Understanding the solid-state calcium metavanadate synthesis pathway

The calcium metavanadate (CaV 2 O 6 ) synthesis was studied by a conventional solid-state reaction in a CaCO 3 - V 2 O 5 mixture (1:1) molecular ratio in air. The synthesis began at 400 degrees C and at temperatures above 620 degrees C speeds up due to formation of an eutectic compound. After one hour at 650 degrees C complete synthesis of the metavanadate is achieved. The crystal phase and the particle morphologies of the CaV 2 O 6 were analyzed by Powder X-ray Diffraction (PXRD), Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). A single phase and rounded particles with smooth faces were found. The combination of several experiments allowed the determination of the synthesis pathway, which occurred from CaCO 3 and not from CaO. If the starting calcium compound is the oxide, the first step could be carbonation process with the atmospheric CO 2 .