GB869128A - Process for the production of niobium and tantalum chlorides - Google Patents

Abstract

Niobium and/or tantalum pentachlorides are obtained from materials containing them in oxidised form, for example as oxides or niobates, by preparing a dry mixture of the material with aluminium in amount at least stoichiometrically equivalent to the reducible metal oxides present, and an amount of carbon, for example pulverised coke, in excess, preferably 50-200%, of that required to form the carbides of the metals, igniting in an inert atmosphere, for example argon or nitrogen, to form a sintered carbide product, cooling it and reacting it with chlorine to convert the carbides to the chlorides, substantially free from oxychloride, from which the niobium and tantalum may be recovered, for example by fractional distillation. The ignition is preferably so effected that a temperature of 1600-2200 DEG C. is reached. The starting material may be an ore or concentrate, in which case any oxides of iron, titanium, or silicon present will yield the corresponding chlorides, which may be recovered. The chlorination is preferably effected at 350 DEG C.-600 DEG C. The starting material may first be calcined at 800-1000 DEG C. to remove water, and the mixture with aluminium and carbon may be compacted or formed into pellets with the aid of a binder such as water, in which case the pellets are first dried at below 100 DEG C.