JP4565084B2 - Absorber for gas mask for absorbing decaborane, and detoxification method for absorbing can that absorbed decaborane - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a gas mask absorption can for removing decaborane, a structure of an air purification filter such as an electric filter, an absorption can that has absorbed decaborane, and a disposal method for the filter.
[0002]
Since the absorption can and filter of the present invention can remove gaseous and particulate decaborane, it is expected to protect (protect) humans from decaborane in the environment where decaborane is used or where decaborane exists.
[0003]
Moreover, since the disposal method of the absorption can, filter, etc. of this invention changes a harmful decaborane into a harmless stable substance, when discarding an absorption can, it is anticipated that it can be discarded without environmental pollution by a decaborane.
[0004]
[Prior art]
Decaborane is used as a rocket fuel, ethylene olefin polymerization catalyst, rubber vulcanizing agent, reducing agent, boron source for forming boron film or boron nitride film, doping source in P-type semiconductor manufacturing, etc. It is a harmful substance for me.
[0005]
As protection against decaborane, in general, an air supply mask, an air respirator or the like is used for breathing, and protective glasses, protective gloves, protective clothes, protective boots, or the like are used as protective equipment.
[0006]
Although a respirating mask for breathing is used to send normal air to the mask by a hose and can be used in a place where a highly toxic substance is present, its range of action is limited due to its structure. Even in the case of an air respirator, there is a limitation in behavior because it carries a heavy cylinder.
[0007]
Further, as a protective mask, although a gas mask equipped with activated carbon or silica gel absorption cans for hydrogen compounds (hydrogen phosphide, hydrogen arsenide, diborane, monosilane, etc.) can be used, there is no dedicated mask for decaborane.
[0008]
[Problems to be solved by the invention]
Therefore, in the safe handling of decaborane, it is useful to develop an absorbent canister for gas masks that has no restrictions on the range of action, has good workability, and is effective against decaborane. It must be able to be discarded.
[0009]
As a gas mask absorption can useful for decaborane, a canister having a structure in which an absorbent obtained by chemically treating activated carbon with iron oxide or the like and incorporating a filter for removing particulate matter is effective. This structure is also effective as a filter for air purification.
[0010]
By the way, when the used absorption can is discarded, a method of incinerating it or a method of immersing it in water is generally used. However, in the former, toxic gas may be generated when the can that absorbed decaborane is incinerated. In the latter case, not all of the decaborane is present in the decaborane state without becoming boric acid. Therefore, it is necessary to safely dispose of decaborane absorbed in the absorption canister after changing it to a non-toxic substance.
As a safe disposal method, it is effective to immerse an absorption can that has absorbed decaborane in alcohol.
[0011]
Therefore, the present invention provides an air purification filter such as a gas mask absorption can and an electric filter effective for decaborane, and also provides a method for safely discarding the absorption can and the filter that absorbed decaborane. is there.
[0012]
[Means for Solving the Problems]
The absorption can is filled with an absorbent that is activated carbon treated with iron oxide or the like in a metal can (impregnated with activated carbon impregnated into activated carbon and then dried), and the outlet of the air flow An electric filter is attached to the side as an air purification filter, and it is sealed with a metal lid.
[0013]
The absorbent is obtained by treating activated carbon with iron oxide or the like, and absorbs and adsorbs gaseous decaborane on the activated carbon. Decaborane absorbed by the absorbent may be adsorbed on activated carbon in the form of decaborane, or may be adsorbed by changing to a stable substance by reacting with iron oxide or the like. In the latter, decaborane is mainly reacted with ferrous oxide in the absorbent. The reaction is B ₁₀ H ₁₄ + (22 / n) FeSO ₄ (H ₂ O) n → 10H ₃ BO ₃ + 22H ₂ + FeSO ₄ (H ₂ O) n, and oxo acid, hydrogen, ferrous oxide (water) Changes to stable substances such as Japanese). In addition, when decaborane passes through the activated carbon treated with iron oxide or the like after changing its state from gas to particles, it is captured by an air cleaning filter.
[0014]
To safely dispose of the can that has absorbed decaborane, the can is soaked in alcohol for a week and then discarded. Decaborane absorbed by the absorbent is absorbed as decaborane, or is converted to boric acid compounds such as oxo acid by reaction with iron oxide, and is captured as particulate decaborane by the filter. There may be. Therefore, all the decaborane is harmless and stable borate (boric acid compound) and can be safely disposed of by immersing the whole (used) absorbent can that has adsorbed decaborane in alcohol.
[0015]
That is, when an absorbent that has absorbed decaborane is immersed in alcohol, a reaction of 80ROH + B ₁₀ H ₁₄ → 10B (OR) ₃ + 111H ₂ proceeds to be converted into borate ester and hydrogen. For example, diborane represented by a borane compound such as decaborane becomes a borate ester when reacted with alcohol.
[0016]
In contrast, decaborane is hydrolyzed in hot water to hydrogen and boric acid, but the reaction is slow. Therefore, in the method of immersing the absorbed can in water, all decaboranes may exist in a decaborane state without becoming safe boric acid.
In addition, in the method of incinerating an absorption can that has absorbed decaborane, harmful substances such as diborane and toxic gas may be generated during combustion.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an external view showing an embodiment of an absorbent can according to the present invention. The size of the absorbent can is determined by the type of the gas mask, the breakthrough time in the operation, and the like, but here, the appearance used in the test is shown.
[0018]
In the can body 4, an absorbent securing cloth 6 incorporating an air purification filter 5 (electric filter) at the bottom of the can body is brought into close contact with the inside of the can body, and the absorbent 1 is filled from above, and the air is again supplied. The can body is sealed with an absorbent securing cloth incorporating a purifying filter and the can lid 2. The absorption can of the present invention is a decaborane absorption can applicable to a conventional gas mask, and the shape of the can itself has the same shape in order to share the gas mask.
[0019]
That is, the top and bottom of the can body are mesh-structured vents 3, and the top side is closed by the can lid 2 detachable from the can body 4, so that gas is absorbed into the can through the can lid. It enters the agent 1 and flows to the bottom of the can body. The top and bottom of the can body are covered with a filter or the like.
[0020]
FIG. 2 is a structural view showing another embodiment of the absorbent can according to the present invention. It is effective to incorporate the air purification filter at the top and bottom of the can body, or only at the bottom, but FIG. 2 shows an example of incorporation at the bottom. The absorbent is covered with a cloth or the like that secures the absorbent at the bottom of the can body, and an air purification filter (electric filter; electrostatic type) is set on top of it, and the absorbent (the absorbent components include activated carbon, iodine Filled with, for example, potassium oxide and ferrous sulfate, etc., treated with activated carbon with iron oxide or the like, and this contains ferrous sulfate, etc. Built in and pressed against the can lid, the absorbent does not come out of the can.
[0021]
Conventional absorption cans for semiconductor doping do not have a filter in the absorption can, and cloth or the like is used for the purpose of securing an absorbent (no filter is incorporated).
In contrast, the absorption can of the present invention has a structure in which a filter is incorporated between the absorbent and its securing cloth to capture and adsorb particulate decaborane. As the filter, an electric filter that does not allow the finest particles having a diameter of about 2 μm after passing through the absorbent to pass therethrough was used. An electric filter is a kind of electrostatic filter material, and is made of felt or non-woven fabric. The electric filter collects particulate and dust decaborane by static electricity charged in the filter. In the silica dust test, a filter of the highest grade in the field of the present invention having a dust collection effect rate of 99.9% is incorporated.
[0022]
FIG. 3 shows a test carried out to obtain an absorption can for a gas mask with respect to decaborane having a structure in which an absorbent chemically treated with iron oxide or the like is filled in order to remove decaborane gas and decaborane particles and a filter is incorporated. It is a figure which shows the test apparatus of. The test absorber was set at the position of the sample, the gas generated by sublimation of decaborane was used, the gas concentration was controlled, and the breakthrough time, particle permeation concentration, adsorbed substance, etc. of the absorber were confirmed.
[0023]
That is, after the air passes through the compressor, the dryer and the filter cylinder, the temperature and humidity are adjusted in the temperature and humidity control tank through the mist mist separator and the valve, and through the valve and the flow meter, contact the decaborane contained in the mantle heater. Generate decaborane-containing gas. The generated decaborane-containing gas is heated to a predetermined temperature by a ribbon heater, and after the decaborane concentration is measured by a test gas concentration measurement port, it is supplied to an absorption can installed at the position of the sample. The gas that has passed through the absorption can is measured at the transmission concentration measurement port, and the absorption capacity of decaborane in the absorption can is measured. The exhaust after the measurement is discharged through a flow meter.
[0024]
FIG. 4 shows a test conducted to obtain an absorbent can for a gas mask that is filled with an absorbent chemically treated with iron oxide or the like to remove decaborane gas and decaborane particles, and further has a structure incorporating a filter. It is a figure which shows an apparatus. The test canister is set at the position of the sample, the gas concentration is controlled using the gas generated by sublimation of decaborane, the gas temperature is also controlled, and the breakthrough curve and the crystal are confirmed. The disposal method of the can that absorbed decaborane was confirmed.
[0025]
That is, after the air passes through the compressor, the dryer and the filter cylinder, the temperature and humidity are adjusted in the temperature and humidity control tank through the mist mist separator and the valve, and through the valve and the flow meter, contact the decaborane contained in the mantle heater. Generate decaborane-containing gas. The generated decaborane-containing gas is adjusted to 20, 30, 40, and 50 ° C. with cooling water from the cooling water circulation device, and then the decaborane concentration is measured at the test gas concentration measuring port. Supplied. The gas that has passed through the absorption can is measured at the transmission concentration measuring port, and the breakthrough point of the absorption capacity of decaborane in the absorption can is measured. The exhaust after the measurement is discharged through a flow meter.
[0026]
【Example】
(Example 1) (About the absorption can)
FIG. 5 shows the result of treating decaborane gas using the absorption can of the present invention (CA-104NII, No. 960930-1) filled with activated carbon treated with iron oxide. There, a test gas having a concentration of 107 ppm was generated by heating decaborane to a temperature of 110 ° C., and it was passed through the absorption can at an aeration temperature of 28 ° C., and the passing concentration of decaborane was measured. As a result, the decaborane concentration of the permeate side gas was 0.05 ppm or less until the test gas passage time was around 200 minutes, but the decaborane concentration of the passage side gas exceeded 0.10 ppm when the passage time was around 400 minutes. showed that.
[0027]
That is, decaborane gas was heated to generate decaborane gas, and aeration was performed in the gas flow direction of the absorption can to confirm the performance of the absorption can. Decaborane has a TLV value (allowable value for long-term exposure) of 0.05 ppm, and therefore exceeds 200 minutes. That is, the use limit of the absorption can of the present invention was confirmed by a test. Therefore, it is natural to check the gas concentration for work that requires a lot of time, but it is necessary to periodically replace the canister.
[0028]
(Example 2) (About the disposal method of used absorbent cans)
Absorbers that absorbed decaborane were immersed in alcohol to change decaborane into a stable and harmless substance. As a result, harmful decaborane could be converted into harmless and stable substances such as alkyl groups and boric acid, so that used absorbent cans could be safely disposed of.
The absorbent can after being immersed in alcohol was effective in natural drying in order to remove the remaining alcohol.
[0029]
In addition, alcohol immersed in an absorption can that has absorbed decaborane requires waste liquid treatment as alcohol, but does not require special treatment.
[0030]
【The invention's effect】
The present invention produces the following effects.
Decaborane gas that passes through the absorption can is adsorbed by activated carbon that has been treated with iron oxide or the like, converted into a stable substance such as hydrogen or a boric acid compound such as oxo acid. Also,
Particulate decaborane that has passed through the activated carbon treated with iron oxide is captured and removed by an air purification filter.
[0031]
Furthermore, when an absorption can that has absorbed decaborane is immersed in alcohol, decaborane is converted into a boric acid compound, which can be safely discarded.
[Brief description of the drawings]
FIG. 1 is an external view of an absorbent can of the present invention.
FIG. 2 is a structural diagram showing a cross-sectional view of another absorbent can of the present invention.
FIG. 3 is a view showing the structure of a test apparatus for confirming breakthrough time, particle permeation concentration, adsorbed substance, etc. of the absorption can using the absorption can of the present invention.
FIG. 4 is a diagram showing the structure of a test apparatus for confirming breakthrough curves, crystals, etc. using the absorption can of the present invention.
FIG. 5 is a diagram showing a breakthrough curve in which the decaborane gas of the absorption can of the present invention is passed and the gas concentration after passing the absorption can and the use limit time of the absorption can are measured.
[Explanation of symbols]
1: Absorbent 2: Can lid 3: Mesh structure (vent hole)
4: Can body 5: Air purification filter (electric filter)
6: Absorbent securing cloth

Claims (2)

Filling the can with a solution of iron oxide to remove decaborane gas and decaborane particles , impregnating with activated carbon and drying, and fitting the top and bottom of the can with mesh cans and bottom lids The gas mask absorption can, wherein an electric filter is incorporated as an air purification filter inside the can lid and the bottom lid.   In order to safely dispose of used cans for gas masks filled with absorbents that have absorbed decaborane, the cans are immersed in an alcohol solution to oxidize the unreacted decaborane in the absorbent cans filter and absorbent. A detoxifying disposal method for used cans for gas masks, characterized in that it is disposed as a stable material.

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