Resist film and method of forming pattern
US-2015168839-A1 · Jun 18, 2015 · US
Low alpha dose barium sulfate particle, and use and process for producing the same
US11040888B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-11040888-B2 |
| Application number | US-201616063748-A |
| Country | US |
| Kind code | B2 |
| Filing date | Dec 23, 2016 |
| Priority date | Dec 25, 2015 |
| Publication date | Jun 22, 2021 |
| Grant date | Jun 22, 2021 |
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Abstract
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The invention provides a low alpha dose barium sulfate particle having a silica content of 0.6% by weight or less, an average particle diameter of 1 μm or less, a sulfur content of 10 ppm or less, and an alpha dose of 0.07 cph/cm2 or less.
First claim
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The invention claimed is: 1. A process for producing a low alpha dose barium sulfate particle comprising: subjecting a crushed ore obtained by crushing barite ore and having an average particle diameter of 5-50 μm, an alpha dose of 1 cph/cm 2 or less, and a silica content in a range of 0.65-1% by weight to: (a) an elutriation treatment and a media grinding in this order; or (b) a media grinding treatment and a sieving treatment in this order; or (c) an elutriation treatment, a media grinding treatment and a sieving treatment in this order, wherein in the media grinding treatment, the crushed ore is ground to a powder ore having an average particle diameter of 1 μm or less while coarse particles are removed by the elutriation treatment and/or the sieving treatment to obtain a powder ore having a silica content of 0.6% by weight or less, thereby obtaining a low alpha dose barium sulfate particle having an average particle diameter of 1 μm or less, a silica content of 0.6% by weight or less, an alpha dose of 0.07 cph/cm 2 or less, and a sulfur content of 10 ppm or less. 2. The process for producing low alpha dose barium sulfate particles according to claim 1 , wherein the crushed ore is subjected to an acid heating treatment, and then to the step (a), (b), or (c). 3. A process for producing a surface-treated low alpha dose barium sulfate particle comprising: subjecting a crushed ore obtained by crushing barite ore and having an average particle diameter of 5-50 μm, an alpha dose of 1 cph/cm 2 or less, and a silica content in a range of 0.65-1% by weight to: (a) an elutriation treatment and a media grinding in this order; or (b) a media grinding treatment and a sieving treatment in this order; or (c) an elutriation treatment, a media grinding treatment and a sieving treatment in this order, wherein in the media grinding treatment, the crushed ore is ground to a powder ore having an average particle diameter of 1 μm or less while coarse particles are removed by the elutriation treatment and/or the sieving treatment to obtain a powder ore having a silica content of 0.6% by weight or less, thereby obtaining a low alpha dose barium sulfate particle having an average particle diameter of 1 μm or less, a silica content of 0.6% by weight or less, an alpha dose of 0.07 cph/cm 2 or less, and a sulfur content of 10 ppm or less, and surface-treating the low alpha dose barium sulfate particle with at least one of silica, silica hydrate and aluminum hydroxide. 4. The process for producing surface-treated low alpha dose barium sulfate particles according to claim 3 , wherein the crushed ore is subjected to an acid heating treatment, and then to the step (a), (b), or (c).
Assignees
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Classifications
Alpha, beta or gamma radiation related properties · CPC title
Ingredients treated with inorganic substances · CPC title
- C01F11/462Primary
Sulfates of Sr or Ba · CPC title
inorganic · CPC title
Sulfates · CPC title
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- What does patent US11040888B2 cover?
- The invention provides a low alpha dose barium sulfate particle having a silica content of 0.6% by weight or less, an average particle diameter of 1 μm or less, a sulfur content of 10 ppm or less, and an alpha dose of 0.07 cph/cm2 or less.
- Who is the assignee on this patent?
- Sakai Chemical Industry Co
- What technology area does this patent fall under?
- Primary CPC classification C01F11/462. Mapped technology areas include Chemistry & Metallurgy.
- When was this patent published?
- Publication date Tue Jun 22 2021 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 2 related publications on this page (citations in our corpus or others sharing the same primary CPC).