Carbochlorination of TiO 2

Abstract

The kinetics of carbochlorination of TiO 2, using TiO 2(s)–carbon(s) powder mixtures and a flowing Ar(g)–Cl 2(g) reaction atmosphere, has been investigated as a function of two parameters: temperature (733–1223 K) and carbon content in the solid mixture. Carbochlorination of TiO 2 exhibits two well-differentiated and successive reaction stages. The first reaction stage occurs immediately and the second stage proceeds at a rate up to two orders of magnitude lower. For both reaction stages, the rate increases with carbon content. The first stage occurs under external chlorine transport control for high carbon contents and under internal mixed control for low carbon contents. The second reaction stage occurs nearly under chemical control at all carbon contents.