High-purity metallic barium

Abstract

This invention provides high-purity metallic barium in which the content of the impurity Zn (zinc) has been reduced. [Solution] Metallic barium having a zinc (Zn) content of 3 wt ppm or less.

Description

Technical Field

[0001] The present invention relates to high-purity metallic barium.

Background Art

[0002] With the advancement of electronic device products, there has been an increasing demand for higher purity of high-purity metals used as raw materials. In ceramic capacitor products, metallic barium is used as a raw material.

[0003] Patent Document 1 discloses in an example that metallic calcium and metallic strontium were produced by an apparatus having a specific configuration. However, Patent Document 1 does not disclose the production of high-purity metallic barium.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] So far, although high-purity metallic barium has been desired, it has not been provided.

[0006] And according to the study by the present inventor, if Zn (zinc) is mixed in high-purity metallic barium at a certain level or more as an impurity metal element, ZnO may be generated due to this Zn in subsequent processing. Since ZnO has a lower Pockels coefficient than barium titanate (BTO), it affects the characteristics of electro-optic elements using BTO. Thus, ZnO is very undesirable as an impurity in electro-optic devices. Therefore, it is not only desired that metallic barium be of high purity, but also desired to reduce the content of Zn (zinc).

[0007] Therefore, an object of the present invention is to provide high-purity metallic barium in which the content of the impurity element Zn (zinc) is reduced. [Means for solving the problem]

[0008] The inventors of this invention, through diligent research and development, have achieved the production of high-purity metallic barium, as described below, and have arrived at the present invention.

[0009] Therefore, the present invention includes (1) the following: (1) Metallic barium with a Zn content of 3 wt ppm or less. [Effects of the Invention]

[0010] This invention provides high-purity metallic barium in which the content of the impurity Zn (zinc) is reduced. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is an explanatory diagram of the structure of the heating furnace used for sublimation purification. [Figure 2] Figure 2 is a graph showing the results of a heating test to determine the temperature of each part inside the inner tube located within the cylindrical tubular structure of the heating furnace used for sublimation purification. [Modes for carrying out the invention]

[0012] The present invention will be described in detail below with reference to specific embodiments. The present invention is not limited to the specific embodiments disclosed below.

[0013] [High-purity metallic barium] This invention relates to metallic barium having a Zn content of 3 wt ppm or less.

[0014] The high-purity metallic barium of the present invention minimizes the formation of ZnO due to its reduced Zn content. ZnO has a lower Pockels coefficient than barium titanate (BTO), which affects the properties of electro-optic elements using BTO. Thus, ZnO is a highly undesirable impurity in electro-optic devices. Therefore, the high-purity metallic barium of the present invention is particularly excellent as a raw material for optoelectronic devices.

[0015] [purity] In a preferred embodiment, the purity of the high-purity metallic barium of the present invention can be, for example, 99 wt% or more, preferably 99.0 wt% or more, preferably 99.1 wt% or more, preferably 99.2 wt% or more, preferably 99.3 wt% or more, preferably 99.4 wt% or more, preferably 99.5 wt% or more, preferably 99.6 wt% or more, preferably 99.7 wt% or more, preferably 99.8 wt% or more, preferably 99.80 wt% or more, preferably 99.81 wt% or more, preferably 99.82 wt% or more, preferably 99.83 wt% or more, and preferably 99.84 wt% or more. The purity of the high-purity metallic barium can be calculated by the means described later in the examples.

[0016] In a preferred embodiment, the purity of the high-purity metallic barium of the present invention can be specified by the purity calculated by setting the value excluding Ca (calcium) and Sr (strontium) to 100 wt%. The purity of the high-purity metallic barium of the present invention, calculated by excluding Ca (calcium) and Sr (strontium), is, for example, 99.9 wt% or higher, preferably 99.90 wt% or higher, preferably 99.91 wt% or higher, preferably 99.92 wt% or higher, preferably 99.93 wt% or higher, preferably 99.94 wt% or higher, preferably 99.95 wt% or higher, preferably 99.96 wt% or higher, preferably 99 It can be 0.97 wt% or more, preferably 99.98 wt% or more, preferably 99.980 wt% or more, preferably 99.981 wt% or more, preferably 99.982 wt% or more, preferably 99.983 wt% or more, preferably 99.984 wt% or more, preferably 99.985 wt% or more, preferably 99.986 wt% or more, preferably 99.987 wt% or more, preferably 99.988 wt% or more.

[0017] [Zn content] In a preferred embodiment, the Zn content (zinc content) of the high-purity metallic barium of the present invention can be, for example, 3 wtppm or less, preferably 2 wtppm or less, preferably 1 wtppm or less, preferably 0.9 wtppm or less, preferably 0.8 wtppm or less, preferably 0.7 wtppm or less, preferably 0.6 wtppm or less, preferably 0.5 wtppm or less, preferably 0.4 wtppm or less, preferably 0.3 wtppm or less, preferably 0.2 wtppm or less, preferably 0.1 wtppm or less, and preferably less than 0.1 wtppm.

[0018] [Impurity element content] In a preferred embodiment, the high-purity metallic barium of the present invention may contain the following impurity elements, each of which is expressed in wtppm unless otherwise specified.

[0019] Li content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0020] Be content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0021] B content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0022] F content: for example, 6 wtppm or less, preferably 3 wtppm or less, preferably 2 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.46 wtppm or less;

[0023] Na content: for example, 5 wtppm or less, preferably 3 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.3 wtppm or less, preferably 0.2 wtppm or less, preferably 0.14 wtppm or less;

[0024] Mg content: for example, 2 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.4 wtppm or less, preferably 0.3 wtppm or less, preferably 0.2 wtppm or less;

[0025] Al content: for example, 6 wtppm or less, preferably 3 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.3 wtppm or less, preferably 0.27 wtppm or less;

[0026] Si content: for example, 9 wtppm or less, preferably 5 wtppm or less, preferably 4 wtppm or less, preferably 3 wtppm or less, preferably 2 wtppm or less, preferably 1.5 wtppm or less, preferably 1.2 wtppm or less;

[0027] P content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0028] S content: For example, 30 wtppm or less, preferably 20 wtppm or less, preferably 10 wtppm or less, preferably 5 wtppm or less, preferably 3 wtppm or less, preferably 2 wtppm or less, preferably 1.5 wtppm or less;

[0029] Cl content: for example, 200 wtppm or less, preferably 150 wtppm or less, preferably 110 wtppm or less;

[0030] Ca content: for example, 4000 wtppm or less, preferably 3000 wtppm or less, preferably 2000 wtppm or less, preferably 1900 wtppm or less, preferably 1500 wtppm or less, preferably 1200 wtppm or less;

[0031] Sc content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0032] Ti content: for example, 20 wtppm or less, preferably 10 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.49 wtppm or less;

[0033] V content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0034] Cr content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0035] Mn content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.2 wtppm or less, preferably 0.1 wtppm or less, preferably 0.07 wtppm or less;

[0036] Fe content: for example, 3 wtppm or less, preferably 2 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.4 wtppm or less, preferably 0.3 wtppm or less, preferably 0.26 wtppm or less, preferably 0.05 wtppm or less, preferably 0.02 wtppm or less;

[0037] Co content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0038] Ni content: for example, 3 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0039] Cu content: for example, 5 wtppm or less, preferably 3 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.09 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0040] Zn content: for example, 2 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0041] Ga content: for example, 2 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0042] Ge content: for example, 1 wtppm or less, preferably 0.7 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0043] As content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably less than 0.01 wtppm;

[0044] Se content: for example, 2 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0045] Br content: for example, 20 wtppm or less, preferably 10 wtppm or less, preferably 7 wtppm or less, preferably 5 wtppm or less, preferably 4.3 wtppm or less, preferably 3 wtppm or less, preferably 2 wtppm or less, preferably 1.7 wtppm or less;

[0046] Rb content: for example, 9 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0047] Sr content: for example, 1000 wtppm or less, preferably 500 wtppm or less, preferably 300 wtppm or less, preferably 280 wtppm or less;

[0048] Zr content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0049] Nb content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0050] Mo content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0051] Ru content: for example, 9 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0052] Rh content: for example, 10 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably less than 1 wtppm;

[0053] Pd content: for example, 1 wtppm or less, preferably 0.7 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0054] Cd content: for example, 3 wtppm or less, preferably 2 wtppm or less, preferably 1 wtppm or less, preferably less than 1 wtppm;

[0055] Sn content: For example, 3 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0056] Sb content: For example, 7 wtppm or less, preferably 6 wtppm or less, preferably 5 wtppm or less, preferably less than 5 wtppm;

[0057] Te content: for example, 20 wtppm or less, preferably 15 wtppm or less, preferably 10 wtppm or less, preferably less than 10 wtppm;

[0058] Content: For example, 200 wtppm or less, preferably 150 wtppm or less, preferably 100 wtppm or less, preferably less than 100 wtppm;

[0059] Cs content: for example, 10 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably less than 1 wtppm;

[0060] Ce content: for example, 10 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably less than 1 wtppm;

[0061] Pr content: for example, 10 wtppm or less, preferably 5 wtppm or less, preferably 1 wtppm or less, preferably less than 1 wtppm;

[0062] Nd content: for example, 10 wtppm or less, preferably 7 wtppm or less, preferably 5 wtppm or less, preferably less than 5 wtppm;

[0063] Gd content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0064] Tb content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0065] Dy content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0066] Ho content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0067] Er content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0068] Yb content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0069] Lu content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably less than 0.1 wtppm;

[0070] Hf content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0071] W content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0072] Re content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably less than 0.01 wtppm;

[0073] Os content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0074] Ir content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.2 wtppm or less, preferably 0.14 wtppm or less;

[0075] Pt content: For example, 3 wtppm or less, preferably 1 wtppm or less, preferably 0.5 wtppm or less, preferably less than 0.5 wtppm;

[0076] Au content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0077] Hg content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably less than 0.05 wtppm;

[0078] Tl content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0079] Pb content: for example, 1 wtppm or less, preferably 0.5 wtppm or less, preferably 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably less than 0.01 wtppm;

[0080] Bi content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably less than 0.01 wtppm;

[0081] Th content: for example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm;

[0082] U content: For example, 0.1 wtppm or less, preferably 0.05 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm.

[0083] [Manufacturing of high-purity barium metal] In a preferred embodiment, the high-purity metallic barium of the present invention can be produced by means described later in the examples.

[0084] [Preferred embodiments of the present invention] In preferred embodiments, the present invention includes (1) and the following: (1) Metallic barium with a Zn content of 3 wt ppm or less. (2) (1) The metallic barium described above, having a purity of 99 wt% or higher. (3) (1) The metallic barium described above, wherein the purity excluding Ca and Sr is 99.9 wt% or higher.

[0085] (4) A barium metal described in any of (1) to (3), having a Cu content of 5 wt ppm or less. (5) A barium metal described in any of (1) to (3), having a Mn content of 1 wt ppm or less.

[0086] (6) A barium metal described in any of (1) to (3), having a Mg content of 2 wt ppm or less. (7) A barium metal described in any of (1) to (3), having an Al content of 6 wt ppm or less.

[0087] (8) A barium metal described in any of (1) to (3), having a Ni content of 3 wt ppm or less. (9) A barium metal described in any of (1) to (3), having an Fe content of 3 wt ppm or less.

[0088] (10) A barium metal described in any of (1) to (3) above, with a purity of 99.5 wt% or higher. (11) A barium metal described in any of (1) to (3), having a purity of 99.95 wt% or higher, excluding Ca and Sr.

[0089] In a preferred embodiment, the high-purity metallic barium of the present invention has a reduced Zn content, thereby minimizing ZnO formation, and is particularly excellent as a raw material for optoelectronic devices. Therefore, the present invention also relates to a raw material for optoelectronic devices consisting of the above-mentioned metallic barium, a raw material for optoelectronic devices containing the above-mentioned metallic barium, a method for manufacturing a raw material for optoelectronic devices using the above-mentioned metallic barium, and the use of the above-mentioned metallic barium for manufacturing a raw material for optoelectronic devices. [Examples]

[0090] The present invention will be described in detail below with reference to examples. The present invention is not limited to the examples illustrated below.

[0091] [Example 1] The high-purity metallic barium of the examples and comparative examples of the present invention was produced as follows.

[0092] [Raw materials] Commercially available barium metal was used as the raw material. The purity of the barium metal, as measured by GDMS, was approximately 98 wt%.

[0093] [Heating furnace used for sublimation purification] Figure 1 shows a diagram illustrating the structure of the heating furnace used for sublimation purification. Referring to Figure 1, the process of sublimation purification using this furnace will be explained below.

[0094] The heating furnace 3 has a cylindrical tubular structure and is designed to heat the inside while maintaining a vacuum. As shown in the figure, for structural and operational convenience, the heating furnace 3, which has a cylindrical tubular structure, is provided with an inner tube 5 inside, and the deposition of Ba metal gas occurs inside this inner tube 5. The raw material 9 is placed at one end of the inner tube 5 on the 5a side, and while maintaining a vacuum, the raw material 9 can be sublimated by heating with external heaters (7a, 7b). The flow of metal gas (13a, 13b) generated when the raw material 9 sublimes due to heating by the heaters (7a, 7b) diffuses inside the inner tube 5 provided inside the vacuum-suctioned cylindrical tubular structure, and diffuses to reach areas far from the heating points by the heaters (7a, 7b). Heating by the heaters (7a, 7b) is performed at one end of the inner tube 5 on the 5a side, which is located inside the cylindrical tubular structure, but not at the other end on the 5b side. As a result, a temperature gradient is created on the inner wall of the inner tube 5, which is located inside the cylindrical tubular structure, from the heated end to the unheated end. Thereupon, the metal gas generated by sublimation is deposited at a location (deposition site) according to the properties of the metal within the temperature gradient from the heated end to the unheated end, forming deposited materials (11a, 11b). Arrow 15 indicates the flow of vacuum suction inside the heating furnace 3.

[0095] [Sublimation purification] Sublimation purification was performed using the heating furnace described in Figure 1 under the following conditions. Maximum set temperature using the external heater at the heating end: 875℃ Temperature holding time for sublimation purification: 20 hours Atmosphere inside the tubular structure: Constantly under vacuum (Vacuum level immediately before heating starts: 6-8 x 10) -2 Pa) Ingredient preparation amount: 102g Heating rate: 5°C / min

[0096] As described above, after 20 hours, the material was allowed to cool naturally for 3 hours, and the deposited material in the 630-660°C portion inside the inner tube of the cylindrical tubular structure was collected and designated as Sample 1.

[0097] The temperature of each part inside the inner tube of the cylindrical tubular structure was measured by removing the Refathermo (common thermal history sensor, manufactured by JFCC) and Thermoproof (manufactured by Nichiyu Giken Kogyo Co., Ltd.) that were installed in each part during preliminary heating tests, measuring them with a micrometer, and observing the discoloration of the seals. The temperature was then calculated from a graph plotting these values. The tolerance for these temperature values ​​was +10 to -10°C. The graph used for the calculation is shown in Figure 2. In Figure 2, distance is expressed as a relative value, with the center of the heater set to 0 and the end of the inner tube 5 set to 1.

[0098] Furthermore, in the same manner as the recovery of Sample 1, the deposited material deposited in the 600-630°C portion of the inner tube located inside the cylindrical tubular structure was recovered and designated as Sample 2, and the deposited material deposited in the 580-600°C portion was recovered and designated as Sample 3.

[0099] [analysis] Samples 1, 2, and 3 obtained in Example 1 were analyzed by GDMS. The GDMS analysis was performed using Astrum from Nu Instruments Ltd. The results are shown in Tables 1-1 to 1-4. Unless otherwise specified, the values ​​are in wtppm. Values ​​indicated with an inequality sign (<) indicate that the value was below the limit of quantification.

[0100] [Table 1-1]

[0101] [Table 1-2]

[0102] [Table 1-3]

[0103] [Table 1-4]

[0104] Tables 1-1 to 1-4 show the total value (wtppm) of impurity elements. For impurity elements, values ​​below the detection limit were counted as 0 wtppm to calculate the total value. Subtracting this total value from 100 wt% gave the purity of Sample 1 a value of 99.6884 wt%. Furthermore, the purity of Sample 1 calculated by excluding Ca (calcium) and Sr (strontium) and setting the value to 100 wt% was 99.9784 wt%. Similarly, the purity of Sample 2 was calculated as 99.8401 wt%. The purity of Sample 2 calculated by excluding Ca (calcium) and Sr (strontium) was 99.9881 wt%. Similarly, the purity of Sample 3 was calculated as 99.4873 wt%. The purity of Sample 3 calculated by excluding Ca (calcium) and Sr (strontium) was 99.9863 wt%.

[0105] [Potential contribution to the SDGs] One embodiment of the present invention provides high-purity metallic barium. Since high precision in materials and components is important for the development of IoT and AI technologies, one embodiment of the present invention has the potential to contribute to the development of IoT and AI technologies. For this reason, one embodiment of the present invention has the potential to contribute to Goal 9 of the United Nations Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation." [Industrial applicability]

[0106] This invention provides high-purity metallic barium in which the content of the impurity Zn (zinc) has been reduced. This invention is industrially useful.

Claims

1. Metallic barium with a Zn content of 3 wt ppm or less.

2. The barium metal according to claim 1, wherein the purity is 99 wt% or higher.

3. The barium metal according to claim 1, wherein the purity excluding Ca and Sr is 99.9 wt% or higher.

4. The metallic barium according to any one of claims 1 to 3, wherein the Cu content is 5 wt ppm or less.

5. The barium metal according to any one of claims 1 to 3, wherein the Mn content is 1 wt ppm or less.

6. The metallic barium according to any one of claims 1 to 3, wherein the Mg content is 2 wt ppm or less.

7. The barium metal according to any one of claims 1 to 3, wherein the Al content is 6 wt ppm or less.

8. The barium metal according to any one of claims 1 to 3, wherein the Ni content is 3 wt ppm or less.

9. The barium metal according to any one of claims 1 to 3, wherein the Fe content is 3 wt ppm or less.

10. The barium metal according to any one of claims 1 to 3, wherein the purity is 99.5 wt% or higher.

11. The barium metal according to any one of claims 1 to 3, wherein the purity excluding Ca and Sr is 99.95 wt% or higher.

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