Production of niobium powder by magnesiothermic reduction of feed preform

To develop an effective production process of niobium powder, a new preform reduction process (PRP) based on the magnesiothermic reduction of feed preform containing niobium oxide (Nb2O5) was investigated. The feed preform was fabricated from slurry, which was made by mixing Nb2O5 powder, flux (e.g., CaCO3) and binder. Various compositions of preform in the form of plates were prepared using a conventional technique, and the fabricated preform was heated at 1 273 K before reduction in order to remove the binder and water. The sintered solid preform containing Nb2O5 was then placed in a stainless steel container, and made to react with magnesium vapor at a constant temperature, ranging between 1 073 and 1 273 K, for six hours. Niobium powder was recovered from the reduced preform by acid leaching. Niobium metal powder with 99 mass% purity was obtained as a result. This process was found to be suitable for producing a homogenous fine powder, when the composition of flux, and reduction conditions are controlled.