The Equilibrium between Titanium Metal, TiCl[sub 2], and TiCl[sub 3] in NaCl-KCl Melts

Abstract

The equilibrium between solid titanium metal, di-, and trivalent titanium chlorides dissolved in an NaC1-KC1 melt was measured under carefully controlled experimental conditions. Divalent titanium was found to be the predominant valence state in the melt, for temperatures of 700~176The "apparent" equilibrium constant (mole fractions replacing activities) for the reaction TiCl~ (NaC1-KC1 melt) W 1/2 Ti ~ (c) = 3/2 TIC12 (NaC1-KC1 melt) was calculated and found to be a function of the total titanium concentration in the melt. Limited data indicated that the equilibrium is exothermic in agreement with expectation. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 137.99.31.134 Downloaded on 2015-05-29 to IP Vol. 104, No. 8 EQUILIBRIUM BETWEEN ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 137.99.31.134 Downloaded on 2015-05-29 to IP

Revaluation of equilibrium quotient between titanium ions and metallic titanium in NaCl–KCl equimolar molten salt

“…On the other hand, the concentration of Ti 4+ is negligible. Other researchers also investigated the concentration of titanium ions in molten salts and obtained similar conclusion [12][13][14].…”

“…Thus, the understanding of the concentrations of each titanium ion in equilibrium with metallic titanium is critical to consider the mechanism. Several researchers investigated the concentration of titanium ions [11][12][13][14]. Mellgren and Opie pointed that the concentrations of titanium ions in molten salt is controlled by the following reaction [11]:…”

“…Fig. 1 shows the relation between concentration quotient and the concentration of titanium ion in the literatures [11][12][13][14]. Considering the Henry's law, the concentration quotient should be constant in the region where the concentrations of titanium ions are low.…”

“…Considering the Henry's law, the concentration quotient should be constant in the region where the concentrations of titanium ions are low. However, the concentration quotient, 60 mol% NaCl-40 mol% SrCl T = 700 °C Vycor glass crucible [11] NaCl-KCl equimolar T = 700 °C Vycor glass crucible [12] LiCl-KCl eutectic T = 500 °C Pyrex glass crucible [13] NaCl-KCl equimolar T = 740 °C Ti crucible [14] NaCl-KCl equimolar T = 740 °C Steinless-steel [14] K' concentration of Ti 2+ . Such a tendency indicates that there is an underestimation of the concentration of Ti 2+ or an overestimation of the concentration of Ti 3+ .…”

“…Relation between the concentration quotient and the concentration of Ti 2+ in the literatures[11][12][13][14].…”