Fluoride compound remover

Abstract

The object of the present invention is to provide a fluoride compound remover that can remove fluorine compounds, particularly phosphoric acid trifluoride (PF3), from exhaust gas. [Solution] The above problem is solved by a fluoride compound remover that contains 60-98% by weight of manganese (Mn) calculated as MnO and 0.5-20% by weight of alkali metals calculated as oxides, and does not contain calcium (Ca).

Description

[Technical Field]

[0001] The present invention relates to a fluoride compound remover and a method for producing the same. [Background technology]

[0002] Fluoride compounds used in semiconductor manufacturing processes and other applications need to be removed before being released into the atmosphere.

[0003] Patent Document 1 discloses a fluorine-containing gas removal agent containing alumina and an alkaline earth metal compound.

[0004] Patent Document 2 discloses a halogenated gas treatment agent comprising calcium oxide or magnesium oxide prepared by calcining under a nitrogen atmosphere, which contains at least one compound selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, and alkali metal fluorides. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] WO2018-230121 [Patent Document 2] JPH09-267027 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Conventional removal agents containing calcium have reduced removal capabilities when the concentration of fluoride compounds in the gas is low. Furthermore, if the removal agent does not contain sufficient moisture, the amount of fluoride compounds removed will also decrease, requiring moisture adjustment during use.

[0007] The object of the present invention is to provide a fluoride compound remover that can sufficiently remove fluoride compounds while suppressing the influence of the concentration of fluoride compounds in the gas and the amount of water in the remover. [Means for solving the problem]

[0008] One embodiment of the present invention is a fluoride compound remover containing 60 to 98% by weight of manganese (Mn) calculated as MnO, and 0.5 to 20% by weight of alkali metals calculated as oxides, but without calcium (Ca), where the weight percentage is based on the weight of the fluoride compound remover.

[0009] Another embodiment is a method for producing the fluoride compound remover described above, comprising the steps of: preparing a manganese compound solution; preparing an alkali metal compound solution; mixing and reacting the manganese compound solution and the alkali metal compound solution to obtain a precipitate; and filtering and drying the precipitate to obtain a remover.

[0010] Another embodiment is a method for removing fluoride compounds from a gas, comprising the steps of: placing the fluoride compound removal agent inside a container; and passing a gas containing a fluoride compound through the container and bringing the gas into contact with the fluoride compound removal agent.

[0011] The fluoride compound removal agent according to the present invention can effectively remove fluoride compounds.

[0012] In this specification, fluoride compound removers are also simply referred to as "remover". [Modes for carrying out the invention]

[0013] The fluoride compound remover contains manganese (Mn) and alkali metals, but does not contain calcium (Ca).

[0014] Manganese (Mn) is calculated as MnO based on the weight of the fluoride compound remover, and is 60-98% by weight in one embodiment, 61-98% by weight in another embodiment, 65-98% by weight in another embodiment, 75-98% by weight in another embodiment, 80-98% by weight in another embodiment, 83-98% by weight in another embodiment, 88-98% by weight in another embodiment, 90-98% by weight in another embodiment, 93-98% by weight in another embodiment, 60-96% by weight in another embodiment, 61-96% by weight in another embodiment, 65-96% by weight in another embodiment, 75-96% by weight in another embodiment, 80-96% by weight in another embodiment, 83-96% by weight in another embodiment, 85-96% by weight in another embodiment, 60-91% by weight in another embodiment, 6 In another embodiment, it is 1-91% by weight, in another embodiment, 65-91% by weight, in another embodiment, 75-91% by weight, in another embodiment, 80-91% by weight, in another embodiment, 83-91% by weight, in another embodiment, 85-91% by weight, in another embodiment, 60-90% by weight, in another embodiment, 61-90% by weight, in another embodiment, 65-90% by weight, in another embodiment, 75-90% by weight, in another embodiment, 80-90% by weight, in another embodiment, 83-90% by weight, in another embodiment, 85-90% by weight, in another embodiment, 60-89% by weight, in another embodiment, 61-89% by weight, in another embodiment, 65-89% by weight, in another embodiment, 75-89% by weight, in another embodiment, 80-89% by weight, in another embodiment, 83-89% by weight, and in another embodiment, 85-89% by weight.

[0015] In one embodiment, the Mn contained in the fluoride compound remover exists partially or entirely as manganese oxide. In one embodiment, the manganese oxide is selected from the group consisting of MnO, Mn3O4, Mn2O3, MnO2, MnO3, Mn2O7, and combinations thereof. In another embodiment, the manganese oxide includes MnO and / or MnO2. In yet another embodiment, the manganese oxide is MnO2.

[0016] The alkali metal is calculated as an oxide based on the weight of the fluoride compound remover, in one embodiment it is 0.5 to 20% by weight, in another embodiment it is 0.8 to 20% by weight, in another embodiment it is 1 to 20% by weight, in another embodiment it is 2.5 to 20% by weight, in another embodiment it is 4 to 20% by weight, in another embodiment it is 5.5 to 20% by weight, in another embodiment it is 7 to 20% by weight, in another embodiment it is 8.5 to 20% by weight, in another embodiment it is 9 to 20% by weight, in another embodiment it is 10.5 to 20% by weight, in another embodiment it is 11 to 20% by weight, and In one embodiment, 0.5 to 18% by weight; in another embodiment, 0.8 to 18% by weight; in another embodiment, 1 to 18% by weight; in another embodiment, 2.5 to 18% by weight; in another embodiment, 4 to 18% by weight; in another embodiment, 5.5 to 18% by weight; in another embodiment, 7 to 18% by weight; in another embodiment, 8.5 to 18% by weight; in another embodiment, 9 to 18% by weight; in another embodiment, 10.5 to 18% by weight; in another embodiment, 11 to 18% by weight; in another embodiment, 0.5 to 16% by weight; in another embodiment, 0.8 to 16% by weight; in another embodiment, 1 to 1 6% by weight, in another embodiment, 2.5-16% by weight, in another embodiment, 4-16% by weight, in another embodiment, 5.5-16% by weight, in another embodiment, 7-16% by weight, in another embodiment, 8.5-16% by weight, in another embodiment, 9-16% by weight, in another embodiment, 10.5-16% by weight, in another embodiment, 11-16% by weight, in another embodiment, 0.5-14% by weight, in another embodiment, 0.8-14% by weight, in another embodiment, 1-14% by weight, in another embodiment, 2.5-14% by weight, in another embodiment, 4-14% by weight, in another embodiment In one embodiment, 5.5-14% by weight; in another embodiment, 7-14% by weight; in yet another embodiment, 8.5-14% by weight; in yet another embodiment, 9-14% by weight; in yet another embodiment, 10.5-14% by weight; in yet another embodiment, 11-14% by weight; in yet another embodiment, 0.5-13% by weight; in yet another embodiment, 0.8-13% by weight; in yet another embodiment, 1-13% by weight; in yet another embodiment, 2.5-13% by weight; in yet another embodiment, 4-13% by weight; in yet another embodiment, 5.5-13% by weight; in yet another embodiment, 7-13% by weight; in yet another embodiment, 8% by weight.5 to 13% by weight, in another embodiment, 9 to 13% by weight, in another embodiment, 10.5 to 13% by weight, in another embodiment, 11 to 13% by weight, in another embodiment, 0.5 to 10% by weight, in another embodiment, 0.8 to 8% by weight, in another embodiment, 1 to 5% by weight.

[0017] In one embodiment, the alkali metal is incorporated into the structure of the manganese oxide. In that case, the manganese oxide is a kind of compound containing an alkali metal, manganese, and oxygen.

[0018] In one embodiment, the alkali metal is selected from the group consisting of lithium (Li), sodium (Na), potassium (K), and combinations thereof. In another embodiment, the alkali metal contains potassium (K). In another embodiment, the alkali metal is potassium (K).

[0019] In one embodiment, the amount of the alkali metal in the fluoride compound remover is calculated as Li2O if it is lithium (Li), Na2O if it is sodium (Na), and K2O if it is potassium (K).

[0020] In one embodiment, the fluoride compound remover does not contain calcium. Conventionally, it is known that a remover containing calcium hydroxide improves the removal ability by containing an appropriate amount of moisture of about a dozen percent. Therefore, a remover containing calcium requires appropriate moisture control during use. Thus, a remover that does not contain calcium has the advantage that moisture adjustment is not required.

[0021] In the description of this specification, "not containing" means that the component is substantially not contained in the fluoride compound remover, and includes a mode of unintentionally containing the target substance such as contamination. In one embodiment, calcium (Ca) is 1% by weight or less based on the weight of the fluoride compound remover. In another embodiment, it is 0.5% by weight or less. In another embodiment, it is 0.2% by weight or less. In another embodiment, it is 0.1% by weight or less. In another embodiment, it is 0.05% by weight or less. In another embodiment, it is 0.01% by weight or less.

[0022] As shown in Table 2, the fluoride compound remover is not affected by the water content in terms of the amount of fluoride compound removed. Therefore, it is not necessary to adjust the water content contained in the fluoride compound remover. The water content of the fluoride compound remover is 0.1 to 11% by weight in one embodiment, 0.1 to 10% by weight in another embodiment, 0.1 to 8% by weight in another embodiment, and 0.1 to 5% by weight in another embodiment, based on the weight of the fluoride compound remover. The water content of the fluoride compound remover is a value obtained by drying the remover at 120°C for one day and dividing the weight difference before and after drying by the weight of the remover before drying.

[0023] The above fluoride compound remover contains Mn and an alkali metal. In one embodiment, the fluoride compound remover may contain additional components in addition to Mn and the alkali metal. A person skilled in the art can select the additional components without substantially changing the desired properties of the fluoride compound remover. In one embodiment, the additional components are selected from the group consisting of copper (Cu), iron (Fe), and combinations thereof. In another embodiment, the additional component contains Cu. In another embodiment, the additional component is Cu. In one embodiment, the additional component forms a composite oxide with Mn.

[0024] The amount of the additional component, calculated as an oxide based on the weight of the fluoride compound remover, is 1-35% by weight in one embodiment, 1-30% by weight in another embodiment, 1-28% by weight in another embodiment, 1-26% by weight in another embodiment, 1-24% by weight in another embodiment, 1-23% by weight in another embodiment, 1-22% by weight in another embodiment, 3-28% by weight in another embodiment, 5-28% by weight in another embodiment, 8-26% by weight in another embodiment, 10-24% by weight in another embodiment, 14-23% by weight in another embodiment, and 18-22% by weight in another embodiment. When the additional component is Cu, the amount of Cu is calculated as CuO.

[0025] In one embodiment, the fluoride compound is an organic fluoride compound (PFC) and / or an inorganic fluoride compound. In one embodiment, the organic fluoride compound (PFC) includes a perfluoroalkyl compound and / or a polyfluoroalkyl compound. In another embodiment, the organic fluoride compound (PFC) is selected from the group consisting of CHF3, CH2F2, CH3F, CF4, C2F6, C4F8, NF3, SF6, C3HF5 and mixtures thereof. In yet another embodiment, the fluoride compound includes an inorganic fluoride compound. In one embodiment, the inorganic fluoride compound is selected from the group consisting of phosphorus trifluoride (PF3), silicon tetrafluoride (SiF4), arsenic trifluoride (AsF3), boron trifluoride (BF3), sulfur hexafluoride (SF6), tungsten hexafluoride (WF6), molybdenum hexafluoride (MoF6), chlorine trifluoride (CIF3), silicon tetrafluoride (SiF4), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), and combinations thereof. In another embodiment, the inorganic fluoride compound includes phosphoric acid trifluoride (PF3). In yet another embodiment, the fluoride compound is phosphoric acid trifluoride (PF3). In one embodiment, the fluoride compound includes phosphoric acid trifluoride (PF3), and the fluoride compound remover is a phosphoric acid trifluoride (PF3) remover.

[0026] The composition of the fluoride compound remover can be determined using methods known to those skilled in the art, such as elemental analysis by X-ray fluorescence analysis (XRF analysis). For example, it can be measured using an X-ray fluorescence spectrometer (Rigaku Corporation, model ZSX Primus II). The composition of the fluoride compound remover does not contain water. Since X-ray fluorescence analysis (XRF analysis) uses a dry sample, the amount of water contained in the remover is not measured.

[0027] The specific surface area (SA) of the removal agent is, in one embodiment, 100 to 700 m². 2 / g, in another embodiment, 120-625m 2 / g, in another embodiment, 197~585m 2 / g, in another embodiment, 210~525m 2 / g, in another embodiment, 251-490m 2 / g, in another embodiment, 350-450m 2 The specific surface area is / g. The specific surface area can be measured by the BET (single point) method in accordance with JIS Z 8830:2013, and for example, a specific surface area measuring device (Macsorb® HMmodel-1201, MOUNTECH Co. Ltd.) can be used.

[0028] In one embodiment, the removal agent is porous. In one embodiment, the pore volume (PV) is 0.05 to 3.0 ml / g, in another embodiment 0.08 to 2.2 ml / g, in another embodiment 0.11 to 1.8 ml / g, in another embodiment 0.18 to 1.2 ml / g, in another embodiment 0.20 to 1.0 ml / g, in another embodiment 0.28 to 0.8 ml / g, in another embodiment 0.35 to 0.7 ml / g, and in another embodiment 0.40 to 0.6 ml / g. The pore volume can be measured, for example, with an automated mercury porosimeter (AutoPore V9620, Micromeritics).

[0029] The bulk density of the removal agent is 0.1 to 3.0 g / ml in one embodiment, 0.3 to 2.7 g / ml in another embodiment, 0.4 to 1.8 g / ml in another embodiment, 0.5 to 1.3 g / ml in another embodiment, 0.4 to 1.2 g / ml in another embodiment, and 0.6 to 0.95 g / ml in another embodiment.

[0030] The shape of the fluoride compound remover is not limited. The fluoride compound remover can be in any shape as long as sufficient removal capacity and strength for fluoride compounds are obtained. In one embodiment, the fluoride compound remover may be irregular in shape, such as crushed. In another embodiment, the fluoride compound remover is selected from the group consisting of granular, cylindrical, spherical, irregular, and combinations thereof. In another embodiment, the fluoride compound remover is cylindrical. In one embodiment, the cross-section of the fluoride compound remover is selected from the group consisting of circular, elliptical, polygonal, rectangular, polylobe, and combinations thereof.

[0031] The size of the fluoride compound remover is not particularly limited. The size of the fluoride compound remover can be any size as long as it can sufficiently remove the fluoride compound and obtain sufficient strength. The diameter of the cross-section of the fluoride compound remover is 0.5 to 8.0 mm in one embodiment, 0.5 to 7.5 mm in another embodiment, 0.5 to 6.8 mm in another embodiment, 0.5 to 5.0 mm in another embodiment, 0.5 to 3.4 mm in another embodiment, 0.6 to 2.8 mm in another embodiment, and 0.8 to 1.5 mm in another embodiment. When the cross-section is elliptical or rectangular, the diameter refers to the major axis. When the cross-section is polylobe or polygonal, the diameter refers to the diameter of the circumscribed circle.

[0032] The length of the fluoride compound remover is 1.0 to 30.0 mm in one embodiment, 2.2 to 24.0 mm in another embodiment, 2.7 to 19.0 mm in another embodiment, 3.2 to 14.0 mm in another embodiment, 3.8 to 12.0 mm in another embodiment, 4.2 to 10.0 mm in another embodiment, and 5.0 to 8.0 mm in another embodiment.

[0033] If the fluoride compound remover is irregular in shape, such as in a crushed form, it can be sorted to some extent by using a sieve. In one embodiment, if the material is irregular in shape, a sieve with an opening of approximately 0.8 to 6 mm can be used.

[0034] In one embodiment, the method for producing the fluoride compound remover is a precipitation method. In one embodiment, the method for producing the fluoride compound remover includes the steps of: preparing a manganese compound solution; preparing an alkali metal compound solution; mixing the manganese compound solution and the alkali metal compound solution and reacting them to obtain a precipitate; and filtering and drying the precipitate to obtain the remover.

[0035] In one embodiment, the manganese compound solution comprises water and the manganese compound. In one embodiment, the manganese compound solution is obtained by mixing water and the manganese compound. In one embodiment, the manganese compound comprises a manganese salt. In one embodiment, the manganese salt is selected from the group consisting of nitrates, sulfates, acetates, chlorides, and combinations thereof. In another embodiment, the manganese salt is selected from the group consisting of manganese nitrate, manganese sulfate, manganese chloride, and combinations thereof. In another embodiment, the manganese compound comprises manganese sulfate. In yet another embodiment, the manganese compound is manganese sulfate.

[0036] If the fluoride compound remover contains the above additional components, in one embodiment, the above additional component compound may be added to the manganese compound solution. In one embodiment, the manganese compound solution contains the manganese compound and the additional component compound. In one embodiment, the additional component compound contains a salt of the additional component. In one embodiment, the salt of the additional component is selected from the group consisting of nitrates, sulfates, acetates, chlorides, and combinations thereof. In another embodiment, the salt of the additional component is selected from the group consisting of nitrates, sulfates, acetates, chlorides, and combinations thereof.

[0037] If the above additional component is copper, in one embodiment, a copper compound may be added to the manganese compound solution. In one embodiment, the manganese compound solution contains a manganese compound and a copper compound. In one embodiment, the copper compound contains a copper salt. In one embodiment, the copper salt is selected from the group consisting of nitrates, sulfates, acetates, chlorides, and combinations thereof. In another embodiment, the copper salt is selected from the group consisting of copper acetate, copper nitrate, copper sulfate, copper chloride, and combinations thereof. In yet another embodiment, the copper salt contains copper sulfate.

[0038] In one embodiment, the alkali metal compound solution comprises water and an alkali metal compound. In one embodiment, the alkali metal compound comprises an alkali metal selected from the group consisting of sodium, potassium, lithium, and combinations thereof. In another embodiment, the alkali metal compound comprises an alkali metal hydroxide, carbonate, and / or permanganate. In yet another embodiment, the alkali metal compound is an alkali metal hydroxide, carbonate, and / or permanganate. In another embodiment, the alkali metal compound comprises at least an alkali metal permanganate. In yet another embodiment, the alkali metal compound comprises at least an alkali metal permanganate and a hydroxide.

[0039] In one embodiment, the alkali metal compound includes an alkali metal selected from the group consisting of sodium, potassium, lithium, and combinations thereof. In one embodiment, the alkali metal hydroxide is selected from lithium hydroxide, sodium hydroxide (caustic soda), potassium hydroxide (caustic potassium), and mixtures thereof. In one embodiment, the alkali metal carbonate is selected from lithium carbonate, sodium carbonate, potassium carbonate, and mixtures thereof. In one embodiment, the alkali metal permanganate is selected from lithium permanganate, sodium permanganate, potassium permanganate, and mixtures thereof. In another embodiment, the alkali metal compound includes at least sodium permanganate and / or potassium permanganate. In yet another embodiment, the alkali metal compound includes at least potassium permanganate.

[0040] In another embodiment, the alkali metal compound is selected from the group consisting of sodium permanganate, potassium permanganate, sodium hydroxide (caustic soda), potassium hydroxide (caustic potassium), and combinations thereof. In another embodiment, the alkali metal compound comprises potassium permanganate and sodium hydroxide (caustic soda) or potassium hydroxide (caustic potassium). In yet another embodiment, the alkali metal compound comprises potassium permanganate and potassium hydroxide (caustic potassium).

[0041] In another embodiment, the alkali metal compound is selected from sodium hydroxide (caustic soda), potassium hydroxide (caustic potassium), sodium carbonate, potassium carbonate, sodium permanganate, potassium permanganate, and mixtures thereof. In another embodiment, the alkali metal compound is selected from sodium hydroxide (caustic soda), potassium hydroxide (caustic potassium), sodium permanganate, potassium permanganate, and mixtures thereof. In another embodiment, the alkali metal compound is selected from potassium hydroxide (caustic potassium), potassium permanganate, and mixtures thereof. In another embodiment, the alkali metal compound includes potassium hydroxide (caustic potassium) and potassium permanganate. In another embodiment, the alkali metal compound is potassium hydroxide (caustic potassium) and potassium permanganate.

[0042] In one embodiment, when the manganese compound solution and the alkali metal compound solution are mixed and reacted, a precipitate is obtained after stirring the mixed solution. The precipitation time is 1 to 10 hours in one embodiment, 2 to 8 hours in another embodiment, 2 to 6 hours in another embodiment, 2 to 5 hours in another embodiment, and 2 to 4 hours in another embodiment. In one embodiment, the precipitation time may include the time for aging the precipitate. In one embodiment, the aging time is 0.5 to 10 hours.

[0043] The resulting precipitate is filtered and dried to obtain a removal agent. In one embodiment, the filtered precipitate is washed with water.

[0044] In one embodiment, the above manufacturing method includes a step of molding the filtered precipitate. In another embodiment, the manufacturing method includes a step of extruding the precipitate using a matrix having holes of a desired shape before the drying step, or a step of crushing the dried precipitate and molding it into an amorphous shape or into a tablet shape after the drying step. In yet another embodiment, the manufacturing method includes a step of extruding the precipitate using a matrix having holes of a desired shape before the drying step.

[0045] The drying temperature of the precipitate is 60-200°C in one embodiment, 70-170°C in another embodiment, and 100-150°C in yet another embodiment. The drying time is 1-24 hours in one embodiment, 3-20 hours in another embodiment, 5-18 hours in another embodiment, 8-16 hours in another embodiment, and 11-16 hours in yet another embodiment.

[0046] The above drying process can be carried out using a dryer. Examples of dryers include mesh belt furnaces, rotary dryers, infrared heating dryers, and hot air circulating dryers.

[0047] A method for removing fluoride compounds from a gas includes the steps of: placing a fluoride compound remover in a container; and passing a gas containing a fluoride compound through the container to bring the gas into contact with the fluoride compound remover.

[0048] In one embodiment, the container includes a fixed bed, a mobile bed, a fluidized bed, and a combination thereof for the removal agent. In another embodiment, the container includes a fixed bed for the removal agent. In one embodiment, the removal agent placed in the container can be a fixed bed, a mobile bed, a fluidized bed, or a combination thereof. In another embodiment, the removal agent placed in the container is a fixed bed.

[0049] In one embodiment, multiple types of removal agents may be placed inside the container. In another embodiment, the fluoride compound removal agent and an additional removal agent separate from the said removal agent are placed inside the container. In another embodiment, the above removal agent is placed in the upper layer of the container and the additional removal agent is placed in the lower layer of the container, or the above removal agent is placed in the lower layer of the container and the additional removal agent is placed in the upper layer of the container. In another embodiment, the above removal agent is placed in the upper layer of the container and the additional removal agent is placed in the lower layer of the container. In another embodiment, the additional removal agent is placed in the upper layer of the container and the above removal agent is placed in the lower layer of the container. The upper layer of the container refers to the inlet side of the container through which the gas passes, and the lower layer refers to the outlet side. In another embodiment, multiple containers may be connected and different removal agents may be placed in each container. In another embodiment, multiple containers are connected, and the above removal agent is placed in the container upstream of the gas passing through, and the above additional removal agent is placed in the container downstream. In another embodiment, multiple containers are connected, with the additional removal agent placed in the container upstream of the passing gas and the removal agent placed in the container downstream. In one embodiment, the additional removal agent is a fluoride compound remover containing calcium. In another embodiment, the additional removal agent is a fluoride compound remover mainly composed of calcium. In yet another embodiment, the additional removal agent is a remover of components other than fluoride compounds.

[0050] In one embodiment, the container is a reaction vessel. In another embodiment, the container is a SUS reaction vessel, in yet another, a cylindrical reaction vessel, and in yet another, a cylindrical SUS reaction vessel. In one embodiment, the container has an inlet and an outlet for passing gas. In one embodiment, there may be multiple containers, and they can be connected by connecting the outlet of one container to the inlet of another.

[0051] The concentration of the fluorinated compound contained in the gas to be brought into contact with the above-mentioned removing agent is, in one embodiment, 0.01 to 10% by volume, in another embodiment, 0.05 to 8% by volume, in another embodiment, 0.1 to 5% by volume, in another embodiment, 0.4 to 3% by volume, in another embodiment, 0.8 to 2.5% by volume, in another embodiment, 0.8 to 1.9% by volume, in another embodiment, 0.8 to 1.5% by volume, in another embodiment, 0.01 to 4.0% by volume, in another embodiment, 0.03 to 3.3% by volume, in another embodiment, 0.05 to 2.2% by volume, in another embodiment, 0.08 to 1.5% by volume, in another embodiment, 0.10 to 0.8% by volume, in another embodiment, 0.12 to 0.5% by volume, in another embodiment, 0.12 to 0.4% by volume, in another embodiment, 0.12 to 0.3% by volume, in another embodiment.

[0052] In the step of passing the gas containing the fluorinated compound through the container, the space velocity (GHSV) of the gas is, in one embodiment, 100 to 1000 h -1 , in another embodiment, 110 to 850 h -1 , in another embodiment, 120 to 650 h -1 , in another embodiment, 150 to 550 h -1 , in another embodiment, 180 to 250 h -1 is.

[0053] The temperature inside the container when the gas is brought into contact with the fluorinated compound removing agent is, in one embodiment, 1 to 70 °C, in another embodiment, 5 to 63 °C, in another embodiment, 10 to 60 °C, in another embodiment, 15 to 55 °C, in another embodiment, 20 to 40 °C. In one embodiment, the temperature inside the container can be adjusted to obtain the desired temperature. In another embodiment, it is also possible to pass the gas at room temperature without adjusting the temperature inside the container.

[0054] The pressure inside the container can be adjusted to obtain the desired pressure. In another embodiment, it is also possible to pass the gas at atmospheric pressure without adjusting the pressure inside the container.

[0055] In one embodiment, the method for removing fluoride compounds from gas can be applied as a gas purification process, such as the treatment of fluoride compound-containing gases in semiconductor manufacturing processes, exhaust gas treatment in chemical plants, and exhaust gas treatment in fluoride compound manufacturing processes. [Examples]

[0056] We prepared removal agents containing calcium and those without calcium, and investigated the amount of phosphorus trifluoride (PF3) gas removed by passing gases of different concentrations of PF3 through them.

[0057] Example 1 275 g of manganese sulfate and 210 g of copper sulfate were added to a sedimentation tank containing 6 L of deionized water, and the mixture was stirred to obtain a manganese sulfate solution. Separately, 150 g of potassium permanganate and 240 g of caustic potassium were added to a container containing 10 L of deionized water, and the mixture was stirred to obtain a potassium permanganate solution. The potassium permanganate solution was added to the manganese sulfate solution while stirring, and the mixture was allowed to react for 3 hours to obtain a precipitate. The precipitate was filtered, washed with deionized water, and dried at 110°C for 14 hours to obtain a removal agent. The removal agent was crushed into 1.2-2.4 mm granules for use.

[0058] Example 2 740 g of manganese sulfate was added to a sedimentation tank containing 13 L of deionized water and stirred to obtain a manganese sulfate solution. Separately, 400 g of potassium permanganate and 460 g of caustic potassium were added to a container containing 23 L of deionized water and stirred to obtain a potassium permanganate solution. The potassium permanganate solution was added to the manganese sulfate solution while stirring, and the mixture was allowed to react for 3 hours to obtain a precipitate. The precipitate was filtered, washed with deionized water, and the resulting wet cake was extruded. The molded product was dried at 110°C for 14 hours to obtain a removal agent. The size of the removal agent was 6 mm in length and 1.0 mm in cross-sectional diameter.

[0059] After drying each of the prepared removal agents, their composition was analyzed using an X-ray fluorescence spectrometer (XRF, Rigaku Corporation, model ZSX Primus II). The results calculated in terms of oxides are shown in Table 1.

[0060] Comparative Example 1 Commercially available soda lime was used as a removal agent. The composition of the soda lime was NaOH: 1% by weight, Ca(OH)2: 81% by weight, H2O: 15% by weight, KOH: 2% by weight, and binder: 1% by weight.

[0061] The amount of PF3 gas removed by the above-mentioned removal agent was measured as follows. 20 ml of the removal agent was filled into a cylindrical SUS reaction vessel (inner diameter 2.1 cm, height 500 mm) with an inlet at the top and an outlet at the bottom, and used as a fixed bed (bulk density: 0.75 g / ml). Nitrogen gas was introduced into the inlet of the reaction vessel at atmospheric pressure, room temperature (approximately 25°C), and space velocity (GHSV) 200 h. -1 The nitrogen gas was flowed as shown below. After 30 minutes, the nitrogen gas was switched to feed gas. The feed gas was nitrogen gas containing 1.0 volume% PF3. The exhaust gas from the outlet of the reaction vessel was measured using a suction-type gas detector (CDS-7, gas detection unit PS-7, Shin-Cosmos Electric Co., Ltd.), and the feed gas was continued to flow until 1 ppm of PF3 was detected. The time from when the feed gas was started to when PF3 was detected in the exhaust gas from the outlet of the reaction vessel was measured and defined as the PF3 gas treatment time.

[0062] Next, the PF3 gas concentration in the feed gas was changed to 0.2 volume%, and the PF3 gas treatment time was measured for each removal agent using a new, unused removal agent, as described above.

[0063] The amount of PF3 gas removed was calculated from the PF3 treatment time and GHSV for each PF3 gas concentration. The amount of PF3 gas removed at a PF3 gas concentration of 1.0 volume% was set to 100, and the amount of PF3 gas removed at a PF3 gas concentration of 0.2 volume% is shown as a relative value. The results are shown in Table 1.

[0064] [Table 1]

[0065] result In the case of soda lime, which has calcium as its main component, the amount of PF3 gas removed decreased by approximately half when the PF3 gas concentration decreased from 1.0% by volume to 0.2% by volume (Comparative Example 1). On the other hand, in the case of a removal agent with manganese as its main component, the amount of PF3 gas removed improved by more than 20% when the PF3 gas concentration decreased from 1.0% by volume to 0.2% by volume (Examples 1 and 2).

[0066] Next, the amount of PF3 gas removed was measured using the above-mentioned removal agent when the water content of the removal agent differed. The above-mentioned removal agent and the removal agent dried at 120°C for one day were prepared as removal agents with different water content (LOD: Loss On Dry). The water content (LOD, %) of both removal agents was calculated by dividing the weight difference before and after drying by the weight of the removal agent. The amount of PF3 gas removed was measured using each of these removal agents in the same manner as in Example 1. The PF3 gas concentration in the feed gas used was set to 1.0 volume%. The amount of PF3 gas removed by the high-water-content removal agent before drying was set to 100, and the amount of PF3 gas removed by the low-water-content removal agent after drying is shown as a relative value. The results are shown in Table 2.

[0067] [Table 2]

[0068] result In soda lime, which mainly consists of calcium hydroxide, the amount of PF3 gas removed decreased significantly as the water content decreased (Comparative Example 2). On the other hand, in removal agents mainly consisting of manganese, PF3 gas could be removed at the same level as at high water content even at low water content (Examples 3 and 4).

[0069] Next, we prepared removal agents with different manganese content and investigated the amount of PF3 gas removed by each agent.

[0070] Example 5 Commercially available manganese oxide powder (98% purity) was used as the removal agent. This removal agent was formed into a disc shape under a pressure of 20 MPa, then crushed before use. The removal agent was in the form of granules with a diameter of 1.1 to 1.7 mm.

[0071] Example 6 620 g of manganese sulfate was added to a container holding 2 L of deionized water and stirred until completely dissolved. Then, 600 ml of 98.0% sulfuric acid was added to obtain a manganese sulfate solution. Separately, 700 g of potassium permanganate was added to a precipitation tank containing 2 L of deionized water heated to 80°C and stirred to obtain a potassium permanganate solution. The manganese sulfate solution was added to the potassium permanganate solution and reacted for 5 hours to obtain a precipitate. The precipitate was filtered, washed with deionized water, and dried at 120°C for 14 hours to obtain a removal agent. The removal agent was formed into a disc shape under a pressure of 20 MPa and then crushed for use. The removal agent was in the form of granules with a diameter of 1.1 to 1.7 mm.

[0072] Example 7 The same removal agent as in Example 2 was prepared. Example 8 The same removal agent as in Example 1 was prepared.

[0073] Comparative Example 3 Commercially available manganese oxide powder (99% purity) was used as the removal agent. This removal agent was formed into a disc shape under a pressure of 20 MPa, then crushed before use. The removal agent was in the form of granules with a diameter of 1.1 to 1.7 mm.

[0074] Comparative Example 4 The environmental purification catalyst (N-150, Clariant Catalyst Co., Ltd.) was crushed to form granules with a diameter of 1.1 to 1.7 mm.

[0075] The amount of PF3 gas removed by each of the above-prepared removal agents was measured using the same method as in Example 1. The PF3 gas concentration in the nitrogen gas passed through the reaction vessel was set to 1.0 volume%.

[0076] [Table 3]

[0077] result Removal agents containing 99% by weight and 34.6% by weight of Mn, respectively, and almost no potassium, showed insufficient PF3 gas removal (Comparative Examples 3 and 4). Removal agents containing 69.3 to 97.6% by weight of manganese and 1.3 to 3.6% by weight of potassium showed sufficient PF3 gas removal (Examples 5 to 8). Removal agents with added Cu also showed sufficient PF3 gas removal (Example 8).

Claims

1. A fluoride compound remover containing 60 to 98% by weight of manganese (Mn) calculated as MnO, and 0.5 to 20% by weight of alkali metals calculated as oxides, but without calcium (Ca), where the weight percentage is based on the weight of the fluoride compound remover.

2. A fluoride compound remover according to claim 1, comprising 65 to 90% by weight of manganese (Mn) calculated as MnO.

3. A fluoride compound remover according to claim 1, comprising 1 to 18% by weight of alkali metals as calculated as oxides.

4. The alkali metal is potassium (K), the fluoride compound remover according to claim 1.

5. Furthermore, the fluoride compound remover according to claim 1 further comprises an additional component selected from the group consisting of copper (Cu), iron (Fe), and combinations thereof.

6. Phosphate trifluoride (PF ３ A fluorine compound remover according to claim 1, which is a remover.

7. The process of preparing a manganese compound solution; A step of preparing an alkali metal compound solution; a step of mixing the manganese compound solution and the alkali metal compound solution and reacting them to obtain a precipitate; A method for producing a fluoride compound remover according to claim 1, comprising the steps of: and filtering and drying the precipitate to obtain a remover.

8. A method for removing a fluoride compound from a gas, comprising the steps of: placing the fluoride compound removal agent of claim 1 inside a container; and passing a gas containing a fluoride compound through the container and bringing the gas into contact with the fluoride compound removal agent.

9. The above fluoride compound is trifluoride phosphoric acid (PF ３ The method of claim 8, including ).

10. The method of claim 8, wherein the temperature inside the container when the gas is brought into contact with the fluoride compound remover is 1 to 70°C.

11. The method of claim 8, wherein the fluoride compound remover of claim 1 and an additional remover separate from said remover are placed in a container.

12. The method of claim 11, wherein the fluoride compound removal agent of claim 1 is placed in the upper layer of the container, and the additional removal agent is placed in the lower layer of the container.

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