JPH01232976A - Fire extinguishant and method for using same for dangerous material difficult to extinguishment - Google Patents

Abstract

PURPOSE:To readily and quickly restrain the fire of dangerous materials difficult to extinguishment and to extinguish the fire in a short time by preparing a main component of boron oxide powder and a sub-component comprising, in any combination, a first component for exerting suffocating and cooling actions, a second component for forming a suffocating and intercepting layer and a third component for absorbing and remove said liquefied material and exerting suffocating action. CONSTITUTION:A main component of fire extinguishing agent must be made of boron oxide containing at least 90wt.% of B2O3 and 2wt.% or less of water content, preferably 0.5wt.% or less. The grain size of boron oxide powder is 5mum-1000mum. Fine pulverulence having 5-200mum grain diameter are suited for filling a fire extinguisher and ones having 200-1000mum grain diameter are suitably scattered by a scoop, bucket, etc. A sub-component comprises, in any combination, a first component for displaying suffocating and cooling action in eutectic relation to the boron oxide with the relatively low melting point, a second component for forming a high strength air intercepting layer to complete the fire extinguishment in eutectc relation to the boron oxide and a third component for exerting both absorbing and removing actions of liquid high temperature burning materials and suffocating and cooling action to melted boron oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fire extinguishing agent for difficult-to-extinguish dangerous substances and a fire extinguishing method using the same.

(Conventional technology and its problems) Dangerous substances that are difficult to extinguish are classified into the following types:

■Metal powder---Mg powder, AI powder, Zn powder, TI powder, Zr
powder, Fe powder, etc. ■Alkali metals...Na, Li, etc. ■Water-inhibited substances...
・Calcium carbide, lime phosphide, quicklime, etc.

■Flammable solids: red phosphorus, yellow phosphorus, sulfur, phosphorus sulfide,
Magnesium, etc. ■ Fire-resistant liquids: alkyl aluminum, alkyl lithium, chlorinated silane, diketene, etc. First of all, metal powders such as Mg, AI, TI, etc. are flammable.
May cause fire and serious explosion.

These metal powders react with water at high temperatures to generate hydrogen, and when water is injected, it may cause a steam explosion and scatter the burning metal powder, so water injection must be avoided at all costs. It was impossible to extinguish the fire with the commonly used carbon dioxide gas, halon, and powder extinguishing agents, and the only way to suppress the fire was to spray dry sand, special powders such as sodium chloride, and sodium carbonate. However, these methods consume a large amount of extinguishing agent, and even after spraying these special powders, hot metal remains inside the fire, leaving the fire unattended for a long time, sometimes even for 30 to 60 minutes. There was a risk of re-combustion depending on the conditions.

Next, the alkali metals such as sodium and potassium in ■ are
There is a risk of spontaneous combustion due to the interaction with water, which generates heat and generates hydrogen. Therefore, in this case as well, water injection is not possible, and furthermore, it is impossible to extinguish the fire with known fire extinguishing agents other than water, such as carbon dioxide gas, halon, and powder fire extinguishing agents. There is also a method of spraying a small amount of dry sand or special powder such as sodium chloride or sodium carbonate, but these methods use slow suffocation and cooling effects to extinguish the fire, so it takes a long time to completely extinguish the fire and consumes a large amount of extinguishing agent. There were some difficulties, such as:

Solid water-prohibiting substances such as calcium carbide and quicklime (2) interact with water to generate heat or flammable gas and burn. These substances are dangerous substances called water-restricted substances.
Furthermore, it is not applicable because it reacts with other known extinguishing agents other than water, and there has been no particularly effective extinguishing method. Suffocating fire extinguishing with dry sand was slightly applicable, but in practice it required a large amount of dry sand and was difficult to extinguish.

-■ Flammable solids such as yellow phosphorus, red phosphorus, and sulfur are dangerous substances that easily ignite at relatively low temperatures. Furthermore, they are solids that burn quickly, and some are toxic or emit toxic gases when burned. Therefore, extinguishing the fire is troublesome.

Among the non-extinguishing liquids listed in (2), alkyl aluminum and chlorinated silane react explosively when they come into contact with water, so it is absolutely necessary to avoid pouring water to extinguish these dangerous substances. It was also difficult or impossible to extinguish the fire with carbon dioxide, halon, or conventional powder fire extinguishers.

(Means for Solving the Problems) As a result of various studies on extinguishing such difficult-to-extinguish and difficult-to-extinguish dangerous materials, the present inventor found that boronic oxide He discovered that spraying powder was extremely effective and could eliminate the drawbacks of conventional extinguishing agents for metal fires, and filed a patent application for this (Patent Application No. 335,445, December 28, 1988).
Further, as a result of various studies, it was found that boron oxide powder can be applied to extinguishing difficult-to-extinguish dangerous materials other than metals, and the extinguishing effect of many kinds of difficult-to-extinguish dangerous materials can be further improved. They discovered this and completed the present invention.

That is, in the present invention, the B, 03 content is 90% by weight or more, the moisture content is 2% by weight or less, and the particle diameter is 5 to 1000μ.
The main component is boron oxide powder, which is eutectic with the main component to lower the melting point of the burning object to exert a suffocation and cooling effect, and a strong suffocation barrier layer is formed on the object. The gist is a fire extinguishing agent for refractory hazardous materials, which contains as subcomponents any one of the second component to form and a third component that absorbs and removes the liquid substance and exhibits a suffocation effect, or any combination thereof. , and further relates to a fire extinguishing method using the same.

The present invention will be explained in more detail below.

The main component of the fire extinguishing agent in the present invention is B2O3 content of 90
It is necessary that the oxidized boron is at least 2% by weight and has a moisture content of 2% by weight or less, preferably 0.5% by weight or less. The boronic oxide that is commercially available today is a first-class reagent and is B.
The content of 2O3 is about 85% by weight and the water content (contained in the form of ferrous acid) is about 10% by weight, but oxidized boron of this grade is inappropriate as the fire extinguishing agent of the present invention. The special grade reagent, which is further purified from the first grade reagent oxidized boron, is B2.
The O3 content is about 97% by weight and the water content is about 2% by weight. Although such a quality makes it possible to use it as a fire extinguishing agent according to the present invention, it is still not sufficient. When this special grade reagent is further heated at 160° C. for about 2 hours, the water content becomes 0.5% or less, and the fire extinguishing performance is significantly improved.

The particle diameter of the oxide wire bundle used in the present invention is 5 μm to
Fine powder with a particle diameter of 5 to 200 μm (ooμm) is passed through filling into a fire extinguisher, and one with a particle size of 200 to 1000 μm is
Suitable for spraying with shovels, buckets, etc. Fine powder with a particle size of less than 5 μm is unsuitable as a fire extinguisher for difficult-to-extinguish dangerous substances according to the present invention because it easily scatters to the surroundings when sprayed. Particles with a particle size larger than 1000 μm are not preferred because they take a long time to melt and require a large amount of powder to extinguish fires.

Next, the subcomponents added to the above main ingredients and their effects will be described.

(1) The first component has a relatively low melting point and thus eutectics with boron oxide to exert suffocation and cooling effects.

: Sodium chloride, potassium chloride, sodium carbonate, magnesium carbonate, sodium tetraborate (anhydrous).

(2) A second component that is eutectic with the oxidized boron to form a strong air barrier layer and complete the fire extinguishing effect.

: Silica sand, silica powder, quartz powder, calcium fluoride (3) A third component that has a liquid absorption and removal effect on liquid burning high-temperature substances, and a suffocation and cooling effect of molten oxidation boron.

Rainbow silica based porous material, silica/alumina based porous material,
The melting points of kaolin, calcium carbonate, and the first component of pearlite are all in the range of 700 to 900°C, which is relatively low, and they easily melt when they come into contact with a hot object that is being burned, and when mixed with boron oxide, they reach a eutectic point. is lower than the above melting point, showing the effect of covering the burning surface well. In addition, these components have a relatively large heat of fusion, so when they melt, they absorb the heat of fusion from the surroundings,
It also has a cooling effect and extinguishes fire.

Applicable fire-retardant hazardous materials: metal powder, alkali metals, flammable solids, and among the second ingredients, silica sand, silica powder, and quartz powder all have 5i02 as their main ingredient, and heat-resistant glass as well-known When these powders are added to boronic oxide, they melt at a temperature lower than the melting point of silica (1,680°C) when they come into contact with a burning object, leaving a glassy surface on the burning surface. It has the effect of forming a strong air barrier layer and ensuring fire extinguishment.

Calcium fluoride also has high heat resistance and is known as a fluxing agent in metal smelting, and can be mixed with boron oxide to lower the melting temperature.

Suitable non-extinguishable hazardous materials: metal powder, magnesium solids, especially when a tank or other complex structure with vertical walls ignites from the bottom, the extinguishing agent melts at low temperatures and adheres to the vertical walls; Due to its high viscosity, it forms a strong air barrier that covers walls and has effective fire extinguishing capabilities. Therefore, it is extremely effective in extinguishing multi-dimensional fires on aircraft that use large amounts of magnesium and magnesium alloys.

When highly heat-resistant porous powders and heat-resistant fine powders such as the third component are sprayed on fires containing refractory liquid hazardous materials or low-melting combustible solids, they absorb the burning liquid substances. , the effect of removing combustibles is exhibited. At even higher temperatures, the main component, boron oxide, melts, causing suffocation and cooling effects.

In addition, water is the cause of fires with water-resistant hazardous materials such as calcium carbide, which generate heat and ignite when it comes into contact with water.
When these porous powders and heat-resistant fine powders are sprinkled, they absorb moisture and, as a result, have the effect of weakening the fire force.

Applicable fire-retardant hazardous materials ■Water-inhibited substances: calcium carbide, quicklime, etc. ■Flammable solids: red phosphorus, sulfur, phosphorus sulfide, etc. (because of their low melting point,
(Burns in a molten state) ■Refractory liquid: Alkylaluminium, chlorinated silane, diketene, etc. The requirements for these subcomponent powders are as follows.

■ Contains 80% by weight or more of silica-based porous material Sin, pore diameter o, i ~ 10
0 μI, bulk specific gravity 0.2 to 0.5, particle size 5 μ to 100
Silica-based porous material with a diameter of 0 μm.

■Silica-alumina porous material Contains 90% or more of the sum of both components of 5in2 and Al2O3, pore diameter 0.1-1000μm, bulk specific gravity 0.3
~0.7, a silica/alumina porous material with a particle size of 5 μm to 1000 μm. This also includes perlite, which is made from nacre.

■Contains silica sand Sin, 90% by weight or more, true specific gravity 2.5 to 2.7
Natural silica sand with a particle size of 1 μm to 500 μm and its processed products.

■ Contains 5 inches of silica powder 293% by weight or more, true specific gravity 2.5-2.6
55 Silica powder with a particle size of 1 m to 500 pm.

■Contains 5i0295% or more of quartz powder by weight, true specific gravity 2.6-2.6
5 Quartz powder with a particle size of 1 μfil to 500 μm, obtained by artificially crushing quartz (crystal).

(2) Kaolin having a high refractoriness, a true specific gravity of 2.55 to 2.65, and an average particle diameter of 0.3 μm to 5 μI is suitable.

■ Sodium chloride aC 1 min 98% by weight or more, it is desirable to reduce Mg salt as much as possible to prevent hygroscopicity, and it is preferable to use moisture-proof processing to prevent solidification, but those with organic substances added , is unsuitable for the use of the present invention. Particle size is 5μ
A suitable range is from m to 500 μm. Melting point is 80
1℃.

(2) Potassium chloride KCI content of 98% by weight or more and Mg salt content as low as possible are preferred from the viewpoint of moisture absorption and prevention of solidification. It is also possible to add a small amount of anti-caking agent. Particle size is 5 μffl ~ 5
A value in the range of 00 μm is suitable. Melting point is 776℃.

■Sodium carbonate anhydride, Na2CO, 99% by weight or more, particle size 5μI
Those with a diameter of 11 to 500 μm are used.

[Phase] Calcium carbonate CaC05 min 98% by weight or more, particle size 1 μm to 200 μm
A range of m is used.

■Magnesium carbonate Mg003 min 97% by weight or more, particle size 1 μm ~ 200
A range of .mu.m is used.

@Calcium fluoride is the main component of fluorite, and is extremely stable with a diameter of 1 μm to 500 μm and a melting point of 1360° C., with an amount of 8% by weight or more.

@Sodium tetraborate (anhydrous) Anhydrous Na2B40. min.99% or more, particle size 5μ■~1
000μ country, true specific gravity 2.36, melting point 741℃.

A necessary condition for achieving the object of the present invention is that the water content in these inert and heat-resistant powders is 5% by weight or less, preferably 2% by weight or less.

Conventionally, surface treatments such as silicone oil, which are used to impart moisture resistance (hydrophobicity) to dry powder fire extinguishers and improve fluidity, or the addition of organic substances such as magnesium stearate, improve the fire extinguishing performance of difficult-to-extinguish hazardous materials. It must be avoided as it significantly inhibits

(Function) In general, the functions and effects necessary for extinguishing a fire include (1) removal effect (removes combustible materials from the source of combustion), (2) suffocation effect (blocks off the oxygen supply source), and (3) cooling effect ( There are four known effects: (4) Suppressing effect (suppressing and preventing chain reactions of combustion). These effects often act synergistically rather than independently.

When spraying high-purity oxidized boron powder with low water content, which is the main component of the fire extinguishing agent of the present invention, on the solid combustion part of the hard-to-extinguish dangerous materials that can be used with the fire extinguishing agent of the present invention, the high temperature of the combustion occurs. Softening begins near the surface of the solid hazardous material (B203
(softening temperature of approximately 320°C), particles begin to adhere to each other and form an ice burn shape, and then melt and form B2O3.
Its melting point is 450°C, which is extremely low for a heat-resistant material), and the powders fuse together, eventually becoming glass-like and transparent. Furthermore, boron oxide has the unique property of maintaining a high viscosity even at temperatures above 700 to 1100°C, so it does not flow out, and since it is starch syrup-like and has extremely strong adhesive strength, it completely covers the surface of the burning part. By covering the fire and blocking air, the suffocation effect is maximized and the fire is completely extinguished. Furthermore, since the boiling point of boron oxide is extremely high at 2250℃,
Since it does not vaporize when extinguishing these difficult-to-extinguish dangerous substances, it exhibits extremely excellent extinguishing ability.

Fires of these refractory hazardous materials occur in oxidizing atmospheres (usually in air), unless the metal oxide is reduced at high temperatures, in vacuum, or in an inert atmosphere. Even if there is, there is no risk that the oxidized boron will be reduced and generate high heat.

In addition, the heat of fusion of boron oxide is 75.7 cal/g, which is comparable to the heat of fusion of ice (79.7 cal/g), so when the extinguishing agent sprayed on the solid combustion part melts,
It absorbs the heat of fusion from the surrounding area and has a great cooling effect.
It acts in the direction of weakening the fire force.

(Example 1) In a shallow stainless steel dish with a diameter of 30 cm, 20 g each of red phosphorus and sulfur, which are typical flammable solid hazardous materials, were placed.
Place it on top, ignite it with a gas torch, and let it pre-burn for 20 seconds. Table 1 shows the results of spraying the fire extinguishing agent of the present invention at this time.

Low-melting combustible substances such as red phosphorus and sulfur have the property of melting and becoming liquid before burning, so a small amount of silica-based porous material is added to high-purity oxidized boron with little moisture. As a result, the fire extinguishing performance is improved, and the same effect can be obtained even if a silica/alumina porous material is added in place of the 1.0~b silica porous material.

(Example 2) In a stainless steel container with a diameter of 10 cm and a depth of 6 cm, 20 g of calcium carbide was taken, 10 a+1 of water was added thereto, acetylene gas was generated, ignited, and after 20 seconds of pre-combustion, the fire extinguishing agent of the present invention was sprayed. Shown in Table 2.

In this way, when a small amount of silica-based porous material is added to high-purity borium oxide powder with low water content, the fire extinguishing performance is improved. In this way, when porous powder is used in combination, it absorbs the moisture that causes calcium carbide fires, and as a result, the fire intensity is weakened and the extinguishing time is shortened.

(Example 3) 20g of Mg powder was placed in a shallow stainless steel dish with a diameter of 30cm.
When the entire surface of the Mg powder was ignited, the burning part was stirred and the Mg powder combusted violently, producing a bright white flame and emitting strong heat. At this point, a fire extinguishing agent prepared by adding a relatively low melting point powder (first component) as a subcomponent of the present invention to a low moisture, high purity oxidized rice powder was sprayed, and Table 3 shows the results.

In this way, high-purity boron oxide powder with a small amount of inert inorganic powder with a relatively low melting point added has an even greater effect when sprayed on the burning part of a metal fire, compared to high-purity boron oxide powder alone. It does not remain in the high-temperature area, but becomes semi-molten and spreads to the relatively low-temperature area on the combustion surface, making the fire extinguishing more complete.

(Example 4) 20g of Mg powder was placed in a stainless steel shallow dish with a diameter of 30cm.
When the entire surface of the Mg powder was ignited, the burning part was stirred and the Mg powder combusted violently, producing a bright white flame and producing strong heat.

At this point, Table 4 shows the results of spraying a fire extinguishing agent prepared by adding an inert, heat-resistant powder with a relatively high melting point (second component) to low-moisture, high-purity boron oxide powder as a subcomponent of the present invention. Shown below.

In this way, silica powder (melting point 1680°C), which has a much higher melting point than boron oxide, and calcium fluoride powder (melting point 13
When a fire extinguishing agent containing a small amount of powder (60℃) comes into contact with the high temperature part of a metal fire, it becomes semi-molten or molten, forming a stronger shell covering the burning surface than when boron oxide is used alone. The fire can be extinguished easily by completely blocking air.

(Example 5) In a stainless steel container with a diameter of 10 cm and a depth of 8 cm, alkyl aluminum 20, a representative material of a non-extinguishable liquid dangerous substance, was placed.
ml and 50 ml of trichlorosilane, respectively,
After igniting and pre-combusting for 30 seconds, a fire extinguishing agent prepared by adding a silica-based porous material (third component), which is a subcomponent of the present invention, to a low-moisture, high-purity boron oxide powder is shown in Table 5. Shown below.

In this way, liquid hazardous materials that are difficult to extinguish can be extinguished by spraying a fire extinguishing agent that is a mixture of high purity boron oxide powder and silica-based porous material powder.

When extinguishing a liquid hazardous material that generates a large amount of combustion heat, such as an alkyl aluminum, first, an inert solid powder such as a porous silica material is sprayed to absorb the liquid, and then the sprayed porous silica material absorbs the liquid. After the surface reaches a high temperature, low-moisture, high-purity boron oxide powder is sprinkled on the surface to form an air-blocking layer of molten boron oxide on the surface, making it easy to completely extinguish the fire.

(Example 6) A magnesium plate with a thickness of 5IllIl+, a width of 10cn+, and a height of 30cm was placed almost vertically on the side of a refractory brick, and the magnesium plate was ignited with a gas torch so that about half of the area of the magnesium plate was combusted violently. Table 6 shows the results of spraying fire extinguishing agent after the explosion occurred.

In this way, when a metal fire occurs on a nearly vertical surface, the powder of the conventional metal fire extinguishing agent falls without adhering to the burning surface, making it impossible to extinguish the fire. The fire extinguishing powder according to the present invention also adhered to the almost vertical combustion surface, and was rapidly melted by the heat of the high temperature part to form an air barrier layer, thereby extinguishing the fire in a short time.

This is due to the apparent resistivity (specific resistance at 25°C of 2.5%) of low moisture, high purity borosilicate oxide, which is the main component of the fire extinguishing agent produced by the method of the present invention.
6x 10I6Ωcm) and a suitable particle size, it easily becomes electrically charged when dispersed in the air or injected into the air from a closed container, and adheres to the burning metal surface, as well as its low melting point (450°C). It can be explained that it melts and becomes vitrified with a little heating. In addition, high-purity boron oxide maintains high viscosity even at high temperatures of 1,100°C or higher, so it sticks to the surface of hot burning metal (which is essentially an oxide) and peels off during and after fire extinguishment. Or falling was not observed at all.

Because the fire extinguishing agent of the present invention has such excellent properties,
It can also be applied to extinguish multi-dimensional fires in aircraft, which use large amounts of magnesium or magnesium alloys today.

(Example 7) In a stainless steel shallow dish with a diameter of 50c+a, 1 Mg powder was added.
．． 0 kg was spread out, ignited with a gas torch, and when the entire surface of the Mg powder was ignited, the whole was stirred and the Mg powder combusted violently with a bright white flame. At this point, the fire was extinguished using a portable fire extinguisher (type 20) filled with a fire extinguishing agent consisting of the main component of boron oxide and a second component, and a conventional commercially available extinguishing agent for metal fires. Table 7 shows the results of extinguishing the fire.

Additionally, in a simultaneous experiment, oxidation was compared with the case of using borine alone, but it took 20 seconds to extinguish the fire, demonstrating the effectiveness of natural silica.

(Effects of the Invention) As described above in detail, according to the present invention, (1) a fire of a non-extinguishable hazardous material can be easily and quickly suppressed and extinguished in a short time.

(2) Compared to conventional powder extinguishing agents such as dry sand, sodium chloride, and sodium carbonate, there is almost no noise or smoke when spraying the powder, and there is no odor or powder scattering to the surrounding area. Fire extinguishing activities are easy.

(3) Compared to conventional extinguishing agents, the extinguishing effect is reliable and the amount of extinguishing agent required is small.

(4) The extinguishing agent of the present invention can be used not only for horizontal fires, but also for horizontal fires.
It is also effective against vertical fires, so it is also effective against three-dimensional metal fires.

(5) Since the combustion surface of refractory hazardous materials is completely covered with a strong layer, post-treatment after extinguishing the fire is easy and the surrounding area is not contaminated.

(6) The fire extinguishing agent powder of the present invention has various outstanding effects, such as being able to be used by filling it into a fire extinguisher, or by storing it in a container and dispersing it with a bucket, shovel, etc.

Procedural amendment (voluntary) R Extinguishing agent for extinguishing hazardous materials and extinguishing method using it 3
, Relationship with the case of the person making the amendment Name of patent applicant: Shin-Etsu Semiconductor Co., Ltd. 4, Agent 6, Contents of amendment 1) The scope of claims in the specification is amended as shown in the attached sheet.

2) "Boron oxide" on page 6, line 13 of the specification is corrected to "boron oxide."

3) r700-1100 on page 15 of the specification, second line from the bottom
``Above ℃'' should be corrected to ``at a temperature of rlloo ℃ or higher.''

Above (attached sheet) Claim 1, B, O, content 90% by weight or more, water content 2
% by weight or less, and the particle diameter is 5 to 1000. The first component is oxidized boron powder, which is eutectic with the main component and lowers the melting point of the burning object to exert a suffocation and cooling effect, forming a strong suffocation barrier layer on the object. The second component and the liquid substance are absorbed and removed.

A fire extinguishing agent for non-extinguishable hazardous materials, which contains as a subcomponent any one of the third components that exerts a suffocation effect or any combination thereof.

2. The extinguishing agent according to claim 1, wherein the first component is at least one selected from the group consisting of sodium chloride, potassium chloride, sodium carbonate, magnesium carbonate, and sodium tetraborate (anhydrous).

3. The fire extinguisher according to claim 1, wherein the second component is at least one selected from the group consisting of silica sand, silica powder, quartz powder, and calcium fluoride.

4. The fire extinguishing agent according to claim 1, wherein the third component is at least one member selected from the group consisting of a silica-based porous material, a silica-alumina-based porous material, kaolin, calcium carbonate, and perlite. , O, content 90% by weight or more, water content 2
% by weight or less, and the particle diameter is 5 to 1000. The first component is oxidized boron powder, which is eutectic with the main component and lowers the melting point of the burning object to exert a suffocation and cooling effect, forming a strong suffocation barrier layer on the object. A fire extinguishing agent containing any one of a second component that absorbs and removes the liquid object and a third component that exerts a suffocation effect or any combination thereof as subcomponents is used to extinguish a burning object. Features: Grass extinguishing method for extinguishing hazardous materials.

6. The fire extinguishing method according to claim 5, wherein the combustion object has a side surface steeply inclined to the ground or a bottom surface facing the ground.

Claims (1)

[Claims] 1. B_2O_3 content 90% by weight or more, water content 2
A first component which contains boron oxide powder as a main component and has a particle diameter of 5 to 1000 μm and which is eutectic with the main component and lowers the melting point of the burning object to exert a suffocating and cooling effect on the object; a second component that forms a strong suffocation barrier layer on the body, and a third component that absorbs and removes the liquid substance and exerts a suffocation effect, or any combination thereof as subcomponents. Extinguishing agent for hazardous materials. 2. The first component is sodium chloride, potassium chloride,
The extinguishing agent according to claim 1, which is at least one selected from the group consisting of sodium carbonate, magnesium carbonate, and sodium tetraborate (anhydrous). 3. The fire extinguisher according to claim 1, wherein the second component is at least one selected from the group consisting of silica sand, silica powder, quartz powder, and calcium fluoride. 4. The extinguishing agent according to claim 1, wherein the third component is at least one selected from the group consisting of a silica-based porous material, a silica-alumina-based porous material, kaolin, calcium carbonate, and perlite. 5, B_2O_3 content 90% by weight or more, moisture content 2
A first component whose main component is boron oxide powder with a particle diameter of 5 to 1000 μm and which is eutectic with the main component and lowers the melting point of the burning object to exert a suffocating and cooling effect on the object; A fire extinguishing agent comprising as subcomponents any one or any combination thereof, a second component that forms a strong suffocation barrier layer on the body, and a third component that absorbs and removes the liquid object and exerts a suffocation effect. A method for extinguishing a hazardous material that is difficult to extinguish and is characterized by being used to extinguish a combustible object that burns. 6. The fire extinguishing method according to claim 1, wherein the burning object has side surfaces steeply inclined to the ground or a bottom surface facing the ground.