Influence of Reacting Atmosphere on Isothermal Decomposition of Ammonium Metavanadate

Ammonium metavanadate (AMV) was decomposed under pure oxygen, air, nitrogen, vacuum and controlled humidity, in the temperature range of 453 to 623 K. Three well established limiting conversions appear corresponding to the formation of ammonium tetravanadate at 453 K (50%), ammonium hexavanadate at 503 K (67%), and V2O5 at 623 K (100%). Oxidizing atmospheres have a retarding effect at 453 K but an accelerating one at 573 to 623 K, as observed from the reaction limiting time and rate constant. In addition to H2O and N2, oxygen plays an important role in the oxidation of ammonia to N2, and in the proton transfer process.