℃ reaches 1±0.5%, which is then used as the ingredient; The fifth fire extinguishing material is subjected to surface activation treatment to obtain the first fire extinguishing agent; the surfactant used in the surface activation treatment is one or more of methoxy silicone oil, hydrogen-containing silicone oil or fluorocarbon silicone oil, and the mass amount of the surfactant added is 0.5 to 2.5% of the fifth fire extinguishing material by weight ratio. A fire extinguishing performance enhancer is added to the first fire extinguishing agent to obtain a second fire extinguishing agent; the fire extinguishing performance enhancer is one or both of magnesium acetate hydrate or carbamide; the amount added is 5-15% of the weight of the first fire extinguishing agent.

2. A fire extinguishing agent prepared by the method of fire extinguishing agent preparation according to claim 1.

3. The application of the extinguishing agent according to claim 2 in fire extinguishing.

Images