Low alpha dose barium sulfate particle, and use and process for producing the same
AssigneeSakai Chemical Industry Co., Ltd.
InventorsSatoru SUEDA, Hironobu OGATA
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Abstract
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.
Claims13
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.
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 and an alpha dose of 1 cph/cm2 or less 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/cm2 or less, and a sulfur content of 10 ppm or less.
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 and an alpha dose of 1 cph/cm2 or less 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/cm2 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.
Dependencies are inferred from the claim text.