JP2010051856A - Method for treating fluorine selective separation agent and fluorine-containing compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating a fluorine selective separation agent and a fluorine-containing compound capable of absorbing in dry condition halogen dissociated from a vaporized halogen-containing compound in a processing agent on site and more selectively increasing a fixed amount of fluorine than in a conventional art so as to selectively separate fluorine from a fluorine-containing compound under dry and low-temperature conditions of less than 800°C. <P>SOLUTION: The gaseous fluorine-containing compound reacts with a fluorine selective separation agent in an environment that is controlled at a temperature of 600°C, and the fluorine in the fluoride is fixed to a catalyst of the fluorine selective separation agent and a solid alkali agent. The fluorine selective separation agent is made by coating an oxide system catalyst exhibiting solid acid coated on the solid alkali agent. This allows the halogen dissociated from the vaporized halogen-containing compound to be catalytically absorbed to the reaction processing agent on site in dry condition, thereby enabling the system to more selectively increase the fixed amount of fluorine than in the conventional art. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluorine selective separating agent and a fluorine-containing compound that can chemically separate and collect fluorine by selectively chemically bonding fluorine by chemically reacting with one or more halogen-containing fluorine-containing compounds. It relates to the processing method.

  A halogen-containing compound having a bond between fluorine and carbon has a strong bond in the molecule and is extremely difficult to decompose. Further, since fluorine is an important substance in fields such as chemistry and refining, a technique for selectively separating and recovering fluorine easily and selectively from the aforementioned halogen-containing compounds is highly desired.

  Conventionally, in order to recover fluorine from a fluorine-containing compound, the fluorine-containing compound is decomposed by heating to an extremely high temperature, and then the exhaust gas is subjected to wet neutralization treatment to produce sludge containing calcium fluoride with calcium hydroxide, An extremely complicated process is required in which the sludge is decomposed with a strong acid such as sulfuric acid and recovered as hydrogen fluoride.

For this reason, it is very expensive and there are few plants that are actually in operation.
Here, a conventionally proposed method for burning a fluorine-containing compound will be described. In the conventional combustion method, since the fluorine-containing compound is decomposed by oxidative decomposition using the combustion heat of the waste or the auxiliary combustor, a processing temperature of at least 850 ° C. or more is used to prevent recombination / generation of harmful substances. And residence time was needed. In order to improve this high temperature treatment, an alkali reaction material method has been proposed.

  In the alkali reaction material method, an alkali and a fluorine-containing compound directly react to remove a halogen component from the reaction system. For this reason, the alkali reactant method is based on the fact that the reaction proceeds spontaneously without being bound by the equilibrium conditions for the decomposition and resynthesis of the fluorine-containing compound, and that the reaction heat of halogen fixation by alkali can be used for the decomposition of the fluorine compound. As described above, the reaction is realized by supplementing only necessary and sufficient reaction heat by electric heating. In this alkali reaction material method, the fluorine-containing compound is easily decomposed in a temperature range of 700 to 850 ° C. (see Patent Document 1).

On the other hand, in the conventional catalytic-type fluorine-containing compound decomposition process, a large amount of water vapor is introduced and the decomposition process is performed using the hydrolysis of the fluorine compound for the purpose of releasing the equilibrium constraint. (See Patent Document 2).
JP 2001-79344 A JP-A-8-57255

  However, the above method is a semi-wet process in which a large amount of water vapor is introduced into the apparatus and a large amount of wet gas is handled, and it is necessary to post-process the wet gas with a wet scrubber or the like. For this reason, the conventional catalytic fluorine-containing compound decomposition process has difficulties in terms of process handling and heat utilization.

  Further, in the case of refractory fluorine compounds such as halons, perfluorocarbons, and some specific chlorofluorocarbons, the limit temperature due to the thermodynamic reaction is high, and it is still necessary to operate at a high temperature around 850 to 1300 ° C. ing.

  An object of the present invention is to solve a conventional problem and to convert a gaseous halogen-containing compound into a reaction treatment agent in order to selectively separate fluorine from a fluorine-containing compound with high efficiency under a low temperature condition of less than 800 ° C. It is another object of the present invention to provide a fluorine selective separation agent that enables on-site dry absorption and can selectively increase the amount of fluorine immobilized compared to conventional ones.

  In addition, another object of the present invention is to dry-absorb gaseous halogen-containing compounds on-site in a reaction treatment agent in order to selectively separate from fluorine-containing compounds with high efficiency under low temperature conditions of less than 800 ° C. It is an object of the present invention to provide a method for treating a fluorine-containing compound capable of increasing the amount of selectively separated and immobilized fluorine as compared with the conventional one.

In order to solve the above problems, the fluorine selective separating agent of the present invention is characterized in that a solid alkaline agent is coated with an oxide-based catalyst exhibiting solid acidity.
The solid alkali agent preferably contains at least one of alkaline earth compounds containing calcium oxide or magnesium oxide as a main component.

  Further, the oxide-based catalyst is selected from at least one of alumina compounds containing γ-alumina or θ-alumina, titania compounds containing anatase-type titania or rutile-type titania. preferable.

  When the fluorine-containing compound is treated using the fluorine selective separating agent as described above, the fluorine-containing compound vaporized under normal pressure in a non-humidified atmosphere is heated in a range of 400 ° C. or higher and lower than 800 ° C. And processing through the fluorine selective separating agent.

  When the temperature is less than 400 ° C., a sufficient decomposition rate cannot be continued immediately after the start of the reaction. This is because the reaction does not proceed at a low temperature of less than 400 ° C. because the influence of the diffusion rate inside the solid phase in the catalyst or solid alkaline agent particles becomes large. In addition, when the reaction temperature is 800 ° C. or higher, the reaction rate is increased and the halogen immobilization rate is improved. However, since the handling property is deteriorated in the process operation, the object of the present invention can be achieved. Can not.

  According to the fluorine selective separating agent of the present invention, the halogen dissociated from the vaporized halogen-containing compound is a reaction treatment agent in order to selectively separate fluorine from the fluorine-containing compound with high efficiency under a low temperature condition of less than 800 ° C. In addition, dry absorption can be performed on-site, and the amount of fluorine immobilized can be selectively increased over the conventional one.

  Further, according to the method for treating a fluorine-containing compound of the present invention, a gaseous halogen-containing compound is subjected to a reaction treatment in order to selectively separate fluorine from the fluorine-containing compound with high efficiency under a low temperature condition of less than 800 ° C. The agent can be dry-absorbed on-site, and the amount of fluorine added with high added value can be selectively increased from that of the conventional one.

Embodiments of the present invention will be described below.
(Fluorine selective separating agent)
The fluorine selective separating agent of the present embodiment is coated with an oxide-based catalyst exhibiting solid acidity on a solid alkaline agent and calcined, and has a solid basicity having halogen fixing property and catalytic activity for fluorine selective dissociation. Solid acidity is compatible with near field.

  Examples of the solid alkali agent include calcined dolomite and calcined calcite containing calcium oxide or magnesium oxide as a component. Firing dolomite and calcined calcite are solid reactants useful for halogen fixation. In the prior art, when the vaporized halogen-containing compound is subjected to a reaction treatment by being brought into contact with calcined dolomite or calcined calcite, a high-temperature condition of 850 ° C. or higher or a large amount of water vapor is required, and a specific halogen is used. Could not be selectively immobilized.

  As the oxide catalyst, at least one catalyst of alumina compound containing γ-alumina or θ-alumina, titania compound containing anatase type titania or rutile type titania, or a mixture thereof Is preferred. These oxide-based catalysts have a relatively high acid strength as unitary oxides.

The weight ratio of the oxide catalyst to the solid alkali agent is preferably 0.2 to 6, preferably 0.5 to 5, and more preferably 1.3 to 4.
(Method for producing fluorine selective separating agent)
Although the manufacturing method of the fluorine selective separation agent of this invention is not limited, Below, the method to manufacture by the following inclusion method is demonstrated.

  The oxide catalyst sol that becomes the catalyst precursor is diluted with distilled water so as to have an appropriate viscosity, and the pulverized and granulated solid alkali agent is mixed in the sol viscous liquid. The mixing ratio is adjusted so that the weight ratio (catalyst / solid alkali agent ratio) of the catalyst (oxide-based catalyst) and solid alkali agent contained in the synthesized fluorine selective separating agent is 0.2-6.

  The mixing operation is performed in a heat-resistant container (for example, porcelain, earthenware), and then in an electric furnace without a lid on the container in order to allow sufficient diffusion of volatiles from the mixture. Bake in an air atmosphere at 3 ° C. for 3 hours. In addition, the temperature in an electric furnace and baking time are not limited to the above-mentioned numerical value, However, What is necessary is just the temperature range and time which can be baked. Also, it is preferable that the heating rate at the time of firing to be heated from room temperature is, for example, 0.5 ° C./min, and cooling is similarly performed at 0.5 ° C./min to room temperature to promote crystal growth. .

  When the particles of the fluorine selective separating agent thus calcined are visually observed, it can be observed that the solid alkali agent particles are connected to each other via the catalyst particles to form large secondary particles. This indicates that the fluorine selective separation agent forms a porous structure by forming particles of the solid alkali agent as secondary particles using fine particles of the catalyst as a binder.

  In the inclusion method, fine particles are included (that is, coated) with a binder component, and each crushed particle is adhered via the binder. Therefore, a large particle (two types) that can be easily adapted to the current alkaline reactor by a simple method. Secondary particles) can be granulated. In addition, you may atomize moderately after baking.

(Separation processing device)
A separation apparatus for separating fluorine from a fluorine-containing compound using the fluorine selective separation agent of the present invention is a continuous gas flow fixed-bed reactor (hereinafter simply referred to as a reactor) as shown in FIG. .

  The reactor 10 fills the reaction tube 22 with a fluorine selective separating agent as a fixed layer 20, continuously circulates the gas in the fixed layer 20, and heats it with an electric heater 23 provided outside the reaction tube 22. It is made to react with the fixed layer 20 made.

  The gas paths 24 to 26 to the reaction tube 22 are provided with gas ports 31 to 33 for carrier gas (for example, inert gas such as argon or nitrogen), oxygen, and fluorine-containing compounds, and mass flow meters 34 to 36, Flow rate adjusting units 40 to 42 including flow rate adjusting valves 37 to 39 are provided. And the pure gas introduced from each gas port 31-33 adjusts the inlet gas of the reaction tube 22 by the flow volume adjustment parts 40-42, and the mixed gas adjusted so that it may become predetermined concentration and predetermined amount The fixed layer 20 in the reaction tube 22 can be supplied via a path 27. Further, a heat-resistant support material 29 made of alumina wool or the like is filled between the lower end of the fixed layer 20 and the bottom of the reaction tube 22.

  A pressure gauge 28 is provided in the passage 27 on the inlet side of the reaction tube 22. Although not shown, a temperature sensor (for example, a thermocouple) for temperature detection is provided in the fixed layer 20, and the electric heater 23 is fixed by a control device (not shown) based on the temperature detection of the temperature sensor. The temperature in the layer 20 is controlled to be in the range of 400 ° C. or higher and lower than 800 ° C.

  Accordingly, the gaseous fluorine-containing compound reacts with the fixed layer 20 (fluorine selective separating agent) in the reaction tube 22 in an environment where the temperature is controlled in the range of 400 ° C. or more and less than 800 ° C., and fluorine of the fluorine compound Is immobilized on the catalyst of the fluorine selective separation agent and the solid alkali agent. As described above, the reaction apparatus 10 is used to treat the fluorine-containing compound.

Now, the fluorine selective separation agent comprised as mentioned above has the following effect.
(1) The fluorine selective separating agent of the present embodiment is formed by coating a solid alkaline agent with an oxide catalyst exhibiting solid acidity. As a result, in order to selectively separate fluorine from a fluorine-containing compound with high efficiency under a low temperature condition of less than 800 ° C., dry absorption is performed on-site with the halogen dissociated from the vaporized halogen-containing compound as a reaction treatment agent. And the amount of fluorine immobilized can be selectively made higher than the conventional one.

  Hereinafter, separation treatments for separating fluorine from halon 1301, which is a hardly decomposable fluorine compound (fluorine-containing compound), are performed in Examples 1 to 3 using a fluorine selective separating agent and comparative examples using a conventional reaction treatment agent. 1-3.

(Examples 1-3)
First, the fluorine selective separating agents of Examples 1 to 3 below were produced by an inclusion method. The inclusion method has an advantage that the target reaction system can be constructed without changing the device design, and the physical distance between the catalyst and the solid alkali agent as the gas fixing agent (reaction treatment material) can be minimized.

  As shown in FIG. 1 (a), alumina sol (manufactured by Nissan Chemical Co., Ltd.) as a catalyst precursor is diluted with distilled water so as to have an appropriate viscosity, and granulated by crushing into the diluted alumina sol viscous liquid. The baked dolomite was mixed. By this mixing, fine particles of the catalyst (catalyst precursor) are coated on the calcined dolomite as a binder.

The mixing ratio was adjusted so that the weight ratio (Al ₂ O ₃ / dolomite ratio) of Al ₂ O ₃ and calcined dolomite contained in the synthesized fluorine selective separating agent was 3.76, 2.00, 1.37. The weight ratio was measured using XRF (fluorescence X-ray analyzer).

Hereinafter, the one with a weight ratio of 3.76 is designated as Example 1, the one with a weight ratio of 2.00 is designated as Example 2, and the one with a weight ratio of 1.37 is designated as Example 3.
6 shows Example 1 (Al ₂ O ₃ / dolomite ratio = 3.76), Example 2 (Al ₂ O ₃ / dolomite ratio = 2.00), and Example 3 (Al ₂ O ₃ / dolomite ratio). = 1.37) is a chart showing the result of analysis by X-ray diffraction using CuKα rays. As shown in FIG. 6, in these mixtures, a peak indicating γ-Al ₂ O ₃ (γ-alumina) (peaks appearing on dotted lines 110 and 120) was greatly observed.

Further, as the peaks indicating _θ-Al 2 _{O 3} (θ- alumina) (peak appearing on the dotted line 130 to 170), only a portion (e.g., a dotted line 140, 150, 160) was observed. In addition, the alumina sol used as the catalyst precursor used in Examples 1 to 3 is the same. From this, it was confirmed that the mixed catalyst contains γ-Al ₂ O ₃ and θ-Al ₂ O ₃ . Also, the peak of θ-Al ₂ O ₃ (θ-alumina) is different from γ-Al ₂ O _{3 in} which a large peak appears, and the amount is estimated to be less than that of γ-Al ₂ O ₃ .

  The mixing operation is carried out in a magnetic crucible 50, and then in the electric furnace 52 at 500 ° C. without the lid of the magnetic crucible 50 in order to allow sufficient diffusion of volatiles from the mixture. Firing was performed in an air atmosphere for 3 hours. At this time, the temperature was increased from room temperature at a rate of 3 ° C./mi, and the cooling was similarly performed at 3 ° C./min to room temperature to promote crystal growth.

  When the obtained particles are visually observed, gray particles seen as baked dolomite are connected to form large secondary particles through white particles seen as γ-alumina as shown in FIG. 1 (b). Was confirmed. This indicates that the catalyst-added reaction treatment agent has a porous structure in which the calcined dolomite particles constitute secondary particles using γ-alumina fine particles and θ-alumina fine particles as a binder.

  In this way, γ-alumina having a high specific surface area and θ-alumina are combined with the calcined dolomite particles (crushed particles) by the inclusion method, and the coexistence effect is emphasized by bringing the reaction fields formed by both into close proximity. .

  In addition, alumina sol is classified into colloidal alumina, and can be made into a high specific surface area porous body of γ-alumina and θ-alumina by firing at about 400 to 500 ° C. Alumina sol is suitable as a catalyst material or a catalyst carrier material because a needle-like crystal grows during firing, so that a structure having a high specific surface area can be easily obtained.

In Examples 1 to 3, the reaction tube 22 of the reaction apparatus 10 shown in FIG. 2 is filled as the fixed layer 20, and Halon 1301 is treated at a reaction temperature of 600 ° C.
Specifically, in the example and the comparative example, the flow rate adjusting unit 40 mixes the mixture so as to have a predetermined concentration (halon 1301: 4.2 vol%) and a predetermined amount (50 ml / min), and this mixed gas is filled. (Fixed layer 20) can be supplied. The outlet gas discharged from the packed bed outlet of the reaction tube 22 was led to an analysis system (not shown) and measured by FID-GC for measuring the fluorine compound.

  As the reaction tube 22, a quartz glass tube having an inner diameter of 10 mm was used. As shown in FIG. 2, the fixed layer 20 has the same weight (about 10 mm) at the same weight for each of the Examples and Comparative Examples so that the support material 29 made of alumina wool does not cause pressure loss at the throttle of the reaction tube 22. Then, the shape of the support material 29 was adjusted so that the upper surface of the support material 29 was horizontal and approximately flat with a long rod, and then the reaction treatment agents of Examples and Comparative Examples were filled to form the fixed layer 20.

Since the mixed gas supplied to the fixed layer 20 is adjusted to a total gas flow rate of 50 ml, the average SV (space velocity) value is calculated from the cylindrical fixed layer volume (φ10 mm, height 15-37 mm). The value is about 2000h- ¹ . This is a value about 10 times larger than that of an actual commercial scale device. The condition in this test example is that the amount of air supplied to the fixed layer 20 is about 10 times the same time, and the reaction When viewed over time, one minute of this device is estimated to be equivalent to about 10 minutes of the actual device in the evaluation per same air volume.

(Comparative Example 1)
The reaction treatment agent of Comparative Example 1 was prepared by simply mixing physically mixed γ-alumina and calcined dolomite at a weight ratio of 1: 1 into the reaction tube 22 of the reaction apparatus 10 as a fixed layer 20, and having a reaction temperature of 600 ° C. 1301 is processed.

(Comparative Example 2)
The reaction treatment agent of Comparative Example 2 is obtained by filling only the calcined dolomite into the reaction tube 22 of the reaction apparatus 10 as the fixed layer 20 and treating halon 1301 at a reaction temperature of 800 ° C.

(Comparative Example 3)
The reaction treatment agent of Comparative Example 3 is obtained by filling only the calcined dolomite into the reaction tube 22 of the reaction apparatus 10 as the fixed layer 20 and treating halon 1301 at a reaction temperature of 600 ° C.

(Measurement of decomposition rate)
Examples 1 to 3 and Comparative Examples 1 to 3 were performed under the above temperature conditions for each example, and the decomposition rate of halon 1301 was measured every 5 minutes until 120 minutes had elapsed from the start of the treatment. The decomposition rates of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in FIG.

  In Comparative Example 3, a sufficient decomposition rate could not be obtained at 600 ° C., and the decomposition rate was 10% or less throughout the course of the reaction. Therefore, in the conventional alkaline reaction method, it is necessary to react at a high temperature operation of about 800 ° C. with a hardly decomposable fluorine compound such as halon 1301. Comparative Example 2 treated at a reaction temperature of 800 ° C. shows that fact, and the decomposition rate of halon 1301 is improved to about 74% in the phagocytic activity. In the case of Comparative Example 2, the decomposition rate after 120 minutes had decreased to approximately 25%. On the other hand, in the comparative example 1 of physical mixing, the initial activity was improved to 98%, but the decomposition rate decreased rapidly immediately after the start of the reaction due to the deterioration of the catalyst function.

On the other hand, as shown in Examples 1 to 3, when the amount of added alumina was increased, the tendency of the decomposition rate of halon 1301 to be improved was recognized. That is, when the alumina content is relatively low as in Example 3 where the weight ratio of alumina to calcined dolomite (Al ₂ O ₃ / dolomite) is 1.37, the decomposition activity is the same as in Comparative Example 3 in which the catalyst is physically mixed. Although it is low, the decomposition activity improves when the alumina content increases as in Example 2 with a weight ratio of 2.00 and Example 1 with a weight ratio of 3.76. In particular, when the weight ratio of γ-alumina and θ-alumina to calcined dolomite is 3.76 and the alumina is excessive as compared with calcined dolomite, the initial decomposition rate is almost 100%, which is superior to conventional reaction conditions at a lower temperature. Show degradation activity.

In the case of Example 1, the most excellent decomposition rate was exhibited until the physical mixing was replaced with Comparative Example 3 in about 50 minutes from the start of the reaction.
From the above, when alumina and calcined dolomite are compounded as in Examples 1 to 3, an improvement in the decomposition activity of halon 1301 is clearly observed. It has been found that the effect of improving the initial activity is affected by the amount of alumina added.

(Halogen immobilization effect)
As can be seen from the results of the above decomposition treatment, Examples 1 to 3 have high efficiency decomposition performance at 600 ° C., which is 200 to 250 ° C. lower than the conventional reaction temperature. Furthermore, in said Examples 1-3 and Comparative Examples 1-3, the content halogen content fixed to each reaction processing agent after performing the said decomposition process for 120 minutes was measured by the ion chromatography. The result is shown in FIG. In FIG. 4, the vertical axis indicates the halogen content (× 10 ⁻³ mol) per unit weight (1.0 g) of the reaction treatment agent. In FIG. 4, A represents the amount of bromide ions (Br ⁻ ), and B represents the amount of fluoride ions (F ⁻ ).

  In Comparative Example 3 performed at a reaction temperature of 600 ° C., fluoride ions could not be confirmed although bromine ions were observed in the recovered sample after the reaction. This is thought to be because bromine spontaneously desorbs by heating in the halon 1301, which is selectively separated and immobilized in the reaction treatment agent of Comparative Example 3. Further, in Comparative Example 3, since calcined dolomite having no catalytic activity is used under the reaction temperature of 600 ° C., the amount of halogen that has been selectively separated is determined because Halon 1301 is hardly decomposable. Were recognized as few.

  In Comparative Example 2, decomposition of Halon 1301 was performed at 800 ° C., which is a higher reaction temperature than Comparative Example 3, so that the decomposition reaction rate of Halon 1301 was sufficiently activated, and the amount of halogen immobilization associated therewith increased. Results were obtained. In Comparative Example 2, the amount of the selectively separated bromine immobilized does not change so much, but the fluorine with high electron withdrawing property is selectively extracted from the Halon 1301 molecule, and the amount of the selectively separated separated fluorine is immobilized. It was confirmed that there was a dramatic increase.

  In Comparative Example 1, it was confirmed that the amount of selectively separated fluorine immobilized was further increased than in Comparative Example 2. In this case, the amount of fluorine immobilized as the halogen species was remarkable, and the amount immobilized was about twice that of Comparative Example 2.

  In Example 1 having a weight ratio of 3.76, the amount of fluorine selectively separated and separated by a little less than about 2 times that in Comparative Example 1 was increased. In Examples 1 to 3 at a reaction temperature of 600 ° C., compared with Comparative Example 2 at a reaction temperature of 800 ° C., the immobilization amount of fluorine selectively separated approximately 4 to 6 times increased. In Examples 1 to 3, the amount of bromine selectively separated was about 0.6 to 0.7 times that of Comparative Example 2. This is considered due to the fact that the γ-alumina and θ-alumina surfaces have sites active for fluorine chemisorption of halon 1301.

  It is considered that γ-alumina and Lewis acid sites on θ-alumina contribute to the sites active for fluorine adsorption (see FIG. 5), that is, the Lewis acid sites are fluoride ions desorbed from halon 1301. It is inferred that the catalytic reaction proceeds as shown in FIG. 5 (indicated by Lewis acid points (L acid points) on γ-alumina and θ-alumina).

  The number of sites contained in the reaction processing agent unit weight is considered to depend on the specific surface area of the reaction processing agent particles and the contents of γ-alumina and θ-alumina, and the specific surface area of the reaction processing agent particles is large. In addition, a reaction treatment agent having a large γ-alumina content and θ-alumina content has a smaller specific surface area and a higher fluorine fixing effect than a reaction treatment agent having a small γ-alumina content and θ-alumina content. It was thought that it should show. However, from the results of Examples 1 to 3 in which the amount of the selectively separated fluorine immobilized tends to increase as the content of alumina decreases, as described later, this indicates that the γ-alumina catalyst and the θ-alumina catalyst. On the other hand, it is inferred that fluorine, which is also a catalyst poison, coexists in the near field with the calcined dolomite, and thus was quickly removed from the adsorption site, and the reduction of the adsorption site in the reaction process was suppressed.

  The coexistence effect of γ-alumina and θ-alumina catalyst and calcined dolomite in the fluorine selective separating agents of Examples 1 to 3 becomes more prominent as the calcined dolomite content increases, and the immobilized amount of selectively separated fluorine tends to increase. was there. On the other hand, in the case of Comparative Example 1 of physical mixing, although the amount of calcined dolomite is relatively large, the initial specific surface areas of the γ-alumina catalyst and the θ-alumina catalyst are small compared to the fluorine selective separating agents of Examples 1 to 3, In addition to the limited number of adsorption sites, the physical distance between the catalyst and the calcined dolomite is relatively large, unlike in Examples 1 to 3, so the halogen immobilization amount is considered to have decreased relatively.

In addition, you may change embodiment of this invention as follows.
○ The method for producing a fluorine selective separating agent is basically performed by two steps of granulation and fired layer as described in the above embodiment, but as a method industrially used as the granulation method, There are various methods such as rolling, fluidized bed, stirring, compression, extrusion, crushing, melting and spraying, and these methods may be used.

  In the above examples, the alumina sol as the catalyst precursor was coated on the calcined dolomite and then calcined. Instead, rutile type titania sol or anatase type titania sol as a catalyst precursor is mixed with calcined dolomite or calcined calcite, and after calcined dolomite or calcined calcite, calcined at 400 ° C. or higher, A fluorine selective separating agent may be formed.

  Alternatively, γ-alumina alone or oxide sol containing θ-alumina alone as an oxide-based catalyst is mixed with calcined dolomite or calcined calcite and coated onto calcined dolomite or calcined calcite, and then 400 ° C. or higher. The fluorine selective separating agent may be formed by baking at less than 800 ° C. Thus, even when γ-alumina alone or θ-alumina is used alone, the Lewis acid sites on γ-alumina alone or θ-alumina contribute as active sites for fluorine adsorption. Become. Accordingly, the Lewis acid point on the γ-alumina alone or on the θ-alumina serves as an electron pair attracting point for fluoride ions desorbed from the halogen-containing compound, and the catalytic reaction can proceed.

(A) is a schematic diagram of a method for producing a fluorine selective separating agent from alumina sol and calcined dolomite, and (b) is an enlarged schematic diagram of a γ-alumina catalyst and calcined dolomite. Schematic of the reaction apparatus. The graph of the decomposition rate of Examples 1-3 and Comparative Examples 1-3. The graph of the amount of halogen fixation of Examples 1-3 and Comparative Examples 1-3. Explanatory drawing of the decomposition | disassembly mechanism of halon 1301 by the fluorine selective separation agent of an Example. (A)-(b) is a chart which shows the result of having analyzed the mixture used in Examples 1-3 by the X-ray diffraction using a CuK alpha ray.

Explanation of symbols

10 ... reactor, 20 ... fixed bed (packed bed), 22 ... reaction tube,
34 ... Mass flow meter, 37 ... Flow rate adjusting valve, 40 ... Flow rate adjusting unit.

Claims (4)

  A fluorine selective separation agent obtained by coating a solid alkaline agent with an oxide-based catalyst exhibiting solid acidity and calcining.   2. The fluorine selective separation agent according to claim 1, wherein the solid alkali agent is selected from at least one of an alkaline earth compound containing calcium oxide or magnesium oxide.   2. The oxide catalyst according to claim 1, wherein the oxide catalyst is selected from at least one of an alumina compound containing γ-alumina or θ-alumina, an titase compound containing anatase type titania or rutile type titania. Item 3. A selective fluorine separation agent according to Item 2.   The gaseous fluorine-containing compound is passed through the fluorine selective separation agent according to any one of claims 1 to 3 heated in a range of 400 ° C or higher and lower than 800 ° C in a non-humidified atmosphere. A method for treating a fluorine-containing compound.

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