アルミニウム化合物の研究 (第10報)

塩基性硫酸アルミニウムおよびその熱分解物のX線的研究

抄録

X-Ray diffraction pattern of various basic aluminum sulfates and their thermal decomposition products were measured with the Norelco X-ray diffraction apparatus. This has enabled clear discrimination of crystalline and non-crystalline substances. The substance having the composition of Al₃(OH)₅(SO₄)₂⋅5H₂O is a perfect crystal compared to the other substances. The process of the formation of this substance in a solution until completion of crystallization was examined and conditions for the crystal formation were established. It was found that five moles of water in this substance can be divided into 3 moles of zeolite-type water and 2 moles of crystal-type, water and that a crystalline substance is formed again at high temperature after partial decomposition of SO₄. On the contrary, thermal decomposition of other substances at above 900° was assumed to result in the final formation of α-Al₂O₃. The foregoing facts are related to the series of pyrolysis curves and infrared absorption spectra.