Determination of α- and β-Calcium Sulfate Hemihydrates in their Mixture Using TG, Calorimeter and XRD

概要

論文の詳細を見る
This quantitative analysis of α- and β-hemihydrates is based on the fact that the transformation ratio of them to II CaSO4 is remarkably different under moderate conditions of heating. When α- and β-hemihydrates are heated at 200°C for 24 hr, they are partly transformed to II CaSO4 with the following composition, respectively αII=55.0%II CaSO4+45.0%αCaSO4·1/2H2O βII=14.8%II CaSO4+85.2%βCaSO4·1/2H2O Therefore, when a mixture of α- and β-hemihydrates is heated under the same condition, the compositions of the heat-treated mixture consist of a mixture of αII and βII. The determination of each component in the mixture of α- and β-hemihydrates can be easily made by the determination of all and 1311 in the heat-treated mixture. Using this technique, determinations of crystal water, heat of hydration and content of II CaSO4 in the mixture of an and βII are examined by means of TG, calorimeter and XRD. The relative standard deviation is used as a measure of scatter of the experimental values. The relative standard deviation is less than 2% for both crystal water and heat of hydration and 3. 74-4. 55% for content of II CaSO4. This indicates that the determination of both crystal water and heat of hydration can be accurately carried out on the mixture of an and βII
無機マテリアル学会の論文