JP2012158482A - Method for recovering molybdenum and cobalt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering molybdenum and cobalt by which both molybdenum and cobalt can be collectively recovered in a good yield, and a method for producing a composite oxide or the like using molybdenum and cobalt recovered by the above method as raw materials.SOLUTION: The method for recovering molybdenum and cobalt includes mixing a composite oxide containing molybdenum and cobalt, a ceramic molded body, and an aqueous solution for extraction prepared by dissolving at least one of ammonia and an organic base in water to thereby extract molybdenum and cobalt from the composite oxide into the aqueous phase. The method for producing a composite oxide includes drying and firing the aqueous phase containing molybdenum and cobalt.

Description

  The present invention relates to a method for recovering molybdenum and cobalt from a composite oxide containing molybdenum and cobalt, and a method for producing a composite oxide or a composite oxide catalyst using molybdenum and cobalt recovered by the method as raw materials. Moreover, this invention relates to the method of manufacturing an unsaturated aldehyde and / or unsaturated carboxylic acid using the catalyst obtained by the manufacturing method of this complex oxide catalyst.

  Conventionally, composite oxides containing molybdenum and cobalt have been widely used, for example, as catalysts in various gas phase catalytic oxidation reactions. However, in general, when a catalyst is used for a certain period of time, its performance deteriorates and is discarded as a waste catalyst. Therefore, it is required to recover and reuse molybdenum and cobalt in the waste catalyst. Therefore, as a method for recovering both molybdenum and cobalt, a composite oxide containing molybdenum and cobalt is treated with an aqueous caustic soda solution to obtain a leachate containing molybdenum, and an insoluble residue is treated with an aqueous sulfuric acid solution to remove cobalt. There has been proposed a method (Patent Document 1) for recovering molybdenum and cobalt, respectively, by obtaining a leachate containing them. As a method of recovering molybdenum, a method of recovering molybdenum by mixing a complex oxide containing molybdenum and cobalt with an aqueous alkali hydroxide solution to obtain a molybdenum-containing aqueous solution (Patent Document 2) has also been proposed. .

JP-A-5-156375 International Publication No. 2007/032228 Pamphlet

  However, the conventional molybdenum and cobalt recovery methods described above first recover molybdenum and then recover cobalt from the residue. Such a recovery method is advantageous when the recovered molybdenum and cobalt are reused separately, but on the other hand, since a plurality of steps are required for the recovery, it is not simple and disadvantageous in terms of cost. On the other hand, there are many catalysts containing both molybdenum and cobalt as catalyst constituent elements, and it is preferable that a method capable of recovering both molybdenum and cobalt together is preferable when reusing them as raw materials for such catalysts. There was a need for such a method.

  Therefore, an object of the present invention is to recover molybdenum and cobalt that can collect both molybdenum and cobalt at a good recovery rate, and a composite oxide using molybdenum and cobalt recovered by the method as raw materials. And a method for producing a composite oxide catalyst. Further, in the presence of the composite oxide catalyst produced by the method for producing a composite oxide catalyst, the compound selected from propylene, isobutylene and tertiary butyl alcohol is subjected to gas phase catalytic oxidation with molecular oxygen, thereby unsaturated. The object is to provide a method for producing aldehydes and / or unsaturated carboxylic acids.

  As a result of intensive studies to solve the above problems, the present inventor has completed the present invention.

That is, this invention consists of the following structures.
(1) By mixing a composite oxide containing molybdenum and cobalt, a ceramic molded body, and an aqueous solution for extraction formed by dissolving at least one of ammonia and an organic base in water, molybdenum and cobalt are converted from the composite oxide. A method for recovering molybdenum and cobalt, wherein cobalt is extracted into an aqueous phase.
(2) The collection method according to (1), wherein the amount of the ceramic molded body used is 1 to 30 parts by mass with respect to 100 parts by mass in total of the composite oxide and the ceramic molded body.
(3) The ceramic molded body is at least one selected from the group consisting of a ceramic molded body mainly composed of oxide, a ceramic molded body mainly composed of carbide, and a ceramic molded body mainly composed of nitride. The recovery method according to (1) or (2) above.
(4) The recovery method according to (3), wherein the oxide in the ceramic molded body containing the oxide as a main component is at least one selected from the group consisting of silica, alumina, zirconia, and mullite.
(5) The composite oxide also includes at least one selected from the group consisting of cesium, potassium and rubidium together with molybdenum and cobalt, and at least one selected from the group consisting of cesium, potassium and rubidium is also extracted into the aqueous phase. The recovery method according to any one of (1) to (4).
(6) The recovery method according to any one of (1) to (5), wherein the pH of the aqueous solution for extraction is 8 or more.
(7) The recovery method according to any one of (1) to (6), wherein a mixing temperature when the composite oxide, the ceramic formed body, and the aqueous solution for extraction are mixed is 0 to 100 ° C. .
(8) The recovery method according to any one of (1) to (7), wherein the organic base is at least one of amines and quaternary ammonium compounds.
(9) The composite oxidation containing molybdenum and cobalt, characterized in that the aqueous phase containing molybdenum and cobalt obtained in the recovery method according to any one of (1) to (8) is dried and then fired. Manufacturing method.
(10) Molybdenum and cobalt contained in the aqueous phase obtained in the recovery method according to any one of (1) to (8) above are used as catalyst raw materials, and an aqueous solution or aqueous slurry containing the catalyst raw materials is dried and then calcined. A method for producing a composite oxide catalyst containing molybdenum and cobalt.
(11) Molybdenum and cobalt contained in the aqueous phase obtained in the recovery method according to any one of (1) to (8) above are used as catalyst raw materials, and an aqueous solution or aqueous slurry containing the catalyst raw materials is subjected to first drying. The composite oxide catalyst containing molybdenum and cobalt is subjected to first firing, then mixed with acid and water, then subjected to second drying, and then subjected to second firing. Manufacturing method.
(12) The method for producing a composite oxide catalyst according to (10) or (11), wherein a catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid is produced.
(13) A composite oxide catalyst is produced by the method described in (10) or (11) above, and in the presence of the catalyst, a compound selected from propylene, isobutylene and tertiary butyl alcohol is vapor-phased with molecular oxygen. A method for producing an unsaturated aldehyde and / or an unsaturated carboxylic acid which undergoes catalytic oxidation.

  According to the present invention, both molybdenum and cobalt can be collected together with a good recovery rate. As a result, a predetermined composite oxide or composite oxide catalyst containing molybdenum and cobalt can be produced at low cost by simply reusing the recovered raw material. Further, by using the obtained composite oxide catalyst, a compound selected from propylene, isobutylene and tertiary butyl alcohol is subjected to gas phase catalytic oxidation with molecular oxygen, thereby producing an unsaturated aldehyde and / or unsaturated compound in high yield. Carboxylic acids can be produced.

Hereinafter, the present invention will be described in detail.
(Molybdenum and cobalt recovery method)
The molybdenum and cobalt recovery method of the present invention recovers molybdenum and cobalt from a composite oxide containing molybdenum and cobalt.

  The composite oxide to which the recovery method of the present invention is applied is not particularly limited as long as it is a composite oxide containing molybdenum and cobalt. For example, the composite oxide may be composed of only molybdenum and cobalt. In addition to molybdenum and cobalt, a composite oxide having one or more metal elements other than these as constituent elements may be used. Examples of other metal elements include bismuth, iron, nickel, manganese, zinc, calcium, magnesium, tin, lead, phosphorus, boron, arsenic, tellurium, tungsten, antimony, silicon, aluminum, titanium, zirconium, cerium, and potassium. , Rubidium, cesium, thallium, vanadium, copper, silver, lanthanum and the like.

A preferred composition of the composite oxide is as shown in the following general formula (1).
_{Mo a Bi b Fe c Co d} A e B f C g O x (1)
(In the formula (1), Mo, Bi, Fe and Co represent molybdenum, bismuth, iron and cobalt, respectively, and A is at least one selected from the group consisting of nickel, manganese, zinc, calcium, magnesium, tin and lead. B represents at least one element selected from the group consisting of phosphorus, boron, arsenic, tellurium, tungsten, antimony, silicon, aluminum, titanium, zirconium and cerium, and C represents potassium, rubidium, cesium and Represents at least one element selected from the group consisting of thallium, O represents oxygen, and when a = 12, 0 <b ≦ 10, 0 <c ≦ 10, 1 ≦ d ≦ 10, 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0 <g ≦ 2, and x is a value determined by the oxidation state of each element. When two or more elements are included, the total content of the two or more elements can be in the range of 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0 <g ≦ 2 when a = 12. Just do it.)

Among the complex oxides having the composition represented by the general formula (1), those having any of the following compositions (excluding oxygen atoms) are more preferable.
_{Mo 12 Bi 0.1-5 Fe 0.5-5 Co 5-10} Cs 0.01-1
_{Mo 12 Bi 0.1-5 Fe 0.5-5 Co 5-10} Sb 0.1-5 K 0.01-1

  The composite oxide may be unused, may be used as a catalyst or the like, and is manufactured as a catalyst or the like but does not have a desired performance (for example, (Including those that have been pulverized in the manufacturing process and those that have deteriorated due to heat load, etc.) (however, composite oxides and kegin heteropolyacids supported on ceramic molded bodies) Is excluded). Examples of the type of catalyst that can be used as the composite oxide include unsaturated aldehyde and unsaturated carboxylic acid production catalysts, unsaturated carboxylic acid production catalysts, and unsaturated nitrile production catalysts. Aldehyde and unsaturated carboxylic acid production catalysts are preferred.

  In the method for recovering molybdenum and cobalt according to the present invention, the above-described composite oxide, a ceramic molded body, and an aqueous solution for extraction formed by dissolving at least one of ammonia and an organic base (base component) in water are mixed. By mixing the composite oxide with the ceramic molded body and the aqueous solution for extraction, molybdenum and cobalt are extracted from the composite oxide into the aqueous phase of the aqueous solution for extraction with a high recovery rate (extraction rate).

  Examples of the ceramic molded body include a ceramic molded body mainly composed of oxide, a ceramic molded body mainly composed of carbide, and a ceramic molded body mainly composed of nitride. Two or more kinds may be used. Among these, a ceramic molded body containing an oxide as a main component is preferable. The content of the oxide, carbide or nitride contained as the main component in the ceramic molded body is preferably 60% by mass or more, and more preferably 70% by mass or more in the ceramic molded body. Examples of the oxide in the ceramic molded body containing an oxide as a main component include silica, alumina, zirconia, mullite, cordierite, and the like. Among these, silica and alumina are preferable. The ceramic molded body mainly composed of an oxide may be a ceramic molded body mainly composed of two or more kinds of oxides, and among them, a ceramic molded body mainly composed of silica and alumina is preferable. In the ceramic molded body mainly composed of two or more kinds of oxides, the total content ratio of two or more kinds of oxides in the ceramic molded body may be in the above range. Examples of the carbide in the ceramic molded body mainly composed of carbide include silicon carbide and tungsten carbide. The ceramic molded body mainly composed of carbide may be a ceramic molded body mainly composed of silicon carbide and tungsten carbide. In a ceramic molded body mainly composed of silicon carbide and tungsten carbide, the total content of silicon carbide and tungsten carbide in the ceramic molded body may be in the above range. Examples of the nitride in the ceramic molded body mainly composed of nitride include silicon nitride and aluminum nitride. The ceramic molded body mainly composed of nitride may be a ceramic molded body mainly composed of silicon nitride and aluminum nitride. In the ceramic molded body mainly composed of silicon nitride and aluminum nitride, the total content ratio of silicon nitride and aluminum nitride in the ceramic molded body may be in the above range.

  The ceramic molded body may be unused, or may be used as an inert filler together with a catalyst. What is used as an inert filler together with a catalyst refers to a ceramic molded body used in a catalytic reaction as a filler inert to the catalytic reaction together with a composite oxide catalyst. When a composite oxide catalyst is used as a catalyst in a catalytic reaction and a ceramic molded body is used as an inert filler, the composite oxide catalyst and the ceramic molded body after use are the composite oxide catalyst and the ceramic molded body. Can be mixed with the aqueous solution for extraction without separation.

  Examples of the shape of the ceramic molded body include a pellet shape, a columnar shape, a spherical shape, a ring shape, and a granular shape that is pulverized and classified after forming. In addition, when using a ceramic molded body, the ceramic molded body was crushed or pulverized together with the ceramic molded body or when the ceramic molded body was used as a manufacturing process or as an inert filler. Or unmolded ceramics may be included.

The size of the ceramic molded body is not particularly limited, but the diameter of the molded body is preferably 1 to 20 mm. In addition, the diameter of a molded object here means the diameter of a sphere for spherical particles, the diameter of a circular cross section for a cylindrical shape, and the maximum diameter of the cross section for other shapes. The bulk density of the ceramic molded body is preferably in the range of 0.5 to 20 g / cm ^3, and more preferably 1.0~5g / cm ^3.

  When mixing the composite oxide, the ceramic formed body, and the aqueous solution for extraction, the amount of the ceramic formed body used is 100 parts by mass in total of the composite oxide and the ceramic formed body. It is preferable that it is 1-30 mass parts. Further, the ceramic molded body is dispersed as a solid phase in a mixed slurry of the composite oxide, the ceramic molded body, and the aqueous solution for extraction. 0.1-10 mass% is preferable with respect to the mixed slurry of an oxide, the said ceramic molded object, and the said aqueous solution for extraction.

  When the base component is ammonia, a compound that decomposes to generate ammonia (hereinafter also referred to as “ammonia generating substance”) may be dissolved in water instead of ammonia. Examples of the ammonia generating substance include ammonium carbonate, ammonium hydrogen carbonate, urea and the like. Only one kind of ammonia generating substance may be used, or two or more kinds may be used in combination.

When the base component is an organic base, examples of the organic base include saturated aliphatic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine and triethylamine, and unsaturated aliphatic amines such as allylamine, diallylamine and triallylamine. Amines such as aromatic amines such as aniline; tetramethylammonium, tetraethylammonium, n-propyltrimethylammonium, tetra-n-propylammonium, tetra-n-butylammonium, 4,4′-trimethylenebis (dimethylpipe Lithium), benzyltrimethylammonium, dibenzyldimethylammonium, 1,1′-butylenebis (4-aza-1-azoniabicyclo [2,2,2] octane), trimethyladamantylammo Various quaternary quaternary ammonium compounds such as hydroxides and halides of ammonium such as um; pyridine, pyrimidine like: and the like.
Among these, at least one of amines and quaternary ammonium compounds is preferable. Only one organic base may be used, or two or more organic bases may be used in combination.

The number of moles of the base component dissolved in the extraction aqueous solution may be larger than the total number of moles of molybdenum and cobalt contained in the composite oxide mixed with the extraction aqueous solution. Specifically, the ratio of the number of moles of the base component to the total number of moles of molybdenum and cobalt may be 1 or more, and is preferably 2 or more.
As the aqueous solution for extraction, an aqueous ammonia solution is preferably used from the viewpoint that the cost can be suppressed low.

  The pH of the aqueous solution for extraction is preferably 8 or more. If the pH of the aqueous solution for extraction is less than 8, the recovery rate of molybdenum and cobalt may be insufficient.

  A mixing method of the composite oxide, the ceramic formed body, and the aqueous solution for extraction is not particularly limited and may be set as appropriate. The composite oxide and the ceramic formed body are immersed in the aqueous solution for extraction. It can carry out suitably by stirring with a stirrer. In addition, when the composite oxide, the ceramic formed body, and the aqueous solution for extraction are mixed, the mixing order of the composite oxide, the ceramic formed body, and the aqueous solution for extraction is not particularly limited. These may be set as appropriate. In addition, it is desirable to crush or grind the composite oxide before mixing.

  The mixing may be performed batchwise or continuously. The mixing temperature when mixing the composite oxide, the ceramic formed body, and the aqueous solution for extraction is preferably 0 to 100 ° C, more preferably 10 to 80 ° C. The mixing time may be appropriately set according to the mixing temperature and the like, but is usually 1 minute to 100 hours, preferably 1 to 24 hours.

  In the molybdenum and cobalt recovery method of the present invention, an aqueous phase containing molybdenum and cobalt extracted by mixing the composite oxide, the ceramic molded body, and the aqueous solution for extraction (hereinafter referred to as “molybdenum and cobalt”). And a solid residue derived from the composite oxide and the ceramic molded body. This recovered slurry of molybdenum and cobalt-containing aqueous solution and residue is subjected to filtration operations such as decantation, natural filtration, vacuum filtration, pressure filtration, centrifugal filtration, etc., so that only molybdenum and cobalt-containing aqueous solutions are used as filtrates. Can be obtained. In addition, when ammonia is used as the base component, the ammonia can be separately collected and reused.

  In the method for recovering molybdenum and cobalt according to the present invention, the molybdenum and cobalt-containing aqueous solution may be used as a recovered material, or the molybdenum and cobalt-containing aqueous solution is further dried, heat-treated, and the like as a solid material. Also good.

  The recovery method of the present invention recovers molybdenum and cobalt in particular at a high recovery rate, and the composite oxide includes at least one selected from the group consisting of cesium, potassium and rubidium together with molybdenum and cobalt. In this case, at least one selected from the group consisting of cesium, potassium and rubidium contained in the composite oxide can be efficiently extracted into the aqueous phase, and can be recovered at a good recovery rate. That is, when the composite oxide contains cesium, potassium or rubidium together with molybdenum and cobalt, cesium, potassium or rubidium contained in the composite oxide can also be efficiently extracted into the aqueous phase. When the composite oxide contains at least two selected from the group consisting of cesium, potassium and rubidium together with molybdenum and cobalt, it is included in the composite oxide. At least two kinds selected from the group consisting of cesium, potassium and rubidium can be efficiently extracted into the aqueous phase, and can be recovered with a good recovery rate.

  Further, the recovery method of the present invention can efficiently extract tungsten contained in the composite oxide into the aqueous phase when the composite oxide contains tungsten as well as molybdenum and cobalt. It can be recovered in a recovery rate.

(Method for producing composite oxide containing molybdenum and cobalt)
In the method for producing a composite oxide containing molybdenum and cobalt of the present invention, the molybdenum and cobalt-containing aqueous solution obtained by the above-described recovery method of the present invention is dried and then fired. As a result, a composite oxide containing at least molybdenum and cobalt is obtained.

  In the method for producing a composite oxide of the present invention, the molybdenum and cobalt-containing aqueous solution obtained in the recovery method of the present invention may be subjected to drying and firing alone, or before drying (in the state of an aqueous solution) or firing. You may add the raw material compound for introduce | transducing metal elements other than molybdenum and cobalt at appropriate time, such as before (dry state). When a raw material compound for introducing a metal element other than molybdenum and cobalt is added, the obtained composite oxide can be adjusted to a desired composition ratio. Further, the composition of the composite oxide to be obtained in the method for producing the composite oxide of the present invention may be the same as or different from the composition of the composite oxide to which the recovery method of the present invention is applied. Also good.

As a raw material compound for introducing other metal elements other than molybdenum and cobalt, various compounds of other metal elements described as constituent elements of the composite oxide to be applied in the section (Method for recovering molybdenum and cobalt) For example, oxides, nitrates, sulfates, carbonates, hydroxides, oxo acids and ammonium salts thereof, halides, and the like may be used.
In addition, when introducing metal elements other than molybdenum and cobalt, a raw material compound for introducing molybdenum or cobalt can also be added to adjust the composition ratio of the resulting composite oxide. Examples of the raw material compound for introducing molybdenum include molybdenum compounds such as molybdenum trioxide, molybdic acid, and ammonium paramolybdate, and examples of the raw material compound for introducing cobalt include cobalt nitrate and cobalt sulfate. Cobalt compounds can be used.

  In the method for producing a composite oxide of the present invention, drying conditions and firing conditions are not particularly limited, and may be appropriately set according to a known method for producing a composite oxide or composite oxide catalyst.

(Production method of composite oxide catalyst)
As a first aspect of the method for producing a composite oxide catalyst of the present invention, molybdenum and cobalt contained in the aqueous phase (molybdenum and cobalt-containing aqueous solution) obtained in the above-described recovery method of the present invention are used as catalyst raw materials, and the catalyst The method of baking after drying the aqueous solution or aqueous slurry containing a raw material is employable. Thereby, a composite oxide catalyst containing at least molybdenum and cobalt is obtained.

  In the first aspect of the method for producing the composite oxide catalyst of the present invention, an aqueous slurry or aqueous solution is prepared by adding other catalyst raw material compounds to the molybdenum and cobalt-containing aqueous solution obtained in the recovery method of the present invention. Alternatively, the molybdenum and cobalt-containing aqueous solution may be once dried, and the resulting dried product, another catalyst raw material compound, and water may be mixed to prepare an aqueous slurry or aqueous solution.

  As said other catalyst raw material compound, what is necessary is just to use the same thing as the raw material compound described in the term of (the manufacturing method of the complex oxide containing molybdenum and cobalt). The amount used thereof may be appropriately set according to the desired catalyst composition. Moreover, in order to adjust to the desired catalyst composition similarly to the manufacturing method of the composite oxide mentioned above, you may use a molybdenum compound and a cobalt compound as a raw material compound.

  In the 1st aspect in the manufacturing method of the complex oxide catalyst of this invention, there is no restriction | limiting in particular about the conditions at the time of preparing aqueous slurry or aqueous solution, and the drying conditions and baking conditions of this aqueous slurry or aqueous solution, and it is desired. According to the type (use) of the catalyst, known conditions may be appropriately employed as a method for producing the catalyst. For example, when the composite oxide catalyst to be obtained is a catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid, JP 2007-117866 A, JP 2007-326787 A, JP 2008-6359 A, JP The methods, conditions, etc. disclosed in Kai 2008-231044 and the like may be adopted as appropriate. Further, when the composite oxide catalyst to be obtained is a catalyst for producing an unsaturated nitrile, the methods and conditions disclosed in JP-B-48-43096, JP-B-59-16817, etc. may be appropriately employed. Good.

  As a second aspect of the method for producing a composite oxide catalyst of the present invention, molybdenum and cobalt contained in the molybdenum and cobalt-containing aqueous solution described above are used as catalyst raw materials, and after drying the aqueous solution or aqueous slurry containing the catalyst raw materials, A composite oxide containing at least molybdenum and cobalt obtained by firing is mixed with an acid and water to obtain an aqueous slurry, and the aqueous slurry is dried and then fired. That is, molybdenum and cobalt contained in the molybdenum and cobalt-containing aqueous solution described above were used as catalyst raw materials, and the aqueous solution or aqueous slurry containing the catalyst raw materials was subjected to first drying, and then subjected to first firing, and then obtained. A mixed oxide catalyst containing at least molybdenum and cobalt is obtained by mixing the fired product with an acid and water, subjecting it to second drying, and then performing second firing.

  Examples of the acid include inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid and boric acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, and adipic acid And organic acids such as phthalic acid. Among these, nitric acid is preferred. Only 1 type may be used for an acid and it may use 2 or more types together.

  The acid may be used as it is or as an aqueous solution. The amount of the acid used may be larger than the number of moles of cobalt contained in the composite oxide. Specifically, it may be usually 1 to 20 mol, preferably 2 to 10 mol, per 1 mol of cobalt.

  In the second aspect of the method for producing a composite oxide catalyst of the present invention, the mixing temperature when the composite oxide is mixed with an acid and water to form an aqueous slurry is preferably 0 to 100 ° C. Preferably it is 10-80 degreeC. The mixing time may be appropriately set according to the mixing temperature and the like, but is usually 1 minute to 100 hours, preferably 1 to 24 hours.

  In the second aspect of the method for producing a composite oxide catalyst of the present invention, when the composite oxide is mixed with an acid and water to form an aqueous slurry, there is no particular limitation on the order of mixing and the mixing method, and the composite oxide Each of acid, acid, and water can be mixed in any order. For example, the other may be added to one of the dispersion and the acid in which the composite oxide is dispersed in water in advance, or the other may be added to one of the aqueous solution in which the complex oxide and the acid are previously dissolved in water. The other may be added to one of the dispersion in which the complex oxide is dispersed in water and the aqueous solution in which the acid is previously dissolved in water. When mixing, the composite oxide is desirably pulverized.

  In the second aspect of the method for producing a composite oxide catalyst of the present invention, the aqueous slurry obtained by mixing the composite oxide with an acid and water may be subjected to second drying alone or mixed. A raw material compound for introducing a metal element other than molybdenum and cobalt may be added at an appropriate time such as before the second drying or before the second baking. By adding a predetermined amount of a raw material compound for introducing a metal element other than molybdenum and cobalt, the resulting composite oxide catalyst can be adjusted to a desired composition ratio.

  In the 2nd aspect in the manufacturing method of the complex oxide catalyst of this invention, as a raw material compound for introduce | transducing other metal elements other than molybdenum and cobalt, (the manufacturing method of the complex oxide containing molybdenum and cobalt) The same raw material compounds as described in the above section may be used. The amount used thereof may be appropriately set according to the desired catalyst composition. Moreover, in order to adjust to the desired catalyst composition similarly to the manufacturing method of the composite oxide mentioned above, you may use a molybdenum compound and a cobalt compound as a raw material compound.

  In the second aspect of the method for producing a composite oxide catalyst of the present invention, the conditions for preparing an aqueous slurry or aqueous solution, the first and second drying conditions, and the first and second firing conditions are particularly There is no limitation, and known conditions may be appropriately employed as a method for producing the catalyst according to the desired type (use) of the catalyst. For example, when the composite oxide catalyst to be obtained is a catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid, JP 2007-117866 A, JP 2007-326787 A, JP 2008-6359 A, JP The methods, conditions, etc. disclosed in Kai 2008-231044 and the like may be adopted as appropriate. Further, when the composite oxide catalyst to be obtained is a catalyst for producing an unsaturated nitrile, the methods and conditions disclosed in JP-B-48-43096, JP-B-59-16817, etc. may be appropriately employed. Good.

  In the present invention, drying refers to heat treatment performed so that the water content of the aqueous slurry or aqueous solution is sufficiently reduced, and the dried product obtained is preferably solid. Moreover, in this invention, baking means operation which heat-processes the dried material obtained after the said drying. Firing may be performed in an atmosphere of an oxidizing gas such as oxygen or air, or may be performed in an atmosphere of a non-oxidizing gas such as nitrogen.

  In the method for producing a composite oxide catalyst of the present invention, after the calcination in the first embodiment or after the second calcination in the second embodiment, heat treatment is performed in the presence of a reducing substance (hereinafter referred to as this reducing property). The heat treatment in the presence of the substance is sometimes referred to simply as “reduction treatment”). Such reduction treatment can effectively improve the catalytic activity. This effect is particularly noticeable when producing an unsaturated aldehyde and unsaturated carboxylic acid production catalyst.

  Preferred examples of the reducing substance include hydrogen, ammonia, carbon monoxide, hydrocarbons, alcohols, aldehydes, and amines. Here, hydrocarbons, alcohols, aldehydes and amines each preferably have 1 to 6 carbon atoms. Examples of hydrocarbons having 1 to 6 carbon atoms include saturated aliphatic hydrocarbons such as methane, ethane, propane, n-butane and isobutane, and unsaturated groups such as ethylene, propylene, α-butylene, β-butylene and isobutylene. Aliphatic hydrocarbons, benzene and the like can be mentioned. Examples of the alcohol having 1 to 6 carbon atoms include saturated aliphatic alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, secondary butyl alcohol, and tertiary butyl alcohol; Examples thereof include unsaturated aliphatic alcohols such as allyl alcohol, crotyl alcohol and methallyl alcohol, and phenol. Examples of aldehydes having 1 to 6 carbon atoms include saturated aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, unsaturated aliphatic aldehydes such as acrolein, crotonaldehyde, and methacrolein. Can be mentioned. Examples of the amine having 1 to 6 carbon atoms include saturated aliphatic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine and triethylamine, unsaturated aliphatic amines such as allylamine and diallylamine, and aniline. Only 1 type may be used for a reducing substance and it may use 2 or more types together.

  The reduction treatment is usually performed by heat-treating the catalyst in an atmosphere of a gas containing the reducing substance. The concentration of the reducing substance in the gas is usually from 0.1 to 50% by volume, preferably from 3 to 30% by volume. , Diluted with helium, argon or the like. In addition, although molecular oxygen may exist in the range which does not impair the effect of a reduction process, it is preferable not to exist normally.

  The temperature of the reduction treatment (that is, the heat treatment temperature during the reduction treatment) is preferably 200 to 600 ° C, more preferably 300 to 500 ° C. The time for the reduction treatment (that is, the heat treatment time for the reduction treatment) is usually 5 minutes to 20 hours, preferably 30 minutes to 10 hours.

  The reduction treatment is preferably carried out by putting the fired body (composite oxide catalyst) after firing into a tube-type or box-type container and circulating a gas containing a reducing substance therein. The gas discharged from the gas may be recycled if necessary. For example, it is also possible to carry out the gas phase catalytic oxidation after filling the catalyst in a reaction tube for gas phase catalytic oxidation, allowing a gas containing a reducing substance to flow therethrough and performing a reduction treatment.

When the reduction treatment is performed, the mass of the calcined product (composite oxide catalyst) after calcination usually decreases, which is considered because the catalyst loses lattice oxygen. And it is preferable that the mass decreasing rate by this reduction process (heat processing) is 0.05-6 mass%, More preferably, it is 0.1-5 mass%. When the reduction proceeds too much and the mass reduction rate becomes too high, the catalytic activity may decrease instead. In this case, the mass reduction rate may be reduced by performing firing again in the atmosphere of the molecular oxygen-containing gas. In addition, a mass reduction rate is calculated | required by following Formula.
Mass reduction rate (%) = (mass of catalyst before reduction treatment−mass of catalyst after reduction treatment) / mass of catalyst before reduction treatment × 100
In the reduction treatment, depending on the type of reducing substance used, the heat treatment conditions, and the like, the reducing substance itself or a decomposition product derived from the reducing substance may remain in the catalyst after the reduction treatment. In such a case, the amount of the residual substance in the catalyst may be separately measured, and this may be subtracted from the catalyst mass including the residue to calculate the mass after the reduction treatment. Since the residue is typically carbon, the mass may be determined by, for example, total carbon (TC) measurement.

  After performing the reduction treatment, if necessary, it may be fired again in an atmosphere of a molecular oxygen-containing gas (this re-firing in the atmosphere of a molecular oxygen-containing gas is “reoxidation”). Sometimes called).

  The molecular oxygen concentration in the gas during reoxidation in the atmosphere of the molecular oxygen-containing gas is usually 1 to 30% by volume, preferably 10 to 25% by volume. As the molecular oxygen source, air or pure oxygen is usually used, and this is diluted with nitrogen, carbon dioxide, water, helium, argon or the like as necessary, and used as a molecular oxygen-containing gas. The reoxidation temperature is usually 200 to 600 ° C, preferably 350 to 550 ° C. The reoxidation time is 5 minutes to 20 hours, preferably 30 minutes to 10 hours.

In the method for producing the composite oxide catalyst of the present invention, a molding treatment is performed as necessary.
What is necessary is just to perform a shaping | molding method in accordance with a conventional method, for example, what is necessary is just to shape | mold into desired shapes, such as a ring shape, a pellet, spherical shape, and granule shape by tableting shaping | molding or extrusion molding. The molding process may be performed at any stage before drying, before firing, before the reduction process, or after the reduction process. Moreover, in the case of a shaping | molding process, in order to improve the mechanical strength of a catalyst, the inorganic fiber etc. which are substantially inactive with respect to the target reaction can also be added.

  The method for producing a composite oxide catalyst of the present invention comprises at least one composite selected from the group consisting of an unsaturated aldehyde and unsaturated carboxylic acid production catalyst, an unsaturated carboxylic acid production catalyst, and an unsaturated nitrile production catalyst. This is a method for producing an oxide catalyst. Especially, it is suitable for the manufacturing method of the composite oxide catalyst of this invention to manufacture the catalyst for unsaturated aldehyde and unsaturated carboxylic acid manufacture.

  Examples of the unsaturated aldehyde and unsaturated carboxylic acid production catalyst include, for example, a catalyst for producing acrolein and acrylic acid by vapor-phase catalytic oxidation of propylene with molecular oxygen, and isobutylene and tertiary butyl alcohol in molecular form. Examples include a catalyst for producing methacrolein and methacrylic acid by gas phase catalytic oxidation with oxygen. Examples of the unsaturated carboxylic acid production catalyst include a catalyst for producing acrylic acid by oxidizing acrolein with molecular oxygen, and a catalyst for producing methacrylic acid by oxidizing methacrolein with molecular oxygen. Etc. Examples of the unsaturated nitrile production catalyst include a catalyst for producing acrylonitrile by ammoxidation of propylene with molecular oxygen, and methacrylonitrile obtained by ammoxidation of isobutylene and tertiary butyl alcohol with molecular oxygen. Examples include catalysts for production.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not restrict | limited to these. In the examples, mL / min representing the gas flow rate is based on STP unless otherwise specified.
In each of the following examples, the activity of the catalyst was evaluated by the following method.

<Catalytic activity test>
A glass reaction tube having an inner diameter of 18 mm is filled with 1 g of catalyst, and 87.5 mL of a mixed gas of isobutylene / oxygen / nitrogen / steam = 1 / 2.2 / 6.2 / 2.0 (molar ratio) is filled in the reaction tube. At a reaction temperature of 350 ° C. for 1 hour, and the outlet gas (the gas after the reaction) was analyzed by gas chromatography. Based on the following formula, the conversion of isobutylene and methacrolein And the total selectivity of methacrylic acid.

・ Conversion rate of isobutylene (%)
= [(Mole number of isobutylene supplied) − (Mole number of unreacted isobutylene)] ÷ (Mole number of supplied isobutylene) × 100
-Total selectivity for methacrolein and methacrylic acid (%)
= (Mole number of methacrolein and methacrylic acid) ÷ [(Mole number of isobutylene supplied) − (Mole number of unreacted isobutylene)] × 100
-Total yield of methacrolein and methacrylic acid (%)
= (Moles of methacrolein and methacrylic acid) ÷ (moles of supplied isobutylene) × 100

Reference Example 1 (Preparation of new catalyst (a1))
441.4 parts by mass of ammonium molybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] was dissolved in 500 parts by mass of warm water, and this was designated as solution A. On the other hand, iron nitrate (III) [Fe (NO ₃ ) ₃ · 9H ₂ O] 202.0 parts by mass, cobalt nitrate [Co (NO ₃ ) ₂ · 6H ₂ O] 436.6 parts by mass and cesium nitrate [CsNO _3] 19.5 parts by mass was dissolved in 200 parts by mass of hot water, and then 97.0 parts by mass of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O] was dissolved, and this was used as Liquid B.

Next, A liquid was stirred, B liquid was added in this, the slurry was obtained, and this slurry was then dried at 250 degreeC with the airflow dryer, and the catalyst precursor was obtained. 18 parts by mass of silica alumina fiber (“RFC400-SL” manufactured by ITM Co., Ltd.) and 2.54 parts by mass of antimony trioxide [Sb ₂ O ₃ ] with respect to 100 parts by mass of the obtained catalyst precursor. After being added and molded into a ring shape having an outer diameter of 6.3 mm, an inner diameter of 2.5 mm, and a length of 6 mm, this molded body was calcined at 545 ° C. for 6 hours under an air stream to obtain a new catalyst (a1). It was.

  This new catalyst (a1) is composed of 0.96 atoms of bismuth, 0.48 atoms of antimony, 2.4 atoms of iron, 7.2 atoms of cobalt, 0.48 atoms of cesium, 4.6 atoms of silicon, 12 atoms of molybdenum, It contains 5.0 atoms of aluminum.

Reference Example 2 (Preparation of used catalyst (b) and used ceramic molded body)
Spherical ceramic molded body as inert filler in reaction tube [Ceramic ball (Z-10) manufactured by Iwao Porcelain Co., Ltd., total content of silica and alumina: 90 mass%, diameter: 6.4 mm] 11 weight Then, 100 parts by mass of a new catalyst (a2) prepared by the same method as in Reference Example 1 was charged thereon. A mixed gas of isobutylene, oxygen, nitrogen and steam is continuously supplied to the reaction tube for a predetermined time, and a gas phase catalytic oxidation reaction to methacrolein and methacrylic acid is performed, and the used catalyst (b) and the used ceramics A molded body was obtained.

Reference Example 3 (Preparation of spent catalyst (c))
A new catalyst (a1) is filled in the reaction tube, and a mixed gas of isobutylene, oxygen, nitrogen and steam is continuously supplied to the reaction tube for a predetermined time to perform a gas phase catalytic oxidation reaction to methacrolein and methacrylic acid. A used catalyst (c) was obtained.

Example 1
(Recovery of molybdenum and cobalt)
New catalyst (a1) obtained in Reference Example 1 (of which 34.6% by mass of molybdenum, 4.0% by mass of iron, 12.8% by mass of cobalt, and 1.9% by mass of cesium) After pulverizing 100 parts by mass, a spherical ceramic molded body (ceramic ball (Z-10) manufactured by Iwao Porcelain Co., Ltd., total content of silica and alumina: 90% by mass, diameter: 6.4 mm) It added in 10 mass parts, 200 mass parts of water, and 272 mass parts of 25 mass% ammonia water, and mixed. The liquid temperature of this mixture was kept at 40 ° C. and stirred for 1 hour, followed by filtration under reduced pressure to obtain a filtrate. The obtained filtrate was heat-treated at 420 ° C. for 2 hours in air, and 64.0 parts by mass of a solid as a recovered product (D) was obtained.
A part of the obtained solid (d) was subjected to elemental analysis with a fluorescent X-ray analyzer (“ZSX Primus II” manufactured by Rigaku Corporation). As a result, 48.5% by mass of molybdenum, 0.0% by mass of iron, 18% of cobalt 0.8 mass% and cesium 2.9 mass%. Therefore, the recovery rates of each element from the new catalyst (a1) were 89.7% molybdenum, 0.0% iron, 94.0% cobalt, and 97.7% cesium.
In addition, the recovery rate (%) of each element was set such that the mass [g] of the element in the obtained solid (d) was x1, and the mass [g] of the element in the new catalyst (a1) was y1. Sometimes calculated by the formula: (x1 / y1) × 100.

Comparative Example 1
(Recovery of molybdenum and cobalt)
New catalyst (a1) obtained in Reference Example 1 (of which 34.6% by mass of molybdenum, 4.0% by mass of iron, 12.8% by mass of cobalt, and 1.9% by mass of cesium) After pulverizing 100 parts by mass, the mixture was added to 200 parts by mass of water and 272 parts by mass of 25% by mass of ammonia water and mixed. The liquid temperature of this mixture was kept at 40 ° C. and stirred for 1 hour, followed by filtration under reduced pressure to obtain a filtrate. The obtained filtrate was heat-treated at 420 ° C. for 2 hours in air, and 60.8 parts by mass of a solid as a recovered product (E) was obtained.
A part of the obtained solid (e) was subjected to elemental analysis with a fluorescent X-ray analyzer (“ZSX Primus II” manufactured by Rigaku Corporation). As a result, molybdenum was 48.7% by mass, iron was 0.6% by mass, cobalt 19 0.1 mass% and cesium 3.0 mass%. Therefore, the recovery rates of each element from the new catalyst (a1) were 85.6% molybdenum, 9.3% iron, 90.7% cobalt, and 96.0% cesium.
In addition, the recovery rate (%) of each element was set such that the mass [g] of the element in the obtained solid (e) was x2, and the mass [g] of the element in the new catalyst (a1) was y1. Sometimes calculated by the formula: (x2 / y1) × 100.

Example 2
(Recovery of molybdenum and cobalt)
Spent catalyst (b) obtained in Reference Example 2 (of which 39.6% by mass of molybdenum, 4.6% by mass of iron, 14.5% by mass of cobalt, 2.3% by mass of cesium) The mixture of 100 parts by mass and 11 parts by mass of the used ceramic formed body was added to 200 parts by mass of water and 272 parts by mass of 25% by mass of ammonia water and mixed. The liquid temperature of this mixture was kept at 40 ° C. and stirred for 4 hours, followed by filtration under reduced pressure to obtain a filtrate. The obtained filtrate was heat-treated in air at 420 ° C. for 2 hours, and 69.9 parts by mass of a solid as a recovered material was collected. (F) was obtained.
A part of the obtained solid (f) was subjected to elemental analysis with a fluorescent X-ray analyzer (“ZSX Primus II” manufactured by Rigaku Corporation). As a result, 48.5% by mass of molybdenum, 0.01% by mass of iron, 18% of cobalt 0.7 mass% and cesium 3.0 mass%. Therefore, the recovery rates of each element from the used catalyst (b) were 85.6% molybdenum, 0.2% iron, 90.1% cobalt, and 91.2% cesium.
The recovery rate (%) of each element is x3 for the element mass [g] in the obtained solid (f), and y2 for the element mass [g] in the used catalyst (b). Is calculated by the formula: (x3 / y2) × 100.

(Evaluation of recovered molybdenum and cobalt)
A composite oxide catalyst containing molybdenum and cobalt was prepared using the solid (f) obtained above, and its catalytic activity was evaluated.
Specifically, after 30 parts by mass of the solid (f) obtained above was pulverized, it was added to 25 parts by mass of water and 32 parts by mass of 60% by mass nitric acid and mixed. After the liquid temperature of this aqueous slurry was kept at 50 ° C. and stirred for 1 hour, 0.27 parts by mass of cesium nitrate [CsNO ₃ ], iron (III) nitrate [Fe (NO ₃ ) _{3 was} added to this aqueous slurry while continuing stirring.・ 9H ₂ O] 16.19 parts by mass, cobalt nitrate [Co (NO ₃ ) ₂ · 6H ₂ O] 6.40 parts by mass and bismuth nitrate [Bi (NO ₃ ) ₃ · 5H ₂ O] 7.78 parts by mass This was designated as C solution.

Meanwhile, 8.88 parts by mass of ammonium molybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] was dissolved in a mixed liquid of 8.76 parts by mass of 25% by mass of ammonia water and 100 parts by mass of water. Was D solution.

  Next, liquid D is stirred, and liquid C is added thereto to obtain an aqueous slurry. Next, the aqueous slurry is transferred to a stainless steel container and dried at 250 ° C. in a box-type dryer. Got. The obtained catalyst precursor was tableted at about 40 MPa, and then crushed and sieved with a sieve having an opening of 2 mm to 710 μm to form granules of 2 mm to 710 μm. This granular catalyst precursor was calcined at 525 ° C. for 6 hours under an air stream to obtain a composite oxide catalyst (g). This composite oxide catalyst (g) contains bismuth 0.96 atoms, iron 2.5 atoms, cobalt 7.2 atoms, and cesium 0.49 atoms with respect to 12 atoms of molybdenum.

  When the catalytic activity of this composite oxide catalyst (g) was evaluated according to the above catalytic activity test, the conversion of isobutylene was 79.7%, and the total selectivity of methacrolein and methacrylic acid was 78.7%. The total yield of methacrolein and methacrylic acid was 62.7%.

  Further, 10.00 g of the composite oxide catalyst (g) obtained above was filled in a glass reaction tube, and 200 mL of a mixed gas of hydrogen / steam / nitrogen = 5/10/85 (molar ratio) was put into the reaction tube. A reduction treatment was performed at 375 ° C. for 8 hours while supplying at a flow rate of / min (STP standard). The mass reduction rate due to this reduction treatment was 0.86%. Then, it reoxidized by heating at 350 degreeC under air circulation for 1 hour, and obtained the complex oxide catalyst (h).

  When the catalytic activity of this composite oxide catalyst (h) was evaluated according to the above catalytic activity test, the conversion of isobutylene was 80.8%, and the total selectivity of methacrolein and methacrylic acid was 77.9%. The total yield of methacrolein and methacrylic acid was 62.9%.

Comparative Example 2
Using the new catalyst (a1) obtained in Reference Example 1, a recovery experiment was performed as follows under the same conditions as in Example 1 of Patent Document 2 (International Publication No. 2007/032228 Pamphlet). That is, 300 parts by mass of a new catalyst (a1) was dispersed in 1200 parts by mass of pure water, 400 parts by mass of a 45% by mass aqueous sodium hydroxide solution was added thereto, and the mixture was stirred at 60 ° C. for 3 hours. Separately, a catalyst component-containing aqueous solution was obtained. After adding 36 mass% hydrochloric acid to the obtained catalyst component containing aqueous solution and adjusting pH to 1.0, it stirred and hold | maintained at 30 degreeC, stirring for 3 hours. The precipitate thus produced was filtered and washed with a 2% by mass aqueous ammonium nitrate solution to obtain 53.2 parts by mass of a catalyst component-containing precipitate (1).
Part of the resulting catalyst component-containing precipitate (1) was subjected to elemental analysis with a fluorescent X-ray analyzer (“ZSX Primus II” manufactured by Rigaku Corporation). As a result, molybdenum was found to be 60.1% by mass, and cobalt was 0.7% by mass. , Cesium 6.3 mass%. Therefore, the recovery rates of each element from the new catalyst (a1) were 30.8% molybdenum, 1.0% cobalt, and 57.8% cesium.
In addition, the recovery rate (%) of each element is the mass [g] of the element in the obtained catalyst component-containing precipitate (1) x4, and the mass [g] of the element in the new catalyst (a1). When y1, it is calculated by the formula: (x4 / y1) × 100.

After crushing 30.0 parts by mass of the resulting catalyst component-containing precipitate (1), it was added to 25.0 parts by mass of water and 3.35 parts by mass of 60% by mass nitric acid and mixed. After the liquid temperature of the aqueous slurry was stirred for 1 hour maintaining the 50 ° C., cesium nitrate _[CsNO 3] 0.18 parts by mass with stirring continued, iron nitrate _{(III) [Fe (NO 3} ) 3 · 9H 2 O 30.37 parts by mass and cobalt nitrate [Co (NO ₃ ) ₂ .6H ₂ O] 64.59 parts by mass are charged and dissolved, and then bismuth nitrate [Bi (NO ₃ ) ₃ · 5H ₂ O] 14.59. A part by mass was added and dissolved, and this was designated as E solution. On the other hand, 33.18 parts by mass of ammonium molybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] was dissolved in a mixed solution of 25 mass% ammonia water 10.97 parts by mass and water 100 parts by mass. Was designated as F solution.

  Next, liquid F is stirred, and liquid E is added thereto to obtain an aqueous slurry. Next, the aqueous slurry is transferred to a stainless steel container and dried at 250 ° C. in a box-type dryer. Got. The obtained catalyst precursor was tableted at about 40 MPa, and then crushed and sieved with a sieve having an opening of 2 mm to 710 μm to form granules of 2 mm to 710 μm. This granular catalyst precursor was calcined at 525 ° C. for 6 hours under an air stream to obtain a composite oxide catalyst (i). This composite oxide catalyst (i) contains bismuth 0.96 atoms, iron 2.5 atoms, cobalt 7.2 atoms, and cesium 0.49 atoms with respect to 12 atoms of molybdenum.

  When the catalytic activity of this composite oxide catalyst (i) was evaluated according to the above catalytic activity test, the conversion of isobutylene was 71.8%, and the total selectivity of methacrolein and methacrylic acid was 83.9%. The total yield of methacrolein and methacrylic acid was 60.2%.

Comparative Example 3 (Recovery of molybdenum and cobalt)
Used catalyst (c) obtained in Reference Example 3 (of which 34.6% by mass of molybdenum, 4.0% by mass of iron, 12.8% by mass of cobalt, and 1.9% by mass of cesium) 100 parts by mass) was added to 200 parts by mass of water and 272 parts by mass of 25% by mass of ammonia water and mixed. The mixture was kept at a temperature of 40 ° C. and stirred for 4 hours, and then filtered under reduced pressure to obtain a filtrate. The obtained filtrate was heat-treated in air at 420 ° C. for 2 hours, and 58.1 parts by mass of a solid as a recovered product was obtained. (J) was obtained.
A part of the obtained solid (j) was subjected to elemental analysis with a fluorescent X-ray analyzer (“ZSX Primus II” manufactured by Rigaku Corporation). As a result, 47.1% by mass of molybdenum, 0.3% by mass of iron, 19% of cobalt 0.8 mass% and cesium 3.2 mass%. Therefore, the recovery rates of each element from the used catalyst (c) were 79.1% molybdenum, 4.4% iron, 89.9% cobalt, and 97.9% cesium.
Note that the recovery rate (%) of each element is x5 for the mass [g] of the element in the obtained solid (j), and y3 for the mass [g] of the element in the used catalyst (c). Calculated by the formula: (x5 / y3) × 100.

Claims (13)

  By mixing a composite oxide containing molybdenum and cobalt, a ceramic molded body, and an aqueous solution for extraction formed by dissolving at least one of ammonia and an organic base in water, molybdenum and cobalt are removed from the composite oxide by water. A method for recovering molybdenum and cobalt, characterized in that the phase is extracted.   The recovery method according to claim 1, wherein the amount of the ceramic molded body used is 1 to 30 parts by mass with respect to 100 parts by mass in total of the composite oxide and the ceramic molded body.   The ceramic molded body is at least one selected from the group consisting of a ceramic molded body mainly composed of oxide, a ceramic molded body mainly composed of carbide, and a ceramic molded body mainly composed of nitride. Item 3. The recovery method according to Item 1 or 2.   The recovery method according to claim 3, wherein the oxide in the ceramic molded body containing the oxide as a main component is at least one selected from the group consisting of silica, alumina, zirconia, and mullite.   The composite oxide includes at least one selected from the group consisting of cesium, potassium and rubidium together with molybdenum and cobalt, and at least one selected from the group consisting of cesium, potassium and rubidium is also extracted into the aqueous phase. The collection | recovery method in any one of 1-4.   The recovery method according to claim 1, wherein the aqueous solution for extraction has a pH of 8 or more.   The collection method according to any one of claims 1 to 6, wherein a mixing temperature when mixing the composite oxide, the ceramic formed body, and the aqueous solution for extraction is 0 to 100 ° C.   The recovery method according to claim 1, wherein the organic base is at least one of amines and quaternary ammonium compounds.   A method for producing a composite oxide containing molybdenum and cobalt, comprising drying the aqueous phase containing molybdenum and cobalt obtained in the recovery method according to any one of claims 1 to 8, followed by firing.   The molybdenum and cobalt contained in the aqueous phase obtained in the recovery method according to any one of claims 1 to 8 are used as catalyst raw materials, and the aqueous solution or aqueous slurry containing the catalyst raw materials is dried and then calcined. A method for producing a composite oxide catalyst containing molybdenum and cobalt.   The molybdenum and cobalt contained in the aqueous phase obtained in the recovery method according to any one of claims 1 to 8 are used as catalyst raw materials, and an aqueous solution or aqueous slurry containing the catalyst raw materials is subjected to first drying, and then the first A method for producing a composite oxide catalyst containing molybdenum and cobalt, comprising: calcining, mixing with acid and water, subjecting to second drying, and then performing second calcining.   The method for producing a composite oxide catalyst according to claim 10 or 11, wherein a catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid is produced.   An unsaturated aldehyde for producing a composite oxide catalyst by the method according to claim 10 or 11, wherein in the presence of the catalyst, a compound selected from propylene, isobutylene and tertiary butyl alcohol is subjected to gas phase catalytic oxidation with molecular oxygen. And / or a method for producing an unsaturated carboxylic acid.