Mechanism of magnesiothermic reduction of TiCl4 by an electronically mediated reaction (EMR)

The mechanism of magnesiothermic reduction of TiCl₄ has been discussed by introducing an electronically mediated reaction (EMR). Feed material, TiCl₄, and magnesium reductant were charged into different locations in molten salt (e.g. MgCl₂) at 1073 K. Current flow between these two different locations was monitored when shortening these electronically isolated sites. Electrochemical potentials of each sites were also measured by interrupting the current during the electronically mediated reaction. Large current, more than 5 amperes, was detected during reaction and its reproducibility was well-confirmed. This result shows titanium metal can be produced by EMR without direct physical contact of feed with reductant. Various kind of molten alkali and alkaline earth chloride was tested for the EMR experiment and about 70% of feed was found to be reduced by a long range EMR, in which titanium deposit and reaction container act as electron conductor. Location of titanium deposition and its morphology seem to depend on reaction mechanism. The present results strongly suggest the concept of EMR plays an important role in the Kroll process which occurs via electron transfer through an electronically conductive medium, e.g., reactor wall and titanium deposit. This suggest that it is possible to control location of titanium deposit by utilizing the long range EMR.