Reduction/carburisation of columbite concentrate
The carbothermic reduction of columbite has been investigated at 1400°C utilising coal and graphite as alternative sources of carbon. Reduction to an iron-carbon matrix and NbC and TaC carbides occurs readily with complete reduction being achieved in 45 min with coal and 100 min with graphite. The reduction occurs by the intermediate formation of iron-niobium-tantalum suboxides. Reduction with CO is slow compared to the reduction with carbon. Reduction of the ilmenite component of the columbite concentrate studied yields titanium oxy-carbide in an iron-carbon matrix. The feasibility of utilising carbothermic reduction as a means of exploiting columbite is discussed.