Study On Electrolysis Reduction Of Titanium Dioxide To Titanium In Molten Salt And The Reduction Mechanism

As one kind of silvery white metal, titanium is the most remarkable structural and functional material that appeared in the twentieth century.It has a series of particular properties such as little density, high strength, high temperature and low temperature resistance,corrosion resistance and widely temperature adaptability etc.It has been widely used in a lot of fields. Since 1860's, many refining technologies to produce titanium have been put forward. Among of these, Kroll process is the method which has been used widely in the world. In this process,the titanium minerals rutile and ilmenite are carbo-chlorinated to produce a TiCl4 vapor.This is then reduced to titanium metal by magnesium metal.But its use has been greatly restricted because of the high producing cost,which is caused by the longer flow,complex process and so on.In this paper, direct electrochemistry reduction TiO2 to produce metal titanium in the system of CaCl2 has been adopted. In the process,the preparation of the cathode material, the option of electrolyte etc that influence the electrolysis effect have been studied. The reduction reaction mechanism of titanium dioxide in molten calcium chloride is studied emphasisly.The reaction mechanism of titanium reduction from titanium dioxide in molten calcium chloride was studied between 1123K and 1183K by cyclic voltammetry, chronoamperometry and A.C. impedance. The titanium reduction reaction is confirmed to conduct in the following two steps TiO2+ 2 e= TiO +O 2- TiO + 2 e= Ti +O 2-The charge number,the activation energy and the charge transferred resistance above two reactions were calculated and obtained by simulating A.C impedance with their equivalent circuits. The two reactions were controlled by the kinetics behavior of charge transferring in the experimental conditions.From the experiment results through six kinds of assembly technology for cathode,it is shown that the different preparation technologies (shape and assembly) of the cathode material have certain influence on the current or current density of electrolysis system.TiO2 flat has been drilled in a hole, then bunched with molybdenum metal stick, and finally fixed with a nut. It is better to electrolysis. Considering the electrolysis temperature,decomposition voltage of the molten salt...