Invention Grant
- Patent Title: Spherical calcium carbonate and method of producing the same
- Patent Title (中): 球形碳酸钙及其制造方法
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Application No.: US12791451Application Date: 2010-06-01
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Publication No.: US08012443B2Publication Date: 2011-09-06
- Inventor: Kenshiro Makino , Kazuo Yamashita
- Applicant: Kenshiro Makino , Kazuo Yamashita
- Applicant Address: JP Tokyo
- Assignee: Okutama Kogyo Co., Ltd.
- Current Assignee: Okutama Kogyo Co., Ltd.
- Current Assignee Address: JP Tokyo
- Agency: Bacon & Thomas, PLLC
- Priority: JP2003-050311 20030227
- Main IPC: C01F11/18
- IPC: C01F11/18

Abstract:
When spherical calcium carbonate is produced by blowing a carbon dioxide gas or a carbon dioxide-containing gas into an aqueous suspension containing calcium hydroxide to react them, after start of the reaction, an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof is added to the reaction mixture when carbonation ratio reaches 2 to 10%, and the reaction is further allowed to continue at a low gas blowing rate of 1.0 NL/minute or lower (step (a)). Subsequently, an aqueous suspension containing calcium hydroxide and an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof are added to the reaction mixture, and a carbon dioxide gas or a carbon dioxide-containing gas is introduced to allow to react and thereby produce spherical calcium carbonate having a mean particle diameter of 10 μm or larger. This production method is performed under high velocity revolution from the start of the reaction to the end of the step (a). This method provides calcite type spherical calcium carbonate showing high brightness and small friction coefficient, and having a shape comparatively close to a true sphere and a mean particle diameter of 10 μm or larger.
Public/Granted literature
- US20100239511A1 SPHERICAL CALCIUM CARBONATE AND METHOD OF PRODUCING THE SAME Public/Granted day:2010-09-23
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