  High purity iron is obtained from vanadium-titanium magnetite (VTM) by
one-step coal-based direct reduction-smelting process with coal as reductant
and sodium carbonate (Na2CO3) as additives. Industrial experiments show that
the process of treating molten iron with a large amount of Na2CO3 is effective
in removing titanium from molten iron. However, the studies are rarely
conducted in thermodynamic relationship between titanium and other components
of molten iron, under the condition of a large amount of Na2CO3 additives. In
this study, through the thermodynamic database software Factsage8.0, the
effects of melting temperature, sodium content and oxygen content on the
removal of titanium from molten iron are studied. The results of thermodynamic
calculation show that the removal of titanium from molten iron needs to be
under the condition of oxidation, and the temperature should be below the
critical temperature of titanium removal (the highest temperature at which
titanium can be removed). Relatively low temperature and high oxygen content
contribute to the removal of titanium from molten iron. The high oxygen content
is conducive to the simultaneous removal of titanium and phosphorus from molten
iron. In addition, from a thermodynamic point of view, excessive sodium
addition inhibits the removal of titanium from molten iron.
