水酸化カルシウムの加熱炭酸化
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- 山田 英夫
- 九州工業技術試験所
書誌事項
- タイトル別名
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- Thermal Carbonation of Calcium Hydroxide
説明
The reaction process of Ca (OH) 2 with CO2 at high temperatures was examined by TGA, DTA, high temperature XRD and SEM. Two kinds of Ca (OH) 2, sample-A (ay. 0.5 μm in diameter, 0.1 μm in thickness, hexagonal plate) and sample-B (ay. 7 μm in diameter, 15 μm in thickness, hexagonal prism), were prepared by mixing a 1/2 mol/l KOH solution with a 1/4 mol/l CaCl2 solution under different conditions.<BR>The thermal carbonation occured in the following three steps : <BR>Step-1, between 250° and 300°C, was regarded as a surface reaction. This reaction made a little weight gain in TG curve and a small exothermic peak in DTA curve to finer particles like sample-A. The thickness of the CaCO3 layer after completion of this process was about 1.2 nm for sample-A.<BR>Step-2, between 300°C and dissociation temperatures of Ca (OH) 2, was regarded as a direct reaction of Ca (OH) 2 with CO2. The reaction rate for this process obeyed the following relation, [1- (1-α) 1/3] n =Kt. The n values for rate equation of sample-A and sample-B were 2 and 3 and the apparent activation energies for this process of sample-A and sample-B were 44.8 and 52.0 kcal/mol, respectively. This reaction would be the diffusion rate controlling process.<BR>Step-3, a reaction between CaO and CO2, occurred immediately after dissociation of Ca (OH) 2. This reaction was dominant at lower CO2 concentration or for larger particles like sample-B.
収録刊行物
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- 石膏と石灰
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石膏と石灰 1982 (178), 121-128, 1982
無機マテリアル学会
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詳細情報 詳細情報について
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- CRID
- 1390282680366086784
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- NII論文ID
- 130004011201
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- ISSN
- 21854351
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- データソース種別
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- JaLC
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可
