Anhydrous chromium sesquioxide - by reducing chromium (vi) cmpd in hydrogen mixed with inert gas

摘要

Anhydrous Cr2O3 is made by reducing a Cr(VI) cpd. non-thermally-decomposable below 300 degrees C e.g. CrO3, by first heating in a non-reducing atmos at 197-280 degrees C then heating in a reducing atmos of H2 optionally mixed initially with an inert gas, at 250-300 degrees C. To avoid incomplete reduction, the latter part of the reduction, is performed using H2 in the absence of inert gas. In the parent patent the reducing atmos, consists of an H2 inert gas mixture (throughout), the reduction being more complete.