发明名称 |
Process for preparing calcium carbonate |
摘要 |
Inexpensive spindle- or rice-like calcium carbonate giving useful properties for brightness, opacity and wire abrasion resistance as a paper filler is provided by taking advantage of the causticization step. When a white liquor is used for slaking a quick lime, the quick lime used in the slaking reaction of a first step has a calcium carbonate content of 10% by weight or less and is slaked with the white liquor at a concentration of 20 to 60% to prepare a milk of lime. When a green liquor is used for slaking a quick lime, the quick lime used in the slaking reaction of a first step has a calcium carbonate content of 0.1 to 10% by weight and is slaked with the green liquor at a concentration of 20 to 60% to prepare a milk of lime. In a second step, causticization reaction takes place at a green liquor loading rate of 0.02 to 0.5 cc (green liquor)/min/g (quick lime) at a reaction temperature of 20 to 105° C. to afford spindle- or rice-like calcium carbonate.
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申请公布号 |
US6627170(B2) |
申请公布日期 |
2003.09.30 |
申请号 |
US19990319074 |
申请日期 |
1999.06.01 |
申请人 |
NIPPON PAPER INDUSTRIES CO., LTD. |
发明人 |
TAKAHASHI KAZUTO;KANAI KIYOSHI;NANRI YASUNORI;OKAMOTO YASUHIRO |
分类号 |
C01F11/18;D21C11/00;D21H17/67;D21H19/38;D21H21/52;(IPC1-7):C01F11/18 |
主分类号 |
C01F11/18 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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