The Thermal Dehydration and Recrystallization of Chromic Hydrate

Abstract

Chromic hydrate, Cr2O3. xH2O, precipitated from aqueous chromic chloride solution with (i) ammonia and (ii) light magnesia, was characterised in air and in nitrogen at temperatures up to 800’C using DTA, TGA, XRD, electron transmission microscopy and BET surface area measurements in order to gain an insight into its reactivity towards a chloridising enpironment. This is relevant to a proposed new low-temperature process for the production of anhydrous chromic chloride, CrCl3. The value of AH glow for NH3-precipitated chromic hydrate in an at- mosphere of nitrogen was found to be -58 kj mol-1 and occurred in two steps at 587 and 636’C.

Keywords

• The Thermal Dehydration
• Recrystallization
• Chromic Hydrate

References

1. Communications Faculty of Sciences University of Ankara Series B Chemistry and Chemical Engineering