Selective Leaching of Vanadium from Boiler Oiled Ash Residue Using Sodium Carbonate-Bicarbonate Binary SolutionAuthor(s): El-Sayed A Manaa
The present work aims to optimize an efficient, economic and environmental hydrothermal method to leach vanadium from boiler ash residue using sodium carbonate and bicarbonate mixture solution. For this purpose, many factors include liquid/solid phase ratio, leaching temperature, leaching time, oxidant addition and it’s percent and ash fineness are studied and optimized. From the obtained results, it is concluded that, maximum vanadium leaching (84.3%) is achieved from grinded ash (74 μm) using carbonate-bicarbonate binary solution at liquid/ash ratio of 20/1 in the presence of KMnO4 as oxidant. The obtained leach liquor is then subjected to pH readjusted at 5-6. This is followed by ammonium chloride (NH4Cl) addition under heating (40°C) and stirring to selective precipitation the leached vanadium species as ammonium meta-metavanadate (NH4VO3). The precipitate is dried at 100°C and then roasted at 750°C to obtain V2O5 oxide.