THE HYDRATION OF THE ALUMINATES OF CALCIUM.: II. THE HYDRATION PRODUCTS OF TRICALCIUM ALUMINATE

Abstract

Further studies on the isometric form of hydrated tricalcium aluminate are reported. These include methods of preparation, crystalline forms, X-ray diffraction pattern, and determinations of solubility and density. The products formed when the hexagonal form of hydrated tricalcium aluminate is dehydrated at definite vapor pressures of Water at 21 °C., were studied. The density, refractive indices, heats of solution in HCl.200 H₂O, and the X-ray diffraction patterns of several probable hydrates were determined. The experimental evidence given indicates that hydrates of 3CaO.Al₂O₃ having 6, 8, 91/2, 101/2, and 12 moles of water are formed, but that the water in excess of 8 moles is very loosely held and that its removal does not materially affect the crystal structure. The exact composition of some of the higher hydrates requires confirmation.