Equlibrium between Liquid Fe‐Ti‐O Slags and Metallic Iron

The compositions of Fe‐Ti‐O melts in equilibrium with molten iron have been determined by melting mixtures of TiO₂, metallic iron and various additions of either Fe₂O₃ or metallic titanium in a high‐frequency induction furnace. The furnace had a vertically segmented water‐cooled copper crucible which enabled the mixture to be melted with vigorous stirring inside a freeze‐lining of about 1 mm thickness. The slag compositions were found to form a curved line in the ternary diagram FeTiO₃ – TiO₂ – Ti₂O₃ with its highest TiO₂ content slightly higher than the pseudobrookite (M₃O₅) composition FeTi₂O₅ ‐ Ti₃O₅. The slags were examined by X‐ray diffraction and microprobe analyses. For all slags the main phase was pseudobrookite (M₃O₅) solid solution with some rutile or Magnéli phase (Ti_nO_2n‐1). The most iron‐rich and the most titanium‐rich slags contained also some FeTiO₃, respectively Ti₂O₃ phase. A melting point diagram is suggested with a eutectic groove running between the M₃O₅ phase and the TiO₂ or Magnéli phase from about 1665°C for the iron‐free to the less than 1500°C for the titanium‐free slags.