Formation of ultrafine Nb₂O₅ powder from ferroniobium via alkoxide

NbCl₅ containing FeCl₃ was produced by direct chlorination of ferroniobium powder. Nb(OBuⁿ)₅ and Nb(OPrⁱ)₅ were synthesized and purified from a NbCl₅-FeCl₃ mixture by ammonia method. Primary separation via chloride and following purification via Nb(OBuⁿ)₅, a decreased iron content under 10 ppm and an industrially available process is proposed. Purification via Nb(OPrⁱ)₅ was effective for tantalum removal. Monodispersed UFP Nb₂O₅ with average particle size of 0.2 μm was obtained by hydrolysis of Nb(OBuⁿ)₅. Characterizations of UFP Nb₂O₅ such as crystal structure and thermal stability were conducted. PZC obtained from electrophoretic measurement was 3.3.