ケイ酸カルシウム水和物の耐酸性に及ぼす原料のCaO/SiO_2モル比および加熱処理温度の影響 Effect of CaO/SiO_2 Mole Ratio of Batch Mixture and Temperature of Thermal Treatment on Acid Resistance of Calcium Silicate Hydrate
Calcium silicate hydrates were synthesized using batch mixtures with Ca/Si molar ratio of 0.4-1.0 under hydrothermal conditions at 180-190°C. Acid resistance was evaluated by measuring the dissolved amounts of the heat-treated products at 800-1100°C when treated with hydrochloric acid solution of pH 2. Xonotlite was formed from the batch mixture with a Ca/Si molar ratio of 1.0, it transform to β-wollastonite by heat treatment, and it was found that the formed β-wollastonite easily dissolved in hydrochloric acid solution of pH 2.<BR>1.1 nm tobermorite was formed from the batch mixture with Ca/Si molar ratio of 0.4 and 0.6, and it transformed to β-wollastonite at temperature above 1000°C, and heat-treated products hardly dissolved in hydrochloric acid solution of pH 2. β-wollastonite was formed from 1.1 nm tobermorite by heat treatment as a phase transition product with excess silica content. It was suggested that the excess silica content was deposited on the surface of β-wollastonite and it improved the acid resistance of heat-treated product.
- Journal of the Society of Inorganic Materials, Japan : セッコウ・石灰・セメント・地球環境の科学
Journal of the Society of Inorganic Materials, Japan : セッコウ・石灰・セメント・地球環境の科学 14(328), 152-158, 2007-05-01
The Society of Inorganic Materials, Japan