Reaction of Hydrogrossular with Hydrogen Chloride Gas at High Temperature

The reaction between hydrogrossular and hydrogen chloride (HCl) gas was performed in a fixed bed reactor above 400 °C. The hydrogrossular was efficiently reacted with HCl gas in the temperature range of 400 to 950 °C and transformed into Ca12Al9.9Si4.05O32Cl5.9 (calcium aluminum chlorosilicate). The crystal structure of the product phase Ca12Al9.9Si4.05O32Cl5.9 was cubic, space group I 3d, with unit cell a = 12.0173(1) Å, and was similar to that of wadalite. The structure consists of a framework of (Al,Si)O4 tetrahedra. A large cavity in the framework accommodates Ca−Cl−Ca linearly coordinated atoms.