Study Of The Titanium Anode Loss And Equilibrium Constant In The Refinement Of Titanium Using Molten Salt Electrolysis

High purity titanium has a series of excellent performances such as high melting point, corrosion resistance, heat resistance, non-magnetism and perfect biocompatibility. Therefore it is widely used in the field of aerospace, navigation, weapon and civil engineering, and the future development is huge. Recently, the method of molten salt electrolysis for high purity titanium production has attracted much attention.Preparation of carbon-carbon thermal reduction of titanium metal used in the preparation of electrolytic refining of titanium, titanium sponge and titanium refining preparation should involve high-titanium (alloys) anodic dissolution problems. Since the price change characteristics of titanium anodic dissolution of titanium makes a lot of restrictions, resulting anodic current density decreases. Understand the electrochemical dissolution of titanium limiting factors and conditions, the basic theoretical issues titanium refining molten salt electrolysis, to improve the anode current density of titanium is important. This subject aims at the dissolution loss of titanium anode and equilibrium constant during the refinement of titanium using molten salt electrolysis. The dissolution loss of titanium anode was measured through two different ways:weight loss method and weight loss improve method. The refinement of titanium was carried out using a crude titanium anode in NaCl-KCl molten salt system. Low-valent titanium in the electrolyte was obtained. Electrolyte was sampled in Ar atmosphere and then analyzed with titration method based on ammonium ferric sulfate dodecahydrate. The equilibrium constant at different temperatures were calculated by analyzing the composition of the electrolyte. Initial results show that:the anode loss reduced with increasing current density and operating temperature. Higher temperature and larger current density increased the anodic polarization, which means reactions with more anodic potentials were easier to take place. The feasibility of this method was firstly tested with a copper anode at room temperature. Then, the loss of titanium anode at high temperature was measured. Heat4hours after electrolysis, the Ti2+and Ti3+ions would reach equilibrium with metal Ti. The equilibrium constant Kc increases with increasing of operating temperature. The equilibrium constant Kc decreases with the concentration of Ti2+and Ti3+ions increases in the electrolyte. The degree of titanium anode electrochemical dissolution depends on the ratio of the concentration of the electrolyte and titanium ions in different valence states. The Measured of the disproportionation equilibrium constant make sure that, lower temperatures favor the electrochemical dissolution of titanium, a titanium anodic electrochemical dissolution to improve current efficiency.