Ferro-niobium

Table 7.2 Influence of nitrogen content on the phase composition of SHS-nitrided ferro-niobium.

Other metals having very stable oxides can be reduced by the aluminothermic reaction to produce useful ferro-alloys. Niobium oxide, NbO, can be reduced to form a ferro-alloy by the inclusion of iron in the reacting mixture as haematite or magnetite, depending on the niobium content which is required in the product. 

The route shown in Fig. 9.12 is one which has been operated commercially in the U.K. on a fairly small scale, quite successfully. As in the case of niobium, it is convenient to use the crude ferro alloy as feed to the chlorination stage. The chloride purification stages lead to pure vanadium trichloride, which is reduced with magnesium in a manner similar to that employed for titanium, zirconium or hafnium. Some of the complexities, applicable in the latter processes owing to the volatile nature of the chlorides, are absent with vanadium. The vanadium metal sponge has some properties in common with the other metal sponges. 

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