Manufacturing method for CHA-type zeolite

Abstract

To provide a manufacturing method of CHA type zeolite capable of removing aluminum from a skeleton structure, and of holding the aluminum removed from the skeleton structure at a region outside the skeleton structure.SOLUTION: A manufacturing method of CHA type zeolite comprises a crystallization step of crystallizing a composition comprising a crystalline silica alumina source, an alkali source, an organic structure directing agent and water; an organic structure directing agent removal step of removing the organic structure directing agent contained in the CHA type zeolite obtained in the crystallization step therefrom; and a steam treatment step of bringing gas containing steam into contact with the CHA type zeolite obtained in the organic structure directing agent removal step. A steam concentration in the gas is 5 vol.% or more and less than 50 vol.%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing CHA-type zeolite. [Background technology]

[0002] CHA-type zeolite is a zeolite with a skeletal structure that has the structure code "CHA" defined by the Structure Commission of the International Zeolite Association, and is used in a variety of catalytic applications, such as cracking catalysts and nitrogen oxide reduction catalysts.

[0003] Since CHA zeolite is sometimes used at high temperatures, it is required to have heat resistance that allows it to maintain catalytic activity even at high temperatures. It is known that the heat resistance of CHA zeolite can be improved by subjecting CHA zeolite to steam treatment to remove aluminum from the framework structure (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6817022 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have further studied the steam treatment performed on CHA-type zeolite and have hypothesized that, depending on the conditions of the steam treatment, excessive aluminum may be removed from the framework structure of CHA-type zeolite, causing the crystal structure to become unstable.

[0006] The present invention is as set forth in the claims, and the gist of the present disclosure is as follows. [1] A method for producing CHA-type zeolite, comprising: a crystallization step for crystallizing a composition containing a crystalline silica-alumina source, an alkali source, an organic structure-directing agent, and water; an organic structure-directing agent removal step for removing the organic structure-directing agent contained in the CHA-type zeolite obtained in the crystallization step; and a steam treatment step for contacting the CHA-type zeolite obtained in the organic structure-directing agent removal step with a gas containing water vapor, wherein the water vapor concentration in the gas is 5% by volume or more and less than 50% by volume. [2] The method for producing a CHA-type zeolite according to [1], wherein the CHA-type zeolite obtained in the organic structure-directing agent removal step satisfies the following formula (1): 0≦M2O バルク / AlO 3バルク ≦0.80 (1) In the above formula (1), MO バルク indicates the number of moles [mol] of alkali metal M in the bulk of CHA-type zeolite in terms of MO, and AlO 3バルク indicates the number of moles of aluminum in the bulk of CHA-type zeolite, calculated as Al2O3 [mol]. [3] A method for producing CHA-type zeolite described in [1] or [2], wherein the organic structure-directing agent removal process is a process for removing the organic structure-directing agent contained in the CHA-type zeolite by calcining the CHA-type zeolite obtained in the crystallization process. [4] The method for producing a CHA-type zeolite described in [3], wherein the calcination in the organic structure-directing agent removal step is carried out in an air atmosphere at a temperature of 500°C or higher and 800°C or lower. [5] A method for producing a CHA-type zeolite according to any one of [1] to [4], wherein the crystalline silica-alumina source is an FAU-type zeolite, and the FAU-type zeolite satisfies the following formula (2): 6≦SiO 2バルク / AlO 3バルク Ratio≦50 (2) In the above formula (2), SiO 2バルク indicates the number of moles of silicon in the bulk of FAU zeolite in terms of SiO2 [mol], and Al2O 3バルクindicates the number of moles of aluminum in the bulk of FAU zeolite in terms of Al2O3 [mol]. [6] A method for producing a CHA-type zeolite described in any one of [1] to [5], wherein the CHA-type zeolite obtained in the steam treatment process has an intraframework Al ratio, represented by the following formula (3), that is 20% or more lower than the CHA-type zeolite obtained in the organic structure-directing agent removal process. Al ratio in framework [%] = (SiO 2バルク / Al2O3 ratio バルク ) / (SiO 2骨格 / AlO 3骨格 ratio)×100 ···(3) In the above formula (3), SiO 2バルク indicates the number of moles of silicon in SiO2 equivalent [mol] in the bulk of CHA-type zeolite, and Al2O 3バルク indicates the number of moles of aluminum in the bulk of CHA-type zeolite in terms of Al2O3 [mol], and SiO 2骨格 indicates the number of moles of silicon in the framework of CHA-type zeolite in terms of SiO2 [mol], and Al2O 3骨格 indicates the number of moles of aluminum in the framework of CHA-type zeolite in terms of Al2O3 [mol]. DETAILED DESCRIPTION OF THE INVENTION

[0007] First, the meaning of each term in this specification will be explained.

[0008] In this specification, "zeolite" refers to a compound having a regular structure in which skeleton atoms (hereinafter also referred to as "T atoms") are arranged via oxygen (O), and the T atoms are composed solely of at least either metal atoms or metalloid atoms. Examples of metal atoms include one or more atoms selected from the group consisting of aluminum (Al), titanium (Ti), iron (Fe), zinc (Zn), gallium (Ga), and tin (Sn). Examples of metalloid atoms include at least one atom selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te).

[0009] "Zeolite" is distinguished from compounds (hereinafter also referred to as "zeolite-related substances") that have a regular structure in which T atoms are oxygen-mediated and contain at least one atom other than a metal or metalloid atom in the T atom. Examples of "zeolite-related substances" include complex phosphorus compounds that contain phosphorus (P) as the T atom, such as aluminophosphate (AlPO) and silicoaluminophosphate (SAPO).

[0010] In this specification, "crystalline aluminosilicate" refers to a zeolite in which the T atoms are aluminum (Al) and silicon (Si). "Crystalline aluminosilicate" exhibits crystalline XRD peaks in its powder X-ray diffraction (hereinafter also referred to as "XRD") pattern, and is distinguished from "amorphous aluminosilicate" which does not exhibit crystalline XRD peaks.

[0011] In this specification, the "ordered structure" of a zeolite refers to a skeletal structure specified by a structure code (hereinafter simply referred to as "structure code") established by the Structure Commission of the International Zeolite Association. For example, "CHA-type zeolite" is a zeolite having a skeletal structure specified by the structure code "CHA," and "FAU-type zeolite" is a zeolite having a skeletal structure specified by the structure code "FAU." The skeletal structure (structure code) of each zeolite can be identified, for example, by comparison with the XRD pattern (hereinafter also referred to as "reference pattern") described in Collection of Simulated XRD Powder Patterns for Zeolites, Fifth Revised Edition, Page 113 (2007).

[0012] In this specification, the XRD patterns include those obtained by XRD measurement under the following conditions. Acceleration voltage / current: 40kV / 20mA Radiation source: CuKα radiation (λ=1.5405Å) Measurement mode: Continuous scan Scan condition: 2.0° / min Measurement range: 2θ=3° to 53° Detector: Semiconductor detector A crystalline XRD peak is a peak that is detected by identifying the 2θ of the peak top in an XRD pattern analysis using general analysis software (e.g., SmartLab Studio II, manufactured by Rigaku Corporation), and an example of such a peak is an XRD peak whose half-width is 2θ=0.50° or less.

[0013] In this specification, "SiO 2骨格 " "Al2O 3骨格 " are the number of moles [mol] of silicon in SiO2 equivalent that constitutes the zeolite framework structure (hereinafter also referred to as "framework"), and the number of moles [mol] of aluminum in Al2O3 equivalent. Al2O 3骨格 SiO 2骨格 Ratio of (SiO 2骨格 / AlO 3骨格 In the following description, the silica-alumina ratio in the framework is also referred to as the silica-alumina ratio in the framework. 2骨格 / AlO 3骨格 Ratio) is 29 It can be determined by Si DDMAS NMR spectrum measurement.

[0014] In this specification, " 29 The "Si DDMAS NMR spectrum" refers to the spectrum of a CHA-type zeolite that does not substantially contain an organic structure-directing agent, measured under the following conditions: 29 This is a Si DDMAS NMR spectrum. 1 H resonance frequency: 600MHz 29 Si resonance frequency: 119.2MHz Rotor rotation speed: 10kHz Repeat time: 30.0 seconds Accumulation count: 2048 times 29Si DDMAS NMR spectra can be measured using a general solid-state nuclear magnetic resonance spectrometer (e.g., AVANCE III 600, manufactured by Bruker). Peak fitting of the obtained NMR spectrum is performed using standard NMR data processing software (software name: ALICE2, manufactured by JEOL) by performing surface integration for each peak using a mixed function of Gaussian and Lorentzian distributions, and the SiO 2骨格 / AlO 3骨格 The ratio can be calculated.

[0015] In this specification, "SiO 2バルク " "Al2O 3バルク " are the moles of the components contained in the entire zeolite (hereinafter also referred to as "bulk"), including the framework and the outside of the framework, in terms of oxides, and are respectively the moles [mol] of silicon in the bulk in terms of SiO2 and the moles [mol] of aluminum in the bulk in terms of Al2O3. 3バルク SiO 2バルク Ratio of (SiO 2バルク / AlO 3バルク In the following explanation, the silica-alumina ratio in the bulk is also referred to as the silica-alumina ratio. 2バルク / AlO 3バルク The ratio can be determined by composition analysis. The composition analysis can be performed, for example, by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0016] As used herein, "excessive" removal of aluminum from the framework means that the SiO 2 before steam treatment 2骨格 / AlO 3骨格 Ratio of SiO after steam treatment to 2骨格 / AlO 3骨格 Ratio (after steam treatment (SiO 2骨格 / AlO 3骨格 Ratio) / Before steam treatment (SiO 2骨格 / AlO 3骨格 This refers to a ratio of greater than 13.0.

[0017] In this specification, the removal of aluminum from the framework structure is "moderate" when the ratio of framework silica-alumina ratio before and after steam treatment (after steam treatment (SiO 2骨格 / AlO 3骨格 Ratio) / Before steam treatment (SiO 2骨格 / AlO 3骨格 This refers to a ratio of greater than 1.0 to 13.0.

[0018] Hereinafter, one embodiment of the present disclosure will be described.

[0019] The production method of this embodiment relates to a method for producing CHA-type zeolite, which includes a crystallization step, an organic structure-directing agent removal step, and a steam treatment step. According to the production method of CHA-type zeolite of this embodiment, aluminum can be appropriately removed from the framework structure.

[0020] The crystallization process is a process of crystallizing a composition (hereinafter also referred to as the "raw material composition") containing a crystalline silica-alumina source, an alkali source, an organic structure-directing agent, and water, and CHA-type zeolite (hereinafter referred to as "CHA-type zeolite Z1") is obtained by the crystallization process.

[0021] The crystalline silica-alumina source used in the crystallization step is a crystalline substance containing silicon and aluminum, and for example, a zeolite containing at least silicon and aluminum as T atoms can be used. Zeolites that can be used as the crystalline silica-alumina source include, for example, zeolites having any of the ANA, *BEA, CHA, EMT, FAU, FER, GIS, LTA, LTL, and MFI crystal structures. Among these zeolites, the CHA zeolite obtained by the production method of this embodiment (hereinafter also referred to as "CHA zeolite Z3") has a silica-alumina ratio (for example, SiO 2骨格 / AlO 3骨格 Since the ratio of the zeolite to the crystalline aluminosilicate is likely to be 10 or more and 30 or less, it is preferable to use an FAU type zeolite, a crystalline aluminosilicate having an FAU type structure is more preferable, and zeolite Y is even more preferable.

[0022] The zeolite that can be used as the crystalline silica-alumina source is not particularly limited in terms of silica-alumina ratio. However, since the CHA-type zeolite Z3 obtained by the production method of this embodiment tends to have a silica-alumina ratio that can improve the heat resistance and catalytic activity, the silica-alumina ratio in the bulk (SiO 2バルク / AlO 3バルク It is preferable that the ratio satisfies the following formula (2): 6≦SiO 2バルク / AlO 3バルク Ratio≦50 (2)

[0023] In addition, the zeolite that can be used as the crystalline silica-alumina source is CHA-type zeolite Z3 obtained by the production method of this embodiment, which has a silica-alumina ratio (for example, SiO 2骨格 / AlO 3骨格 The silica-alumina ratio in the bulk (SiO 2バルク / AlO 3バルク It is more preferable that the ratio (a) satisfies the following formula (4), and it is particularly preferable that the ratio (b) satisfies the following formula (5): 6≦SiO 2バルク / AlO 3バルク Ratio≦25 (4) 6≦SiO 2バルク / AlO 3バルク Ratio≦15 (5)

[0024] The cation type of zeolite that can be used as a crystalline silica-alumina source is not particularly limited, and examples thereof include proton type (H + type) can be used.

[0025] The alkali source used in the crystallization step is a compound containing an alkali metal, preferably an alkali metal hydroxide, more preferably at least one hydroxide selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, and even more preferably at least one hydroxide of sodium and potassium.

[0026] The source of the organic structure directing agent used in the crystallization step is a substance containing an organic structure directing agent that directs the CHA structure, specifically a salt containing an organic cation that directs the CHA structure.

[0027] Examples of organic cations that direct the CHA structure (organic structure-directing agents that direct the CHA structure) include quaternary ammonium cations that direct the CHA structure, and are preferably at least one selected from the group consisting of (1-adamantyl)trimethylammonium, choline cation, and trimethylbenzylammonium cation, and more preferably (1-adamantyl)trimethylammonium (hereinafter also referred to as "TMAda") cation.

[0028] The salt containing a cation that directs the CHA structure is preferably at least one selected from the group consisting of sulfates, nitrates, halides, and hydroxides, more preferably at least one of halides and hydroxides, and even more preferably hydroxides.

[0029] The water used in the crystallization step may be water contained separately from the above-mentioned raw materials, such as ion-exchanged water, but the water used in the crystallization step may also be structured water derived from the above-mentioned raw materials or water in a solvent in which the raw materials are dissolved.

[0030] The raw material composition crystallized in the crystallization step may be composed only of the above-mentioned crystalline silica-alumina source, alkali source, organic structure-directing agent and water, but may contain other raw materials other than these raw materials in order to finely adjust the composition of the raw material composition. Examples of other raw materials include an alumina source contained separately from the crystalline silica-alumina source, a silica source contained separately from the crystalline silica-alumina source, and seed crystals.

[0031] The silica source is a compound containing silicon, and examples thereof include at least one selected from the group consisting of silica sol, fumed silica, colloidal silica, precipitated silica, and amorphous silicic acid.

[0032] The alumina source is a compound containing aluminum, and examples thereof include at least one selected from the group consisting of aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum chloride, aluminum nitrate, metallic aluminum, pseudoboehmite, alumina sol, and aluminum alkoxide.

[0033] The seed crystal is not particularly limited as long as it is directed toward the CHA structure, and for example, CHA-type zeolite can be used.

[0034] The molar ratio of alumina to silica in the raw material composition is not particularly limited, but is preferably 6 or more and 50 or less, since this tends to result in a silica-alumina ratio that can improve the heat resistance and catalytic activity of the CHA-type zeolite Z3 obtained by the production method of this embodiment. When the CHA-type zeolite Z3 obtained by the production method of this embodiment has a silica-alumina ratio (for example, SiO 2骨格 / AlO 3骨格 Since the ratio is likely to be 10 or more and 30 or less, the SiO 2バルク / AlO 3バルク The ratio is preferably 6 or more and 25 or less, and more preferably 6 or more and 15 or less.

[0035] The molar ratio of the organic structure-directing agent (hereinafter also referred to as "SDA") to silica in the raw material composition (hereinafter also referred to as "SDA / SiO2 ratio") is preferably 0.01 or more and 0.50 or less, more preferably 0.05 or more and 0.30 or less, and even more preferably 0.10 or more and 0.20 or less.

[0036] The molar ratio of alkali metal to silica in the raw material composition (hereinafter also referred to as "M / SiO2 ratio") is preferably 0.1 or more and 1.0 or less, more preferably 0.1 or more and 0.5 or less. In the M / SiO2 ratio, when the raw material composition contains two or more alkali metals, M refers to the total number of moles of the alkali metals.

[0037] The molar ratio of water (H2O) to silica in the raw material composition (hereinafter also referred to as "H2O / SiO2 ratio") is preferably 3 or more and 50 or less, and more preferably 10 or more and 40 or less. From the viewpoint of imparting appropriate fluidity to the raw material composition, the H2O / SiO2 ratio is preferably 20 or more and 35 or less.

[0038] When the raw materials contained in the raw material composition contain hydroxide, the molar ratio of hydroxide ions (hereinafter also referred to as "OH") to silica in the raw material composition (hereinafter also referred to as "OH / SiO ratio") is preferably 0.1 or more and 1.0 or less, more preferably 0.3 or more and 0.7 or less.

[0039] Preferable molar ratios of the raw material compositions are in the following ranges. SiO2 / Al2O3 ratio: 6 or more and 50 or less SDA / SiO2 ratio: 0.01 or more and 0.50 or less M / SiO2 ratio: 0.1 or more and 1.0 or less H2O / SiO2 ratio: 3 or more and 50 or less OH / SiO2 ratio: 0.1 or more and 1.0 or less

[0040] The crystallization of the raw material composition in the crystallization step can be carried out by hydrothermal treatment, which can be carried out by placing the raw material composition in a sealed pressure-resistant container and heating it.

[0041] The temperature of the hydrothermal treatment is not particularly limited as long as it is a temperature at which the crystallization of the raw material composition proceeds, but is preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. Once the raw material composition crystallizes, there is no need to increase the hydrothermal treatment temperature more than necessary. Therefore, the temperature of the hydrothermal treatment is sufficient as long as it is 200°C or lower, preferably 180°C or lower, and more preferably 170°C or lower.

[0042] The hydrothermal treatment time is not particularly limited as long as it is a time required for the raw material composition to crystallize, but is preferably from 1 hour to 168 hours, and particularly preferably from 24 hours to 120 hours. The treatment pressure in the hydrothermal treatment can be autogenous pressure.

[0043] In the hydrothermal treatment, the raw material composition may be crystallized in a state where it is stirred, or may be crystallized in a state where it is left to stand.

[0044] Here, in the crystallization step, only the above-described crystallization treatment for crystallizing the raw material composition may be carried out, but after the crystallization treatment of the raw material composition, a washing treatment and a drying treatment may also be carried out.

[0045] In the washing treatment, CHA-type zeolite Z1 (solid phase) and a liquid phase are separated by a known method, and the CHA-type zeolite Z1 obtained as a solid phase is washed with pure water.

[0046] In the drying treatment, moisture is removed from the CHA-type zeolite Z1. The treatment conditions for the drying treatment are arbitrary, but an example is to leave the CHA-type zeolite Z1 in air at 50°C or higher and 150°C or lower for 2 hours or longer. The air in this case may be air containing water vapor or air not containing water vapor. Specific examples of the air include dry air generated in a general dry air generator or an industrial plant.

[0047] CHA-type zeolite Z1 can be obtained as a crystalline product by the above-mentioned crystallization step. CHA-type zeolite Z1 contains at least silicon and aluminum as T atoms, and preferred CHA-type zeolite Z1 is a CHA-type crystalline aluminosilicate.

[0048] The CHA-type zeolite Z1 after crystallization contains the SDA and alkali metal ions contained in the raw material composition. In the organic structure-directing agent removal step described below, the SDA contained in the CHA-type zeolite Z1 obtained in the crystallization step is removed to obtain a CHA-type zeolite that is substantially free of SDA (hereinafter also referred to as "CHA-type zeolite Z2"). Note that "substantially free of SDA" can be exemplified by the fact that the SDA content in CHA-type zeolite Z2 is 1% by mass or less.

[0049] To remove SDA in the organic structure-directing agent removal step, a calcination treatment can be used to calcinate the CHA-type zeolite Z1 obtained in the crystallization step. Note that, in this specification, calcination refers to a treatment carried out in an atmosphere with a water vapor concentration of less than 5% by volume, and is a treatment that is distinguished from the steam treatment described below.

[0050] The firing conditions may be any conditions that allow the organic structure-directing agent to be removed, and from the viewpoint of facilitating efficient removal of the organic structure-directing agent, firing is preferably performed in an air atmosphere at 500° C. to 800° C. The firing time may be any conditions that allow the organic structure-directing agent to be removed, and is not particularly limited, but may be, for example, 1 hour to 24 hours.

[0051] When CHA-type zeolite Z1 is subjected to the above-mentioned calcination treatment, SDA contained in CHA-type zeolite Z1 converts to protons (H + ) and SDA is removed from CHA-type zeolite.

[0052] Here, in the organic structure-directing agent removal step, only the above-described SDA removal treatment for removing the SDA contained in the CHA-type zeolite Z1 may be performed, or an ion exchange treatment may be further performed after the SDA removal treatment.

[0053] The ion exchange treatment is a treatment for replacing at least a portion of the counter cations of the CHA-type zeolite Z2 after the SDA removal treatment with any cation, such as one or more cations selected from the group consisting of protons, ammonium ions, alkali metal ions, alkaline earth metal ions, and transition metal ions.

[0054] For the ion exchange treatment, for example, a method of contacting CHA-type zeolite Z2 with a solution containing any cation can be used. A known ion exchange method such as a batch method or a flow method can be used to contact CHA-type zeolite Z2 with a solution containing any cation, and known treatment conditions such as contact time and number of contacts can also be used.

[0055] The lower the alkali metal content of CHA-type zeolite Z2, the easier it is to remove aluminum from the framework structure in the steam treatment step described below. Therefore, when attempting to remove as much aluminum as possible from the framework structure (within a range in which the removal of aluminum from the framework structure is appropriate), it is preferable that the counter cation of CHA-type zeolite Z2 after the SDA removal treatment be substituted with a cation other than an alkali metal, and ammonium ion (NH + It is more preferred that it is substituted with .

[0056] The counter cation of CHA-type zeolite Z2 is ammonium ion (NH4 +To replace the CHA type zeolite Z2 with ammonium nitrate, for example, the CHA type zeolite Z2 after the SDA removal treatment is dispersed (immersed) in an ammonium aqueous solution (for example, at least one of a 0.1 to 30 wt% ammonium nitrate aqueous solution and a 0.1 to 30 wt% ammonium chloride aqueous solution), and the CHA type zeolite Z2 is brought into contact with the ammonium aqueous solution at 50 to 90°C for 1 to 48 hours, and the CHA type zeolite Z2 is recovered and then dried. The above-mentioned treatment may be repeated two or more times.

[0057] The ion exchange treatment may be a treatment to replace the counter cations of CHA-type zeolite Z2 with one type of cation, or may be a treatment to replace the counter cations of CHA-type zeolite Z2 with two or more types of cations. Specifically, the ion exchange treatment may be a treatment to replace the counter cations of CHA-type zeolite Z2 with ammonium ions and alkali metal ions.

[0058] When the counter cation of CHA-type zeolite Z2 is replaced with an ammonium ion and an alkali metal ion, for example, the counter cation of CHA-type zeolite Z2 can be replaced with an ammonium ion (NH + ), and the obtained CHA type zeolite Z2 is dispersed (immersed) in a 0.01 to 20.0 wt% aqueous alkali metal solution (for example, one or more selected from the group consisting of an aqueous sodium nitrate solution, an aqueous potassium nitrate solution, an aqueous sodium chloride solution, and an aqueous potassium chloride solution), and the CHA type zeolite Z2 is contacted with the aqueous alkali metal solution at 50 to 100°C for 1 to 48 hours, and the CHA type zeolite Z2 is recovered and then dried. The treatment of substitution with alkali metal ions may be repeated two or more times. By this operation, CHA type zeolite Z2 containing ammonium ions and alkali metal ions as counter cations of CHA type zeolite Z2 can be obtained.

[0059] The above-described conditions for the ion exchange treatment are merely examples, and the type of cation in the solution brought into contact with CHA type zeolite Z2 can be changed depending on the type of cation to be replaced. Furthermore, the content of counter cations in CHA type zeolite Z2 after the ion exchange treatment may be adjusted by adjusting the time for which CHA type zeolite Z2 is brought into contact with the solution or the concentration of cations in the solution brought into contact with CHA type zeolite Z2. Furthermore, the type of cation in the solution brought into contact with CHA type zeolite Z2 may be a single type or multiple types.

[0060] CHA-type zeolite Z2 is obtained by removing SDA from CHA-type zeolite Z1, and is a CHA-type zeolite containing at least silicon and aluminum as T atoms, and is preferably a CHA-type crystalline aluminosilicate.

[0061] The composition of CHA-type zeolite Z2 is not particularly limited as long as it does not substantially contain SDA. However, from the viewpoint of facilitating the removal of aluminum from the framework structure in the steam treatment step described later (within a range in which the removal of aluminum from the framework structure is appropriate), it is preferable to use a zeolite containing AlO 3バルク The number of moles of alkali metal M in bulk converted to MO (hereinafter referred to as "MO バルク ") ratio (hereinafter referred to as "M2O バルク / AlO 3バルク ") preferably satisfies the following formula (1): 0≦M2O バルク / AlO 3バルク ≦0.80 (1)

[0062] In the above formula (1), MO バルク / AlO 3バルク is 0 means that no alkali metal is contained in CHA-type zeolite Z2 (i.e., the detection limit). バルク / AlO 3バルク can be determined by the method described in the Examples below.

[0063] When CHA-type zeolite Z2 contains an alkali metal ion as a counter cation (the cation type is an alkali metal type), the MO バルク / AlO 3バルク It is more preferable that the following formula (6) is satisfied. By performing the steam treatment described later using alkali metal-type CHA-type zeolite Z2 that satisfies the following formula (6), the CHA-type zeolite Z3 obtained by the production method of this embodiment has a silica-alumina ratio (for example, SiO 2骨格 / AlO 3骨格 The ratio is likely to be between 10 and 30. 0.40≦M2O バルク / AlO 3バルク ≦0.80 (6)

[0064] In CHA-type zeolite Z2, the silica-alumina ratio in the framework (SiO 2骨格 / AlO 3骨格 The silica-alumina ratio (for example, SiO ) is not particularly limited, but is preferably 6 or more and 50 or less, since the CHA-type zeolite Z3 obtained by the production method of this embodiment is likely to have a silica-alumina ratio that can improve the heat resistance and catalytic activity. 2骨格 / AlO 3骨格 The ratio of SiO2 to SiO2 is likely to be 10 or more and 30 or less. 2骨格 / AlO 3骨格 The ratio is preferably 6 or more and 25 or less, and more preferably 6 or more and 15 or less.

[0065] In CHA-type zeolite Z2, the silica-alumina ratio in the bulk (SiO 2バルク / AlO 3バルク The silica-alumina ratio (for example, SiO ) is not particularly limited, but is preferably 6 or more and 50 or less. 2骨格 / AlO3骨格 The ratio of SiO2 to SiO2 is likely to be 10 or more and 30 or less. 2バルク / AlO 3バルク The ratio is preferably 6 or more and 25 or less, and more preferably 6 or more and 15 or less.

[0066] In the CHA-type zeolite Z2, the framework Al ratio is not particularly limited, but can be, for example, more than 80% and 110% or less. The framework Al ratio is determined based on the silica-alumina ratio (SiO 2バルク / AlO 3バルク The silica-alumina ratio in the framework (SiO 2骨格 / AlO 3骨格 The alumina ratio (ratio of alumina to silica) in the framework is less than 100%, which means that the alumina ratio (ratio of alumina to silica) in the framework is lower than the alumina ratio (ratio of alumina to silica) in the bulk. Al ratio in framework [%] = (SiO 2バルク / AlO 3バルク ratio) / (SiO 2骨格 / AlO 3骨格 ratio)×100 ···(3)

[0067] CHA-type zeolite Z3 is produced by subjecting CHA-type zeolite Z2 to steam treatment, which will be described later.

[0068] In the steam treatment step, CHA type zeolite Z2 is contacted with a gas containing steam. The water vapor concentration in the gas contacted with CHA type zeolite Z2 is 5% by volume or more and less than 50% by volume, relative to 100% by volume of the gas contacted with CHA type zeolite Z2. If the water vapor concentration in the gas contacted with CHA type zeolite Z2 is 50% by volume or more, aluminum will be removed excessively from the framework structure. On the other hand, if the water vapor concentration in the gas contacted with CHA type zeolite Z2 is less than 5% by volume, aluminum may not be removed from the framework structure.

[0069] The water vapor concentration in the gas contacted with CHA-type zeolite Z2 may be 5% by volume or more and less than 50% by volume. However, CHA-type zeolite Z3 may have a silica-alumina ratio (for example, SiO 2骨格 / AlO 3骨格 Since the ratio is likely to be 10 or more and 30 or less, it is preferably 5% or more and 40% or less, and more preferably 5% or more and 30% or less. The water vapor concentration can be calculated from the water vapor partial pressure in the gas brought into contact with CHA-type zeolite Z2, assuming an ideal gas.

[0070] The treatment temperature for the steam treatment is, for example, 500°C or higher and lower than 900°C, and preferably 550°C or higher and 850°C or lower. When the cation type of CHA type zeolite Z2 is NH4 type (containing ammonium ions as counter cations), the treatment temperature for the steam treatment is more preferably 550°C or higher and 750°C or lower. For CHA type zeolite Z2 whose cation type is NH4 type, when the treatment temperature for the steam treatment is 550°C or higher and 750°C or lower, CHA type zeolite Z3 has a silica-alumina ratio (for example, SiO 2骨格 / AlO 3骨格 The ratio is likely to be between 10 and 30.

[0071] The time for the steam treatment can be, for example, 1 hour or more and 72 hours or less. CHA-type zeolite Z3 has a silica-alumina ratio (e.g., SiO 2骨格 / AlO 3骨格 Since the ratio is likely to be 10 or more and 30 or less, the steam treatment time is preferably 10 hours or more and 30 hours or less.

[0072] The gas to be contacted with CHA type zeolite Z2 contains other gases in addition to water vapor. Examples of other gases include air and an inert gas such as at least one of argon and nitrogen. An inert gas is preferable, and a mixed gas of an inert gas and air may also be used. The air may contain water vapor or may not contain water vapor. When the gas contains water vapor, the amount of water vapor contained in the air is adjusted so that the total concentration of the water vapor in the air and the water vapor separately contained in the air is 5% by volume or more and less than 50% by volume relative to 100% by volume of the gas to be contacted with CHA type zeolite Z2. When the water vapor contained in the air alone makes the water vapor concentration of the gas to be contacted with CHA type zeolite Z2 5% by volume or more and less than 50% by volume, it is not necessary to separately add water vapor to the air. Specific examples of air include air with a water vapor concentration of less than 50% by volume, dry air generated in a general dry air generator or industrial plant, and pressurized air such as instrumentation air. When the gas is an inert gas, the inert gas contains water vapor in an amount of 5% by volume or more and less than 50% by volume relative to 100% by volume of the gas to be contacted with CHA-type zeolite Z2. Specific examples of the inert gas include argon with a water vapor concentration of less than 50% by volume and pressurized nitrogen such as instrument nitrogen.

[0073] The steam treatment may be carried out under atmospheric pressure or under pressure. The steam treatment may be carried out in a sealed container or under a stream of air or an inert gas. When the steam treatment is carried out under a stream of air or an inert gas, the flow rate of the gas may be, for example, 10 to 50 mL / min, and preferably 20 to 40 mL / min.

[0074] The method for generating water vapor is not particularly limited, and examples include a method of vaporizing water and mixing it with a gas (vapor), and a method of treating the CHA-type zeolite Z2 to be steam-treated in a water-containing state.

[0075] In the steam treatment step, by contacting the CHA-type zeolite Z2 obtained in the organic structure-directing agent removal step with a gas having a water vapor concentration of 5% by volume or more and less than 50% by volume, aluminum can be appropriately removed from the framework structure (i.e., the SiO of CHA-type zeolite Z2 (before steam treatment) 2骨格 / AlO 3骨格 of CHA-type zeolite Z3 (after steam treatment) versus SiO 2骨格 / AlO 3骨格 The ratio (ratio of framework silica-alumina ratio before and after steam treatment) is greater than 1.0 and less than 13.0).

[0076] The skeletal silica-alumina ratio before and after the steam treatment may be more than 1.0 and not more than 13.0, but is more preferably 1.30 or more and 13.0 or less. When the skeletal silica-alumina ratio before and after the steam treatment is 1.30 or more, it is believed that the heat resistance of CHA type zeolite Z3 is further improved. Furthermore, the skeletal silica-alumina ratio before and after the steam treatment is even more preferably 1.30 or more and 10 or less, and particularly preferably 1.30 or more and 2.5 or less. When the skeletal silica-alumina ratio before and after the steam treatment is 10 or less (particularly 2.5 or less), CHA type zeolite Z3 has a silica-alumina ratio (e.g., SiO ) that is more suitable as a catalyst compared to when it is outside this range. 2骨格 / AlO 3骨格 The ratio is likely to be between 10 and 30.

[0077] In CHA-type zeolite Z3, the silica-alumina ratio in the framework (SiO 2骨格 / AlO 3骨格 ) is not particularly limited as long as it is more than 1.0 times and not more than 13.0 times the silica-alumina ratio in the framework of CHA-type zeolite Z2, but from the viewpoint of obtaining a silica-alumina ratio more suitable as a catalyst, it is preferably 10 or more and 50 or less, and more preferably 10 or more and 30 or less.

[0078] In CHA-type zeolite Z3, the silica-alumina ratio (SiO 2バルク / AlO3バルク Although the silica-alumina ratio in the bulk is not particularly limited, the silica-alumina ratio in the bulk is usually not likely to change before and after steam treatment. For this reason, in CHA-type zeolite Z3, the silica-alumina ratio in the bulk (SiO 2バルク / AlO 3バルク The ratio) is preferably 6 or more and 50 or less, more preferably 6 or more and 25 or less, and particularly preferably 6 or more and 15 or less, similarly to CHA-type zeolite Z2.

[0079] The Al ratio in the framework of CHA-type zeolite Z3 is determined from the silica-alumina ratio in the framework and the silica-alumina ratio in the bulk, and is not particularly limited as long as it satisfies these silica-alumina ratio restrictions, but is preferably 20% or more and 80% or less.

[0080] As mentioned above, the silica-alumina ratio in the framework increases by steam treatment, but the silica-alumina ratio in the bulk usually does not change much before and after steam treatment. Therefore, the framework Al ratio of CHA-type zeolite Z3 is usually smaller than the framework Al ratio of CHA-type zeolite Z2. The difference in the framework Al ratios between CHA-type zeolite Z3 and CHA-type zeolite Z2 (the value obtained by subtracting the framework Al ratio of CHA-type zeolite Z3 from the framework Al ratio of CHA-type zeolite Z2) is preferably 20% or more. When the difference in the framework Al ratios between CHA-type zeolite Z3 and CHA-type zeolite Z2 is 20% or more, Al released from the framework by steam treatment more easily interacts with T atoms in the framework compared to when the difference is less than 20%. As a result, it is believed that the heat resistance of CHA-type zeolite Z3 is further improved.

[0081] The difference in the framework Al ratio between CHA type zeolite Z3 and CHA type zeolite Z2 tends to vary depending on the steam treatment temperature, water vapor concentration, and steam treatment time. For example, when the steam treatment temperature is 500°C or higher and lower than 900°C and the water vapor concentration is 5% by volume or higher and lower than 50% by volume, the difference in the framework Al ratio between CHA type zeolite Z3 and CHA type zeolite Z2 can be made 20% or higher by setting the steam treatment time to 10 hours or longer.

[0082] In the CHA type zeolite Z3, the BET specific surface area is not particularly limited, but is preferably 500 m 2 / g or more 900m 2 / g or less, and 2 / g or more 850m 2 / g or less, 540m 2 / g or more 800m 2 / g or less.

[0083] In CHA-type zeolite Z3, the micropore volume is not particularly limited, but can be 0.20 mL / g or more and 0.40 mL / g or less, 0.21 mL / g or more and 0.38 mL / g or less, or 0.22 mL / g or more and 0.36 mL / g or less.

[0084] CHA-type zeolite Z3 is a CHA-type zeolite obtained by removing a portion of the aluminum from the framework of CHA-type zeolite Z2, and is a CHA-type zeolite containing at least silicon and aluminum as T atoms, and is preferably a CHA-type crystalline aluminosilicate.

[0085] According to the production method of this embodiment described above, it is possible to produce CHA-type zeolite Z3 from which aluminum has been appropriately removed from the framework structure. CHA-type zeolite Z3 obtained by the production method of this embodiment can be used in various catalytic applications such as cracking catalysts and nitrogen oxide reduction catalysts, and is thought to be a zeolite with a stable crystal structure. Furthermore, when the framework silica-alumina ratio before and after steam treatment is set to 1.30 or more, it is thought to result in a zeolite with even better heat resistance. [Example]

[0086] The present embodiment will be described below with reference to examples, but the present embodiment is not limited to these examples.

[0087] (crystal structure) The XRD measurement of the sample was carried out using a general powder X-ray diffractometer (device name: Ultima IV, manufactured by Rigaku Corporation). The measurement conditions are as follows. The obtained XRD pattern was compared with a reference pattern to identify the crystal structure of the sample. Acceleration voltage / current: 40kV / 20mA Radiation source: CuKα radiation (λ=1.5405Å) Measurement mode: Continuous scan Scan condition: 2.0° / min Measurement range: 2θ=3° to 53°

[0088] ( 29 Si DDMAS NMR measurement) A general solid-state nuclear magnetic resonance spectrometer (device name: AVANCE III 600, manufactured by Bruker) was used to measure the sample. 29 Si DDMAS NMR spectrum was measured under the following conditions: 1 H resonance frequency: 600MHz 29 Si resonance frequency: 119.2MHz Rotor rotation speed: 10kHz Repeat time: 30.0 seconds Accumulation count: 2048 times

[0089] obtained 29 For Si DDMAS NMR spectra, the area of ​​the peaks with peak tops above -114 ppm and below -107 ppm is called Q. 4 (0Al)(Si(OSi)4), and the area of ​​the peak with a peak top between -107 ppm and -103 ppm is Q 4 (1Al)(Si(OAl)(OSi)3), the area of ​​the peak with a peak top between -103 ppm and -100 ppm is Q 3 (0Al)(Si(OH)(OSi)3), the area of ​​the peak with a peak top between -100 ppm and -96 ppm is Q 4 (2Al)(Si(OAl)(OSi)3), respectively.

[0090] Peak fitting was performed using standard NMR data processing software (software name: ALICE2, JEOL), and surface integration was performed for each peak using a mixed function of Gaussian and Lorentzian distributions, and the SiO 2骨格 / AlO 3骨格 The ratio was calculated. SiO 2骨格 / AlO 3骨格 Ratio=2×(Q 4 (0Al)+Q 4 (1Al)+Q 4 (2Al)+Q 4 (3Al)+Q 3 (0Al)) / (0.25×Q 4 (1Al) + 0.50 × Q 4 (2Al) + 0.75 × Q 4 (3Al))) ···(7)

[0091] (composition analysis) A sample solution was prepared by dissolving the sample in hydrofluoric acid. The sample solution was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) using a general ICP device (device name: ICPE-9000, manufactured by Shimadzu Corporation) to determine the SiO content in the sample. 2バルク / AlO 3バルク ratio, Na2O バルク / AlO3バルク and K2O バルク / AlO 3バルク asked for.

[0092] (BET specific surface area and micropore volume) The amount of nitrogen gas adsorbed onto the sample was measured using a standard nitrogen adsorption apparatus (apparatus name: BELSORP Max, manufactured by Microtrac-Bell). The BET specific surface area of ​​the sample was determined by applying the BET method to the nitrogen gas adsorption isotherm. The micropore volume was also determined by applying the t-plot method to the nitrogen gas adsorption isotherm. The t-plot method was performed using the analysis software provided with the nitrogen adsorption apparatus (product name: BEL Master (version 7), manufactured by Microtrac-Bell). The nitrogen gas adsorption was performed using the standard constant volume method. The measurement conditions are as follows: Gas used: 99.999% nitrogen Measurement temperature: -196℃ Pretreatment: 400°C, 12 hours of reduced pressure heating (below 2 Pa)

[0093] (Steam treatment) The zeolite powders were packed into atmospheric pressure fixed-bed flow-type reactor tubes. A water vapor-containing gas (steam) was passed through the reactor tubes to perform steam treatment of the zeolite samples. The gas composition and treatment conditions are shown below. Sample mass: 0.4g, 0.5g or 1.0g Gas composition: Water 10% or 20% by volume Argon Remainder Gas flow rate: 30 mL / min Processing temperature: 600℃, 700℃ or 800℃ Heating time from room temperature: 1 hour Retention time: 24 hours Pressure: atmospheric pressure

[0094] [Example 1] A raw material composition having the following composition was obtained by mixing an aqueous solution of (1-adamantyl)trimethylammonium hydroxide (TMAdaOH), pure water, sodium hydroxide, and FAU-type zeolite (product name: HSZ-350HUA, manufactured by Tosoh Corporation, cation type: H-type, bulk SiO2 / Al2O3 ratio = 11.1, crystalline aluminosilicate). SiO2 / Al2O3 ratio =11.1 SDA(TMAda) / SiO2 ratio =0.20 Na / SiO2 ratio =0.10 K / SiO2 ratio =0.10 H2O / SiO2 ratio =20.0 OH / SiO2 ratio =0.40

[0095] The obtained raw material composition was filled into a 23 mL sealed container, and the raw material composition was stirred while rotating the sealed container at 20 rpm, followed by hydrothermal treatment for 96 hours at 170°C. The crystallized product after the hydrothermal treatment was separated into solid and liquid, washed with pure water, and then dried in air at 80°C for 24 hours to obtain CHA-type zeolite Z1 (CHA-type crystalline aluminosilicate).

[0096] The above-mentioned CHA-type zeolite Z1 was calcined in air at 600°C for 10 hours to remove SDA (TMAda) contained in the CHA-type zeolite Z1, thereby obtaining CHA-type zeolite Z2 (a CHA-type crystalline aluminosilicate). The obtained CHA-type zeolite Z2 was SiO 2バルク / AlO 3バルク Ratio is 9.9, SiO 2骨格 / AlO 3骨格 Ratio is 9.8, Al ratio in the framework is 101%, Na2O バルク / AlO 3バルク Ratio is 0.25, K2O バルク / AlO 3バルク The ratio of M2O / Al2O3 was 0.38 and the bulk M2O / Al2O3 ratio was 0.63.

[0097] The aforementioned CHA-type zeolite Z2 was dispersed in a 4 wt% aqueous ammonium nitrate solution and subjected to ion exchange treatment at 80°C for 24 hours under static conditions. The solid matter was subjected to solid-liquid separation, washed with pure water, and then dried in air at 80°C for 24 hours. This procedure was repeated three times to obtain CHA-type zeolite Z2 (CHA-type crystalline aluminosilicate) with a cation type of NH4. The obtained CHA-type zeolite Z2 of NH4 type was SiO 2バルク / AlO 3バルク Ratio is 9.9, SiO 2骨格 / AlO 3骨格 The ratio is 11.2, the Al ratio in the framework is 88%, and Na2O バルク / AlO 3バルク Ratio less than 0.02 (detection limit), K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was less than 0.05 (detection limit).

[0098] NH4-type CHA-type zeolite Z2 was subjected to steam treatment at 600°C for 24 hours under a steam concentration of 10% by volume. The resulting CHA-type zeolite Z3 (CHA-type crystalline aluminosilicate) had a BET specific surface area of ​​749 m 2 / g, micropore volume 0.27mL / g, SiO 2バルク / AlO 3バルク Ratio is 9.9, SiO 2骨格 / AlO 3骨格 Ratio is 15.2, framework Al ratio is 65%, bulk Na2O バルク / AlO 3バルク Ratio less than 0.02 (detection limit), K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was less than 0.05 (detection limit).

[0099] [Example 2] CHA-type zeolite Z3 (CHA-type crystalline aluminosilicate) was obtained in the same manner as in Example 1, except that the temperature of the steam treatment was set to 700° C. The obtained CHA-type zeolite Z3 had a BET specific surface area of ​​720 m2 / g, micropore volume 0.27mL / g, SiO 2バルク / AlO 3バルク Ratio is 9.9, SiO 2骨格 / AlO 3骨格 ratio is 26.0, framework Al ratio is 38%, Na2O バルク / AlO 3バルク Ratio less than 0.02 (detection limit), K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was less than 0.05 (detection limit).

[0100] [Example 3] CHA-type zeolite Z3 (CHA-type crystalline aluminosilicate) was obtained in the same manner as in Example 1, except that the temperature of the steam treatment was 800° C. The obtained CHA-type zeolite Z3 had a BET specific surface area of ​​546 m 2 / g, micropore volume 0.23mL / g, SiO 2バルク / AlO 3バルク Ratio is 9.9, SiO 2骨格 / AlO 3骨格 Ratio is 140.0, Al ratio in the framework is 7%, Na2O バルク / AlO 3バルク Ratio less than 0.02 (detection limit), K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was less than 0.05 (detection limit).

[0101] [Example 4] CHA-type zeolite Z2 (CHA-type zeolite Z2 that was not ion-exchanged) was obtained in the same manner as in Example 1, and then subjected to steam treatment at 800°C for 24 hours under a steam concentration of 20% by volume. The obtained CHA-type zeolite Z3 (CHA-type crystalline aluminosilicate) had a BET specific surface area of ​​724 m 2 / g, micropore volume 0.25mL / g, SiO 2バルク / AlO 3バルク Ratio is 9.9, SiO 2骨格 / AlO3骨格 The ratio is 13.4, the Al ratio in the framework is 74%, and Na2O バルク / AlO 3バルク Ratio is 0.25, K2O バルク / AlO 3バルク Ratio is 0.38 and M2O バルク / AlO 3バルク The ratio was 0.63.

[0102] [Example 5] CHA-type zeolite Z2 with an NH4 cation type was obtained in the same manner as in Example 1, and then 1.01 g of the zeolite was dispersed in 50.5 g of a 0.22 wt% aqueous solution of sodium nitrate and subjected to ion exchange treatment at 80°C for 24 hours under static conditions. The solid matter was subjected to solid-liquid separation, washed with pure water, and then dried in air at 80°C for 24 hours. This procedure was repeated three times to obtain CHA-type zeolite Z2 (CHA-type crystalline aluminosilicate) containing ammonium ions and sodium ions as counter cations. The obtained zeolite Z2 had a SiO 2バルク / AlO 3バルク Ratio is 9.8, SiO 2骨格 / AlO 3骨格 The ratio is 11.2, the Al ratio in the framework is 87%, and Na2O バルク / AlO 3バルク Ratio is 0.23, K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was 0.23 to 0.26.

[0103] 0.4 g of CHA-type zeolite Z2 was subjected to steam treatment at 800°C for 24 hours under a steam concentration of 10% by volume. The obtained CHA-type zeolite Z3 (CHA-type crystalline aluminosilicate) was SiO 2バルク / AlO 3バルク Ratio is 9.8, SiO 2骨格 / AlO 3骨格 The ratio is 40.8, the Al ratio in the framework is 24%, and Na2O バルク / AlO 3バルク Ratio is 0.22, K2O バルク / AlO 3バルクRatio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was 0.23 to 0.26.

[0104] [Example 6] CHA-type zeolite Z2 with an NH4 cation type was obtained in the same manner as in Example 1, and then 1.01 g of the zeolite was dispersed in 50.8 g of a 0.43 wt % aqueous sodium nitrate solution and subjected to ion exchange treatment at 80°C for 24 hours under static conditions. The solid matter was subjected to solid-liquid separation, washed with pure water, and then dried in air at 80°C for 24 hours. This procedure was repeated three times to obtain CHA-type zeolite Z2 (CHA-type crystalline aluminosilicate) containing ammonium ions and sodium ions as counter cations. The obtained CHA-type zeolite Z2 had a SiO 2バルク / AlO 3バルク Ratio is 9.7, SiO 2骨格 / AlO 3骨格 Ratio is 11.0, Al ratio in the framework is 88%, Na2O バルク / AlO 3バルク Ratio is 0.35, K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was 0.35-0.38.

[0105] 0.5 g of CHA-type zeolite Z2 was subjected to steam treatment at 800°C for 24 hours under a steam concentration of 10% by volume. The obtained CHA-type zeolite Z3 (CHA-type crystalline aluminosilicate) was SiO 2バルク / AlO 3バルク Ratio is 9.7, SiO 2骨格 / AlO 3骨格 Ratio is 32.2, Al ratio in the framework is 30%, Na2O バルク / AlO 3バルク Ratio is 0.35, K2O バルク / AlO 3バルク Ratio is less than 0.03 (detection limit) and M2O バルク / AlO 3バルク The ratio was 0.35-0.38.

[0106] [Comparative Example 1] A raw material composition having the following composition was obtained by mixing an aqueous TMAdaOH solution, pure water, sodium hydroxide, aluminum hydroxide, amorphous silica (product name: Nipsil LP, manufactured by Tosoh Silica Corporation), and FAU-type zeolite (product name: HSZ-320NAA, manufactured by Tosoh Corporation, cation type: Na type, bulk SiO2 / Al2O3 ratio = 5.7, crystalline aluminosilicate). SiO2 / Al2O3 ratio =34 TMAda / SiO2 ratio =0.19 Na / SiO2 ratio =0.24 OH / SiO2 ratio =0.43 H2O / SiO2 ratio =12

[0107] The obtained raw material composition was filled into an 80 mL sealed container, and the raw material composition was stirred by rotating the sealed container at 40 rpm, followed by hydrothermal treatment at 150°C for 5 days. The crystallized product (CHA-type zeolite Z1) after the hydrothermal treatment was subjected to solid-liquid separation, washed with pure water, and then calcined in air at 600°C for 10 hours to remove SDA (TMAda) contained in CHA-type zeolite Z1. The obtained CHA-type zeolite Z2 was obtained by SiO 2バルク / AlO 3バルク Ratio is 22.4, SiO 2骨格 / AlO 3骨格 Ratio is 22.9, Al ratio in the framework is 98%, Na2O バルク / AlO 3バルク Ratio is 0.53, K2O バルク / AlO 3バルク Ratio is 0 and M2O バルク / AlO 3バルク The ratio was 0.53, which was a CHA-type zeolite.

[0108] For each example and comparative example, the composition of zeolite Z2, the composition of zeolite Z3, the SiO 2骨格 / AlO 3骨格 SiO2 ratio of zeolite Z3 2骨格 / AlO 3骨格 The ratios (the ratios of silica to alumina before and after steam treatment) are shown in Tables 1 to 3 below.

[0109] [Table 1]

[0110] [Table 2]

[0111] [Table 3]

[0112] As can be seen from Table 3 above, the silica-alumina ratio before and after steam treatment was 1.36 to 12.50 in Examples 1 to 6. From these results, it was understood that the production methods of Examples 1 to 6 were able to adequately remove aluminum from the skeletal structure.

Claims

1. A crystallization step of crystallizing and washing a composition comprising a crystalline silica-alumina source, an alkali source, an organic structure directing agent, and water; an organic structure directing agent removal step of removing the organic structure directing agent contained in the CHA-type zeolite obtained in the crystallization step; a steam treatment step of contacting the CHA-type zeolite obtained in the organic structure-directing agent removal step with a gas containing water vapor, The water vapor concentration in the gas is 5% by volume or more and less than 50% by volume, A method for producing a CHA-type zeolite, wherein the CHA-type zeolite obtained in the steam treatment step has a framework Al ratio, represented by the following formula (3), that is 20% or more lower than the CHA-type zeolite obtained in the organic structure-directing agent removal step. Al ratio in framework [%] = (SiO2 bulk / Al2O3 bulk ratio) / (SiO2 framework / Al2O3 framework ratio) × 100 (3) In the above formula (3), SiO2 bulk indicates the number of moles [mol] of silicon in the bulk of the CHA-type zeolite, converted into SiO2, Al2O3 bulk indicates the number of moles [mol] of aluminum in the bulk of the CHA-type zeolite, converted into Al2O3, SiO2 skeleton indicates the number of moles [mol] of silicon in the skeleton of the CHA-type zeolite, converted into SiO2, and Al2O3 skeleton indicates the number of moles [mol] of aluminum in the skeleton of the CHA-type zeolite, converted into Al2O3.

2. The method for producing a CHA-type zeolite according to claim 1, wherein the CHA-type zeolite obtained in the organic structure-directing agent removal step satisfies the following formula (1): 0≦M ２ O バルク / Al ２ O ３バルク ≦0.80 ・・・(1) In the above formula (1), M ２ O バルク is the M of alkali metal M in the bulk of CHA-type zeolite ２ The number of moles [mol] is calculated as O, and Al ２ O ３バルク is the amount of aluminum in the bulk of CHA-type zeolite. ２ O ３ The converted number of moles [mol] is shown.

3. A method for producing CHA-type zeolite as described in claim 1 or 2, wherein the organic structure-directing agent removal process is a process for removing the organic structure-directing agent contained in the CHA-type zeolite by calcining the CHA-type zeolite obtained in the crystallization process.

4. The method for producing a CHA-type zeolite according to claim 3, wherein the calcination in the organic structure-directing agent removal step is carried out in an air atmosphere at 500°C or higher and 800°C or lower.

5. The crystalline silica-alumina source is an FAU-type zeolite, The method for producing CHA-type zeolite according to any one of claims 1 to 4, wherein the FAU-type zeolite satisfies the following formula (2): 6≦SiO ２バルク / Al ２ O ３バルク Ratio≦50...(2) In the above formula (2), SiO ２バルク is the SiO of silicon in the bulk of FAU-type zeolite ２ The number of moles [mol] is calculated as Al. ２ O ３バルク is the amount of aluminum in the bulk of the FAU zeolite. ２ O ３ The converted number of moles [mol] is shown.

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