Mechanochemical synthesis of rare earth orthovanadates from R₂O₃ (R = rare earth elements) and V₂O₅ powders

Lanthanum oxide (La₂O₃) and vanadium pentoxide (V₂O₅) mixture was milled by planetary ball mill to investigate the formation of lanthanum orthovanadate (LaVO₄) by mechanochemical reaction. The formation of LaVO₄ during milling was monitored by a suite of analytical methods including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and inductivity coupled plasma-atomic emission spectrometry (ICP-AES). The LaVO₄ powder prepared by 4 h milling consists of particles with size up to several microns and has specific surface area of 9.70 m²/g. The mechanochemical method can be applied to the synthesis of other rare earth orthovanadates (RVO₄; R = Y, Nd, Sm, Gd, Dy and Er). RVO₄ prepared by this method has both zircon-type low pressure phase and scheelite-type high pressure one.