Metal evaporation method, metal recovery method, and metal evaporation promoting material

Abstract

To provide a metal evaporation method in which rare metal can be easily recovered.SOLUTION: A metal evaporation method evaporates at least a part of metal composition by heating, in a non-contact manner in the same container, a metal composition containing rare metal elements and a perovskite-type complex oxide expressed by Formula (1): ABHaO3-b (1) (where A denotes one or more kinds of elements selected from a group consisting of lanthanoid element and elements of group 2 in the periodic table, B denotes one or more kinds of elements selected from a group consisting of elements of group 3 in the periodic table, elements of group 4 in the periodic table and transition metal element of a fourth period of the element periodic table, symbols a and b are amounts of hydrogen and oxygen vacancy, respectively, and represent numerical values in the following range: 0≤a≤1.0, 0≤b≤0.5).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a metal evaporation method, a metal recovery method, and a metal evaporation promoter. [Background technology]

[0002] Rare metals are widely used industrially due to their excellent stability, catalytic activity, etc. Furthermore, rare metals are expensive resources, and there is a high demand for their effective utilization.

[0003] For example, there is a great need for technology that can efficiently recover rare metals contained in waste materials that contain used rare metals.

[0004] Known techniques for recovering rare metals include a method for separating volatile carbonyls containing nickel carbonyl and / or cobalt carbonyl-containing compounds carbonylated with carbon monoxide (see, for example, Patent Document 1).

[0005] Also known is a hydrometallurgical method for recovering nickel and cobalt from nickel oxide ore by high pressure acid leaching (HPAL) using sulfuric acid (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2023-518880 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-350766 Summary of the Invention [Problem to be solved by the invention]

[0007] However, rare metal separation methods using carbonyl (CO) are difficult to handle from a safety standpoint due to the toxicity of CO. Furthermore, rare metal recovery methods using high-temperature pressure acid leaching raise concerns about high energy costs and the increase in CO2 emissions during energy production.

[0008] An object of the present invention is to provide a metal evaporation method that facilitates the recovery of rare metals. [Means for solving the problem]

[0009] In order to solve the above problems, the metal evaporation method according to the present invention involves heating a metal component containing a rare metal element and a perovskite-type composite oxide represented by the following formula (1) in the same vessel without contact, thereby evaporating at least a portion of the metal component.

[0010] formula: ABH a O 3-b (1) (In the formula, A is one or more elements selected from the group consisting of lanthanoid elements and elements of Group 2 of the periodic table, B is one or more elements selected from the group consisting of elements of Group 3 of the periodic table, elements of Group 4 of the periodic table, and transition metal elements of the fourth period of the periodic table, and the symbols a and b represent the amounts of hydrogen and oxygen vacancies and represent numerical values within the following ranges: 0≦a≦1.0, 0≦b≦0.5.) [Effects of the Invention]

[0011] According to the present disclosure, a metal evaporation method that makes it easy to recover rare metals can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example in which CoO powder is heated in the coexistence of perovskite-type composite oxide powder. [Figure 2] FIG. 1 is a diagram showing an example in which CoO powder is heated in the absence of perovskite-type composite oxide powder. [Figure 3] FIG. 1 is an X-ray diffraction pattern of CoO powder before heating. [Figure 4] This is an X-ray diffraction pattern of CoO powder after heating at 1000°C for 10 hours in the air in the presence of perovskite-type composite oxide powder. [Figure 5] This is an X-ray diffraction pattern of CoO powder after heating at 1000°C for 10 hours in the air without the coexistence of perovskite-type composite oxide powder. [Figure 6] 1 is a graph comparing the relationship between the firing temperature and weight change of CoO in the presence and absence of perovskite-type composite oxide powder. [Figure 7] FIG. 1 is a diagram showing an example in which NiO powder is heated in the coexistence of perovskite-type composite oxide powder. [Figure 8] FIG. 1 is a diagram showing an example in which NiO powder is heated in the absence of perovskite-type composite oxide powder. [Figure 9] FIG. 1 is an X-ray diffraction diagram of NiO powder before heating. [Figure 10] This is an X-ray diffraction pattern of NiO powder after heating in the air at 1000°C for 10 hours in the presence of perovskite-type composite oxide powder. [Figure 11] FIG. 1 is an X-ray diffraction pattern of NiO powder after heating at 1000°C for 10 hours in the air without the coexistence of perovskite-type composite oxide powder. [Figure 12] 1 is a graph comparing the relationship between the firing temperature and weight change of NiO in the presence and absence of perovskite-type composite oxide powder. [Figure 13] FIG. 1 is a diagram showing an example in which Fe2O3 powder is heated in the coexistence of perovskite-type composite oxide powder. [Figure 14] FIG. 1 is a diagram showing an example in which Fe2O3 powder is heated in the absence of perovskite-type composite oxide powder. [Figure 15] This is an X-ray diffraction diagram of Fe2O3 powder before heating. [Figure 16] This is an X-ray diffraction pattern of Fe2O3 powder after heating at 1000°C for 10 hours in the air in the presence of perovskite-type composite oxide powder. [Figure 17]This is an X-ray diffraction pattern of Fe2O3 powder after heating at 1000°C for 10 hours in the air without the coexistence of perovskite-type composite oxide powder. [Figure 18] 1 is a graph comparing the relationship between the calcination temperature and the weight change of Fe2O3 in the presence and absence of perovskite-type composite oxide powder. [Figure 19] 1 is a graph comparing the relationship between the firing temperature and the weight change of CoO, NiO, and Fe2O3 in the coexistence of perovskite-type composite oxide powder. [Figure 20] 1 is a graph comparing the relationship between the firing temperature and the weight change of CoO, NiO, and Fe2O3 in the absence of a perovskite-type composite oxide powder. [Figure 21] 1 is a graph comparing the relationship between the firing temperature and the weight change of perovskite-type composite oxide powder in the absence of a coexistent material, in the presence of CoO powder, in the presence of NiO powder, and in the presence of Fe2O3 powder.

[0013] Hereinafter, embodiments of the present invention will be described in detail.

[0014] <Metal evaporation method> The metal evaporation method of the present disclosure is a method for evaporating at least a portion of a metal component containing a rare metal element by heating the metal component containing a rare metal element and a perovskite-type composite oxide in a non-contact manner in the same container.

[0015] The rare metal is not particularly limited, and may be, for example, one or more rare elements selected from metals belonging to groups 6, 7, 8, 9, and 10 of the periodic table. These rare metals may be contained alone or in combination of two or more. Among these, the rare metal is preferably one or more elements selected from the group consisting of Co, Ni, Pd, and Pt, and more preferably Co and Ni.

[0016] A metal component containing a rare metal element indicates that the metal element contained in the metal component is a rare metal element. The metal component containing a rare metal element may be in any state, such as a rare metal element in part or in whole, an alloy containing the rare metal element, or a metal oxide containing the rare metal element.

[0017] For example, if the rare metal element is Co (cobalt) and the metal component is a metal oxide, the metal component containing the rare metal element is CoO (cobalt (II) oxide), Co2O3 (cobalt (III) oxide), or Co3O4 (cobalt (II, III) oxide). Also, if the rare metal element is Ni (nickel) and the metal component is a metal oxide, the metal component containing the rare metal element is NiO (nickel oxide). Furthermore, if the rare metal elements are Co and Ni and the metal component is a metal oxide, the metal component containing the rare metal element is a mixture of CoO (cobalt (II) oxide) and NiO (nickel oxide), or a composite oxide of Co and Ni (such as NiCo2O4).

[0018] The metal component containing the rare metal element is preferably in a solid phase, which allows it to be kept out of contact with the perovskite complex oxide.

[0019] Furthermore, the metal component containing a rare metal element is preferably in the form of a powder. The average particle size of the powder of the metal component is not particularly limited, but is, for example, 100 μm or more when the metal component is a simple metal or alloy, and 5 μm to 100 μm when the metal component is a metal oxide, preferably 10 μm to 80 μm, and more preferably 20 μm to 50 μm. Here, the average particle size is the median diameter d50 in the cumulative particle size distribution measured with a laser diffraction / scattering particle size distribution analyzer.

[0020] When the metal component is a metal oxide, if the average particle size of the powder of the metal component is 5 μm or more and 100 μm or less, the surface area of the metal component increases, making the metal component more likely to evaporate.

[0021] Perovskite complex oxides have a perovskite structure, which is represented by ABO3 and, in an ideal cubic system, is a three-dimensional structure in which the A site is located at the vertices of the cube, the B site is located at the center of the cube, and O is located at the face center.

[0022] The perovskite complex oxide is a perovskite complex oxide represented by the following composition formula (1). formula: ABH a O 3-b (1)

[0023] In formula (1), A is one or more elements selected from the group consisting of lanthanoid elements and elements of Group 2 of the periodic table.

[0024] Here, examples of lanthanoid elements include La, Ce, Pr, and Nd, with La being preferred. Examples of elements from Group 2 of the periodic table include Ca, Sr, and Ba, with Sr being preferred. The lanthanoid elements and elements from Group 2 of the periodic table can be used alone or in combination of two or more.

[0025] In formula (1), B is one or more elements selected from the group consisting of elements of Group 3 of the periodic table, elements of Group 4 of the periodic table, and transition metal elements of the fourth period of the periodic table.

[0026] Examples of elements in Group 3 of the periodic table include Sc and Y, with Sc being preferred. Examples of elements in Group 4 of the periodic table include Ti, Zr, and Hf. Examples of transition metal elements in the fourth period of the periodic table include Cr, Mn, Fe, Co, Ni, Cu, and Zn. The elements in Group 3 of the periodic table and the transition metal elements in the fourth period of the periodic table can be used alone or in combination of two or more.

[0027] In formula (1), the symbol a represents the amount of hydrogen, and the range of a is 0≦a≦1.0, preferably 0≦a≦0.5, and more preferably 0≦a≦0.3.

[0028] In formula (1), the symbol b represents the amount of oxygen vacancies, and the range of b is 0≦b≦0.5, preferably 0≦b≦0.25, and more preferably 0≦b≦0.15.

[0029] Specific examples of perovskite-type complex oxides include (La 0.7 Sr 0.2 Ba 0.1 )ScO 2.85 , Sr(Zr 0.9 Y 0.1 )O 2.95 , CaMnO3, etc.

[0030] The perovskite composite oxide preferably has a tolerance factor (t) defined by the following formula (2) in the range of 0.75 to 1.15, preferably in the range of 0.8 to 1.10, and more preferably in the range of 0.9 to 1.05. formula: t=(r A +r O ) / (2 1 / 2 ·(r B +r O )) (2)

[0031] In formula (2), r A is the arithmetic mean of the ionic radii of the cations at the A site in the above composition formula (1), i.e., A. B is the arithmetic mean of the ionic radii of the B site cations in the composition formula (1), i.e., B. O is an oxide ion (O 2- ) is the ionic radius of the O is 1.40 Å.

[0032] Here, the tolerance factor (t) indicates the degree of distortion in the crystal structure of a perovskite complex oxide. A tolerance factor of 1 is considered to be an ideal perovskite structure (cubic crystal system).

[0033] A tolerance factor greater than 1 means that the size of the A-site cations is too large relative to the size of the B-site cations, resulting in a distorted perovskite structure. Conversely, a tolerance factor less than 1 means that the size of the B-site cations is too large relative to the size of the A-site cations, resulting in a distorted perovskite structure.

[0034] The tolerance factor may be calculated from the ionic radius of each ion using the above-mentioned formula, based on a paper describing the size of the ionic radius (RD Shannon, Acta Cryst., A32, 751 (1976)).

[0035] The composite oxide represented by the above composition formula (1) is a known substance disclosed in K. Nomura et al., J. Mater. Res., 22, 2647 (2007), and can be obtained by known methods such as solid-state reaction and coprecipitation, for example, as described in Experimental Chemistry Lectures, 4th Edition, Vol. 16, Inorganic Compounds, edited by the Chemical Society of Japan, Maruzen, 1993. For example, in the solid-state reaction method, compounds containing the metal elements represented by the above composition formula, such as oxides, carbonates, and organic compounds, are used as starting materials, mixed to achieve a metal element ratio similar to that of the target oxide, and calcined to obtain the desired perovskite-type composite oxide. The specific calcination temperature and calcination time are not particularly limited, as long as they are conditions under which the desired composite oxide is formed. For example, calcination at a temperature of approximately 1200 to 1500°C for approximately 10 to 40 hours is sufficient. When carbonates, organic compounds, or the like are used as raw materials, it is preferable to calcinate the raw materials before calcining to decompose them, and then calcinate them to form the desired composite oxide. For example, when carbonates are used as raw materials, calcination can be performed at approximately 1000 to 1200°C for approximately 10 hours, followed by calcination under the above-mentioned conditions. The calcination method is not particularly limited, and any method such as an electric heating furnace or a gas heating furnace can be used. The calcination atmosphere is usually an oxidizing atmosphere such as an oxygen stream or air, but if the raw materials contain a sufficient amount of oxygen, it is also possible to calcinate in an inert atmosphere, for example.

[0036] The perovskite complex oxide is preferably in a solid phase state, which allows it to be kept out of contact with metal components including rare metal elements.

[0037] The perovskite complex oxide is preferably in the form of a powder. The average particle size of the perovskite complex oxide powder is not particularly limited, but is, for example, 5 μm to 100 μm, preferably 10 μm to 80 μm, and more preferably 20 μm to 50 μm. Here, the average particle size is the median diameter d50 in the cumulative particle size distribution measured with a laser diffraction / scattering particle size distribution analyzer.

[0038] When the average particle size of the perovskite complex oxide is 5 μm or more and 100 μm or less, the surface area of the perovskite complex oxide increases, and the vapor of the metal component vaporized from the metal component containing the rare metal element easily comes into contact with the surface of the perovskite complex oxide, thereby increasing the vapor pressure of the metal component and facilitating evaporation.

[0039] Heating in the same container means heating the metal component containing the rare metal element and the perovskite complex oxide in the same space. The shape and volume of the container are not limited as long as it has a space in which the metal component containing the rare metal element and the perovskite complex oxide can be placed without contacting each other.

[0040] The container is preferably made of a ceramic such as alumina from the viewpoint of fire resistance and chemical stability when heating the metal component containing the rare metal element and the perovskite complex oxide.Furthermore, the container is preferably a container with a lid and an open top from the viewpoint of placing the metal component containing the rare metal element and the perovskite complex oxide therein.

[0041] The non-contact state means that the metal component containing the rare metal element and the perovskite complex oxide are placed in a container with an arbitrary distance therebetween.

[0042] Figure 1 shows an example of heating CoO powder in the presence of perovskite-type composite oxide powder in the atmosphere. In this example, powder of CoO, a metal component containing rare metal elements, and powder of LSBS ((La)) as a perovskite-type composite oxide were used. 0.7 Sr 0.2 Ba 0.1 )ScO 2.85 ) powder is placed in the container 1 without contacting with the NiO powder. FIG. 7 shows an example in which NiO powder is heated in the atmosphere in the presence of perovskite-type composite oxide powder. In this example, NiO powder, which is a metal component containing rare metal elements, and LSBS powder, which is a perovskite-type composite oxide, are placed in the container 1 without contacting with each other.

[0043] The heating temperature is not particularly limited and is, for example, 700 to 1600°C, preferably 800 to 1500°C, and more preferably 900 to 1400°C.

[0044] The heating time is not particularly limited and is, for example, 2 to 30 hours, preferably 5 to 20 hours, and more preferably 7 to 15 hours.

[0045] The evaporation of the metal component refers to the vaporization or sublimation of the metal component from the metal component containing the rare metal element by heating.

[0046] The metal component containing the rare metal element to be evaporated may be in any state, such as a simple rare metal, an alloy containing the rare metal element, or a metal oxide containing the rare metal element.

[0047] In the metal evaporation method of the present disclosure, the evaporation rate of the metal component containing the rare metal element can be controlled by heating the metal component containing the rare metal element and the perovskite complex oxide in a non-contact manner in the same container, which makes it easy to recover the rare metal.

[0048] Furthermore, the metal evaporation method of the present disclosure involves simply heating a metal component containing a rare metal element and a perovskite-type composite oxide in the same vessel without contact, thereby reducing energy costs. Furthermore, the metal evaporation method of the present disclosure does not use CO, allowing for safe recovery of rare metals.

[0049] Furthermore, in the metal evaporation method of the present disclosure, since the perovskite complex oxide used is the perovskite complex oxide represented by the above composition formula (1), the evaporation rate of the metal component containing the rare metal element can be controlled with high precision.

[0050] In the metal evaporation method of the present disclosure, the evaporation rate of the metal component containing a rare metal element can be controlled even when the metal component containing a rare metal element and the perovskite complex oxide are heated in the atmosphere, which eliminates the need for large-scale equipment such as a pressurizing device and reduces the cost of evaporating and recovering the metal component containing a rare metal element.

[0051] In the metal evaporation method of the present disclosure, the tolerance factor (t) of the perovskite complex oxide used is in the range of 0.75 to 1.15, so that the evaporation rate of metal components including rare metal elements can be controlled with even higher precision.

[0052] In the metal evaporation method of the present disclosure, the metal components to be evaporated include one or more rare metal elements selected from the group consisting of Co, Ni, Pd, and Pt, making it easy to recover these rare metals, and therefore, high-value-added metals can be reused efficiently at low cost using a simple method.

[0053] <Metal recovery method> The metal recovery method of the present disclosure is a method for recovering a metal component evaporated by the metal evaporation method of the present disclosure described above. That is, in the metal recovery method of the present disclosure, a metal component containing a rare metal element and a perovskite-type composite oxide represented by the above formula (1) are heated in a non-contact manner in the same container, thereby recovering the evaporated metal component containing the rare metal element.

[0054] Any means may be used to recover the metal components. For example, a duct may be connected in advance to a container from which the metal components have evaporated, and the evaporated metal components may be recovered through the duct by reducing the pressure inside the container.

[0055] In the metal recovery method of the present disclosure, by recovering the metal components evaporated by the metal evaporation method of the present disclosure, the evaporation rate of the metal components containing the rare metal elements to be recovered can be controlled, making it easy to recover rare metals.

[0056] Furthermore, the metal recovery method of the present disclosure involves simply heating a metal component containing a rare metal element and a perovskite-type composite oxide in the same vessel without contact, thereby reducing energy costs. Furthermore, the metal recovery method of the present disclosure does not use CO, so rare metals can be recovered safely.

[0057] In the metal recovery method of the present disclosure, the rare metal elements are two or more elements selected from the group consisting of Co, Ni, Pd, and Pt, and a metal component containing two or more elements is separated and recovered for each element. For example, if the rare metal elements contained in the metal component are Co and Ni, Co and Ni can be separated and recovered.

[0058] Specifically, when metal components containing Co and Ni are heated to 1100°C or higher and 1300°C or lower without contact with a perovskite-type composite oxide, the metal components containing Co evaporate first, and then when heated to 1400°C or higher and 1500°C or lower, the metal components containing Ni evaporate. Therefore, the Co and Ni components can be recovered separately over time.

[0059] In addition, in the metal recovery method of the present disclosure, the metal component containing a rare metal element contains Fe, and the metal component containing the rare metal element is recovered by separating it from Fe. For example, if the rare metal element contained in the metal component is Co and the metal component containing a rare metal element further contains Fe, Co can be recovered by separating it from Fe.

[0060] Specifically, when a metal component containing Fe and Co is heated without contact with a perovskite-type composite oxide, the Co component evaporates, but the Fe component hardly evaporates, making it possible to recover only the Co component from the metal component containing Fe and Co.

[0061] <Metal evaporation accelerator> The metal evaporation promoter of the present disclosure contains a perovskite-type composite oxide and is heated together with a metal component containing a rare metal element in the same container without contact, thereby promoting the evaporation of the metal component containing the rare metal element.

[0062] That is, the metal evaporation promoter of the present disclosure contains the perovskite-type composite oxide used in the metal recovery method of the present disclosure described above.

[0063] Specifically, the perovskite complex oxide contained in the metal evaporation promoting material of the present disclosure is a perovskite complex oxide represented by the above composition formula (1).

[0064] Furthermore, the perovskite composite oxide preferably has a tolerance factor (t) defined by the above formula (2) in the range of 0.75 to 1.15, preferably in the range of 0.8 to 1.10, and more preferably in the range of 0.9 to 1.05.

[0065] The rare metal contained in the metal component whose evaporation is promoted by the metal evaporation promoting material of the present disclosure may be the rare metal that is the target of evaporation by the metal evaporation method of the present disclosure described above.

[0066] That is, the rare metal is not particularly limited, but is, for example, one or more rare elements selected from metals belonging to groups 6, 7, 8, 9, and 10 of the periodic table. These rare metals may be contained alone or in combination of two or more. Among these, the rare metal is preferably one or more elements selected from the group consisting of Co, Ni, Pd, and Pt, and more preferably Co and Ni.

[0067] The metal evaporation promoter of the present disclosure contains the perovskite-type composite oxide used in the metal evaporation method of the present disclosure, and therefore can control the evaporation rate of metal components including rare metal elements, making it easier to recover rare metals.

[0068] Furthermore, since the metal evaporation promoter of the present disclosure is simply heated together with the metal oxide containing the rare metal element in the same container without contact, the energy cost for recovering the rare metal can be reduced. Furthermore, by using the metal evaporation promoter of the present disclosure, rare metals can be recovered without using CO, so that rare metals can be recovered safely.

[0069] Furthermore, in the metal evaporation promoter of the present disclosure, the perovskite complex oxide used is the perovskite complex oxide represented by the above composition formula (1), so that the evaporation rate of the metal component containing the rare metal element can be controlled with high precision.

[0070] In the metal evaporation promoter of the present disclosure, the tolerance factor (t) of the perovskite complex oxide used is in the range of 0.75 to 1.15, so that the evaporation rate of metal components including rare metal elements can be controlled with even higher precision.

[0071] In the metal evaporation promoter of the present disclosure, the rare metals contained in the metal components whose evaporation is promoted include one or more rare metal elements selected from the group consisting of Co, Ni, Pd, and Pt, making it easy to recover these rare metals, and therefore high-value-added metals can be reused efficiently at low cost using a simple method. [Example]

[0072] The present invention will be explained in more detail below by way of experimental examples.

[0073] [Experimental Example 1] As shown in Figure 1, powder of CoO (Sigma-Aldrich) was used as a metal component containing rare metal elements, and perovskite-type complex oxide LSBS ((La 0.7 Sr 0.2 Ba 0.1 )ScO 2.85 ) (tolerance factor 0.924) powder (Kyoritsu Material Co., Ltd.) was placed in an alumina container 1 (rectangular, volume: approximately 15 cm) without contact with the powder. 3 ), the container was covered with an alumina container 1 of the same size, and heated in the air at 1000 to 1400° C. for 10 hours.

[0074] Figure 3 is an X-ray diffraction pattern of CoO powder before heating, and Figure 4 is an X-ray diffraction pattern of CoO powder after heating in air at 1000°C for 10 hours in the presence of powder of the perovskite-type complex oxide LSBS. Rietveld analysis of the X-ray diffraction pattern in Figure 3 confirmed the presence of CoO, as well as trace amounts of Co and Co3O4, before heating. Rietveld analysis of the X-ray diffraction pattern in Figure 4 confirmed the presence of Co3O4 and trace amounts of CoO after heating.

[0075] The weight change of CoO before and after heating in the presence of powder of the perovskite-type complex oxide LSBS was measured, and the results are shown in Figures 6 and 19.

[0076] In addition, the oxidation state of cobalt in cobalt oxide changes from 0 to +2 to +3 depending on the temperature and oxygen concentration during the manufacturing process, so metal Co and three types of oxides (CoO(II), Co2O3(III), Co3O4(II, III)) can exist in cobalt oxide. Therefore, the following method was used to accurately evaluate the weight change of cobalt oxide.

[0077] (1) The CoO reagent was weighed using an electronic balance in air at room temperature before and after calcination, and powder X-ray diffraction measurements and Rietveld analysis were performed under the same conditions to determine the type and proportion (mol%) of metallic Co and cobalt oxide contained in the reagent.

[0078] (2) The reference weight values before and after calcination were calculated using the following formula from the molar percentages of metallic Co, CoO(II), Co2O3(III), and Co3O4(II,III) contained in the reagent before and after calcination. Reference value for weight = Co formula weight (g / mol) × Co mol% + CoO formula weight (g / mol) × CoO mol% + Co2O3 formula weight (g / mol) × Co2O3 mol% ÷ 2 + Co3O4 formula weight (g / mol) × Co3O4 mol% ÷ 3 = 58.93 × Co mol% + (58.93 + 16.00) × CoO mol% + (58.93 × 2 + 16.00 × 3) × Co2O3 mol% ÷ 2 + (58.93 × 3 + 16.00 × 4) × Co3O4 mol% ÷ 3

[0079] (Example of standard value for pre-baking weight) 58.93×0.0083+(58.93+16.00)×0.9748+(58.93×2+16.00×3)×0÷2+(58.93×3+16.00×4)×0.0169÷3=74.8873

[0080] Example of standard weight after firing) After firing at 1000°C in air, with LSBS: 58.93×0+(58.93+16.00)×0.3311+(58.93×2+16.00×3)×0÷2+(58.93×3+16.00×4)×0.6689÷3=78.4975

[0081] (3) The percentage of weight change due to the change in the oxidation state of Co due to firing can be evaluated from the reference values of the weight before firing and the weight after firing. In the above example, the change in the oxidation state of Co is predicted to result in a weight increase of 4.82% based on the following formula: (Standard weight after firing - Standard weight before firing) ÷ (Standard weight before firing) × 100 = (78.4975 - 74.8873) ÷ 74.8873 × 100 = 4.82%

[0082] (4) The net weight change before and after firing (e.g., 4.29 - 4.82 = -0.53%) can be calculated using the actual weight change measured using an electronic balance (e.g., (1.0435 g - 1.0006 g) ÷ (1.0006 g) × 100 = 4.3%) and the predicted weight change due to the change in the oxidation state of Co in (3) above (4.82%).

[0083] [Experimental Example 2] As shown in FIG. 2, only CoO powder was placed in a container 1 as a metal component containing a rare metal element, and the rest was heated in the same manner as in Experimental Example 1.

[0084] Figure 3 is an X-ray diffraction pattern of the CoO powder before heating, and Figure 5 is an X-ray diffraction pattern of the CoO powder after heating at 1000°C for 10 hours in air without the coexistence of perovskite-type composite oxide powder. Rietveld analysis of the X-ray diffraction pattern in Figure 3 confirmed the presence of CoO and trace amounts of Co and Co3O4 before heating. Rietveld analysis of the X-ray diffraction pattern in Figure 5 confirmed the presence of Co3O4 and trace amounts of CoO after heating.

[0085] The weight change of CoO was confirmed before and after heating for 10 hours at 1000 to 1400°C in the air without the coexistence of perovskite-type composite oxide powder. The results are shown in Figures 6 and 20.

[0086] The weight change before and after heating of the perovskite complex oxide LSBS in the presence of CoO was examined using the same method as in Experimental Example 1. The weight change before and after heating of the perovskite complex oxide LSBS in the absence of CoO was also examined using the same method as in Experimental Example 2. The results are shown in Figure 21.

[0087] 21, it was confirmed that at 1000°C, the weight loss in the presence and absence of CoO was almost the same, but at 1100 to 1400°C, the weight loss in the presence of CoO was greater than the weight loss in the absence of CoO. These weight losses are presumed to be due to the evaporation of water and Ba contained in LSBS, suggesting that CoO is not absorbed into LSBS.

[0088] [Experimental Example 3] As shown in Figure 7, NiO powder (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in container 1 instead of CoO as a metal component containing a rare metal element, and heated in the air at 1000 to 1500°C for 10 hours, except that the other conditions were the same as in Experimental Example 1.

[0089] Figure 9 is an X-ray diffraction pattern of the NiO powder before heating, and Figure 10 is an X-ray diffraction pattern of the NiO powder after heating at 1000°C for 10 hours in air without the coexistence of perovskite-type composite oxide powder. Figures 9 and 10 confirm peaks indicating the presence of NiO before and after heating.

[0090] The weight change of NiO before and after heating in the air at 900 to 1500°C for 10 hours in the presence of perovskite-type composite oxide powder was confirmed. The results are shown in Figures 12 and 19.

[0091] [Experimental Example 4] As shown in FIG. 8, only NiO powder was placed in a container 1 as a metal component containing a rare metal element, and the rest was heated in the same manner as in Experimental Example 3.

[0092] Figure 9 is an X-ray diffraction pattern of the NiO powder before heating, and Figure 11 is an X-ray diffraction pattern of the NiO powder after heating at 1000°C for 10 hours in the air without the coexistence of perovskite-type composite oxide powder. Figures 9 and 11 confirm peaks indicating the presence of NiO before and after heating.

[0093] The weight change of NiO was measured before and after heating in air at 1000°C for 10 hours in the absence of perovskite-type composite oxide powder. The results are shown in Figures 12 and 20.

[0094] The weight change before and after heating of the perovskite complex oxide LSBS in the presence of NiO was examined using the same method as in Experimental Example 1. The weight change before and after heating of the perovskite complex oxide LSBS in the absence of NiO was also examined using the same method as in Experimental Example 2. The results are shown in Figure 21.

[0095] 21, it was confirmed that at 900°C, the weight loss in the presence and absence of NiO was almost the same, but at 1000 to 1500°C, the weight loss in the presence of NiO was greater than the weight loss in the absence of NiO. These weight losses are presumed to be due to the evaporation of water and Ba contained in LSBS, suggesting that NiO is not absorbed into LSBS.

[0096] [Experimental Example 5] As shown in FIG. 13, Fe2O3 powder (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in container 1 instead of CoO as a metal component containing a rare metal element, and heated at 900 to 1300°C, except that the heating was carried out in the same manner as in Experimental Example 1.

[0097] Figure 15 is an X-ray diffraction pattern of Fe2O3 powder before heating, and Figure 16 is an X-ray diffraction pattern of Fe2O3 powder after heating in air at 1000°C for 10 hours in the presence of perovskite-type composite oxide powder. Figures 15 and 16 confirm peaks indicating the presence of Fe2O3 before and after heating.

[0098] The weight change of Fe2O3 before and after heating in air at 1000°C for 10 hours in the presence of perovskite-type composite oxide powder was confirmed. The results are shown in Figures 18 and 19.

[0099] [Experimental Example 6] As shown in FIG. 14, only Fe2O3 powder was placed in the container 1 as the metal component containing the rare metal element, and the rest was heated in the same manner as in Experimental Example 5.

[0100] Figure 15 is an X-ray diffraction pattern of NiO powder before heating, and Figure 17 is an X-ray diffraction pattern of Fe2O3 powder after heating at 1000°C for 10 hours in air without the coexistence of perovskite-type composite oxide powder. Figures 15 and 17 confirm peaks indicating the presence of Fe2O3 before and after heating.

[0101] The weight change of Fe2O3 was confirmed before and after heating for 10 hours at 900-1500°C in the air without the coexistence of perovskite-type composite oxide powder. The results are shown in Figures 18 and 20.

[0102] The weight change before and after heating of the perovskite-type composite oxide LSBS in the presence of Fe2O3 was investigated using the same method as in Experimental Example 1. Furthermore, the weight change before and after heating of the perovskite-type composite oxide LSBS in the absence of Fe2O3 was investigated using the same method as in Experimental Example 2. The results are shown in Figure 21.

[0103] From Figure 21, it was confirmed that the weight loss in the presence and absence of Fe2O3 was almost the same between 900 and 1000°C, but the weight loss in the presence of Fe2O3 was greater than the weight loss in the absence of Fe2O3 between 1100 and 1500°C. These weight losses are presumed to be due to the evaporation of water and Ba contained in LSBS, suggesting that Fe2O3 is not absorbed by LSBS.

[0104] From FIG. 6, it was found that in the temperature range of 1100 to 1300°C, the amount of CoO evaporated (volatilized) increased by 1.1 to 1.8 times in the presence of perovskite-type composite oxide powder compared to the case in which perovskite-type composite oxide powder was not present.

[0105] Furthermore, from FIG. 12, it was found that the amount of NiO evaporated (volatilized) in the temperature range of 1000 to 1500°C increases by several to several tens of times in the presence of perovskite-type composite oxide powder compared to the case in which perovskite-type composite oxide powder is not present.

[0106] Furthermore, it was found from FIG. 18 that the amount of Fe2O3 evaporated (volatilized) did not change even when heated at 900 to 1300°C, regardless of whether perovskite-type composite oxide powder was present or not.

[0107] Furthermore, Figure 19 shows that in the presence of perovskite-type composite oxide powder, the evaporation amounts of CoO, NiO, and Fe2O3 vary depending on the heating temperature, and CoO and NiO can be separated and recovered from Fe2O3, and further CoO and NiO can be separated and recovered.

[0108] Furthermore, it was found from FIG. 20 that in the absence of perovskite-type composite oxide powder, CoO could be separated from Fe2O3 and recovered, but NiO could not be separated from CoO and Fe2O3 and recovered.

[0109] These results indicate that by using the metal evaporation method, metal recovery method, or metal evaporation promoter of the present disclosure, it is possible to selectively recover CoO and NiO from, for example, secondary battery materials, fuel cell materials, catalyst materials, and magnet materials containing CoO, NiO, and Fe2O3.

[0110] Preferred embodiments of the present invention will be described below.

[0111] (Appendix 1) A metal evaporation method comprising heating a metal component containing a rare metal element and a perovskite-type composite oxide represented by the following formula (1) in the same vessel without contact, thereby evaporating at least a portion of the metal component: formula: ABH a O 3-b (1) (In the formula, A is one or more elements selected from the group consisting of lanthanoid elements and elements of Group 2 of the periodic table, B is one or more elements selected from the group consisting of elements of Group 3 of the periodic table, elements of Group 4 of the periodic table, and transition metal elements of the fourth period of the periodic table, and the symbols a and b represent the amounts of hydrogen and oxygen vacancies and represent numerical values within the following ranges: 0≦a≦1.0, 0≦b≦0.5.)

[0112] (Appendix 2) 2. The metal evaporation method according to claim 1, wherein the metal component and the perovskite complex oxide are heated in the atmosphere.

[0113] (Appendix 3) 3. The metal evaporation method according to claim 1, wherein the perovskite complex oxide has a tolerance factor (t) defined by the following formula (2) in the range of 0.75 to 1.15: formula: t=(r A +r O ) / (2 1 / 2 ·(r B +r O )) (2) (In the formula, r A is the arithmetic mean of the ionic radii of A, r B is the arithmetic mean of the ionic radii of B, r Ois an oxide ion (O 2- ) is the ionic radius of

[0114] (Appendix 4) 4. The metal evaporation method according to any one of claims 1 to 3, wherein the rare metal element is one or more elements selected from the group consisting of Co, Ni, Pd, and Pt.

[0115] (Appendix 5) A metal recovery method, comprising recovering the metal component evaporated by the metal evaporation method according to any one of appendices 1 to 4.

[0116] (Appendix 6) the rare metal elements are two or more elements selected from the group consisting of Co, Ni, Pd, and Pt, 6. The metal recovery method according to claim 5, wherein the metal component containing the two or more elements is separated and recovered by element.

[0117] (Appendix 7) the metal component includes Fe, 7. The metal recovery method according to claim 5, wherein the metal component is separated from the Fe and recovered.

[0118] (Appendix 8) 8. The metal recovery method according to any one of Appendices 5 to 7, wherein the metal component containing Co and Ni as the rare metal elements is heated at 1100°C or higher and 1300°C or lower to evaporate the metal component containing Co, and then heated at 1400°C or higher and 1500°C or lower to evaporate the metal component containing Ni, thereby separating and recovering Co and Ni.

[0119] (Appendix 9) It contains a perovskite-type composite oxide represented by the following formula (1): A metal evaporation promoter that promotes evaporation of a metal component containing a rare metal element by being heated together with the metal component without contacting the metal component in the same container. formula: ABH a O 3-b (1) (In the formula, A is one or more elements selected from the group consisting of lanthanoid elements and elements of Group 2 of the periodic table, B is one or more elements selected from the group consisting of elements of Group 3 of the periodic table, elements of Group 4 of the periodic table, and transition metal elements of the fourth period of the periodic table, and the symbols a and b represent the amounts of hydrogen and oxygen vacancies and represent numerical values within the following ranges: 0≦a≦1.0, 0≦b≦0.5.)

[0120] (Appendix 10) 10. The metal evaporation-promoting material according to claim 9, wherein the perovskite complex oxide has a tolerance factor (t) defined by the following formula (2) in the range of 0.75 to 1.15: formula: t=(r A +r O ) / (2 1 / 2 ·(r B +r O )) (2) (In the formula, r A is the arithmetic mean of the ionic radii of A, r B is the arithmetic mean of the ionic radii of B, r O is an oxide ion (O 2- ) is the ionic radius of

[0121] (Appendix 11) 11. The metal evaporation promoter according to claim 9, wherein the rare metal element is one or more elements selected from the group consisting of Co, Ni, Pd, and Pt.

[0122] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0123] 1 container

Claims

1. A metal evaporation method comprising heating a metal component containing a rare metal element and a perovskite-type composite oxide represented by the following formula (1) in the same vessel without contact, thereby evaporating at least a portion of the metal component: formula: ABH ａ O ３－ｂ (1) (In the formula, A is one or more elements selected from the group consisting of lanthanoid elements and elements of Group 2 of the Periodic Table, B is one or more elements selected from the group consisting of elements of Group 3 of the Periodic Table, elements of Group 4 of the Periodic Table, and transition metal elements of the Fourth Period of the Periodic Table, and the symbols a and b represent the amounts of hydrogen and oxygen vacancies and represent numerical values within the following ranges: 0≦a≦1.0, 0≦b≦0.5.)

2. 2. The metal evaporation method according to claim 1, wherein the metal component and the perovskite complex oxide are heated in the atmosphere.

3. 2. The metal evaporation method according to claim 1, wherein the perovskite complex oxide has a tolerance factor (t) defined by the following formula (2) in the range of 0.75 to 1.15: formula: t=(r Ａ +r Ｏ ) / (2 １／２ ・(r Ｂ +r Ｏ )) (2) (In the formula, r Ａ is the arithmetic mean of the ionic radii of A, r Ｂ is the arithmetic mean of the ionic radii of B, r Ｏ is an oxide ion (O ２－ ) is the ionic radius of

4. 2. The metal evaporation method according to claim 1, wherein the rare metal element is one or more elements selected from the group consisting of Co, Ni, Pd, and Pt.

5. A metal recovery method, comprising recovering the metal component evaporated by the metal evaporation method according to claim 1 .

6. the rare metal element is two or more elements selected from the group consisting of Co, Ni, Pd, and Pt, The metal recovery method according to claim 5 , wherein the metal component containing the two or more elements is separated and recovered for each element.

7. the metal component includes Fe, The metal recovery method according to claim 5 , wherein the metal components are recovered by separating them from the Fe.

8. 6. The metal recovery method according to claim 5, wherein the metal component containing Co and Ni as the rare metal elements is heated at 1100°C or higher and 1300°C or lower to evaporate the metal component containing Co, and then heated at 1400°C or higher and 1500°C or lower to evaporate the metal component containing Ni, thereby separating and recovering Co and Ni.

9. It contains a perovskite complex oxide represented by the following formula (1): A metal evaporation promoter that promotes evaporation of a metal component containing a rare metal element by being heated together with the metal component without contacting the metal component in the same container. formula: ABH ａ O ３－ｂ (1) (In the formula, A is one or more elements selected from the group consisting of lanthanoid elements and elements of Group 2 of the Periodic Table, B is one or more elements selected from the group consisting of elements of Group 3 of the Periodic Table, elements of Group 4 of the Periodic Table, and transition metal elements of the Fourth Period of the Periodic Table, and the symbols a and b represent the amounts of hydrogen and oxygen vacancies and represent numerical values within the following ranges: 0≦a≦1.0, 0≦b≦0.5.)

10. 10. The metal evaporation promoter according to claim 9, wherein the perovskite complex oxide has a tolerance factor (t) defined by the following formula (2) in the range of 0.75 to 1.15: formula: t=(r Ａ +r Ｏ ) / (2 １／２ ・(r Ｂ +r Ｏ )) (2) (In the formula, r Ａ is the arithmetic mean of the ionic radii of A, r Ｂ is the arithmetic mean of the ionic radii of B, r Ｏ is an oxide ion (O ２－ ) is the ionic radius of

11. 11. The metal evaporation promoter according to claim 9, wherein the rare metal element is at least one element selected from the group consisting of Co, Ni, Pd, and Pt.

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