JP2004330109A - Method for manufacturing metal-deposited oxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an industrially advantageous metal-deposited oxide simply with ease without using a solubility improving agent and without necessitating a solvent removing step even when a metallic compound has low solubility. <P>SOLUTION: The metal-deposited oxide in which the metallic compound is deposited on an oxide carrier is manufactured by adding powder of the metallic compound to a wet cake of a hydrous oxide which is an oxide precursor to be fired and has a moisture content suitable for kneading, kneading them so that the powder of the metallic compound is dissolved in the moisture in the wet cake and the metallic compound is adsorbed on the hydrous oxide, and compacting, drying and firing the kneaded material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a metal-supported oxide by supporting a metal compound on an oxide carrier. Although not particularly limited, a denitration catalyst or the like using a raw metal compound having low solubility in water is provided. The present invention relates to a method for producing a metal-supported oxide suitable for producing a metal-supported oxide useful as a catalyst.
[0002]
[Prior art]
Generally, as a method for producing a metal-supported oxide useful as a catalyst such as a denitration catalyst, an oxide such as alumina, titania, or zirconia is used as a raw material, and this oxide is formed into a predetermined dosage form, dried, and calcined. To prepare an oxide carrier, then impregnating the oxide carrier with a metal compound solution of a catalyst metal, removing the solvent and calcining to produce an impregnating method, and a suitable amount of water for molding. A kneading method in which a required amount of a metal compound of a catalytic metal is dissolved in advance, and a solution of the metal compound is added to the raw material oxide and kneaded, formed into a predetermined dosage form, dried, and calcined. It has been known.
[0003]
Here, when producing the metal-supported oxide by the former impregnation method, a solvent removal step of removing the solvent of the metal compound solution impregnated in the oxide carrier is inevitably required, and for the step of removing the solvent, In addition, there is a problem that the manufacturing cost increases and the manufacturing period becomes longer.
On the other hand, the latter kneading method uses only an amount of water suitable for molding, and therefore does not require a solvent removal step as in the impregnation method, and can be said to be an industrially advantageous method.
[0004]
However, in the latter kneading method, when a metal compound of a catalyst metal such as a vanadium compound, a tungsten compound, a niobium compound, and a lead compound is hardly soluble and has low solubility, it corresponds to a catalyst metal to be supported on an oxide carrier. A large amount of solvent is required to dissolve the required amount of the metal compound, and eventually a solvent removal step is required after kneading to adjust the water content suitable for molding. There was a problem that the advantages of the law could not be used.
[0005]
Therefore, conventionally, in order to solve such a problem, for example, when the catalyst metal is vanadium, a vanadium compound such as ammonium vanadate is dissolved in a suitable amount of water for molding together with a solubility improver such as oxalic acid. Thus, a vanadium compound solution is prepared, and a vanadium-supported oxide is produced by a kneading method using the vanadium compound solution. When the catalyst metal is tungsten, an amine compound such as ethanolamine is used as a solubility enhancer together with a tungsten compound such as ammonium paratungstate, and when vanadium and tungsten are simultaneously supported, a sulfur compound is used together with these compounds. 2. Description of the Related Art A uniform metal compound solution is prepared by simultaneously adding a solubility enhancer of an acid or ethanolamine, and is impregnated or kneaded. (See, for example, Non-Patent Document 1, Patent Documents 1, 2, 6, and 7).
[0006]
However, in this method, use of a solubility improver such as oxalic acid or an amine is essential to dissolve the low-solubility metal compound in a solvent in an amount suitable for kneading, and the cost of the reagent used increases. In addition, a reagent dissolution step is required, and when amines or the like are used, equipment for detoxifying the gas generated during sintering from the solubility improver is required, which raises the problem of increasing the production cost. Was.
[0007]
By the way, a metal oxide such as alumina is often used as a catalyst carrier. These oxide carriers are precipitated as an oxide precursor having a hydroxyl group by adding a basic reagent such as ammonia to an acidic aqueous solution containing a metal compound, and after washing the cake, humidity control, drying and firing are performed. A method using an oxide carrier is generally used. The precursor thus obtained has various names depending on the kind, but all are hydroxides or compounds having a residual hydroxyl group as a condensate obtained by partially dehydrating and condensing a hydroxyl group. Here, a compound having a residual hydroxyl group in a condensate in which a part of these hydroxyl groups is dehydrated and condensed is collectively referred to as a hydrated oxide, and a hydroxide and a hydrated oxide precipitated from an acidic metal aqueous solution are collectively referred to. It is referred to as an oxide precursor.
[0008]
As a method for supporting the active metal on the metal oxide carrier, a method of impregnating the carrier with an aqueous solution of a metal compound, followed by drying and firing is generally used. However, a method using a hydrated oxide which is an oxide precursor before firing is also known. For example, a 10% -methylamine solution containing ammonium paratungstate, a methylamine solution containing ammonium molybdate, or an aqueous solution of ammonium metavanadate and oxalic acid is added to a hydrated oxide of titanium (solitized metatitanic acid). After kneading, molding, drying and firing to produce a metal-supported oxide (see Patent Documents 3 and 4), or adding an aqueous solution of ammonium metavanadate and ammonium paratungstate to a metatitanic acid slurry A method of producing a metal-supported oxide by evaporating the formed slurry solution to dryness, adding a slurry solution of the third component or water to the obtained solid, kneading, molding, drying and calcining ( Patent Literature 5) has been proposed.
[0009]
However, even in these methods, the operation of using a solubility improver such as methylamine or oxalic acid and the operation of evaporating and drying the slurry solution are performed, and thus have the same problems as the above-mentioned conventional methods.
[0010]
[Non-Patent Document 1] Kodansha Co., Ltd., November 10, 1974, “Catalyst Preparation”, pp. 148-160
[Patent Document 1] JP-A-58-143,838
[Patent Document 2] JP-A-58-143,839
[Patent Document 3] JP-A-59-35,026
[Patent Document 4] JP-A-59-35,028
[Patent Document 5] JP-A-1-151940
[Patent Document 6] JP-A-8-229,412
[Patent Document 7] Japanese Patent Application Laid-Open No. 2000-464
[0011]
[Problems to be solved by the invention]
Therefore, the present inventors have solved the problem of producing a metal-supported oxide by using a solubility improver or employing a solvent removal step, and are simple, easy, and an industrially advantageous metal-supported oxide. As a result of intensive studies to develop a production method, even if the metal compound has low solubility, the metal compound dissolved in water comes into contact with the hydrated oxide, which is the oxide precursor before firing, so that the hydration of the metal compound is prevented. It is found that the substance is adsorbed by the substance and easily migrates into the solid phase, and even if a small amount of water is used, by combining with the kneading operation, the dissolved component is dissolved in the solid phase using the small amount of water as a solvent. As a result, it is found that the undissolved component is newly dissolved and adsorbed on the precursor, and the process proceeds continuously until the adsorption capacity of the precursor is reached. Can be solved at once It found that, and have completed the present invention.
[0012]
Therefore, an object of the present invention is to provide a simple, easy and industrially advantageous metal-supported oxide without using a solubility enhancer or a solvent removing step, even if the metal compound has low solubility. It is to provide a manufacturing method.
[0013]
[Means for Solving the Problems]
That is, the present invention is to add a metal compound powder to a wet cake of an oxide precursor having a water content suitable for molding, which is an oxide precursor before firing, and knead the mixture to the water in the wet cake. While dissolving the metal compound powder, the metal compound is adsorbed on the hydrated oxide of the wet cake, then molded, dried and calcined to produce a metal-supported oxide in which the metal compound is supported on an oxide carrier. This is a method for producing a metal-supported oxide.
[0014]
In the present invention, the oxide precursor before calcining is not particularly limited as long as it can be finally calcined to become an oxide carrier supporting a desired metal such as a catalyst metal, and is suitably used as an oxide carrier of the catalyst. There are no particular restrictions on the hydrated aluminum oxide such as boehmite, titanic acid, hydrated titanium oxide, zirconium hydroxide, silicon hydroxide and the like. These can be used alone or as a precursor mixture of a composite oxide of two or more oxides. For example, it is common to use a composite oxide such as alumina-silica, titania-silica, zirconia-silica, alumina-titania-silica as a carrier as a catalyst carrier depending on the requirements that the catalyst should have, and the present invention Can also be applied to the oxide precursor of these composite oxide carriers before firing.
[0015]
There is no particular limitation on the method for preparing such a hydrated oxide, and in general, for example, a basic compound such as ammonia is added to a homogeneous acidic solution of a raw material compound containing a metal such as aluminum, titanium and zirconium. It is easily obtained by adjusting the pH, precipitating a hydroxide or a hydrated oxide having a hydroxyl group in a solution, separating the solution into solids and liquids, and washing and dehydrating as necessary.
[0016]
Here, as the raw material compound, for example, aluminum, titanium, chlorides such as zirconium, fluoride, bromide, iodide, nitrate, sulfate, carbonate, acetate, phosphate, borate, oxalate, Hydrofluoric acid salts, silicates, iodates, oxoacid salts, ammonium salts, alkoxides and the like can be mentioned, and only one of them can be used alone, or two or more can be used as a mixture. .
[0017]
The oxide precursor thus prepared is kneaded to obtain a wet cake having a water content suitable for forming a desired dosage form. The moisture contained in the wet cake, for example, when kneaded with the metal compound powder of the catalyst metal, dissolves a part of the metal compound powder and transfers the dissolved metal compound into the hydrated oxide to be adsorbed. It works. In other words, even if an undissolved reagent is present, the oxide precursor has the ability to adsorb the dissolved reagent, so that the dissolved component is transferred to the solid phase by adsorption to the precursor and newly undissolved. The dissolution and further adsorption of the component in water proceeds continuously until the adsorption capacity of the precursor is reached. Therefore, by using the precursor before firing, even a small amount of water can be effectively used as a solvent.
[0018]
Here, the moisture content suitable for kneading to form a desired dosage form is usually 30% by weight or more and 150% by weight or less, preferably 50% by weight or more and 90% by weight or less. If the water content is less than 30% by weight, the problem of poor moldability tends to occur, while if it exceeds 150% by weight, the problem of requiring a humidity control step and prolonging the catalyst preparation period tends to occur. Here, the water content is a total water content including both free water and water generated by a dehydration condensation reaction during firing, and specifically, the oxide precursor is heated to 400 ° C. or higher, preferably, It is a water content measured by a weight loss when the oxide is fired at a temperature of 500 ° C. or more. The present invention can be applied to solvents other than water, but in most cases, water is used as the solvent from the industrial point of view of economy.
[0019]
The metal compound to be added to the wet cake of the oxide precursor may be any compound containing a metal to be supported, and may be appropriately selected depending on the use of the metal-supported oxide to be produced. Is a method particularly suitable for supporting a low-solubility metal compound on an oxide carrier. Therefore, the solubility of the metal component in water is preferably 10,000 mg / L or less, more preferably 100 mg / L or more and 5,000 mg / L. The following metal compounds are used. The principle of the present invention can be applied to a compound that dissolves in a solvent even in a trace amount, but if the compound is dissolved at 100 mg / L or less, it takes time to continuously advance adsorption and dissolution. Not practical from an implementation point of view. In addition, when a metal content of 10,000 mg / L or more can be dissolved, the desired amount of the supported metal can all be dissolved in a water amount suitable for molding in many cases.
[0020]
Specific examples of such low solubility metal compounds include, for example, niobium compounds, zirconium compounds, lead compounds, mercury compounds, thallium compounds, and the like, in addition to vanadium compounds and tungsten compounds. The forms of these metal compounds include chloride, fluoride, bromide, iodide, nitrate, sulfate, oxalate, carbonate, acetate, phosphate, borate, oxalate, hydrofluoride, silica Acid salts, iodate salts, oxo acid salts, ammonium salts, alkoxides and the like can be mentioned, but the solubility of the same metal compound varies greatly depending on these forms. When preparing a catalyst, any form of compound may be used as long as the solubility is high, and a compound that can be easily treated in the preparation process or a compound that does not adversely affect the catalyst after preparation must be used. It is advantageous. However, the compound in the form desired to be used does not always have high solubility, and may not be used due to low solubility or may require a solubility enhancer. Compounds that are advantageous for application of the present invention include vanadates such as ammonium vanadate, tungstates such as ammonium tungstate, oxysalts such as zirconium oxychloride and niobium oxychloride, lead oxalate, niobium oxalate, and oxalate. Oxalates such as manganese oxide can be exemplified.
[0021]
In the present invention, the metal compound powder is added to the wet cake of the oxide precursor, and the mixture is kneaded to dissolve the metal compound powder in the water of the wet cake and to mix the oxide precursor in the wet cake with the oxide precursor in the wet cake. Adsorb metal compounds. Here, the kneading of the wet cake and the metal compound powder can be performed by using the same apparatus and conditions as those conventionally used when producing this type of metal-supported oxide. Specifically, automatic kneading is performed. It can be performed under normal conditions of normal temperature and normal pressure using a device such as a vessel.
[0022]
The kneaded product of the wet cake and the metal compound powder obtained as described above is then molded, dried and fired to obtain a metal-supported oxide in which the metal compound is supported on an oxide carrier.
Here, the conditions of molding, drying, and firing are set according to the use of the metal-supported oxide to be manufactured, and are performed under the same conditions as those conventionally performed when manufacturing this type of metal-supported oxide. be able to.
[0023]
The metal-supported oxide produced by the method of the present invention is the same as that produced by a conventional impregnation method or kneading method.For example, an oxidation catalyst supporting vanadium metal, denitration supporting vanadium and molybdenum or tungsten, etc. It is suitably used for applications such as catalysts.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described based on examples and comparative examples.
[0025]
[Example 1] (Preparation of alumina precursor gel)
Aluminum nitrate 9-hydrate (Al (NO ₃ ) ₃ ・ 9H ₂ O) 800 g was dissolved in pure water to obtain a 1 L aqueous solution of aluminum nitrate (solution A). In addition, sodium aluminate (NaAl ₂ O ₃ = 81.97) was dissolved in pure water to prepare 1 L of an aqueous solution of sodium aluminate (solution B). Next, 20 L of pure water was put into a 35 L enameled vessel, and heated with an electromagnetic heater. When the temperature of the hot water reached 75 ° C., 250 ml of an aluminum nitrate aqueous solution (solution A) was charged and stirred. At this time, the pH value was 2.5. Subsequently, 800 cc of an aqueous solution of sodium aluminate (solution B) was added at a time to adjust the pH value to 10. By this operation, the alumina precursor was precipitated in the solution to form a slurry solution. After further stirring for 5 minutes, the slurry solution was filtered to obtain a wet cake of an alumina precursor. This cake was dispersed again in 20 L of pure water, stirred for 30 minutes, and then filtered again three times to remove sodium sulfate generated during precipitation. The filter cake after washing three times was collected without any particular humidity control operation and was baked at 500 ° C. The water content of the cake was measured using the weight loss as moisture, and was found to be 86.0% by weight. .
[0026]
[Example 2] (Measurement of saturated dissolution concentration of ammonium vanadate)
In 120 ml of pure water, ammonium vanadate reagent (NH ₄ VO ₃ ) 4.54 g, and stirred at room temperature for 3 hours. A large amount of undissolved reagent remained in the solution. After the filtrate obtained by filtering this solution was allowed to stand overnight, a sample was taken from the upper portion of the solution, and the concentration of vanadium was measured by an atomic absorption spectrophotometer. The result was 2,800 mg / L. 0.34 g of the .98 g dissolved.
[0027]
[Example 3] (Measurement of equilibrium adsorption amount of alumina precursor gel)
The same amount of ammonium vanadate reagent (NH 2 ₄ VO ₃ 4.54 g (1,980 mg as a vanadium content) was completely dissolved in 2,500 ml of pure water sufficient to uniformly dissolve, and 140 g of the gel obtained in Example 1 was added thereto and stirred at room temperature for 3 hours. After that, the mixture was filtered off. The concentration of vanadium in the filtrate was measured by an atomic absorption spectrophotometer and found to be 329 mg / L. The amount of the unadsorbed vanadium content determined from this concentration and 2.63 L of water present in the system (2,500 ml of charged water and 120 ml of water contained in the gel) was 863 mg. From this, it was found that the vanadium adsorption capacity of the alumina precursor prepared in Example 1 was 7.98 mg per 1 g of the precursor gel (water content: 86% by weight), and 57.0 mg per 1 g of the calcined alumina.
[0028]
From this, 140 g of the alumina precursor gel obtained in Example 1 (19.6 g of TiO 2 after firing at 500 ° C.) ₂ It becomes. ) Adsorbs 1,117 mg of vanadium and 120 ml of water contained in the gel can dissolve 336 mg of vanadium from the saturated dissolution amount of Example 2, so that the cake after washing and filtration without performing any special humidity control operation is used. On the other hand, it is considered that 3.33 g of ammonium vanadate reagent containing 1,453 mg of vanadium can be directly dissolved and supported by kneading without using a solubility enhancer such as oxalic acid.
[0029]
Example 4 (V ₂ O ₅ / Al ₂ O ₃ Preparation of catalyst)
140 g of the alumina precursor gel obtained in Example 1 was added to an ammonium vanadate reagent (NH ₄ VO ₃ 2.78 g (vanadium content: 1,213 mg) was directly kneaded to obtain a yellow uniform gel. Next, the gel was molded in an extruder without performing special humidity control, and then dried at 120 ° C. for 3 hours in a thermostatic dryer. The dried product was pulverized to an appropriate length and then fired at 500 ° C. for 3 hours in a muffle furnace through which air was passed. V supported on the catalyst thus prepared ₂ O ₅ When the amount was quantified with an atomic absorption spectrophotometer, ₂ O ₅ / Al ₂ O ₃ = 10/90 weight ratio. When the physical properties were measured, the BET surface area was 147 cm. ² / G, the pore volume by a mercury intrusion method was 0.54 ml / g, and the average pore diameter was 15.3 nm.
[0030]
Example 5 (V ₂ O ₅ / Al ₂ O ₃ Reaction test of catalyst)
V obtained in Example 4 ₂ O ₅ / Al ₂ O ₃ The catalyst was pulverized and sized with a sieve having an opening of 0.85 to 1.15 mm, and 1.0 ml of the catalyst was filled in a reaction tube to conduct a denitration reaction test. Assuming that the temperature of the catalyst layer is 170 ° C., NO: 250 ppm and O ₂ : N containing 5% ₂ The gas was fed with GHSV = 30,000 (30 NL / h) together with ammonia (NH3 / NO molar ratio = 1.0). When the NO concentration in the outlet gas was measured by a NOx meter, it was 103 ppm, and the denitration rate was 58.8%. Here, the denitration rate was calculated by the following equation.
Denitration rate (%) = [[(NO concentration at inlet)-(NO concentration at outlet)] / (NO concentration at inlet)] × 100
[0031]
[Example 6] (Preparation of titania precursor gel)
Titanium tetrachloride (TiCl ₄ ) 500 g was mixed with crushed ice produced from pure water, and then made up to 1,000 ml with pure water to obtain a titanium tetrachloride aqueous solution (solution C). Further, 28% by weight of aqueous ammonia was diluted with the same weight of pure water to prepare 14% by weight of aqueous ammonia (solution D).
[0032]
Next, 20 L of pure water was placed in a 35 L enamel container, and heated with an electromagnetic heater. When the temperature of the hot water reached 75 ° C., 500 ml of an aqueous solution of titanium tetrachloride (solution C) was charged and stirred. At this time, the pH value was 1.1. Subsequently, 710 cc of an aqueous ammonia solution (solution D) was added at a time to adjust the pH value to 8.5. By this operation, the titania precursor was precipitated in the solution to form a slurry solution. After further stirring for 5 minutes, the slurry solution was filtered to obtain a wet cake of the titania precursor. This cake was again dispersed in 20 L of pure water, stirred for 30 minutes, and then filtered again three times to remove ammonium chloride generated during precipitation. The filter cake after washing three times was collected without any particular humidity control operation and calcined at 500 ° C., and the water content of the cake was measured using the weight loss as moisture, and was found to be 85.0% by weight. .
[0033]
[Example 7] (Measurement of vanadium saturated dissolution concentration in the presence of molybdenum)
In 170 ml of pure water equal to the amount of water contained in 200 g of the gel obtained in Example 6, ammonium vanadate reagent (NH ₄ VO ₃ 4.54 g) and ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ ・ 4H ₂ O) 10.0 g was added, and the mixture was stirred at room temperature for 3 hours. A large amount of undissolved reagent remained in the solution. After the filtrate obtained by filtering this solution was allowed to stand overnight, a sample was taken from the upper portion of the solution, and the vanadium concentration and the molybdenum concentration were measured by an atomic absorption spectrophotometer. The results were 2,800 mg / L and 32,000 mg / L. In addition, 0.34 g of 1.98 g of the total vanadium content was dissolved, and 5,430 mg of the total molybdenum content was all dissolved.
[0034]
Example 8 (Measurement of vanadium equilibrium adsorption amount of titania precursor gel in the presence of molybdenum)
The same amount of ammonium vanadate reagent (NH 2 ₄ VO ₃ ) With 4.54 g (1,980 mg of vanadium) together with ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ ・ 4H ₂ O) Dissolve completely 2.16 g (1,173 mg as molybdenum component) in 2,500 ml of pure water sufficient to uniformly dissolve, and add 200 g of the gel obtained in Example 6 and add it at room temperature for 3 hours. After stirring, the mixture was filtered off. The concentrations of vanadium and molybdenum in the filtrate were 17 mg / L and 435 mg / L as measured with an atomic absorption spectrophotometer. The amounts of unadsorbed vanadium and molybdenum determined from this concentration and 2.67 L of water present in the system (2,500 ml of charged water and 170 ml of water contained in the gel) were 45 mg and 1,161 mg. Thus, the titania precursor prepared in Example 6 had a vanadium adsorption capacity of 9.8 mg / g of precursor gel (water content: 85% by weight), 65.0 mg / g of titania after firing, and a small amount of molybdenum adsorption. Yes, vanadium was well adsorbed even in the presence of molybdenum.
[0035]
Thus, the titania precursor gel obtained in Example 6 selectively adsorbs vanadium even when a large amount of molybdenum coexists. Therefore, even when molybdenum is supported together with vanadium, a kneaded molybdenum reagent together with a vanadium reagent is used for a cake after washing and filtration without performing a specific humidity control operation, so that a solubility improver such as oxalic acid is not used. Can be carried. At this time, the loading limit of molybdenum is up to an amount substantially corresponding to the molybdenum saturated dissolution amount of water contained in the gel.
[0036]
Example 9 (V ₂ O ₅ -MoO ₃ / TiO ₂ Preparation of catalyst)
200 g of the titania precursor gel obtained in Example 6 was spread over a plastic vat and allowed to stand for 2 days to adjust the humidity, thereby adjusting the total weight to 82 g and the water content to 63%. The gel was charged with ammonium vanadate reagent (NH ₄ VO ₃ 4.54 g (1,980 mg as vanadium) and ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ ・ 4H ₂ O) 2.16 g (1,173 mg as molybdenum content) of powder were mixed and directly kneaded to obtain a yellow-green uniform gel. Next, the gel was extruded through an extruder to form a gel, and then dried at 120 ° C. for 3 hours in a thermostatic drier. The dried product was pulverized to an appropriate length and then fired at 500 ° C. for 3 hours in a muffle furnace through which air was passed. V supported on the catalyst thus prepared ₂ O ₅ Quantity and MoO ₃ When the amount was quantified with an atomic absorption spectrophotometer, ₂ O ₅ / MoO ₃ / TiO ₂ = 10/5/85 by weight. When the physical properties were measured, the BET surface area was 81 cm. ² / G, the pore volume by a mercury intrusion method was 0.151 ml / g, and the average pore diameter was 27.2 nm.
[0037]
Example 10 (V ₂ O ₅ -MoO ₃ / TiO ₂ DeNOx reaction test of catalyst)
V obtained in Example 9 ₂ O ₅ -MoO ₃ / TiO ₂ A NOx removal reaction test was carried out in the same manner as in Example 5 except that a catalyst was used. As a result, the NO concentration in the outlet gas was 15.5 ppm, and the NOx removal rate was 93.8%.
[0038]
[Example 11] (Measurement of saturated dissolution concentration of ammonium paratungstate)
An ammonium paratungstate reagent ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ ・ 5H ₂ O) 2.0 g, and the mixture was stirred at room temperature for 3 hours. A large amount of undissolved reagent remained in the solution. After the filtrate obtained by filtering this solution was allowed to stand overnight, a sample was taken from the upper portion of the solution, and the tungsten concentration was measured by an atomic absorption spectrophotometer. The result was 6,800 mg / L. 1.16 g of 41 g was dissolved.
[0039]
[Example 12] (Tungsten equilibrium adsorption measurement of titania precursor gel in the presence of vanadium)
Ammonium vanadate reagent (NH ₄ VO ₃ 4.54 g (1,980 mg of vanadium) and ammonium paratungstate ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ ・ 5H ₂ O) Dissolve completely in 2,500 ml of pure water sufficient to uniformly dissolve 2.00 g (1,410 mg as a tungsten content), and add 200 g of the gel obtained in Example 6 and leave at room temperature for 3 hours. After stirring, the mixture was filtered off. The vanadium concentration and the tungsten concentration in the filtrate were measured with an atomic absorption spectrophotometer, and were 25 mg / L and 224 mg / L. The amounts of unadsorbed vanadium and tungsten determined from this concentration and 2.67 L of water present in the system (2,500 ml of charged water and 170 ml of water contained in the gel) were 67 mg and 600 mg. Thus, the titania precursor prepared in Example 6 adsorbed 9.6 mg of vanadium per 1 g of precursor gel (water content: 85% by weight), and simultaneously adsorbed 4.0 mg of tungsten.
[0040]
From this, it is considered that when tungsten is used in place of molybdenum, tungsten is adsorbed on the precursor gel, so that it can be supported by kneading without using a solubility improver such as an amine. The limiting amount of the tungsten content of the prepared titania precursor gel is 200 g of gel (TiO 2). ₂ (Equivalent to 30 g) is 800 mg as an adsorbed portion and 1,156 mg as a saturated dissolved portion with respect to 170 g of water contained in the gel, for a total of 1,956 mg.
[0041]
Example 13 (V ₂ O ₅ -WO ₃ / TiO ₂ Preparation of catalyst)
200 g of the titania precursor gel obtained in Example 6 was spread over a plastic vat and allowed to stand for 2 days to adjust the humidity, thereby adjusting the total weight to 82 g and the water content to 63%. The gel was charged with ammonium vanadate reagent (NH ₄ VO ₃ 4.54 g (1,980 mg of vanadium) and ammonium paratungstate ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ ・ 5H ₂ O) 2.00 g (1,410 mg of tungsten) of powder were mixed and directly kneaded. Next, the gel was extruded through an extruder to form a gel, and then dried at 120 ° C. for 3 hours in a thermostatic drier. The dried product was pulverized to an appropriate length and then fired at 500 ° C. for 3 hours in a muffle furnace through which air was passed. V supported on the catalyst thus prepared ₂ O ₅ Quantity and WO ₃ When the amount was quantified with an atomic absorption spectrophotometer, ₂ O ₅ / WO ₃ / TiO ₂ = 10/5/85 by weight. When the physical properties were measured, the BET surface area was 82 cm. ² / G, the pore volume by the mercury intrusion method was 0.240 ml / g, and the average pore diameter was 26.1 nm.
[0042]
Example 14 (V ₂ O ₅ -WO ₃ / TiO ₂ DeNOx reaction test of catalyst)
V obtained in Example 9 ₂ O ₅ -WO ₃ / TiO ₂ A denitration reaction test was performed in the same manner as in Example 5 except that a catalyst was used. As a result, the NO concentration in the outlet gas was 17.5 ppm, and the denitration rate was 93.0%.
[0043]
[Example 15] (Preparation of titania-silica composite precursor gel)
Silicon tetrachloride (SiCl ₄ 30.0 g) was dissolved in 100 ml of methanol (solution E). This solution E was mixed with 1,500 ml of the solution C prepared in Example 6 to make 1600 ml (solution F). A wet cake of a titania-silica precursor was obtained in the same manner as in Example 6, except that 533 ml of this solution F was used instead of solution C (500 ml) of example 6. The cake was baked at 500 ° C., and the water content was measured to be 87.0% by weight.
[0044]
[Example 16] (Measurement of equilibrium adsorption of vanadium in titania-silica precursor gel in the presence of molybdenum)
Except that the gel obtained in Example 11 was used, the mixture was charged in the same manner as in Example 8, stirred for 3 hours, and then filtered off. The vanadium concentration and the molybdenum concentration in the filtrate were measured by an atomic absorption spectrophotometer, and were 30 mg / L and 277 mg / L. The amounts of unadsorbed vanadium and molybdenum determined from this concentration and 2.675 L of water present in the system (2,500 ml of water charged and 175 ml of water contained in the gel) were 80 mg and 742 mg / L. Thus, the titania-silica precursor prepared in Example 11 had a vanadium adsorption capacity of 9.5 mg / g of the precursor gel (water content: 87.5%), 76.0 mg / g of the calcined titania-silica, and molybdenum. The amount of adsorption was 2.2 mg per 1 g of gel and 17.2 mg per 1 g of titania-silica after calcination.
This shows that the titania-silica precursor gel also favorably adsorbs vanadium as in the case of the titania precursor.
[0045]
Example 17 (V ₂ O ₅ -MoO ₃ / TiO ₂ -SiO ₂ Preparation of catalyst)
V was obtained in the same manner as in Example 9 except that the titania-silica precursor gel obtained in Example 11 was used. ₂ O ₅ -MoO ₃ / TiO ₂ -SiO ₂ A catalyst was prepared. V supported on the prepared catalyst ₂ O ₅ Quantity and MoO ₃ When the amount was quantified with an atomic absorption spectrophotometer, ₂ O ₅ / MoO ₃ / TiO ₂ / SiO ₂ = 10/5/82/3. When the physical properties were measured, the BET surface area was 94 cm. ² / G, the pore volume by a mercury intrusion method was 0.25 ml / g, and the average pore diameter was 20.1 nm.
[0046]
Example 18 (V ₂ O ₅ -MoO ₃ / TiO ₂ -SiO ₂ DeNOx reaction test of catalyst)
V obtained in Example 13 ₂ O ₅ -MoO ₃ / TiO ₂ -SiO ₂ As a result of performing a denitration reaction test in the same manner as in Example 5 except that the catalyst was used, the NO concentration in the outlet gas was 18.3 ppm, and the denitration rate was 92.7%.
【The invention's effect】
According to the method of the present invention, alumina, titania, oxides such as zirconia or alumina-silica, titania-composite oxides such as titania-low solubility, without requiring the use of a solubility enhancer or a solvent removal step. An oxide supporting a metal component can be produced using a metal compound.

Claims (6)

A metal compound powder is added to a wet cake of an oxide precursor having a hydroxyl group before calcination and having a water content suitable for kneading, and the metal compound powder is kneaded and the above-mentioned metal compound powder is added to the water in the wet cake. Is dissolved and the metal compound is adsorbed on the oxide precursor in the wet cake state, then molded, dried and calcined to produce a metal-supported oxide in which the metal compound is supported on an oxide carrier. A method for producing a metal-supported oxide. The method for producing a metal-supported oxide according to claim 1, wherein the oxide precursor is a precursor of alumina, titania, zirconia, or silica. The method for producing a metal-supported oxide according to claim 1, wherein the oxide precursor before firing is a precursor of a composite oxide containing two or more types of oxides. The method for producing a metal oxide according to any one of claims 1 to 3, wherein the composite oxide is a composite oxide of alumina-silica, titania-silica, zirconia-silica, and alumina-titania-silica. The method for producing a metal-supported oxide according to claim 1, wherein the oxide precursor before the calcination is a hydrated oxide containing boehmite, titanic acid, hydrated titanium oxide, or zirconia hydroxide. The method for producing a metal-supported oxide according to any one of claims 1 to 5, wherein the moisture content of the wet cake suitable for kneading is 30 to 150% by weight.