On the tantalum behaviour during niobium precipitation from gaseous phase

The process of joint reduction of NbCl5 and TaCl5 in the range of low concentrations of tantalum in the gas phase was studied. The distributions of tantalum concentrations from the niobium precipitate and also the effect of the support and the composition of the gas mixture NbCl5 + TaCl5 + H2 on the tantalum content in the precipitate were determined. It was established that in the course of hydrogen reduction of NbCl5 the niobium is freed from tantalum. The results of purification of the obtained niobium precipitate from the hard-to-remove tantalum impurity in the concentration range from 2.5x10-2 to 5.0x10-5 wt.% Ta are evaluated