There have been carried out studies aimed at reaching the 100 per cent yield of sodium metavanadate and hydrochloride synthesis from vanadium pentoxide and sodium chloride in presence of water vapor. Quartz sand was added into reaction medium as the support of reaction mixture. Experiments were carried out for various support content (20 to 200% ratio to the reaction mixture) and its various granulation (grain diameter: 2 mm, 3 mm and 4 mm). 100% conversion of V2O5 into NaVO3 was reached for silica diameter of 3 mm and its 80% mass ratio to the reaction mixture.