Method for producing zeolite

Abstract

Provided is a method for producing industrially useful zeolite mainly by utilizing a waste material including aluminum such as aluminum dross in combination with silica or the like.　The method for producing zeolite includes: a first step for treating a nitrogen-containing aluminum compound having an aluminum content in a specified range with an alkaline aqueous solution and a second step for subsequently treating the nitrogen-containing aluminum compound with a weakly acidic aqueous solution, thereby obtaining an oxygen-containing aluminum compound; and a third step for bringing an aluminum compound (A) including the oxygen-containing aluminum compound into contact with silica (B) and water (C).　The above method is less likely to be affected by a history and a chemical composition of the nitrogen-containing aluminum compound during the production of zeolite.

Description

Zeolite manufacturing method

[0001] The present invention relates to a method for producing zeolites.

[0002] Zeolites have pore structures of various sizes, and products with these pore structures are manufactured. Due to their unique properties, zeolites are used in various fields, such as solid acid catalysts and adsorbents.

[0003] Many methods for artificially producing zeolites have been reported, including those using coal combustion ash as a raw material, hydrothermal synthesis using aluminum-containing compounds such as (pseudo)boehmite or zeolite itself as a raw material in combination with silica, and methods using a structure-directing agent such as an ammonium salt to control pore size and three-dimensional structure. It is known that FAU-type zeolites and MSE-type zeolites can be obtained by selecting, for example, a quaternary ammonium salt as the structure-directing agent. It is also known that SAPO-type zeolites can be obtained by using a cyclic amine such as morpholine in combination with phosphoric acid as a structure-directing agent. SAPO-type zeolites are suitable for use as catalysts in the MTO (methanol-to-olefins) reaction, which produces olefins using methanol as a raw material, and in the isomerization reaction of lubricating oils.

[0004] Compositions containing a significant proportion of aluminum are found not only in general waste (so-called non-burnable waste) but also in industrial waste generated in the aluminum refining process, such as so-called aluminum dross. However, these are rarely reused, and although some are used for landfill, they are generally accumulated in disposal sites such as landfills. Meanwhile, with the continuous development of industry, it is becoming increasingly difficult to secure disposal sites.

[0005] Furthermore, from the viewpoint of global environmental issues, there is a demand for the development of methods for effectively utilizing the above waste materials.

[0006] From these viewpoints, various methods for producing zeolites using aluminum contained in the waste materials have been reported. Examples include a method of treating aluminum-containing waste materials and a raw material containing silicic acid with an alkaline aqueous solution, concentrating and heating the resulting supernatant to obtain zeolite (Patent Document 1), a method of treating aluminum dross with an alkaline aqueous solution, mixing the resulting supernatant with silicic acid, and then subjecting the resulting mixture to ultrasonic treatment to produce zeolite (Patent Document 2), and a method of producing zeolite by combining a mixture obtained by reacting aluminum dross with sodium hydroxide with sodium silicate and a (nitrite) salt (Patent Document 3).

[0007] In the above-mentioned method, it is expected that a compound containing aluminum hydroxide is generated during the process and serves as an aluminum source. However, a method has also been disclosed in which (pseudo)boehmite, which is an example of aluminum hydroxide, is used as an aluminum compound raw material to efficiently produce zeolite, and in which (pseudo)boehmite of a specific composition is used (Patent Document 4).

[0008] JP 2005-231906 A JP 2002-179423 A JP 2003-192336 A JP 2017-206415 A

[0009] It is generally difficult to obtain a stable composition from the waste materials that can be used as aluminum raw materials, and therefore it seems difficult to obtain zeolites with stable compositions and properties.

[0010] Therefore, the present inventors have an object to provide a method for producing zeolite with stable performance using aluminum-containing waste as a raw material, and for producing zeolite with stable performance even when aluminum-containing waste with different compositions, lots, etc. is used as a raw material.

[0011] As a result of investigations into the above-mentioned problems, the present inventors have found that zeolite of stable quality can be produced by using, as an aluminum source, an aluminum-containing compound obtained by a process including a step of treating an aqueous solution such as a supernatant obtained by mixing an aluminum composition with an alkaline aqueous solution with an aqueous solution having a specific pH (weakly acidic region), and have completed the present invention.

[0012] That is, the present invention includes the following features described in [1] to [6]. [1] A method for producing a zeolite, comprising the following first to third steps: (Step 1) contacting a nitrogen-containing aluminum composition (a) containing 25 to 95 wt % aluminum with an alkaline aqueous solution to obtain an aluminum-containing aqueous solution (α); (Step 2) contacting the aluminum-containing aqueous solution (α) with an aqueous solution having a pH of 3.5 to 6.5 to obtain an oxygen-containing aluminum compound (β); (Step 3) contacting an aluminum compound (A) containing the oxygen-containing aluminum compound (β), silica (B), and water (C) at 100 to 400°C for 1 to 240 hours. [2] A method for producing a zeolite according to [1], further using a phosphorus-containing compound (D) in the third step; [3] A method for producing a zeolite according to [2], wherein the phosphorus-containing compound (D) is phosphoric acid; [4] A method for producing a zeolite according to [1], further using a nitrogen-containing compound (E) in the third step. [5] The method for producing a zeolite according to [4], wherein the nitrogen-containing compound (E) is a cyclic nitrogen-containing compound. [6] The method for producing a zeolite according to any one of [1] to [5], wherein the nitrogen-containing aluminum composition (a) is aluminum dross.

[0013] According to the above-described zeolite production method, zeolite with stable performance can be produced using aluminum-containing waste as a raw material, and the results suggest that zeolite with stable performance can also be produced using aluminum-containing waste with different compositions, lots, and the like as a raw material.

[0014] Hereinafter, embodiments of the present invention will be described in detail. Note that the embodiment described below shows an example of a typical embodiment of the present invention, and the scope of the present invention should not be interpreted narrowly by this. Note that the expression "A to B" regarding a numerical range means A or more and B or less, unless otherwise specified. For example, the expression "1 to 5%" means 1% or more and 5% or less.

[0015] The present invention is characterized by a method for producing zeolite, comprising the following first to third steps: (1) a step of contacting a nitrogen-containing aluminum composition (a) containing 25 to 95 wt % aluminum with an alkaline aqueous solution to obtain an aluminum-containing aqueous solution (α); (2) a step of contacting the aluminum-containing aqueous solution (α) with an aqueous solution having a pH of 3.5 to 6.5 to obtain an oxygen-containing aluminum compound (β); and (3) a step of contacting an aluminum compound (A) containing the oxygen-containing aluminum compound (β) with silica (B) and water (C) at 100 to 400°C for 1 to 240 hours.

[0016] Each component and production method will be described in detail below. <Nitrogen-Containing Aluminum Composition (a)> The nitrogen-containing aluminum composition (a) used in the first step of the present invention is not particularly limited as long as the aluminum content is 25 to 95 wt%. A preferred lower limit of the aluminum content is 40 wt%, more preferably 50 wt%, and even more preferably 60 wt%. On the other hand, a preferred upper limit of the aluminum content is 90 wt%, more preferably 87 wt%, and even more preferably 85 wt%. It is obvious that a higher aluminum content is preferable, but when using waste materials, etc., as described below, their composition generally tends to be inconsistent. The aluminum content in the present invention is a value determined by the method described in the Examples below.

[0017] The nitrogen-containing aluminum composition (a) is preferably an aluminum-containing compound generally considered to have low utility value, such as general waste such as incineration ash of garbage, industrial waste such as aluminum dross, or volcanic eruptions, etc. In consideration of the production process, such compounds may be considered to include nitrogen-containing aluminum compounds that have reacted with nitrogen in the air, etc.

[0018] Among the nitrogen-containing aluminum compositions (a) described above, aluminum dross discharged in an aluminum refining process is preferred.

[0019] In the present invention, such a nitrogen-containing aluminum composition (a) is contacted with an alkaline aqueous solution in the first step described below to obtain an aluminum-containing aqueous solution (α), and then, in the second step described below, this aluminum-containing aqueous solution (α) is contacted with an aqueous solution of a specific pH to obtain an oxygen-containing aluminum compound (β).

[0020] <Alkaline aqueous solution> The alkaline aqueous solution used in the present invention is not particularly limited as long as it is a known alkaline aqueous solution. Preferably, it is an aqueous solution of an alkali metal hydroxide salt or an ammoniacal aqueous solution, more preferably an aqueous solution of an alkali metal hydroxide salt. Such an aqueous solution is preferably used as an aqueous solution of 0.1 to 10 normal (N). A more preferred lower limit of the concentration is 0.2N, even more preferably 0.3N, and particularly preferably 0.35N. On the other hand, a more preferred upper limit is 5N, even more preferably 3N, and particularly preferably 2N.

[0021] <Aqueous solution having a pH of 3.5 to 6.5> The aqueous solution having a pH of 3.5 to 6.5 used in the present invention corresponds to a known weakly acidic aqueous solution. Specific examples include aqueous solutions of salts obtained by reacting a weakly alkaline compound with an acidic compound, such as an aqueous solution of ammonium chloride or an aqueous solution of ammonium bromide, but there are no particular limitations on these. A preferred specific example is an aqueous solution of an ammonium halide salt, and more preferably an aqueous solution of ammonium chloride.

[0022] The lower limit of the pH is preferably 3.7, more preferably 3.9, and even more preferably 4.0, while the upper limit of the pH is preferably 6.0, more preferably 5.7, and even more preferably 5.5.

[0023] <Silica (B)> The silica (B) used in the present invention can be any known component without any limitations.Preferably, gel-type silica or sol-type silica is used, and various commercially available products are available, so these can be appropriately selected and used.In addition, the silica can also be prepared by using commercially available colloidal silica, etc., and appropriately combining heating and stirring.

[0024] <Water (C)> Any known water can be used as the water (C) in the present invention without any restrictions, and preferred examples include deionized water and pure water.

[0025] <First Step> The first step of the present invention is a step of contacting the nitrogen-containing aluminum composition (a) with an alkaline aqueous solution to obtain an aluminum-containing aqueous solution (α).

[0026] The ratio of the alkaline aqueous solution (liters) to the nitrogen-containing aluminum composition (a) (grams) used varies depending on the concentration of the alkaline aqueous solution and the aluminum content, but is generally 1 / 5000 to 10 / 1 / (liters / gram) by weight, more preferably 1 / 1000 to 5 / 1 (liters / gram), and even more preferably 1 / 500 to 1 / 2 (liters / gram).

[0027] The time for contacting the alkaline aqueous solution with the nitrogen-containing aluminum composition (a) varies depending on the concentration of the alkaline aqueous solution and the aluminum content, but is preferably 0.5 to 24 hours, more preferably 0.8 to 18 hours, and even more preferably 1 to 12 hours.

[0028] The temperature at which the alkaline aqueous solution is brought into contact with the nitrogen-containing aluminum composition (a) varies depending on the concentration of the alkaline aqueous solution and the aluminum content, but is preferably room temperature to 100°C, more preferably 40 to 90°C, and even more preferably 50 to 80°C.

[0029] When the use ratio, time and temperature are within the above-mentioned ranges, the aluminum-containing aqueous solution (α) tends to be obtained efficiently, taking into consideration the concentration of the aqueous solution and the like.

[0030] By using the alkaline aqueous solution, aluminum can generally be eluted from the nitrogen-containing aluminum composition (a) and extracted as an oxygen-containing aluminum compound.

[0031] <Second Step> The second step of the present invention is a step of contacting the aluminum-containing aqueous solution (α) with an aqueous solution having a pH of 3.5 to 6.5 (hereinafter, sometimes referred to as a "weakly acidic aqueous solution") to obtain an oxygen-containing aluminum compound (β).

[0032] The ratio of the aluminum-containing aqueous solution (α) to the weakly acidic aqueous solution is preferably such that the amount of the weakly acidic aqueous solution is at least enough to neutralize the basic (metal) components, such as alkali metals, contained in the aluminum-containing aqueous solution (α). Under such conditions, an aqueous solution of a salt of the basic (metal) component, such as an alkali metal, can be obtained, while the oxygen-containing aluminum compound (β) tends to precipitate in the neutral range, which tends to easily reduce the basic (metal) component in the oxygen-containing aluminum compound (β).

[0033] The contact treatment is preferably carried out in combination with stirring or bubbling with an inert gas in order to carry out the reaction as uniformly as possible.

[0034] The time for which the aluminum-containing aqueous solution (α) is brought into contact with the weakly acidic aqueous solution varies depending on the concentration of the aluminum-containing aqueous solution (α), but is preferably 1 to 60 minutes, more preferably 2 to 40 minutes, and even more preferably 3 to 30 minutes.

[0035] The temperature at which the aluminum-containing aqueous solution (α) is brought into contact with the weakly acidic aqueous solution varies depending on the concentration of the alkaline aqueous solution and the aluminum content, but is preferably 10 to 50°C, more preferably 15 to 45°C, and even more preferably 20 to 40°C.

[0036] After the contact treatment, the solid and liquid are preferably separated by filtration or decantation to obtain the oxygen-containing aluminum compound (β) as a solid component. This solid portion is preferably thoroughly washed with water. Furthermore, washing with warm water (preferably water at 30 to 50°C) is preferred. Any conventionally known method can be used for the washing method without any restrictions. This washing method makes it possible to efficiently remove salts derived from the basic (metal) component (e.g., sodium or potassium) from the oxygen-containing aluminum compound (β). If salts derived from the basic (metal) component remain in the oxygen-containing aluminum compound (β), they may hinder zeolite crystal growth and structure control in the third step described below.

[0037] Within the above temperature and time ranges, the basic (metal) component tends to be easily separated from the oxygen-containing aluminum compound (β), and the solid-liquid separation tends to be easily and efficiently carried out.

[0038] The present inventors also believe that the second step may be able to reduce the effects of variations in the performance and structure of the nitrogen-containing aluminum composition (a) in the third step described below, because the method of the second step may tend to facilitate the separation of components that may be mixed into the aqueous solution depending on the composition of the nitrogen-containing aluminum composition (a).

[0039] <Third Step> The third step of the present invention includes a step of contacting the aluminum compound (A) containing the oxygen-containing aluminum compound (β) with silica (B) and water (C), and then contacting them under conditions of 100 to 400°C and 1 to 240 hours, and after this step, a zeolite can be obtained.

[0040] In the third step, it is possible to use any known method for producing zeolite, known as hydrothermal synthesis, without any restrictions, except that an aluminum compound (A) containing the oxygen-containing aluminum compound (β) is used.

[0041] The aluminum compound (A) may be the oxygen-containing aluminum compound (β) alone, or may be a combination of the oxygen-containing aluminum compound (β) and a known aluminum compound, such as zeolite, alumina, or boehmite, which is usually used in producing zeolites. The content of the oxygen-containing aluminum compound (β) is preferably 20% by weight or more, more preferably 40% by weight or more, even more preferably 50% by weight or more, and particularly preferably 60% by weight or more, based on the aluminum compound (A) being 100% by weight. The preferred upper limit is, of course, 100% by weight.

[0042] A preferred method for the third step using each of the above components will be described below. In the zeolite production method of the present invention, the aluminum compound (A) containing water (C) is contacted with silica (B) containing water (C) and generally heated for a certain period of time to obtain zeolite, which is an oxide containing aluminum and silicon. The heating temperature after the contact is in the range of 100 to 400°C. The lower limit of this temperature range is preferably 130°C, more preferably 150°C, and even more preferably 170°C. Meanwhile, the upper limit of this temperature range is preferably 350°C, more preferably 320°C, and even more preferably 300°C. Within this temperature range, zeolite can be efficiently obtained by the reaction of the aluminum compound with silica.

[0043] The contact time at the above temperature is in the range of 1 to 240 hours. The lower limit of the above temperature range is preferably 6 hours, more preferably 12 hours, and even more preferably 15 hours. On the other hand, the upper limit of the above temperature range is preferably 120 hours, more preferably 100 hours, and even more preferably 80 hours. Within this time range, zeolite can be efficiently obtained by the reaction of the aluminum compound with silica. It is also preferable to use a known method for homogenizing the reaction field, such as by stirring, for the purposes of "increasing the reaction rate" and "obtaining a homogeneous zeolite."

[0044] The temperature in the step of contacting the aluminum compound (A) containing water (C) with the silica (B) containing water (C) is not limited to the above-mentioned temperature range. The temperature range in the contacting step is preferably 0°C or higher and lower than 100°C, more preferably 10 to 80°C, and even more preferably room temperature to 60°C. There is no particular limitation on the time required for the contacting step. Although it depends on the scale of the contacting, it is preferably 10 seconds to 12 hours, more preferably 30 seconds to 8 hours, and even more preferably 1 minute to 6 hours.

[0045] Furthermore, a preliminary step such as stirring within a certain temperature range may be included between the contacting step and the heating and holding step. In this case, the preferred temperature range is the same as the temperature range during the contacting step. In addition to the time for the preliminary step, an operation such as gradual heating up to the heating and holding step is also possible, and the time required for this is preferably 1 minute to 12 hours, more preferably 5 minutes to 8 hours, and even more preferably 10 minutes to 6 hours.

[0046] Although there are no particular limitations on the ratios of the aluminum compound (A), silica (B), and water (C) used, it is preferable to use the aluminum compound (A) in the range of 0.1 to 10% by weight relative to the water (C). The preferred lower limit of this range is 0.3% by weight, more preferably 0.5% by weight, and even more preferably 0.8% by weight. On the other hand, the preferred upper limit of this range is 7% by weight, more preferably 6% by weight, and even more preferably 5% by weight.

[0047] The silica (B) is preferably used in an amount of 0.05 to 5% by weight relative to the water (C). The lower limit of this range is preferably 0.1% by weight, more preferably 0.2% by weight, and even more preferably 0.25% by weight. The upper limit of this range is preferably 4% by weight, more preferably 3% by weight, and even more preferably 2% by weight.

[0048] By keeping the use ratio within the above range, zeolite can be produced efficiently.

[0049] In the third step of the present invention, components other than the aluminum compound (A), silica (B), and water (C) can be used as appropriate. Preferred examples of such components include known organic structure-directing agents. These components are said to have the function of controlling the higher-order structure of silica or aluminosilicate. Specific examples include quaternary ammonium salts, hydroxyamines, and cyclic oxyamines.

[0050] Specific examples of the quaternary ammonium salt include salts containing an ammonium ion (cation) containing 4 moles of a substituent, such as a hydrocarbon group having 1 to 10 carbon atoms per mole of nitrogen atom, and an anion, such as a halo ion, such as a hydroxy ion, chloride ion, bromide ion, or iodide ion. The hydrocarbon group preferably has 1 to 8 carbon atoms, even more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. On the other hand, the anion is more preferably a hydroxy ion, bromide ion, or iodide ion, with a hydroxy ion being even more preferred. More specific examples of such quaternary ammonium salts include tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dimethyldipropylammonium hydroxide, tetrapropylammonium bromide, and bis-1,6-(tripropylammonium)hexamethylenediiodide. Dimethyldipropylammonium hydroxide is particularly preferred. The use of such a structure-directing agent tends to facilitate the production of FAU-type zeolites, MSE-type zeolites, and the like.

[0051] On the other hand, when an ammonium salt having only a hydrocarbon group with a small number of carbon atoms, such as tetraethylammonium hydroxide, is used in combination with, for example, morpholine, which will be described later, it may be possible to produce a zeolite such as a SAPO type.

[0052] Specific examples of the hydroxyamines include trialcoholamines such as trimethanolamine, triethanolamine, tripropanolamine, tributanolamine, trihexanolamine, trioctanolamine, and tridecanolamine, alkyldialcoholamines such as methyldimethanolamine, ethyldiethanolamine, propyldipropanolamine, butyldibutanolamine, hexyldihexanolamine, octyldioctanolamine, and decyldidecanolamine, and dialkylalcoholamines such as dimethylmethanolamine, diethylethanolamine, dipropylpropanolamine, dibutylbutanolamine, dihexylhexanolamine, dioctyloctanolamine, and didecyldecanolamine. Among these, trialcoholamines are preferred, and triethanolamine is particularly preferred.

[0053] Examples of the cyclic oxyamines include oxycyclic amines having a six-membered ring, such as morpholine and oxazine, and oxycyclic amines having a five-membered ring, such as oxazolidine and oxazoline. Among these, oxycyclic amines having a six-membered ring structure are preferred, and morpholine is particularly preferred. The use of such organic structure-directing agents tends to make it easier to obtain, for example, SAPO-type zeolites.

[0054] In this way, a wide variety of zeolites can be produced by selecting the structure-directing agent.

[0055] In the present invention, the ratio of the silica (B) to the organic structure-directing agent as described above is preferably in the range of 1.5 to 10 in terms of the silicon atom / nitrogen atom molar ratio. The lower limit of this ratio is more preferably 1.7, even more preferably 1.9, and particularly preferably 2.0. On the other hand, the upper limit of this ratio is more preferably 9, even more preferably 8, and particularly preferably 7.

[0056] A preferred component that can be used in combination is a phosphorus-containing compound (D). Examples of the phosphorus-containing compound (D) include phosphoric acid and aluminum phosphate, with phosphoric acid being more preferred. It is also possible to use an aqueous solution of the alkaline compound in combination, as appropriate. The phosphorus-containing compound (D) is preferably used in a range of 0.1 to 10% by weight relative to the water (C). The preferred lower limit of this range is 0.3% by weight, more preferably 0.5% by weight, and even more preferably 0.8% by weight. Meanwhile, the preferred upper limit of this range is 7% by weight, more preferably 6% by weight, and even more preferably 5% by weight.

[0057] A preferred component that can be used in combination is a nitrogen-containing compound (E). The nitrogen-containing compound (E) can be selected appropriately depending on the desired zeolite structure. For example, when producing a zeolite as a catalyst for the MTO reaction as described above, a cyclic nitrogen-containing compound can be used as the nitrogen-containing compound (E). The nitrogen-containing compound (E) is preferably used in an amount ranging from 0.2 to 20% by weight relative to the water (C). The preferred lower limit of this range is 0.6% by weight, more preferably 1.0% by weight, and even more preferably 1.5% by weight. On the other hand, the preferred upper limit of this range is 15% by weight, more preferably 12% by weight, and even more preferably 10% by weight.

[0058] Furthermore, since zeolite is a crystal, a method in which zeolite seed crystals are used in combination to promote crystal growth is generally preferably used.

[0059] By using the above-mentioned method, a slurry containing solid zeolite is often obtained. Such a slurry is usually subjected to solid-liquid separation, and the solid portion is preferably thoroughly washed with water and then dried by a known method such as heat drying or reduced pressure drying. The temperature range for the above-mentioned method is usually between room temperature and 200°C. The time required for the drying depends on the drying temperature and other factors, but is often between 1 hour and 120 hours.

[0060] The dried zeolite can be further calcined. Such calcination is preferably carried out in an air atmosphere at 400°C or higher and 850°C or lower for 0.1 to 20 hours. The lower limit of the temperature range is more preferably 500°C, even more preferably 550°C, and particularly preferably 600°C. On the other hand, the upper limit of the temperature range is more preferably 800°C, even more preferably 750°C, and particularly preferably 700°C.

[0061] In addition to the above, an ion exchange method can also be used in combination, and such an ion exchange method can be appropriately selected from known methods and carried out.

[0062] The zeolite production method of the present invention, which includes the "first step" to the "third step," is preferably carried out using different reaction apparatuses and treatment apparatuses for each step. Industrially, it is preferable to transfer or supply the contents obtained in each step between reactors via piping. Therefore, various reactants are generally used in a liquid phase such as a liquid, solution, or slurry. However, if the particles have excellent fluidity, they can be transferred in a solid state through piping and supplied to the next step.

[0063] By using the zeolite production method of the present invention, it may be possible to produce a desired zeolite having performance equivalent to that of conventional products, even if raw materials with variable composition and quality, such as waste materials such as aluminum dross, are used. A method for producing zeolites with such properties will be industrially useful because it will be easy to produce zeolites similar to conventional products even if the business environment changes, such as the depletion of natural resources.

[0064] The zeolite obtained by the production method of the present invention can be used for a variety of known applications. Examples include adsorbents for polar compounds such as water and alcohol, ion exchange resins, and (solid acid) catalysts for various reactions. It is also possible to produce modified zeolites by carrying out a modification reaction using compounds containing elements that are likely to exhibit acidity, such as elements from Groups 4 and 5 of the periodic table.

[0065] Preferred examples of the catalyst include catalysts for use in known catalysts such as catalysts for C1 chemicals, such as catalysts for producing olefins by the dehydration reaction of alcohols, catalysts for producing aromatic polyols by reacting hydrogen peroxide with aromatic compounds to obtain aromatic polyols, catalysts for producing olefins that enable the selective production of various olefins by decomposing hydrocarbon compounds such as naphtha, catalysts for producing phenol used in the process of producing phenol from alcohol and benzene, catalysts for producing alkylated aromatic compounds by Friedel-Crafts alkylation of aromatic compounds, catalysts for isomerizing various hydrocarbons such as paraffins, olefins, and alkylbenzenes, and catalysts for isomerization, disproportionation, and transalkylation of various alkylbenzenes.

[0066] For example, the obtained zeolite can be used to produce olefins using methanol as a raw material. Any known method can be appropriately selected for this production method. One example is a method in which zeolite is packed into a ring reactor to form a fixed bed, and methanol is supplied to this fixed bed to produce hydrocarbon compounds such as ethane and ethylene. The temperature during this process is, for example, 150 to 300°C, allowing for continuous hydrocarbon production. Of course, the unreacted methanol in the above production method can be recovered or directly recycled and reused as a raw material.

[0067] EXAMPLES Hereinafter, examples will be disclosed to further explain the present invention in detail, but the present invention is not limited to these examples.

[0068] (Method for measuring aluminum content of raw aluminum-containing compound) Using a Supermini 200 Rigaku type X-ray fluorescence analyzer manufactured by Rigaku Corporation, measurements were taken under helium atmosphere at a scan speed of 1° / min for aluminum, magnesium, chlorine, potassium, silicon, and phosphorus, and 2° / min for other elements, with a step width of 0.01° / step, to obtain measurements of the weight ratio as metal, and calculate the weight % value.

[0069] (Method for measuring X-ray diffraction of zeolite) A Smart Lab Rigaku X-ray diffraction measuring device manufactured by Rigaku Corporation was used, and CuKa radiation was used as the X-ray source. Other measurement conditions were as follows: Scan range: 2θ = 5 to 70°, Scan speed: 4° / min, Step width: 0.01° / step, Tube voltage: 40 kV, Tube current: 100 mA.

[0070] (Method of measuring specific surface area) A BELSORP manufactured by MicrotracBEL was used, and the adsorption gas was N ２ The specific surface area was calculated by the BET method using the above formula: 1. Before the measurement, the sample was pretreated at 200° C. for 2 hours in a vacuum.

[0071] (NH ３ -Method for evaluating the acidity of solids (zeolites) by TPD) Using MicrotracBEL's BELCAT-II, after pretreatment at 300°C in an argon (Ar) atmosphere, ２ After pretreatment with O / Ar gas mixture again, NH ３ was adsorbed at 100°C, and the temperature of the zeolite sample was raised from 100°C to 700°C at a rate of 5°C / min in an Ar atmosphere. The desorbed ammonia was quantified using a BELMass quadrupole mass spectrometer, and the amount of acid per unit weight was evaluated.

[0072] (Method of Analyzing Reaction Gas) In Examples 1 and 2, and Comparative Example 1, gas analysis was performed in a conventional manner using a BELMass quadrupole mass spectrometer manufactured by MicroBEL Corp. In Examples 3 to 5 and Reference Example 1, gas analysis was performed in a conventional manner using a gas chromatograph equipped with an FID detector.

[0073] Example 1 (Sodium hydroxide treatment of aluminum-containing compound) 5.01 grams of aluminum dross (lot name: AD-2-as; aluminum content: 73.83 wt %) was mixed with 500 milliliters of a 0.5 mol / liter aqueous sodium hydroxide solution in a Teflon (registered trademark) beaker at 70°C and stirred for 90 minutes. The mixture was filtered, and the resulting filtrate was designated as aqueous solution (1). It is well known that the aluminum dross contains nitrogen due to its characteristics during its production process.

[0074] (Contact and Mixing Treatment with Ammonium Chloride) The aqueous solution (1) was added to 100 mL of a 3 mol / L aqueous ammonium chloride solution (pH: approximately 4.4) at room temperature and stirred for 5 minutes. The resulting solid was then filtered and thoroughly washed with distilled water at 50°C. No Na was detected at this stage. The solid thus obtained was dried overnight at 120°C to obtain an oxygen-containing aluminum compound (1). Its composition was similar to that of boehmite.

[0075] (Hydrothermal synthesis) A solution containing the oxygen-containing aluminum compound (1), phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: purity 85%), and distilled water was prepared in a beaker A, and a solution containing morpholine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: purity 98%), tetraethylammonium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: 20%), and distilled water was prepared in a beaker B.

[0076] The contents of beaker A and beaker B were mixed and thoroughly stirred at room temperature for 30 minutes. At this stage, the ratio of Al2O3 / P2O5 / SiO2 / (morpholine / tetraethylammonium) / distilled water was adjusted to 1.0 / 1.0 / 0.6 / 2.0 / 52. Distilled water was then added and the mixture was further stirred at room temperature for 1 hour.

[0077] The mixture was then transferred to a hydrothermal synthesis apparatus and subjected to hydrothermal synthesis for 24 hours at 200° C. The resulting reaction product was subjected to solid-liquid separation by centrifugation, and the solid portion was thoroughly washed with distilled water at 50° C., dried overnight at 120° C., and then calcined in a calcination apparatus at 600° C. for 6 hours to obtain sample (1).

[0078] (Ion exchange) 1.17 g of the sample (1) was added to 100 mL of an aqueous ammonium nitrate solution (0.44 mol / L), stirred for 2 hours, and then centrifuged for solid-liquid separation. This procedure was repeated. The resulting solid was thoroughly washed with distilled water and then dried overnight at 60°C.

[0079] The resulting solid was then heated to 500° C. at a rate of 5° C. / min and calcined at 500° C. for 2 hours. The resulting solid (1) was subjected to X-ray diffraction measurement and found to be SAPO-type zeolite.

[0080] (Reaction of Methanol Using Zeolite) Using a MicrotracBEL BELCAT-II-SP type apparatus, 0.3 g of the zeolite was packed into a reaction tube and heat-treated at 500° C. for 1 hour in a nitrogen stream of 10 ml / min.

[0081] Thereafter, the reaction tube was maintained at 450° C. and methanol was supplied to the reaction tube at a rate of 10 ml / min for 5 hours. Analysis of the resulting gas revealed that ethane and ethylene were produced.

[0082] Example 2 A solid (2) was obtained in the same manner as in Example 1, except that aluminum dross (aluminum content: 70.43% by weight) with "lot name: AD-1-as" was used instead of "lot name: AD-2-as." This solid (2) was also a SAPO zeolite.

[0083] From the results of Examples 1 and 2 above, it was found that the method of the present invention could produce the desired zeolite regardless of the composition of the aluminum composition used as the raw material.

[0084] Comparative Example 1 Sodium was detected from the liquid (1) that was not subjected to the ammonium chloride contact / mixing treatment in Example 1. It was expected that an aluminum source containing sodium would be disadvantageous in terms of structural control in a method for producing zeolite by hydrothermal synthesis.

[0085] Example 3 (Treatment of Aluminum-Containing Compound with Sodium Hydroxide) An aqueous solution (3) was obtained in the same manner as in Example 1, except that aluminum dross (lot name: AD-9-as; aluminum content: 78.45 wt %) was used instead of "lot name: AD-2-as."

[0086] (Contact / Mixing Treatment with Ammonium Chloride) The same procedure as in Example 1 was carried out except that the aqueous solution (3) was used instead of the aqueous solution (1), to obtain an oxygen-containing aluminum compound (3).

[0087] (Hydrothermal synthesis) A solution containing the oxygen-containing aluminum compound (3), phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: purity 85%), and distilled water was prepared in a beaker A, and a solution containing morpholine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: purity 98%), tetraethylammonium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: 20%), and distilled water was prepared in a beaker B.

[0088] The contents of beaker A and beaker B were mixed and thoroughly stirred at room temperature for 30 minutes. At this stage, the molar ratio of Al2O3 / PO5 / SiO2 / morpholine / tetraethylammonium / distilled water was adjusted to 1.0 / 1.0 / 0.6 / 1.5 / 0.5 / 75. Distilled water was then added and the mixture was further stirred at room temperature for 1 hour.

[0089] The mixture was then transferred to a hydrothermal synthesis apparatus and allowed to stand for 24 hours at 200°C. The resulting reaction product was subjected to solid-liquid separation by centrifugation, and the solid portion was thoroughly washed with distilled water at 50°C, dried overnight at 120°C, and then calcined in a calciner at 600°C for 6 hours to obtain sample (3). This sample (3) was also a SAPO-type zeolite.

[0090] (Ion Exchange) A solid (3) was obtained in the same manner as in Example 1, except that the sample (3) was used instead of the sample (1).

[0091] (Reaction of methanol using zeolite) The solid (3) was compression-molded and tablet-molded to obtain tablet (3). 0.2445 g of the tablet (3) was packed into a fixed-bed fluidized reactor and heat-treated at 480°C for 1 hour under a nitrogen gas flow at a flow rate of 20 ml / min.

[0092] Thereafter, the reaction tube was maintained at 450° C., and a methanol / nitrogen stream adjusted to a vapor concentration of 7.3% by bubbling nitrogen through methanol at a rate of 20 mL / min was supplied to the reaction tube for 5 hours at a weight hourly space velocity (WHSV) of 0.5 / hr. Analysis of the resulting gas revealed that ethylene and propylene were produced.

[0093] The surface area of ​​the solid, the amount of acid in the solid, the ethylene and propylene contents determined by gas chromatography after 5 hours of reaction, and the catalyst (solid) life are shown in Table 1 below.

[0094] The catalyst life is defined as follows: Catalyst life is the reaction time from the time when the methanol conversion rate reached its maximum during the methanol reaction until the conversion rate reached a value 0.5% lower than the maximum value.

[0095] Example 4 Sample (4) was obtained in the same manner as in Example 3, except that the hydrothermal synthesis was carried out with stirring at 200° C. for 24 hours. This sample (4) was also a SAPO-type zeolite.

[0096] Reference Example 1 A methanol reaction was carried out in the same manner as in Example 1, except that a commercially available SAPO-type zeolite (trade name: AQUSOA (registered trademark)-Z02) manufactured by Mitsubishi Chemical Corporation was used as the sample (catalyst) instead of the solid (1).

[0097] Various results are shown in Table 1 below. The results of Examples 1 to 4 also demonstrated that desired zeolites such as SAPO-type zeolites can be obtained without being significantly affected by the aluminum content of the raw material aluminum dross. Furthermore, it was demonstrated that zeolites having performance levels equivalent to those of commercially available zeolites can be obtained even from aluminum dross.

[0098] [Example 5] (Hydrothermal synthesis) The oxygen-containing aluminum compound (3), colloidal silica (SIGMA, LUDOX (registered trademark) HS-30, SiO ２ Concentration 30%, Na ２ SO ４ : 0.04%), sodium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd., 97%), and tetrapropylammonium bromide (SIGMA, 98%) were reacted in the presence of distilled water.

[0099] The ratio of each component was NaOH / tetrapropylammonium bromide / SiO ２ / Al ２ O ３ / H ２The molar ratio of the substances in terms of O was adjusted to 0.20 / 0.08 / 1.00 / 0.02 / 27.82. Sodium hydroxide was dissolved in distilled water, and the oxygen-containing aluminum compound (3), tetrapropylammonium bromide, and colloidal silica were added thereto, followed by stirring at room temperature for 1 hour.

[0100] The stirred mixture was then transferred to a hydrothermal synthesis apparatus and subjected to hydrothermal synthesis at 175°C for 120 hours under static conditions without stirring. The resulting reaction product was subjected to solid-liquid separation by centrifugation, and the solid portion was thoroughly washed with distilled water at 50°C, dried overnight at 105°C, and then calcined in a calciner at 550°C for 5 hours to obtain sample (5). X-ray diffraction measurement results indicated that sample (5) was an MFI zeolite.

[0101] Thereafter, ion exchange was carried out in the same manner as in Example 3, and the resulting solid was heated to 500°C at a rate of 5°C / min and calcined at 500°C for 2 hours to obtain solid (5). X-ray diffraction measurement revealed that solid (5) was MFI zeolite. Various results are shown in Table 1.

[0102] The above results demonstrate that zeolites with desired structures can be produced even from aluminum dross by selecting a conventional structure-directing agent.

[0103]

Claims

1. A method for producing zeolite, comprising the following first to third steps: (1st step) a step of contacting a nitrogen-containing aluminum composition (a) containing 25 to 95% by weight of aluminum with an alkaline aqueous solution to obtain an aluminum-containing aqueous solution (α); (2nd step) a step of contacting the aluminum-containing aqueous solution (α) with an aqueous solution having a pH of 3.5 to 6.5 to obtain an oxygen-containing aluminum compound (β); and (3rd step) a step of contacting an aluminum compound (A) containing the oxygen-containing aluminum compound (β), silica (B), and water (C) under conditions of 100 to 400° C. and 1 to 240 hours.

2. The method for producing a zeolite according to claim 1, further comprising using a phosphorus-containing compound (D) in the third step.

3. The method for producing a zeolite according to claim 2, wherein the phosphorus-containing compound (D) is phosphoric acid.

4. The method for producing a zeolite according to claim 1, further comprising using a nitrogen-containing compound (E) in the third step.

5. The method for producing a zeolite according to claim 4, wherein the nitrogen-containing compound (E) is a cyclic nitrogen-containing compound.

6. The method for producing a zeolite according to claim 1, wherein the nitrogen-containing aluminum composition (a) is aluminum dross.

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