Phase equilibria in the low-TiO2 part of the CaO–MgO–SiO2–Al2O3–TiO2 system at a fixed MgO/CaO mass ratio of 0.2 and Al2O3/SiO2 mass ratio of 0.4.

Adding titanium oxide has become a common practice in modern blast furnace operating procedures. The blast furnace slag is based on the CaO–MgO–Al 2 O 3 –SiO 2 –TiO 2 low titanium slag system rather than CaO–MgO–Al 2 O 3 –SiO 2 system. Phase equilibria in the CaO–SiO 2 –Al 2 O 3 –MgO–TiO 2 system in the low-TiO 2 part have been experimentally determined by means of high temperature equilibration and quenching technique followed by electron probe X-ray microanalysis. Introducing a small quantity of titanium-bearing materials can lower the liquidus temperature. The TiO 2 content in the slag should be controlled below 4.6 wt%, otherwise it will enter the perovskite phase region where the liquidus temperatures increases rapidly. The compositions of the solid solutions corresponding to the liquidus have been precisely measured and should be utilized for developing the thermodynamic database. [ABSTRACT FROM AUTHOR]