Low-alpha bismuth oxide

Abstract

The objective of this invention is to provide bismuth oxide with reduced alpha radiation. The means by which this invention solves this objective is a bismuth oxide powder having an alpha radiation content of less than 0.002 cph / cm² and a bismuth oxide purity of 99.99 wt% or higher.

Description

[Technical Field]

[0001] This invention relates to a low-alpha bismuth oxide. [Previous Technology]

[0002] Bismuth oxide is used in electronic components such as rheostats and ceramic capacitors, or in magnetic materials such as ferrites, and has already occupied an important position as an electronic material.

[0003] In recent years, the effects of alpha rays have gradually attracted attention as a cause of software errors in semiconductor circuits. Therefore, there is a growing demand to reduce the generation of alpha rays from all parts of semiconductor materials.

[0004] Patent Document 1 discloses metallic bismuth with reduced alpha radiation and a method for manufacturing the same. However, Patent Document 1 does not disclose bismuth oxide with reduced alpha radiation and a method for manufacturing the same.

[0005] Patent documents 2-5 disclose bismuth oxide and a method for manufacturing the same. However, patent documents 2-5 do not disclose bismuth oxide with reduced alpha radiation and a method for manufacturing the same. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent No. 6271642 [Patent Document 2] Japanese Patent No. 5120663 [Patent Document 3] Japanese Patent No. 3928023 [Patent Document 4] Japanese Patent No. 4619428 [Patent Document 5] Japanese Patent No. 4185197 [Summary of the Invention]

[0007] [Problem to be solved by the invention] Thus, it is now required to reduce the generation of alpha rays from all parts of semiconductor materials.

[0008] Therefore, the object of the present invention is to provide bismuth oxide with reduced alpha radiation. [Technical means to solve the problem]

[0009] The inventors have conducted diligent research and discovered that the above-mentioned problems can be achieved by the following method, thereby completing the present invention.

[0010] This invention comprises the following (1). (1) A bismuth oxide powder having an alpha radiation amount of less than 0.002 cph / cm2 and a bismuth oxide purity of more than 99.99 wt%. [Effects of the Invention]

[0011] The present invention provides bismuth oxide with reduced alpha radiation. The bismuth oxide of the present invention reduces the amount of alpha radiation, minimizing the generation of alpha radiation, which is a cause of software errors in semiconductor circuits, and can be widely used as a semiconductor material.

Implementation Method

[0013] Hereinafter, the present invention will be described in detail with reference to specific embodiments. The present invention is not limited to the specific embodiments described below.

[0014] [Bismuth Oxide Powder] The present invention relates to a bismuth oxide powder, wherein the alpha ray content is below 0.002 cph / cm2 and the bismuth oxide purity is above 99.99 wt%.

[0015] [α-ray amount] In suitable embodiments, the α-ray amount of the bismuth oxide powder of the present invention may be set to, for example, 0.002 cph / cm² or less, preferably 0.0015 cph / cm² or less, preferably 0.0014 cph / cm² or less, preferably 0.0013 cph / cm² or less, preferably 0.0012 cph / cm² or less, preferably 0.0011 cph / cm² or less, preferably 0.001 cph / cm² or less. The value of the α-ray amount can be determined using the means described in the following examples.

[0016] [Purity] In suitable embodiments, the purity of the bismuth oxide powder of the present invention may be, for example, 99.99 wt% or more, preferably 99.995 wt% or more, and more preferably 99.996 wt% or more. The purity of the bismuth oxide powder can be calculated using the methods described in the following examples.

[0017] [Specific Surface Area] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.1 to 1.0 m² / g, preferably in the range of 0.1 to 0.9 m² / g, preferably in the range of 0.1 to 0.8 m² / g, preferably in the range of 0.1 to 0.7 m² / g, preferably in the range of 0.1 to 0.6 m² / g, preferably in the range of 0.1 to 0.5 m² / g, preferably in the range of 0.1 to 0.4 m² / g, preferably in the range of 0.1 to 0.3 m² / g, preferably in the range of 0.1 to 0.25 m² / g, preferably in the range of 0.1 to 0.24 m² / g, preferably in the range of 0.1 to 0.23 m² / g, preferably in the range of 0.1 to 0.22 m² / g. The specific surface area of ​​bismuth oxide powder can be determined using the methods described in the following examples.

[0018] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.1 to 0.21 m² / g, 0.1 to 0.20 m² / g, 0.1 to 0.19 m² / g, 0.1 to 0.18 m² / g, or 0.1 to 0.17 m² / g.

[0019] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.1 to 0.16 m2 / g, the range of 0.1 to 0.15 m2 / g, or the range of 0.1 to 0.14 m2 / g.

[0020] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.11 to 1.0 m² / g, preferably in the range of 0.11 to 0.9 m² / g, preferably in the range of 0.11 to 0.8 m² / g, preferably in the range of 0.11 to 0.7 m² / g, preferably in the range of 0.11 to 0.6 m² / g, preferably in the range of 0.11 to 0.5 m² / g, preferably in the range of 0.11 to 0.4 m² / g, preferably in the range of 0.11 to 0.3 m² / g, preferably in the range of 0.11 to 0.25 m² / g, preferably in the range of 0.11 to 0.24 m² / g, preferably in the range of 0.11 to 0.23 m² / g, preferably in the range of 0.11 to 0.22 m² / g.

[0021] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.11 to 0.21 m2 / g, the range of 0.11 to 0.20 m2 / g, the range of 0.11 to 0.19 m2 / g, the range of 0.11 to 0.18 m2 / g, or the range of 0.11 to 0.17 m2 / g.

[0022] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.11 to 0.16 m2 / g, the range of 0.11 to 0.15 m2 / g, or the range of 0.11 to 0.14 m2 / g.

[0023] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.12 to 1.0 m² / g, preferably in the range of 0.12 to 0.9 m² / g, preferably in the range of 0.12 to 0.8 m² / g, preferably in the range of 0.12 to 0.7 m² / g, preferably in the range of 0.12 to 0.6 m² / g, preferably in the range of 0.12 to 0.5 m² / g, preferably in the range of 0.12 to 0.4 m² / g, preferably in the range of 0.12 to 0.3 m² / g, preferably in the range of 0.12 to 0.25 m² / g, preferably in the range of 0.12 to 0.24 m² / g, preferably in the range of 0.12 to 0.23 m² / g, preferably in the range of 0.12 to 0.22 m² / g.

[0024] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.12 to 0.21 m² / g, the range of 0.12 to 0.20 m² / g, the range of 0.12 to 0.19 m² / g, the range of 0.12 to 0.18 m² / g, or the range of 0.12 to 0.17 m² / g.

[0025] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.12 to 0.16 m2 / g, the range of 0.12 to 0.15 m2 / g, or the range of 0.12 to 0.14 m2 / g.

[0026] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.13 to 1.0 m² / g, preferably in the range of 0.13 to 0.9 m² / g, preferably in the range of 0.13 to 0.8 m² / g, preferably in the range of 0.13 to 0.7 m² / g, preferably in the range of 0.13 to 0.6 m² / g, preferably in the range of 0.13 to 0.5 m² / g, preferably in the range of 0.13 to 0.4 m² / g, preferably in the range of 0.13 to 0.3 m² / g, preferably in the range of 0.13 to 0.25 m² / g, preferably in the range of 0.13 to 0.24 m² / g, preferably in the range of 0.13 to 0.23 m² / g, preferably in the range of 0.13 to 0.22 m² / g.

[0027] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.13 to 0.21 m² / g, the range of 0.13 to 0.20 m² / g, the range of 0.13 to 0.19 m² / g, the range of 0.13 to 0.18 m² / g, or the range of 0.13 to 0.17 m² / g.

[0028] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.13 to 0.16 m2 / g, the range of 0.13 to 0.15 m2 / g, or the range of 0.13 to 0.14 m2 / g.

[0029] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.15 to 1.0 m² / g, preferably in the range of 0.15 to 0.9 m² / g, preferably in the range of 0.15 to 0.8 m² / g, preferably in the range of 0.15 to 0.7 m² / g, preferably in the range of 0.15 to 0.6 m² / g, preferably in the range of 0.15 to 0.5 m² / g, preferably in the range of 0.15 to 0.4 m² / g, preferably in the range of 0.15 to 0.3 m² / g, preferably in the range of 0.15 to 0.25 m² / g, preferably in the range of 0.15 to 0.24 m² / g, preferably in the range of 0.15 to 0.23 m² / g, preferably in the range of 0.15 to 0.22 m² / g.

[0030] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.15 to 0.21 m2 / g, the range of 0.15 to 0.20 m2 / g, the range of 0.15 to 0.19 m2 / g, or the range of 0.15 to 0.18 m2 / g.

[0031] In a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.16 to 1.0 m² / g, preferably in the range of 0.16 to 0.9 m² / g, preferably in the range of 0.16 to 0.8 m² / g, preferably in the range of 0.16 to 0.7 m² / g, preferably in the range of 0.16 to 0.6 m² / g, preferably in the range of 0.16 to 0.5 m² / g, preferably in the range of 0.16 to 0.4 m² / g, preferably in the range of 0.16 to 0.3 m² / g, preferably in the range of 0.16 to 0.25 m² / g, preferably in the range of 0.16 to 0.24 m² / g, preferably in the range of 0.16 to 0.23 m² / g, preferably in the range of 0.16 to 0.22 m² / g.

[0032] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.16 to 0.21 m2 / g, the range of 0.16 to 0.20 m2 / g, the range of 0.16 to 0.19 m2 / g, or the range of 0.16 to 0.18 m2 / g.

[0033] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.17 to 1.0 m² / g, preferably in the range of 0.17 to 0.9 m² / g, preferably in the range of 0.17 to 0.8 m² / g, preferably in the range of 0.17 to 0.7 m² / g, preferably in the range of 0.17 to 0.6 m² / g, preferably in the range of 0.17 to 0.5 m² / g, preferably in the range of 0.17 to 0.4 m² / g, preferably in the range of 0.17 to 0.3 m² / g, preferably in the range of 0.17 to 0.25 m² / g, preferably in the range of 0.17 to 0.24 m² / g, preferably in the range of 0.17 to 0.23 m² / g, preferably in the range of 0.17 to 0.22 m² / g.

[0034] Alternatively, in a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, the range of 0.17 to 0.21 m2 / g, the range of 0.17 to 0.20 m2 / g, the range of 0.17 to 0.19 m2 / g, or the range of 0.17 to 0.18 m2 / g.

[0035] In suitable embodiments, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.19 to 1.0 m² / g, preferably in the range of 0.19 to 0.9 m² / g, preferably in the range of 0.19 to 0.8 m² / g, preferably in the range of 0.19 to 0.7 m² / g, preferably in the range of 0.19 to 0.6 m² / g, preferably in the range of 0.19 to 0.5 m² / g, preferably in the range of 0.19 to 0.4 m² / g, preferably in the range of 0.19 to 0.3 m² / g, preferably in the range of 0.19 to 0.25 m² / g, preferably in the range of 0.19 to 0.24 m² / g, preferably in the range of 0.19 to 0.23 m² / g, preferably in the range of 0.19 to 0.22 m² / g.

[0036] In a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.20 to 1.0 m² / g, preferably in the range of 0.20 to 0.9 m² / g, preferably in the range of 0.20 to 0.8 m² / g, preferably in the range of 0.20 to 0.7 m² / g, preferably in the range of 0.20 to 0.6 m² / g, preferably in the range of 0.20 to 0.5 m² / g, preferably in the range of 0.20 to 0.4 m² / g, preferably in the range of 0.20 to 0.3 m² / g, preferably in the range of 0.20 to 0.25 m² / g, preferably in the range of 0.20 to 0.24 m² / g, preferably in the range of 0.20 to 0.23 m² / g, preferably in the range of 0.20 to 0.22 m² / g.

[0037] In a suitable embodiment, the specific surface area of ​​the bismuth oxide powder of the present invention may be set to, for example, in the range of 0.21 to 1.0 m² / g, preferably in the range of 0.21 to 0.9 m² / g, preferably in the range of 0.21 to 0.8 m² / g, preferably in the range of 0.21 to 0.7 m² / g, preferably in the range of 0.21 to 0.6 m² / g, preferably in the range of 0.21 to 0.5 m² / g, preferably in the range of 0.21 to 0.4 m² / g, preferably in the range of 0.21 to 0.3 m² / g, preferably in the range of 0.21 to 0.25 m² / g, preferably in the range of 0.21 to 0.24 m² / g, preferably in the range of 0.21 to 0.23 m² / g, preferably in the range of 0.21 to 0.22 m² / g.

[0038] [Bulk Density] In suitable embodiments, the bulk density of the bismuth oxide powder of the present invention may be, for example, set in the range of 2.5 to 6.0 g / cm³, preferably in the range of 2.5 to 5.5 g / cm³, preferably in the range of 2.5 to 5.0 g / cm³, preferably in the range of 2.5 to 4.9 g / cm³, and preferably in the range of 2.5 to 4.8 g / cm³. The bulk density of the bismuth oxide powder can be determined using the methods described in the following examples.

[0039] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 2.5–4.6 g / cm³, 2.5–4.5 g / cm³, 2.5–4.4 g / cm³, 2.5–4.3 g / cm³, 2.5–4.2 g / cm³, 2.5–4.1 g / cm³, 2.5–4.0 g / cm³, 2.5–3.9 g / cm³, or 2.5–3.8 g / cm³.

[0040] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 2.5 to 3.7 g / cm3, the range of 2.5 to 3.6 g / cm3, or the range of 2.5 to 3.5 g / cm3.

[0041] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.0 to 6.0 g / cm3, more preferably the range of 3.0 to 5.5 g / cm3, more preferably the range of 3.0 to 5.0 g / cm3, more preferably the range of 3.0 to 4.9 g / cm3, and more preferably the range of 3.0 to 4.8 g / cm3.

[0042] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.0 to 4.6 g / cm3, 3.0 to 4.5 g / cm3, 3.0 to 4.4 g / cm3, 3.0 to 4.3 g / cm3, 3.0 to 4.2 g / cm3, 3.0 to 4.1 g / cm3, 3.0 to 4.0 g / cm3, 3.0 to 3.9 g / cm3, or 3.0 to 3.8 g / cm3.

[0043] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.0 to 3.7 g / cm3, 3.0 to 3.6 g / cm3, or 3.0 to 3.5 g / cm3.

[0044] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.1 to 6.0 g / cm3, preferably the range of 3.1 to 5.5 g / cm3, preferably the range of 3.1 to 5.0 g / cm3, preferably the range of 3.1 to 4.9 g / cm3, or preferably the range of 3.1 to 4.8 g / cm3.

[0045] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.1 to 4.6 g / cm3, 3.1 to 4.5 g / cm3, 3.1 to 4.4 g / cm3, 3.1 to 4.3 g / cm3, 3.1 to 4.2 g / cm3, 3.1 to 4.1 g / cm3, 3.1 to 4.0 g / cm3, 3.1 to 3.9 g / cm3, or 3.1 to 3.8 g / cm3.

[0046] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.1 to 3.7 g / cm3, 3.1 to 3.6 g / cm3, or 3.1 to 3.5 g / cm3.

[0047] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.2 to 6.0 g / cm3, preferably the range of 3.2 to 5.5 g / cm3, preferably the range of 3.2 to 5.0 g / cm3, preferably the range of 3.2 to 4.9 g / cm3, or preferably the range of 3.2 to 4.8 g / cm3.

[0048] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.2–4.6 g / cm³, 3.2–4.5 g / cm³, 3.2–4.4 g / cm³, 3.2–4.3 g / cm³, 3.2–4.2 g / cm³, 3.2–4.1 g / cm³, 3.2–4.0 g / cm³, 3.2–3.9 g / cm³, or 3.2–3.8 g / cm³.

[0049] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.2 to 3.7 g / cm3, 3.2 to 3.6 g / cm3, or 3.2 to 3.5 g / cm3.

[0050] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.3 to 6.0 g / cm3, preferably the range of 3.3 to 5.5 g / cm3, preferably the range of 3.3 to 5.0 g / cm3, preferably the range of 3.3 to 4.9 g / cm3, or preferably the range of 3.3 to 4.8 g / cm3.

[0051] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.3 to 4.6 g / cm3, 3.3 to 4.5 g / cm3, 3.3 to 4.4 g / cm3, 3.3 to 4.3 g / cm3, 3.3 to 4.2 g / cm3, 3.3 to 4.1 g / cm3, 3.3 to 4.0 g / cm3, 3.3 to 3.9 g / cm3, or 3.3 to 3.8 g / cm3.

[0052] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.3 to 3.7 g / cm3, 3.3 to 3.6 g / cm3, or 3.3 to 3.5 g / cm3.

[0053] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.4 to 6.0 g / cm3, preferably the range of 3.4 to 5.5 g / cm3, preferably the range of 3.4 to 5.0 g / cm3, preferably the range of 3.4 to 4.9 g / cm3, or preferably the range of 3.4 to 4.8 g / cm3.

[0054] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.4 to 4.6 g / cm3, 3.4 to 4.5 g / cm3, 3.4 to 4.4 g / cm3, 3.4 to 4.3 g / cm3, 3.4 to 4.2 g / cm3, 3.4 to 4.1 g / cm3, 3.4 to 4.0 g / cm3, 3.4 to 3.9 g / cm3, or 3.4 to 3.8 g / cm3.

[0055] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.4 to 3.7 g / cm3, 3.4 to 3.6 g / cm3, or 3.4 to 3.5 g / cm3.

[0056] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.5 to 6.0 g / cm3, preferably the range of 3.5 to 5.5 g / cm3, preferably the range of 3.5 to 5.0 g / cm3, preferably the range of 3.5 to 4.9 g / cm3, or preferably the range of 3.5 to 4.8 g / cm3.

[0057] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.5–4.6 g / cm³, 3.5–4.5 g / cm³, 3.5–4.4 g / cm³, 3.5–4.3 g / cm³, 3.5–4.2 g / cm³, 3.5–4.1 g / cm³, 3.5–4.0 g / cm³, 3.5–3.9 g / cm³, or 3.5–3.8 g / cm³.

[0058] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.5 to 3.7 g / cm3 or 3.5 to 3.6 g / cm3.

[0059] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.7 to 6.0 g / cm3, preferably the range of 3.7 to 5.5 g / cm3, preferably the range of 3.7 to 5.0 g / cm3, preferably the range of 3.7 to 4.9 g / cm3, or preferably the range of 3.7 to 4.8 g / cm3.

[0060] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.7–4.6 g / cm³, 3.7–4.5 g / cm³, 3.7–4.4 g / cm³, 3.7–4.3 g / cm³, 3.7–4.2 g / cm³, 3.7–4.1 g / cm³, 3.7–4.0 g / cm³, 3.7–3.9 g / cm³, or 3.7–3.8 g / cm³.

[0061] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.8 to 6.0 g / cm3, preferably the range of 3.8 to 5.5 g / cm3, preferably the range of 3.8 to 5.0 g / cm3, preferably the range of 3.8 to 4.9 g / cm3, preferably the range of 3.8 to 4.8 g / cm3.

[0062] Alternatively, in a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 3.8–4.6 g / cm³, 3.8–4.5 g / cm³, 3.8–4.4 g / cm³, 3.8–4.3 g / cm³, 3.8–4.2 g / cm³, 3.8–4.1 g / cm³, 3.8–4.0 g / cm³, or 3.8–3.9 g / cm³.

[0063] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 4.0 to 6.0 g / cm3, more preferably the range of 4.0 to 5.5 g / cm3, more preferably the range of 4.0 to 5.0 g / cm3, more preferably the range of 4.0 to 4.9 g / cm3, and more preferably the range of 4.0 to 4.8 g / cm3.

[0064] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 4.5 to 6.0 g / cm3, preferably the range of 4.5 to 5.5 g / cm3, preferably the range of 4.5 to 5.0 g / cm3, preferably the range of 4.5 to 4.9 g / cm3, or preferably the range of 4.5 to 4.8 g / cm3.

[0065] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 4.6 to 6.0 g / cm3, more preferably the range of 4.6 to 5.5 g / cm3, more preferably the range of 4.6 to 5.0 g / cm3, more preferably the range of 4.6 to 4.9 g / cm3, and more preferably the range of 4.6 to 4.8 g / cm3.

[0066] In a suitable embodiment, the bulk density of the bismuth oxide powder of the present invention may be set to, for example, the range of 4.7 to 6.0 g / cm3, preferably the range of 4.7 to 5.5 g / cm3, preferably the range of 4.7 to 5.0 g / cm3, preferably the range of 4.7 to 4.9 g / cm3, or preferably the range of 4.7 to 4.8 g / cm3.

[0067] [Average Particle Size D50] In suitable embodiments, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, a range of 10–30 μm, preferably 11–30 μm, preferably 12–30 μm, preferably 13–30 μm, preferably 14–30 μm, preferably 15–30 μm, or preferably 16–30 μm. The average particle size D50 of the bismuth oxide powder can be determined using the methods described in the following examples.

[0068] In a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 10 to 29 μm, preferably in the range of 11 to 29 μm, preferably in the range of 12 to 29 μm, preferably in the range of 13 to 29 μm, preferably in the range of 14 to 29 μm, preferably in the range of 15 to 29 μm, or preferably in the range of 16 to 29 μm.

[0069] Alternatively, in a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 10 to 25 μm, preferably in the range of 11 to 25 μm, preferably in the range of 12 to 25 μm, preferably in the range of 13 to 25 μm, preferably in the range of 14 to 25 μm, preferably in the range of 15 to 25 μm, or preferably in the range of 16 to 25 μm.

[0070] Alternatively, in a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 10 to 20 μm, preferably in the range of 11 to 20 μm, preferably in the range of 12 to 20 μm, preferably in the range of 13 to 20 μm, preferably in the range of 14 to 20 μm, preferably in the range of 15 to 20 μm, or preferably in the range of 16 to 20 μm.

[0071] Alternatively, in a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, a range of 10 to 19 μm, preferably a range of 11 to 19 μm, preferably a range of 12 to 19 μm, preferably a range of 13 to 19 μm, preferably a range of 14 to 19 μm, preferably a range of 15 to 19 μm, or preferably a range of 16 to 19 μm.

[0072] Alternatively, in a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 10 to 18 μm, preferably in the range of 11 to 18 μm, preferably in the range of 12 to 18 μm, preferably in the range of 13 to 18 μm, preferably in the range of 14 to 18 μm, preferably in the range of 15 to 18 μm, or preferably in the range of 16 to 18 μm.

[0073] Alternatively, in a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 10 to 17 μm, preferably in the range of 11 to 17 μm, preferably in the range of 12 to 17 μm, preferably in the range of 13 to 17 μm, preferably in the range of 14 to 17 μm, preferably in the range of 15 to 17 μm, or preferably in the range of 16 to 17 μm.

[0074] In a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 20 to 30 μm, preferably in the range of 25 to 30 μm, preferably in the range of 26 to 30 μm, preferably in the range of 27 to 30 μm, or preferably in the range of 28 to 30 μm.

[0075] Alternatively, in a suitable embodiment, the average particle size D50 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 20 to 29 μm, preferably in the range of 25 to 29 μm, preferably in the range of 26 to 29 μm, preferably in the range of 27 to 29 μm, or preferably in the range of 28 to 29 μm.

[0076] [Average Particle Size D10] In suitable embodiments, the average particle size D10 of the bismuth oxide powder of the present invention may be set to, for example, a range of 4 to 10 μm, preferably a range of 4 to 9 μm, or more preferably a range of 4 to 8 μm. The average particle size D10 of the bismuth oxide powder can be determined using the methods described in the following examples.

[0077] Alternatively, in a suitable embodiment, the average particle size D10 of the bismuth oxide powder of the present invention may be set to, for example, a range of 4 to 7 μm, preferably a range of 4 to 6 μm, or preferably a range of 4 to 5 μm.

[0078] In a suitable embodiment, the average particle size D10 of the bismuth oxide powder of the present invention may be set to, for example, a range of 5 to 10 μm, preferably a range of 5 to 9 μm, or preferably a range of 5 to 8 μm.

[0079] Alternatively, in a suitable embodiment, the average particle size D10 of the bismuth oxide powder of the present invention may be set to, for example, a range of 5 to 7 μm, preferably a range of 5 to 6 μm.

[0080] In a suitable embodiment, the average particle size D10 of the bismuth oxide powder of the present invention may be set to, for example, in the range of 6 to 10 μm, more preferably in the range of 6 to 9 μm, or more preferably in the range of 6 to 8 μm.

[0081] In a suitable embodiment, the average particle size D10 of the bismuth oxide powder of the present invention may be set to, for example, a range of 7 to 10 μm, preferably a range of 7 to 9 μm, or preferably a range of 7 to 8 μm.

[0082] [Average Particle Size D90] In suitable embodiments, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, a range of 100–150 μm, more preferably a range of 100–140 μm, or more preferably a range of 100–135 μm. The average particle size D90 of the bismuth oxide powder can be determined using the methods described in the following examples.

[0083] Alternatively, in a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, a range of 100 to 130 μm.

[0084] In a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, the range of 110 to 150 μm, more preferably the range of 110 to 140 μm, or more preferably the range of 110 to 135 μm.

[0085] Alternatively, in a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, a range of 110 to 130 μm.

[0086] In a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, the range of 120 to 150 μm, more preferably the range of 120 to 140 μm, or more preferably the range of 120 to 135 μm.

[0087] Alternatively, in a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, a range of 120 to 130 μm.

[0088] In a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, the range of 125 to 150 μm, more preferably the range of 125 to 140 μm, or more preferably the range of 125 to 135 μm.

[0089] Alternatively, in a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, a range of 125 to 130 μm.

[0090] In a suitable embodiment, the average particle size D90 of the bismuth oxide powder of the present invention may be set to, for example, the range of 130 to 150 μm, more preferably the range of 130 to 140 μm, or more preferably the range of 130 to 135 μm.

[0091] [Particle Size Distribution] In a suitable embodiment, the bismuth oxide powder of the present invention can be used as an indicator of the degree of concentration of particle size distribution by the following formula: ("Average Particle Size D90" - "Average Particle Size D10") / "Average Particle Size D50" The value obtained is, for example, set to the range of 4.0 to 10.0, more preferably the range of 4.0 to 9.0, and more preferably the range of 4.0 to 8.0.

[0092] Alternatively, in a suitable embodiment, the bismuth oxide powder of the present invention may be set to a value obtained by the above formula as an indicator of the concentration of particle size distribution, for example, in the range of 4.0 to 7.0, 4.0 to 6.0, or 4.0 to 5.0.

[0093] In a suitable embodiment, the bismuth oxide powder of the present invention may be set to a value obtained by the above formula as an indicator of the concentration of particle size distribution, for example, in the range of 5.0 to 10.0, more preferably in the range of 5.0 to 9.0, or more preferably in the range of 5.0 to 8.0.

[0094] In a suitable embodiment, the bismuth oxide powder of the present invention may be set to a value obtained by the above formula as an indicator of the concentration of particle size distribution, for example, in the range of 6.0 to 10.0, more preferably in the range of 6.0 to 9.0, or more preferably in the range of 6.0 to 8.0.

[0095] In a suitable embodiment, the bismuth oxide powder of the present invention may be set to a value obtained by the above formula as an indicator of the concentration of particle size distribution, for example, in the range of 7.0 to 10.0, more preferably in the range of 7.0 to 9.0, or more preferably in the range of 7.0 to 8.0.

[0096] [Solubility of Bismuth Oxide Powder] In a suitable embodiment, the bismuth oxide powder of the present invention is a bismuth oxide powder that exhibits excellent solubility in the solubility test described later in the examples.

[0097] In a suitable embodiment, the bismuth oxide powder of the present invention can be prepared by adding 5.0 g of bismuth oxide powder to 500 ml of a 200 g / L methanesulfonic acid aqueous solution and stirring for 10 minutes, resulting in a turbidity of 0-5 and a color of 0-5. Preferably, it can be prepared with a turbidity of 0-4 and a color of 0-4; more preferably, it can be prepared with a turbidity of 0-3 and a color of 0-3; more preferably, it can be prepared with a turbidity of 0-2 and a color of 0-2; more preferably, it can be prepared with a turbidity of 0-1 and a color of 0-1; and most preferably, it can be prepared with a turbidity of 0 and a color of 0. The turbidity and color can be measured by the means described in the following examples.

[0098] [Impurity Content of Bismuth Oxide Powder] In suitable embodiments, the impurity content of bismuth oxide powder for each element can be set within the following ranges. Unless otherwise specified, the following values ​​are in wtppm. The impurity content of each element can be determined by the means described in the examples below.

[0099] Li: For example, 0.005 wtppm or less, preferably less than 0.005 wtppm; Be: For example, 0.005 wtppm or less, preferably less than 0.005 wtppm; B: For example, 0.5 wtppm or less, preferably 0.47 wtppm or less; F: For example, 0.1 wtppm or less, preferably 0.07 wtppm or less; Na: For example, 5 wtppm or less, preferably 1 wtppm or less, preferably 0.2 wtppm or less, preferably 0.13 wtppm or less; Mg: For example, 0.05 wtppm or less, preferably 0.02 wtppm or less, preferably 0.016 wtppm or less; Al: For example, 1.0 wtppm or less, preferably 0.5 wtppm or less, preferably 0.45 wtppm or less; Si: For example, 15 wtppm or less, preferably 13 wtppm or less; P: For example, 0.05 The concentrations of the following compounds are preferred: S: less than 3 wtppm, preferably less than 1 wtppm, preferably less than 0.5 wtppm, preferably less than 0.49 wtppm; Cl: less than 12 wtppm, preferably less than 10 wtppm, preferably less than 9 wtppm, preferably less than 8.7 wtppm; K: less than 0.05 wtppm, preferably less than 0.05 wtppm; Ca: less than 0.5 wtppm, preferably less than 0.2 wtppm, preferably less than 0.11 wtppm; Sc: less than 0.005 wtppm, preferably less than 0.005 wtppm.

[0100] Ti: for example, 0.5 wtppm or less, preferably 0.46 wtppm or less; V: for example, 0.005 wtppm or less, preferably less than 0.005 wtppm; Cr: for example, 0.01 wtppm or less, preferably 0.006 wtppm or less; Mn: for example, 0.01 wtppm or less, preferably less than 0.01 wtppm; Fe: for example, 0.5 wtppm or less, preferably 0.2 wtppm or less, preferably 0.10 wtppm or less; Co: for example, 0.005 wtppm or less, preferably less than 0.005 wtppm; Ni: for example, 0.1 wtppm or less, preferably 0.01 wtppm or less, preferably 0.005 wtppm or less, preferably less than 0.005 wtppm; Cu: for example, 1.0 wtppm or less, preferably 0.5 wtppm or less. The concentrations of the following compounds are preferred: Zn: less than 0.1 wtppm, preferably less than 0.05 wtppm, and more preferably less than 0.05 wtppm; Ga: less than 0.5 wtppm, preferably less than 0.34 wtppm; Ge: less than 0.05 wtppm, preferably less than 0.05 wtppm; As: less than 0.05 wtppm, preferably less than 0.05 wtppm; Se: less than 0.1 wtppm, preferably less than 0.1 wtppm; Br: less than 0.05 wtppm, preferably less than 0.04 wtppm.

[0101] Rb: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Sr: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Y: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Zr: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Nb: for example, below 0.5 wtppm, preferably below 0.5 wtppm; Mo: for example, below 0.5 wtppm, preferably below 0.5 wtppm; Ru: for example, below 0.05 wtppm, preferably below 0.010 wtppm; Rh: for example, below 0.01 wtppm, preferably below 0.008 wtppm; Pd: for example, below 0.01 wtppm, preferably below 0.01 wtppm. Ag: for example, less than 0.2 wtppm, preferably less than 0.1 wtppm, more preferably less than 0.05 wtppm; Cd: for example, less than 0.1 wtppm, preferably less than 0.07 wtppm; Sn: for example, less than 10 wtppm, preferably less than 5 wtppm, more preferably less than 3 wtppm, more preferably less than 2.6 wtppm; Sb: for example, less than 0.01 wtppm, preferably less than 0.01 wtppm; Te: for example, less than 0.7 wtppm, preferably less than 0.66 wtppm;

[0102] I: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Cs: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Ba: For example, below 0.05 wtppm, preferably below 0.034 wtppm; La: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Ce: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Pr: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Nd: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Sm: For example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; Eu: For example, 0.005 Below 0.005 wtppm, preferably below 0.005 wtppm; Gd: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Tb: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Dy: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Ho: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Er: for example, below 0.005 wtppm, preferably below 0.005 wtppm.

[0103] Tm: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Yb: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Lu: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Hf: for example, below 0.01 wtppm, preferably below 0.01 wtppm; W: for example, below 2 wtppm, preferably below 2 wtppm; Re: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Os: for example, below 0.005 wtppm, preferably below 0.005 wtppm; Ir: for example, below 0.05 wtppm, preferably below 0.03 wtppm; Pt: for example, below 0.01 wtppm, preferably below 0.01 wtppm. Hg: for example, below 0.05 wtppm, preferably not reaching 0.05 wtppm; Tl: for example, below 0.01 wtppm, preferably not reaching 0.01 wtppm; Pb: for example, below 0.05 wtppm, preferably not reaching 0.05 wtppm; Th: for example, below 0.005 wtppm, preferably not reaching 0.005 wtppm; U: for example, below 0.005 wtppm, preferably not reaching 0.005 wtppm.

[0104] [Bi2O3 Single Phase of Bismuth Oxide Powder] In suitable embodiments, the bismuth oxide powder of the present invention can be prepared into a bismuth oxide powder that is determined to be a single phase of Bi2O3 by XRD determination. The determination of a single phase of Bi2O3 by XRD determination can be made by the means described in the following examples. That is, as in the following XRD determination, when all peaks of the sample are consistent with the peaks of Bi2O3, and no peaks characteristic of Bi5O7NO3 at 10-15° or around 30° are observed, it is determined that a single phase of Bi2O3 has been formed.

[0105] [Suitable Embodiments] In suitable embodiments, the present invention includes the following embodiments (1). (1) A bismuth oxide powder having an alpha radiation amount of 0.002 cph / cm2 or less and a bismuth oxide purity of 99.99 wt% or more. (2) The bismuth oxide powder as described in (1) having a specific surface area in the range of 0.1 to 1.0 m2 / g.

[0106] (3)The bismuth oxide powder described in any one of (1) to (2) has a bulk density in the range of 2.5 to 6.0 g / cm3. (4)The bismuth oxide powder described in any one of (1) to (3) has a D50 in the range of 10 to 30 μm.

[0107] (5)The bismuth oxide powder described in any one of (1) to (4) has a Na content of less than 5 wtppm. (6)The bismuth oxide powder described in any one of (1) to (5) has a value of (“average particle size D90” - “average particle size D10”) / “average particle size D50” in the range of 4.0 to 10.0.

[0108] (7) Bismuth oxide powder as described in any one of (1) to (6), wherein 5.0 g of bismuth oxide powder is added to 500 ml of 200 g / L methanesulfonic acid aqueous solution and stirred for 10 minutes, and the turbidity is 0 to 5 and the color is 0 to 5.

[0109] (8)The bismuth oxide powder described in any one of (1) to (7) has the following content: Li content less than 0.005 wtppm, Be content less than 0.005 wtppm, B content less than 0.5 wtppm, F content less than 0.1 wtppm, Na content less than 5 wtppm, Mg content less than 0.05 wtppm, Al content less than 1.0 wtppm, Si content less than 15 wtppm, P content less than 0.05 wtppm, S content less than 3 wtppm, Cl content less than 12 wtppm, K content less than 0.05 wtppm, Ca content less than 0.5 wtppm, Sc content less than 0.005 wtppm, Ti content less than 0.5 wtppm, V content less than 0.005 wtppm, Cr content less than 0.01 wtppm, Mn content less than 0.01 wtppm, and Fe content less than 0.5 wtppm. The following concentrations of minerals are specified: Co content below 0.005 wtppm, Ni content below 0.1 wtppm, Cu content below 1.0 wtppm, Zn content below 0.1 wtppm, Ga content below 0.5 wtppm, Ge content below 0.05 wtppm, As content below 0.05 wtppm, Se content below 0.1 wtppm, Br content below 0.05 wtppm, Rb content below 0.005 wtppm, Sr content below 0.005 wtppm, Y content below 0.005 wtppm, Zr content below 0.005 wtppm, Nb content below 0.5 wtppm, Mo content below 0.5 wtppm, Ru content below 0.05 wtppm, Rh content below 0.01 wtppm, Pd content below 0.01 wtppm, Ag content below 0.2 wtppm, and Cd content below 0.1 wtppm. The content of Sn is below 10 wtppm, Sb is below 0.01 wtppm, Te is below 0.7 wtppm, I is below 0.005 wtppm, Cs is below 0.005 wtppm, Ba is below 0.05 wtppm, La is below 0.005 wtppm, Ce is below 0.005 wtppm, Pr is below 0.005 wtppm, Nd is below 0.005 wtppm, Sm is below 0.005 wtppm, Eu is below 0.005 wtppm, Gd is below 0.005 wtppm, Tb is below 0.005 wtppm, Dy is below 0.005 wtppm, and Ho is 0.The following concentrations of pollutants are specified: Er (below 0.005 wtppm), Tm (below 0.005 wtppm), Yb (below 0.005 wtppm), Lu (below 0.005 wtppm), Hf (below 0.01 wtppm), Re (below 0.005 wtppm), Os (below 0.005 wtppm), Ir (below 0.05 wtppm), Pt (below 0.01 wtppm), Hg (below 0.05 wtppm), Tl (below 0.01 wtppm), Pb (below 0.05 wtppm), Th (below 0.005 wtppm), and U (below 0.005 wtppm).

[0110] In a suitable embodiment, the present invention can be manufactured as a combination of one, two, three, four, five, six, seven, or eight of the embodiments described in (1), (2), (3), (4), (5), (6), (7), and (8). In this case, the specific items described in (1) to (8) above can be defined as the numerical ranges described above in this specification. [Example]

[0111] Hereinafter, the present invention will be described in detail by way of example embodiments. The present invention is not limited to the following embodiments.

[0112] [Example 1: Manufacturing of bismuth oxide powder] [Example 1] Prepare metallic bismuth (purity 99.99%, alpha ray amount 0.000043 cph / cm2) as raw material.

[0113] The metallic bismuth was dissolved in 8.4 mol / L concentrated nitric acid and diluted with pure water to achieve a Bi concentration of 100 g / L to obtain a metallic bismuth nitric acid solution.

[0114] Add 12 mol / L ammonia solution to the bismuth nitric acid solution at a rate of 1 ml / s until the pH of the solution becomes 8.5 or higher.

[0115] The slurry generated by adding ammonia to a bismuth nitric acid solution is repulped and washed, and solid-liquid separation is performed by suction filtration.

[0116] The precipitate obtained by solid-liquid separation is dried at 70°C overnight to obtain the dried precipitate.

[0117] The obtained precipitate was dried and calcined at 700°C for 2 hours under normal atmospheric pressure to obtain bismuth oxide powder (sample 1).

[0118] [Comparative Example 1] The precipitate dried in the same manner as in Example 1 was calcined at 500°C for 2 hours under normal atmospheric pressure to obtain bismuth oxide powder (sample 2).

[0119] [Example 2] The precipitate dried in the same manner as in Example 1 was calcined at 720°C for 2 hours under normal atmospheric pressure to obtain bismuth oxide powder (sample 3).

[0120] [Example 3] The precipitate dried in the same manner as in Example 1 was calcined at 680°C for 2 hours under normal atmospheric pressure to obtain bismuth oxide powder (sample 4).

[0121] [Example 2: Analysis of Bismuth Oxide Powder] [D10, D50, D90] The bismuth oxide powders (samples 1, 2, 3, and 4) obtained in Example 1 were measured using a particle size analyzer (Microtrac, model MT3300EXII) by laser diffraction and scattering. The obtained particle size values ​​D10, D50, and D90 are summarized and shown in Table 1.

[0122] [Table 1] Sample 1 (Roasted at 700℃) Sample 2 (Roasted at 500℃) Sample 3 (Roasted at 720℃) Sample 4 (Roasted at 680℃) D 10 (μm) 5.63 3.52 4.74 7.59 D 50 (μm) 16.5 7.96 28.4 16.2 D 90 (μm) 131.1 18.2 127.6 131.7 Specific surface area (m²) 2 / g) 0.13 1.47 0.17 0.22 Bulk density (g / cm³) 3 ) 3.5 1.5 4.8 3.8

[0123] [BET Specific Surface Area] The BET specific surface area of ​​the bismuth oxide powders (samples 1, 2, 3 and 4) obtained in Example 1 was measured using a specific surface area measuring apparatus (Quantachrome, Monosorb MS-21). The obtained specific surface area values ​​are summarized and shown in Table 1.

[0124] [Bulk Density] The bulk density of the bismuth oxide powders (samples 1, 2, 3 and 4) obtained in Example 1 was determined. The bulk density was measured by adding 1 ml of each sample to a 5 ml graduated cylinder. The obtained bulk density values ​​are summarized and shown in Table 1.

[0125] [XRD Determination] XRD determination was performed on the bismuth oxide powders (sample 1, sample 2, sample 3 and sample 4) obtained in Example 1. The conditions for XRD determination are summarized and shown in Table 2 below.

[0126] [Table 2] Manufacturer Rigaku Co., Ltd. model SmartLab Tube voltage (kV) 40 Tube current (mA) 30 Measurement speed (deg / min) 25 Measurement step (deg) 0.01 Entrance slit 2 / 3 deg Long side restricts slit 10.0 mm Light-receiving slit 1 8.000 mm Light-receiving slit 13.000 mm

[0127] The obtained XRD results are shown in Figures 1A, 1B, 1C, and 1D. Figure 1A shows the XRD results of bismuth oxide powder of Sample 1 (calcined at 700°C) obtained in Example 1. Figure 1B shows the XRD results of bismuth oxide powder of Sample 2 (calcined at 500°C) obtained in Example 1. Figure 1C shows the XRD results of bismuth oxide powder of Sample 3 (calcined at 720°C) obtained in Example 1. Figure 1D shows the XRD results of bismuth oxide powder of Sample 4 (calcined at 680°C) obtained in Example 1. In each figure, for comparison, the graphs of Bi2O3 and Bi5O7NO3 are shown side by side with the graphs of the sample results. In Figures 1A, 1B, 1C and 1D, the top section shows the samples 1, 2, 3 and 4 respectively, the middle section shows the sample Bi5O7NO3, and the bottom section shows the sample Bi2O3.

[0128] As shown in Figure 1A, all peaks of sample 1 are consistent with those of Bi2O3, indicating that a single phase of Bi2O3 has been formed. The characteristic 10-15° peak or the peak near 30° of Bi5O7NO3 was not observed in sample 1.

[0129] On the other hand, as shown in Figure 1B, since the peaks of sample 2 are consistent with the peaks of Bi5O7NO3, it can be known that a considerable amount of Bi5O7NO3 is present. Since the peaks of Bi2O3 appear around 25° or 45°, it can also be known that Bi2O3 is present.

[0130] As shown in Figures 1C and 1D, samples 3 and 4, like sample 1, all have peaks consistent with those of Bi2O3, indicating that a single phase of Bi2O3 has been formed. The characteristic 10-15° peak or peak near 30° of Bi5O7NO3 was not observed in samples 3 and 4.

[0131] [Example 3: Dissolution test] A dissolution test was conducted on the bismuth oxide powder (sample 1 and sample 2) obtained in Example 1 to study its solubility.

[0132] Prepare 500 ml of an aqueous solution of 200 g / L methanesulfonic acid in a beaker. Place a 64 mm stir bar in the beaker and stir continuously at 360 rpm.

[0133] Add 5.0 g of bismuth oxide of sample 1 or sample 2 to the aqueous methanesulfonic acid solution in the beaker and stir continuously.

[0134] Observe the state of bismuth oxide dissolution in the methanesulfonic acid aqueous solution, and take out a portion of the solution at fixed intervals and measure it using a digital turbidimeter (manufacturer: Kyoritsu Chemical Research Institute, product name: (model) DTC-4DG).

[0135] The turbidity colorimeter was used for measurements under the following conditions: Turbidity measurement wavelength: 860 nm; Colorimetry measurement wavelength: 390 nm

[0136] The results obtained are summarized and shown in Table 3.

[0137] [Table 3] Sample 1 (Roasted at 700℃) Sample 2 (Roasted at 500℃) Sample 3 (Roasted at 720℃) Sample 4 (Roasted at 680℃) Turbidity chromaticity Turbidity chromaticity Turbidity chromaticity Turbidity chromaticity 5 min More than 20 0 More than 20 0 15.1 0 0.9 0 10 min 0 0 More than 20 0 0 0 0 0 15 min 0 0 5.8 0 0 0 0 0 20 min 0 0 0 0 0 0 0 0

[0138] Photographs of the appearance of bismuth oxide of sample 1 dissolved in methanesulfonic acid aqueous solution are shown in Figure 2A (after 0 minutes of immersion), Figure 2B (after 5 minutes of immersion), Figure 2C (after 10 minutes of immersion), Figure 2D (after 15 minutes of immersion), and Figure 2E (after 20 minutes of immersion).

[0139] As shown in Figures 2A to 2E, in the bismuth oxide of sample 1, the turbid solution immediately after being added (0 minutes later) becomes a slightly white and transparent solution after 5 minutes, and becomes a colorless and transparent solution after 10 minutes.

[0140] Photographs of the appearance of bismuth oxide in sample 2 after being dissolved in the aqueous methanesulfonic acid solution are shown in Figure 3A (after 0 minutes of immersion), Figure 3B (after 5 minutes of immersion), Figure 3C (after 10 minutes of immersion), Figure 3D (after 15 minutes of immersion), and Figure 3E (after 20 minutes of immersion).

[0141] As shown in Figures 3A to 3E, in the bismuth oxide of sample 2, the white and yellow mixed yellow turbid solution immediately after being added (after 0 minutes) maintained the same degree of yellow turbidity after 5 minutes, became a solution with residual light yellow turbidity after 10 minutes, became a light yellow transparent solution after 15 minutes, and became a colorless transparent solution after 20 minutes.

[0142] In Samples 1 and 2, although the reason for the large difference in solubility in the dissolution test of Example 3 is unclear, the inventors believe that the difference in solubility is caused by the difference in the characteristics shown in the analysis results of the bismuth oxide powder of Example 2.

[0143] [Example 4: Alpha Ray Measurement] Alpha ray measurement was performed on the bismuth oxide powder (sample 1) obtained in Example 1. Since it was difficult to measure directly in the form of oxide powder, the bismuth oxide powder (sample 1) was heated to 450°C for 5 hours under atmospheric pressure with a hydrogen flow rate of 0.5 L / min to reduce it to metallic Bi. The obtained metallic Bi was then cast into a plate shape (28 cm × 31 cm, approximately 2.5 mm thick) using a graphite mold. After acid washing with 3 mol / L dilute nitric acid at room temperature, the alpha ray measurement was performed using a Model-1950 apparatus manufactured by Alpha Sciences Inc. In this apparatus, the gas used was 90% argon and 10% methane, with a gas flow rate of 250 ml / min. The measurement time for both the background and the sample was set to 104 hours. The first 4 hours of the measurement period were designated as the time required for rinsing the measurement chamber, and the remaining 5 to 104 hours were designated as the time required for data measurement. Since trace amounts of alpha rays (background (BG) alpha rays) are emitted from the measurement device, the value obtained by subtracting the background alpha ray count from the alpha ray count measurement data was evaluated as the alpha ray count of metallic bismuth. The obtained results are shown in Table 4 below.

[0144] [Table 4] Alpha ray dose (cph / cm) 2 ) Sample 1 0.001044

[0145] As shown in Table 4, the metallic bismuth obtained by reducing bismuth oxide of sample 1 has an extremely low α-ray content, that is, the estimated α-ray content of bismuth oxide powder (sample 1) is at least below 0.002 cph.

[0146] [Example 5: Impurity Determination] The impurity content of the bismuth oxide powder (sample 1) obtained in Example 1 was determined by GD-MS. The determination by GD-MS was performed under the following conditions: Apparatus: Astrum (manufactured by Nu Instruments); Discharge current: 2.0 mA; Discharge voltage: 1.0 kV; Discharge time: approximately 1 hour; Discharge gas: Ar

[0147] The results obtained are shown in Tables 5-1 to 5-3 below. In Tables 5-1 to 5-3, unless otherwise specified, the values ​​of impurity content are in wtppm. In the tables, the inequality sign (<) indicates that the lower limit of quantitation not specified separately has been reached.

[0148] [Table 5-1] analyze element wtppm analyze element wtppm Li <0.005 Ti 0.46 Be <0.005 V <0.005 B 0.47 Cr 0.006 F 0.07 Mn <0.01 Na 0.13 Fe 0.10 Mg 0.016 Co <0.005 Al 0.45 Ni <0.005 Si 13 Cu <0.5 P 0.032 Zn <0.05 S 0.49 Ga 0.34 Cl 8.7 Ge <0.05 K <0.05 As <0.05 Ca 0.11 Se <0.1 Sc <0.005 Br 0.04

[0149] [Table 5-2] analyze element wtppm analyze element wtppm Rb <0.005 I <0.005 Sr <0.005 Cs <0.005 Y <0.005 Ba 0.034 Zr <0.005 La <0.005 Nb <0.5 Ce <0.005 Mo <0.5 Pr <0.005 Ru 0.010 Nd <0.005 Rh 0.008 Sm <0.005 Pd <0.01 Eu <0.005 Ag 0.05 Gd <0.005 Cd 0.07 Tb <0.005 Sn 2.6 Dy <0.005 Sb <0.01 Ho <0.005 Te 0.66 Er <0.005

[0150] [Table 5-3] analyze element wtppm Tm <0.005 Yb <0.005 Lu <0.005 Hf <0.01 W <2 Re <0.005 Os <0.005 Ir 0.03 Pt <0.01 Hg <0.05 TI <0.01 Pb <0.05 Th <0.005 U <0.005

[0151] Regarding the impurity content measured above, if it is counted and totaled as the lower limit value when it does not reach the lower limit value, the impurity content of sample 1 is calculated to be 31.99 wtppm.

[0152] Based on the impurity content of 31.99 wtppm, the purity of the bismuth oxide powder in Sample 1 is calculated to be 99.9968 wt%. [Industrial Applicability]

[0153] The present invention provides bismuth oxide with reduced alpha radiation. The present invention is of industrial usefulness. [Simplified Explanation of the Diagram]

[0012] [Figure 1A] shows the XRD results of bismuth oxide powder of Sample 1 (calcined at 700℃) obtained in Example 1. [Figure 1B] shows the XRD results of bismuth oxide powder of Sample 2 (calcined at 500℃) obtained in Example 1. [Figure 1C] shows the XRD results of bismuth oxide powder of Sample 3 (calcined at 720℃) obtained in Example 1. [Figure 1D] shows the XRD results of bismuth oxide powder of Sample 4 (calcined at 680℃) obtained in Example 1. [Figure 2A] is a photograph of the appearance of bismuth oxide of Sample 1 after dissolving in a methanesulfonic acid aqueous solution (after 0 minutes). [Figure 2B] is a photograph of the appearance of bismuth oxide of Sample 1 after dissolving in a methanesulfonic acid aqueous solution (after 5 minutes). [Figure 2C] is a photograph of the appearance of bismuth oxide of Sample 1 after dissolving in a methanesulfonic acid aqueous solution (after 10 minutes). [Figure 2D] is a photograph of the appearance of bismuth oxide in sample 1 after dissolution in methanesulfonic acid aqueous solution (15 minutes after immersion). [Figure 2E] is a photograph of the appearance of bismuth oxide in sample 1 after dissolution in methanesulfonic acid aqueous solution (20 minutes after immersion). [Figure 3A] is a photograph of the appearance of bismuth oxide in sample 2 after dissolution in methanesulfonic acid aqueous solution (0 minutes after immersion). [Figure 3B] is a photograph of the appearance of bismuth oxide in sample 2 after dissolution in methanesulfonic acid aqueous solution (5 minutes after immersion). [Figure 3C] is a photograph of the appearance of bismuth oxide in sample 2 after dissolution in methanesulfonic acid aqueous solution (10 minutes after immersion). [Figure 3D] is a photograph of the appearance of bismuth oxide in sample 2 after dissolution in methanesulfonic acid aqueous solution (15 minutes after immersion). [Figure 3E] is a photograph of the appearance of bismuth oxide in sample 2 after dissolution in methanesulfonic acid aqueous solution (20 minutes after immersion).

Claims

1. A bismuth oxide powder having an alpha radiation amount of less than 0.002 cph / cm2 and a bismuth oxide purity of more than 99.99 wt%.

2. The bismuth oxide powder of claim 1 has a specific surface area in the range of 0.1 to 1.0 m2 / g.

3. The bismuth oxide powder of claim 1 has a bulk density in the range of 2.5 to 6.0 g / cm3.

4. The bismuth oxide powder of claim 1 has a particle size D50 in the range of 10 to 30 μm.

5. The bismuth oxide powder in request item 1 has a Na content of less than 5 wtppm.

6. Bismuth oxide powder as claimed in claim 1, wherein, The value of "particle size D90" - "particle size D10" / "particle size D50" is in the range of 4.0 to 10.

0.

7. Bismuth oxide powder as claimed in claim 1, wherein, When 5.0 g of bismuth oxide powder is added to 500 ml of a 200 g / L methanesulfonic acid aqueous solution and stirred for 10 minutes, the turbidity is 0-5 and the color is 0-5.

Images