Zeolite production method

Abstract

To provide a method for producing industrially useful zeolite mainly using waste containing aluminum such as aluminum dross in combination with silica.SOLUTION: A zeolite production method comprises: a first step of treating a nitrogen-containing aluminum compound having a specific aluminum content range with an alkaline aqueous solution; a second step of treating with a weakly acidic aqueous solution to obtain an oxygen-containing aluminum compound; and a third step of bringing an aluminum compound (A) containing the oxygen-containing aluminum compound, silica (B), and water (C) into contact with each other. The method tends to be less affected by the history or composition of the nitrogen-containing aluminum compound when producing zeolite.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] Zeolite has pore structures of various sizes, and products having such pore structures are manufactured. Zeolite is used in various fields such as solid acid catalysts and adsorbents due to its unique properties.

[0003] Methods for artificially producing zeolite include, in addition to a method using coal combustion ash as a raw material, a method of hydrothermal synthesis in combination with silica or the like using an aluminum-containing compound such as (pseudo) boehmite or zeolite (itself) as a raw material, and a method of controlling the pore diameter and three-dimensional structure by using a structure-directing agent typified by an ammonium salt in combination. For example, when a quaternary ammonium salt is selected as the above structure-directing agent, it is known that FAU-type zeolite and MSE-type zeolite can be obtained. It is also known that when a cyclic amine such as morpholine is used in combination with phosphoric acid as a structure-directing agent, SAPO-type zeolite can be obtained. The SAPO-type zeolite is suitably used as a catalyst for the MTO reaction (Methanol To Olefins reaction) for producing olefins from methanol and as a catalyst for the isomerization reaction of lubricating oil.

[0004] Compositions containing aluminum in a corresponding proportion exist not only in general waste (so-called non-combustible waste), but also in industrial waste discharged in the aluminum refining process, so-called aluminum dross and other waste. However, these are rarely reused, and although some are used for landfill, they are generally accumulated at disposal sites such as landfills. On the other hand, with the continuous development of the industry, it is becoming difficult to secure landfills and the like.

[0005] Also, from the perspective of global environmental problems and the like, development of effective utilization methods for the above waste is demanded.

[0006] From these viewpoints, various methods for producing zeolites using aluminum contained in the above-mentioned waste have been reported. For example, a method of obtaining a zeolite by concentrating and heating a supernatant obtained by treating a raw material containing waste containing aluminum and silicic acid with an alkaline aqueous solution (Patent Document 1), a method of producing a zeolite by mixing a supernatant obtained by treating aluminum dross with an alkaline aqueous solution and silicic acid and then performing ultrasonic treatment (Patent Document 2), a method of producing a zeolite by combining a mixture obtained by reacting aluminum dross with sodium hydroxide, sodium silicate, and (sub)nitrate (Patent Document 3), etc. can be mentioned.

[0007] In addition, in the above-mentioned method, a compound containing aluminum hydroxide is expected to be generated midway and serve as an aluminum source. As a method for efficiently producing zeolite using (pseudo)boehmite, which is an example of aluminum hydroxide, as an aluminum compound raw material, a method of using (pseudo)boehmite with a specific composition is also disclosed (Patent Document 4).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] The waste that can be used as the above-mentioned aluminum raw material generally makes it difficult to obtain a material with a stable composition. For this reason, it seems difficult to obtain zeolites with stable compositions and properties.

[0010] Therefore, the present inventors have an object of providing a method for producing zeolite with stable performance using waste containing aluminum as a raw material, and also a method for producing zeolite with stable performance even using waste containing aluminum with different compositions, lots, etc. as raw materials.

Means for Solving the Problems

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

[0012] That is, the present invention includes the matters described in the following [1] to [6]. [1] A method for producing zeolite including the following first step to third step. (First step) A step of bringing a nitrogen-containing aluminum composition (a) containing 25 to 95% by weight of aluminum into contact with an alkaline aqueous solution to obtain an aluminum-containing aqueous solution (α). (Second step) A step of bringing the aluminum-containing aqueous solution (α) into contact with an aqueous solution having a pH of 3.5 to 6.5 to obtain an oxygen-containing aluminum compound (β). (Third step) A step of bringing an aluminum compound (A) containing the oxygen-containing aluminum compound (β), silica (B), and water (C) into contact under the conditions of 100 to 400 ° C. for 1 to 240 hours. [2] The method for producing zeolite according to [1], wherein a phosphorus-containing compound (D) is further used in the third step. [3] The method for producing zeolite according to [2], wherein the phosphorus-containing compound (D) is phosphoric acid. [4] The method for producing zeolite according to [1], wherein a nitrogen-containing compound (E) is further used in the third step. [5] The method for producing zeolite according to [4], wherein the nitrogen-containing compound (E) is a cyclic nitrogen-containing compound. [6] The method for producing zeolite according to any one of [1] to [5], wherein the nitrogen-containing aluminum composition (a) is aluminum dross.

Advantages of the Invention

[0013] According to the method for producing zeolite, zeolite with stable performance can be produced using waste containing aluminum as a raw material. It is suggested that zeolite with stable performance can also be produced using waste containing aluminum with different compositions, lots, etc. as raw materials. As a result, the obtained results are as follows.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments according to the present invention will be described in detail. Note that the embodiments described below show an example of typical embodiments of the present invention, and the scope of the present invention is not construed narrowly thereby. Note that the description of "A to B" regarding a numerical range represents A or more and B or less unless otherwise specified. For example, the description of "1 to 5%" means 1% or more and 5% or less.

[0015] The present invention is characterized by a method for producing zeolite including the following first step to third step. (First Step) A step of bringing a nitrogen-containing aluminum composition (a) containing 25 to 95% by weight of aluminum into contact with an alkaline aqueous solution to obtain an aluminum-containing aqueous solution (α). (Second Step) A step of bringing the aluminum-containing aqueous solution (α) into contact with an aqueous solution having a pH of 3.5 to 6.5 to obtain an oxygen-containing aluminum compound (β). (Third Step) A step of bringing an aluminum compound (A) containing the oxygen-containing aluminum compound (β), silica (B), and water (C) into contact under the conditions of 100 to 400°C for 1 to 240 hours.

[0016] Hereinafter, each component and the production method will be described in detail. <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 satisfies 25 to 95% by weight. The preferable lower limit of the aluminum content is 40% by weight, more preferably 50% by weight, and still more preferably 60% by weight. On the other hand, the preferable upper limit of the aluminum content is 90% by weight, more preferably 87% by weight, and still more preferably 85% by weight. Although it is obvious that a higher aluminum content is more suitable, when using waste or the like described later, its composition generally tends not to be constant. In addition, the aluminum content in the present invention is a value specified 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 like incineration ash of garbage, industrial waste such as aluminum dross, and ejecta from volcanoes. Considering the production process of such compounds, it is reasonable to think that they contain nitrogen-containing aluminum compounds that have reacted with nitrogen in the air or the like.

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

[0019] In the present invention, such a nitrogen-containing aluminum composition (a) is brought into contact with an alkaline aqueous solution in the first step described below to obtain an aluminum-containing aqueous solution (α). Further, in the second step described below, this aluminum-containing aqueous solution (α) is brought into contact with an aqueous solution having 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, and 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 preferable lower limit value of the concentration is 0.2 N, still more preferably 0.3 N, and particularly preferably 0.35 N. On the other hand, a more preferable upper limit value is 5 N, still more preferably 3 N, and particularly preferably 2 N.

[0021] <(aqueous solution with pH of 3.5 to 6.5)> The aqueous solution with 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 formed by the reaction of weakly alkaline and acidic compounds such as ammonium chloride aqueous solution and ammonium bromide aqueous solution, but there is no particular limitation. A preferred specific example is an aqueous solution of an ammonium halide salt, and more preferably an ammonium chloride aqueous solution.

[0022] A preferred lower limit value of the pH is 3.7, more preferably 3.9, and still more preferably 4.0. On the other hand, a preferred upper limit value of the pH is 6.0, more preferably 5.7, and still more preferably 5.5.

[0023] <Silica (B)> For the silica (B) used in the present invention, known components can be used without limitation. Preferably, it is gel-like silica or sol-like silica, and since there are various commercially available products, these can be appropriately selected and used. In addition, the above-mentioned silica can also be prepared by using commercially available colloidal silica or the like and appropriately using heating and stirring in combination.

[0024] <Water (C)> For the water (C) used in the present invention, known substances can be used without limitation. Preferably, deionized water, pure water, etc. can be mentioned.

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

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

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

[0028] The temperature for bringing the alkaline aqueous solution into contact with the nitrogen-containing aluminum composition (a) depends on the concentration of the alkaline aqueous solution and the aluminum content, but preferably it is from room temperature to 100 °C. More preferably, it is 40 to 90 °C, and even more preferably, it is 50 to 80 °C.

[0029] Within the ranges of the usage ratio, time, and temperature as described above, there is a tendency to efficiently obtain the aluminum-containing aqueous solution (α) from the viewpoints including the concentration of the aqueous solution and the like.

[0030] By using the alkaline aqueous solution, generally, aluminum can 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 bringing the aluminum-containing aqueous solution (α) into contact with an aqueous solution having a pH of 3.5 to 6.5 (hereinafter sometimes referred to as "weak acidic aqueous solution") to obtain an oxygen-containing aluminum compound (β).

[0032] The use ratio of the aluminum-containing aqueous solution (α) and the weakly acidic aqueous solution is preferably such that the amount of the weakly acidic aqueous solution is not less than the amount required 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 a basic (metal) component such as an alkali metal can be formed, while the oxygen-containing aluminum compound (β) tends to precipitate in the neutral region, so that the basic (metal) component in the oxygen-containing aluminum compound (β) tends to be easily reduced.

[0033] In order to carry out the contact treatment as uniformly as possible, it is preferable to use a method such as stirring or bubbling with an inert gas in combination.

[0034] The time for bringing the aluminum-containing aqueous solution (α) into contact with the weakly acidic aqueous solution depends on the concentration of the aluminum-containing aqueous solution (α) and the like, but is preferably 1 to 60 minutes. More preferably, it is 2 to 40 minutes, and still more preferably, it is 3 to 30 minutes.

[0035] The temperature for bringing the aluminum-containing aqueous solution (α) into contact with the weakly acidic aqueous solution depends on the concentration of the alkaline aqueous solution and the aluminum content, but is preferably 10 to 50°C. More preferably, it is 15 to 45°C, and still more preferably, it is 20 to 40°C.

[0036] After the contact treatment, preferably, solid-liquid separation is carried out by filtration or the decantation method to obtain the oxygen-containing aluminum compound (β) as a solid component. This solid part is preferably washed sufficiently with water. Further, it is preferably washed with warm water (preferably water at 30 to 50°C). As the washing method, a conventionally known method can be used without limitation. By this washing, salts derived from the basic (metal) components (for example, sodium and potassium) can be efficiently removed from the oxygen-containing aluminum compound (β). If salts derived from the basic (metal) components remain in the oxygen-containing aluminum compound (β), it may become an obstacle to zeolite crystal growth and structure control in the third step described later.

[0037] If the ranges of the temperature and time are set as such, it is easy to separate the basic (metal) component from the oxygen-containing aluminum compound (β), and there is a tendency for the solid-liquid separation and the like to proceed efficiently.

[0038] In addition, the present inventor believes that the second step may be able to reduce the influence of the performance due to the composition of the nitrogen-containing aluminum composition (a) and the variation in structure in the third step described later. This is presumably because the method of this second step tends to easily separate the 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 bringing an aluminum compound (A) containing the oxygen-containing aluminum compound (β), silica (B), and water (C) into contact with each other, and then bringing them into contact under the conditions of 100 to 400 °C for 1 to 240 hours, and zeolite can be obtained after this step.

[0040] It is considered that the third step can be used without limitation the so-called hydrothermal synthesis method of known zeolite, basically except for using the aluminum compound (A) containing the oxygen-containing aluminum compound (β).

[0041] The aluminum compound (A) may be only the oxygen-containing aluminum compound (β), or may be a mode in which a known aluminum compound such as zeolite, alumina, boehmite, etc., which are usually used in the production of zeolite, and the oxygen-containing aluminum compound (β) are used in combination. When the aluminum compound (A) is 100% by weight, the content of the oxygen-containing aluminum compound (β) is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and particularly preferably 60% by weight or more. The preferable upper limit is, of course, 100% by weight.

[0042] Next, a preferred method for the third step using each of the above components will be described. In the method for producing zeolite of the present invention, the aluminum compound (A) containing water (C) and silica (B) containing water (C) are brought into contact with each other, 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 above contact is in the range of 100 to 400 °C. The preferable lower limit of the above temperature range is 130 °C, more preferably 150 °C, and still more preferably 170 °C. On the other hand, the preferable upper limit of the above temperature range is 350 °C, more preferably 320 °C, and still more preferably 300 °C. Within such a temperature range, zeolite can be efficiently obtained by the reaction of the aluminum compound and silica.

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

[0044] In addition, the temperature of the step of bringing the aluminum compound (A) containing water (C) and silica (B) containing water (C) into contact with each other is not limited to the above temperature range. The temperature range of this contact step is preferably 0 °C or higher and less than 100 °C. More preferably, it is 10 to 80 °C, and still more preferably, it is room temperature to 60 °C. Also, there is no particular limitation on the time required for this contact step. Although it depends on the scale of contact, it is preferably 10 seconds to 12 hours, more preferably 30 seconds to 8 hours, and still more preferably 1 minute to 6 hours.

[0045] Also, it is possible to include a preliminary step such as stirring within a certain temperature range from the contact to the heating and holding steps. In this case, the preferred temperature range is the same as the temperature range during the contact step. In addition to the time of the preliminary step, operations such as gradually heating up to the heating and holding steps are 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] The ratio of using the aluminum compound (A), silica (B), and water (C) is not particularly limited, but the aluminum compound (A) is preferably used in the range of 0.1 to 10% by weight based on the water (C). The preferred lower limit of the 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 the 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 the range of 0.05 to 5% by weight based on the water (C). The preferred lower limit of the range is 0.1% by weight, more preferably 0.2% by weight, and even more preferably 0.25% by weight. On the other hand, the preferred upper limit of the range is 4% by weight, more preferably 3% by weight, and even more preferably 2% by weight.

[0048] By being within the range of the above-mentioned usage ratios, zeolite can be efficiently produced.

[0049] In the third step of the present invention, components other than the aluminum compound (A), silica (B), and water (C) can be appropriately used. Such components preferably include known organic structure-directing agents. It is said that such components may have a function of controlling the higher-order structure of silica or aluminosilicate. Specifically, quaternary ammonium salts, hydroxyamines, cyclic oxyamines, etc. can be exemplified.

[0050] Specific examples of the quaternary ammonium salt include salts containing an ammonium ion (cation) having 4 moles of substituents such as hydrocarbon groups having 1 to 10 carbon atoms per mole of nitrogen atoms, and anions such as hydroxy ions, chloride ions, bromide ions, and iodide ions. The hydrocarbon group is more preferably a hydrocarbon group having 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. On the other hand, as the anion, hydroxy ions, bromide ions, and iodide ions are more preferable, and hydroxy ions are still more preferable. More specific examples of such quaternary ammonium salts include, for example, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dimethyldipropylammonium hydroxide, tetrapropylammonium bromide, bis-1,6-(tripropylammonium) hexamethylene diiodide, and the like. Particularly preferred is dimethyldipropylammonium hydroxide. When using such a structure directing agent, there is a tendency to easily produce FAU-type zeolite, MSE-type zeolite, and the like.

[0051] On the other hand, an ammonium salt having only hydrocarbon groups with a small number of carbon atoms, such as tetraethylammonium hydroxide, may be able to produce zeolites such as SAPO-type when used in combination with, for example, morpholine described later.

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

[0053] Examples of the cyclic oxyamines include oxycyclic amines having a 6-membered ring such as morpholine and oxazine, and oxycyclic amines having a 5-membered ring such as oxazolidine and oxazoline. Among these, oxycyclic amines having a 6-membered ring structure are preferred, and morpholine is particularly preferably used. When such an organic structure-directing agent is used, for example, it tends to be easier to obtain a SAPO-type zeolite.

[0054] In this way, by selecting the structure-directing agent, various types of zeolites can be prepared.

[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 more preferable lower limit value of the ratio is 1.7, more preferably 1.9, and particularly preferably 2.0. On the other hand, the more preferable upper limit value of the ratio is 9, more preferably 8, and particularly preferably 7.

[0056] Examples of the preferred components that can be used in combination include phosphorus-containing compound (D). Examples of the phosphorus-containing compound (D) include phosphoric acid and aluminum phosphate, among which phosphoric acid is more preferred. Further, the aqueous solution of the alkaline compound can be used in combination as appropriate. The phosphorus-containing compound (D) is preferably used in the range of 0.1 to 10% by weight based on water (C). The preferred lower limit of the above 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 the above range is 7% by weight, more preferably 6% by weight, and even more preferably 5% by weight.

[0057] Examples of the preferred components that can be used in combination include nitrogen-containing compound (E). The nitrogen-containing compound (E) can be appropriately selected according to the desired zeolite structure. For example, when producing zeolite as a catalyst for the above MTO reaction, examples of the nitrogen-containing compound (E) include cyclic nitrogen-containing compounds. The nitrogen-containing compound (E) is preferably used in the range of 0.2 to 20% by weight based on water (C). The preferred lower limit of the above 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 the above range is 15% by weight, more preferably 12% by weight, and even more preferably 10% by weight.

[0058] In addition, since zeolite is crystalline, a method of using zeolite seed crystals in combination is generally preferably used to promote its crystal growth.

[0059] By using the above method, a slurry containing solid zeolite is often obtained. Such a slurry is usually preferably subjected to solid-liquid separation, the solid part is thoroughly washed with water, and dried by a known method such as heat drying or vacuum drying. The temperature range in the above method is usually carried out in the range of room temperature to 200°C. The time required for the drying depends on the drying temperature and the like, but is often 1 hour to 120 hours.

[0060] The dried zeolite can be further calcined. Such calcination conditions are carried out in an air atmosphere, preferably at 400°C or higher and 850°C or lower for 0.1 to 20 hours. A more preferable lower limit value of the temperature range is 500°C, more preferably 550°C, and particularly preferably 600°C. On the other hand, a more preferable upper limit value of the temperature range is 800°C, 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. Such an ion exchange method can be appropriately selected and implemented from known methods.

[0062] The method for producing zeolite including the "first step" to "third step" of the present invention is preferably usually carried out using different reactors and processing apparatuses for each step. Industrially, it is preferable to move and supply the contents obtained in each step through pipes between reactors. Therefore, various reactants are generally used in a liquid phase such as a liquid, solution, slurry, etc. However, as long as the particles have excellent fluidity, they can also be moved in a solid state through the pipe and supplied to the next step.

[0063] By using the method for producing zeolite of the present invention, for example, even when using raw materials with inconsistent compositions and qualities such as waste like aluminum dross, it may be possible to produce a desired zeolite having the same performance as conventional products. Such a method for producing zeolite is industrially useful because it is easy to produce the same zeolite as before even when 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 various known applications. For example, adsorbents for polar compounds such as water and alcohol, ion exchange resins, (solid acid) catalysts for various reactions, etc. can be mentioned. It is also possible to carry out a modification reaction using a compound containing an element that is likely to exhibit acidity such as Group 4 and Group 5 of the periodic table to obtain a modified zeolite.

[0065] Examples of the catalyst include catalysts for so-called C1 chemicals such as catalysts for producing olefins by dehydration reaction of alcohols, etc., catalysts for producing aromatic polyols by reacting hydrogen peroxide with aromatic compounds, catalysts for producing olefins that can selectively produce 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 type alkylation of aromatic compounds, isomerization catalysts for various hydrocarbons such as paraffin, olefin, and alkylbenzene, isomerization, disproportionation, and transalkylation catalysts for various alkylbenzenes, etc. The use of known catalysts can be cited as preferred examples.

[0066] For example, using the obtained zeolite, olefins can be produced with methanol as a raw material. Such a production method can appropriately select known methods. As an example, a method is to fill a cyclic reaction device with zeolite to form a fixed bed, and supply methanol to this fixed bed to obtain hydrocarbon compounds such as ethane and ethylene. The temperature at this time can be, for example, 150 to 300 °C, and hydrocarbon production can be carried out continuously. Of course, the unreacted methanol in the above production method can also be reused as a raw material by methods such as recovery or direct circulation.

Examples

[0067] Hereinafter, examples are disclosed to explain the present invention in more detail, but the present invention is not limited by these examples.

[0068] (Method for measuring the aluminum content of the raw material aluminum-containing compound) Using a Rigaku Supermini 200 Rigaku type fluorescence X-ray measuring device manufactured by Rigaku Corporation, under a helium atmosphere, the scan speed is 1 ° / min for aluminum, magnesium, chlorine, potassium, silicon, and phosphorus, and 2 ° / min for other elements, and the step width is 0.01 ° / step. The measured value of the weight ratio as a metal is obtained, and the numerical value of the weight% is calculated.

[0069] (X-ray Diffraction Measurement Method of Zeolite) Performed using a Rigaku Smart Lab Rigaku type X-ray diffractometer manufactured by Rigaku Corporation, with CuKa rays as the X-ray source. Other measurement conditions are as follows. Scanning range: 2θ = 5 to 70° Scan speed: 4° / min Step width: 0.01° / step Tube voltage: 40 kV Tube current: 100 mA

[0070] (Specific Surface Area Measurement Method) Using BELSORP manufactured by MicrotracBEL, with N 2 as the adsorption gas, the specific surface area was calculated by the BET method. Before measurement, pretreatment was carried out in a vacuum state at 200 °C for 2 hours.

[0071] (NH 3 (Evaluation Method of Acid Amount of Solid (Zeolite) by NH Using BELCAT-II manufactured by MicrotracBEL, after pretreatment at 300 °C in an argon (Ar) atmosphere, H 2 After pretreatment again with a mixed gas of O / Ar, NH 3 was adsorbed at 100 °C, and the zeolite sample was heated from 100 °C to 700 °C at a rate of 5 °C / min under an Ar atmosphere. The desorbed ammonia was quantified with a quadrupole mass spectrometer BELMass, and the acid amount per unit weight was evaluated.

[0072] (Analysis Method of Reaction Gas) In Example 1, Example 2, and Comparative Example 1, gas analysis was performed by a conventional method using a BELMass quadrupole mass spectrometer manufactured by MicroBEL. In Examples 3 to 5 and Reference Example 1, gas analysis was performed by a conventional method using gas chromatography 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 at 70 °C in a Teflon (registered trademark) beaker and stirred for 90 minutes. The filtrate obtained by filtering the mixture was designated as aqueous solution (1). Incidentally, it is well known that the aluminum dross contains nitrogen due to its properties during the production process.

[0074] (Contact and mixing treatment with ammonium chloride) The aqueous solution (1) was added to 100 milliliters of a 3 mol / liter aqueous ammonium chloride solution (pH: approximately 4.4) at room temperature, stirred and mixed for 5 minutes, and then the resulting solid was filtered off and thoroughly washed with distilled water at 50 °C. At this stage, Na was not detected. The solid thus obtained was dried at 120 °C overnight to obtain an oxygen-containing aluminum compound (1). Its composition was similar to boehmite.

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

[0076] The content of beaker A and the content of beaker B were mixed and thoroughly stirred and mixed at room temperature for 30 minutes. At this stage, Al 2 O 3 / P 2 O 5 / SiO 2 / (morpholine / tetraethylammonium) / distilled water was adjusted so that the ratio became 1.0 / 1.0 / 0.6 / 2.0 / 52. Thereafter, distilled water was added and the mixture was further stirred and mixed at room temperature for 1 hour.

[0077] Next, the mixed solution was transferred to a hydrothermal synthesis apparatus, and hydrothermal synthesis was carried out at 200 °C for 24 hours. The obtained reaction product was subjected to solid-liquid separation by centrifugation. The solid part was thoroughly washed with distilled water at 50 °C and dried at 120 °C overnight. Then, it was calcined in a firing apparatus under the conditions of 600 °C for 6 hours to obtain Sample (1).

[0078] (Ion exchange) 1.17 grams of the Sample (1) was added to 100 milliliters of an ammonium nitrate aqueous solution (0.44 mol / liter), stirred for 2 hours, and then subjected to solid-liquid separation by centrifugation. This operation was repeated again. The obtained solid part was thoroughly washed with distilled water and then dried at 60 °C overnight.

[0079] Next, the obtained solid was heated at a rate of 5 °C / min to 500 °C and calcined at 500 °C for 2 hours. As a result of X-ray diffraction measurement of the obtained Solid (1), it was a SAPO-type zeolite.

[0080] (Reaction of methanol using zeolite) Using a BELCAT-II-SP type apparatus manufactured by MicrotracBEL, 0.3 grams of the zeolite was filled in a reaction tube and heat-treated at 500 °C for 1 hour under a nitrogen stream of 10 milliliters / min.

[0081] Thereafter, the reaction tube was maintained at 450 °C, and methanol was supplied to the reaction tube at a rate of 10 milliliters / min for 5 hours. As a result of the analysis of the obtained gas, ethane and ethylene were produced.

[0082] [Example 2] Solid (2) was obtained in the same manner as in Example 1, except that aluminum dross with a lot name of "Lot name; AD-1-as" (aluminum content 70.43 wt%) was used instead of "Lot name; AD-2-as". This Solid (2) was also a SAPO-type zeolite.

[0083] From the results of Example 1 and Example 2 above, according to the method of the present invention, the desired zeolite was obtained regardless of the composition of the aluminum composition used as a raw material.

[0084] [Comparative Example 1] Sodium was detected from the liquid (1) without performing the ammonium chloride contact and mixing treatment of Example 1. An aluminum source containing sodium was expected to be disadvantageous from the viewpoint of structure control in the method for producing zeolite by hydrothermal synthesis.

[0085] [Example 3] (Sodium hydroxide treatment of aluminum-containing compound) 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% by weight) was used instead of "lot name; AD-2-as".

[0086] (Contact and mixing treatment with ammonium chloride) The aqueous solution (3) was used instead of the aqueous solution (1) and the same procedure as in Example 1 was carried out to obtain an oxygen-containing aluminum compound (3).

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

[0088] The content of beaker A and the content of beaker B were mixed and thoroughly stirred and mixed at room temperature for 30 minutes. At this stage, the molar ratio of Al 2 O 3 / P 2 O 5 / SiO 2 / morpholine / tetraethylammonium / distilled water was adjusted to 1.0 / 1.0 / 0.6 / 1.5 / 0.5 / 75. Then, distilled water was added and the mixture was further stirred and mixed at room temperature for 1 hour.

[0089] Next, the mixed solution was transferred to a hydrothermal synthesis apparatus, and hydrothermal synthesis was carried out at 200 °C for 24 hours while standing still. The obtained reactant was subjected to solid-liquid separation by centrifugation, the solid part was thoroughly washed with distilled water at 50 °C, dried at 120 °C overnight, and then calcined in a firing apparatus at 600 °C for 6 hours to obtain sample (3). This sample (3) was also a SAPO-type zeolite.

[0090] (Ion exchange) 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 tabletted to obtain tablet (3). 0.2445 grams of the tablet (3) was filled into a fixed-bed flow reactor and heat-treated at 480 °C for 1 hour under a nitrogen stream at a flow rate of 20 milliliters per minute.

[0092] Thereafter, the reaction tube was maintained at 450 °C, and nitrogen was bubbled through methanol at a rate of 20 milliliters per minute to obtain a methanol / nitrogen gas stream with a vapor concentration of 7.3%. The methanol / nitrogen gas stream was supplied to the reaction tube for 5 hours at a space velocity (Weight Hourly Space Velocity; WHSV) of 0.5 / hour. As a result of analyzing the obtained gas, ethylene and propylene were produced.

[0093] The surface area of the solid, the amount of acid in the solid, the content of ethylene and propylene determined by gas chromatography at the time when the reaction time reached 5 hours, and the catalyst (solid) life are described in Table 1 below.

[0094] Incidentally, the catalyst life is defined as follows. Catalyst life: During the reaction of the methanol, the reaction time at the point when the conversion rate of the methanol became 0.5% lower than the highest value after the point when the conversion rate of the methanol showed the highest value.

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

[0096] [Reference Example 1] The reaction of methanol 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 a sample (catalyst) instead of the solid (1).

[0097] Various results are shown in Table 1 described below. From the results of Examples 1 to 4, it was shown that a desired zeolite such as a SAPO type can be obtained without being significantly affected by the aluminum content of the raw material aluminum dross. It was also shown that a zeolite having a performance equivalent to that of a commercially available zeolite 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 (manufactured by Fuji Film 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 adjusted so that the molar ratio as NaOH / tetrapropylammonium bromide / SiO 2 / Al 2 O 3 / H 2 O was 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, followed by stirring at room temperature for 1 hour.

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

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

[0102] From the above results, it was shown that zeolites with a desired structure can be produced even from aluminum dross by selecting a conventional structure-directing agent.

[0103]

Table 1

Claims

1. A method for producing zeolite, comprising the following first to third steps: (First 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). (Second 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). (Third step) A step of contacting the 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. 2. The method for producing a zeolite according to claim 1, wherein the nitrogen-containing aluminum composition (a) is aluminum dross.

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