Electrochemical behaviors of Ti(III) in molten NaCl-KCl under various contents of fluoride

Abstract

In order to investigate an optimal concentration of fluoride in alkali chloride melt which the Ti(III) can be reduced into metallic titanium in one step, a systematic study of the electrochemical properties of Ti(III) was carried out in molten NaCl-KCl. KF was used as a source of fluoride ions, and the molar ratio of fluoride ions and titanium ([F−]/[Tin+] ratio) was employed as a parameter to illustrate the influence of fluoride anions on the electrochemical behaviors of Ti(III). The experiments were carried out with various concentrations of fluoride ions using a glassy carbon electrode at a temperature of 1023K. Transient electrochemical techniques, such as cyclic voltammetry and square wave voltammetry, were performed to reveal the reduction steps and reduction potentials of the electroactive species. Results suggest that there are two steps for Ti(III) ion reduction in molten NaCl-KCl: Ti(III)→Ti(II) and Ti(II)→Ti. Ti(III) can be reduced directly to Ti in one step when KF was added in the melt in increasing amount.