The hydration reaction of the following substances were examined from the quantitative viewpoint : P-CSA (free lime-C₄AF-anhydrite type expansive additive), combination of P-CSA, C₃A and gypsum, combination of P-CSA and alite. In the hydration reaction of P-CSA, free lime reacts abruptly with water in the initial stage to form calcium hydroxide, and later C₄AF and anhydrite react gradually to form ettringite. In the hydration reaction of C₃A-gypsum-P-CSA system, the reaction ratio of C₃A was relatively small in the initial stage of hydration but rapidly increased during 3 to 7 days of reaction period. The reaction ratio of gypsum and anhydrite showed a high value i the initial stage. As a result, although the mole ratio of SO₃/Al₂O₃ in the starting composition of the system showed a similar value to the theoretical value of monosulfate, the mole ratio of SO₃/Al₂O₃ increased in the initial stage of reaction, and ettringite was formed. It is inferred that P-CSA realizes expansion by generating a large quantity of ettringite utilizing the reaction of C₃A in cement, in combination with the reaction to generate calcium hydroxide from free lime in the expansive additive.

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For the purpose of effective HCl gas removal from municipal solid waste incineration, a comparison was made for CaO and Na₂CO₃ sorbent for HCl sorption, in terms of HCl sorption capacity as well as HCl sorption rate. HCl gas sorption tests of CaO and Na₂CO₃ were conducted by using a flowtype tube reactor packed with fine particles under the particle diameters of 5 μm in the temperature range of 473-1073 K, at a total flow rate of 3×10^-4 m³·min^-1, of which the inlet gas mixture were HCl (1000 ppm) -N₂. As the results, a maximum conversion value of 0.92 for HCl removal by CaO was obtained at 873 K. On the other hand a maximum conversion value of 0.87 was obtained for Na₂ CO₃ at 673 K. The rates of HCl sorption by CaO and Na₂CO₃ were explained by chemical reaction rate control under the present conditions. The pore of CaO was confirmed to disappear by sintering above the temperature of 973 K, which led to the reduction of HCl sorption capacity. A maximum HCl sorption capacity of Na₂CO₃ was obtained at 673 K, in which the crystal structure of Na₂CO₃ started to transform to Natrite. The reduction of HCl sorption capacity was attributable to the reduction of pore volume caused by the change in crystal structure.

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中空球状凝集粒子と過酸化水素 (H₂O₂) の発泡作用を利用して水酸アパタイト (Ca₁₀ (PO₄) ₆ (OH) ₂; HAp) 多孔体を作製した.伸空球状HAp凝集粒子は硝酸カルシウム (Ca (NO₃) ₂) とリン酸水素アンモニウム ((NH₄) ₂HPO₄) の混合水溶液を600℃で噴霧熱分解し, さらに得られた粉体を600℃で1時間か焼して調製した.HAp粉体に異なる濃度のH₂O₂水溶液を加えて得られたスラリーを吸引ろ過し, 直径20mmおよび厚さ4mmの成形体を作製した.この成形体を50℃で1時間加熱したのち, 900℃から1200℃の温度範囲でそれぞれ5時間焼成した.1000℃, 5時間焼成した場合に焼結体の全気孔率は最大 (71.7%) となり, その時の気孔径は0.7μm, 5～100μmおよび100～200μmの範囲に存在していた.また, 発泡剤であるH₂O₂の濃度を0～20 mass%の範囲で変化させることによって, HAp多孔体の全気孔率を61.2%から71.7%まで直線的に変化させることができた.

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Calcium phosphate films were deposited on stainless steel plate under various pH conditions of electrolytic solution of CaHPO₄·2H₂O by electrochemical procedure at room temperature. The pH at electrolyte dissolution was adjusted by nitric acid and the subsequent pH was adjusted by ammonium hydroxide. Calcium-deficient hydroxyapatite film a-DAp was deposited with pH 0.96 at the electrolyte dissolution and with pH 5.82 at the electrolysis initiation. The pH of the electrolytic solution was nearly constant from start to about 200 min and gradually decreased to about 3 after 400 min. The a-DAp had a feature of broccoli-like mass of which crystallinity was very low and the molar ratio Ca/P of 0.98. The low molar ratio was explained by substitution of H⁺ for Ca²⁺ during long time electrolysis in the bath of pH about 3.

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