2007 Volume 48 Issue 8 Pages 2244-2251
With a view to developing a new process for the production of metallic titanium (Ti) powder, the preform reduction process (PRP) based on the calciothermic reduction of Ti concentrates or ore (TiO2) was investigated in this study. A Ti feed preform was fabricated at room temperature by casting and drying a prepared slurry that constituted a mixture of Ti concentrates (upgraded ilmenite (UGI), 97.1% TiO2) or Ti ore (rutile, 96.4% TiO2 with iron (Fe) as the major impurity), flux (CaCl2), and binder. In some experiments, carbon (C) powder was added into the slurry for an efficient Fe removal. The fabricated feed preform was calcined at 1273 K for removing the water and binder present in the preform. During the calcination of the feed preform, some metal impurities such as Fe were removed by selective chlorination. Multiple pieces of the sintered preform were then reacted with metallic calcium (Ca) vapor at 1273 K in a stainless steel reaction vessel, and Ti oxide (TiO2) in the preform was reduced to metal. After reduction, the reduced preform was subjected to a leaching process using an acetic acid solution and a hydrochloric acid solution in order to remove the by-product calcium oxide (CaO), excess reductant Ca, and other impurities in the sample. After leaching, the obtained powder was then rinsed and dried; this powder was shown to be metallic Ti with a purity of 99% up. It was experimentally demonstrated that PRP is a feasible technique to produce metallic Ti powder directly from Ti concentrates or ore.