Study On The Preparation Of Titanium By Electrolysis Of Titanium Dioxide In Fluoride Dissolved Salts

Metal titanium and its alloys are widely used in many fields because of their high specific strength,good corrosion resistance and good biocompatibility.However,the current industrial methods for preparing titanium have defects such as complex process flow,resulting in The production cost of titanium has always been high,which limits the application of titanium in the low-end and low-end fields and civilian fields.Therefore,it is of great significance to explore a titanium preparation process with a simple production process.This study draws on the successful experience of industrial electrolysis of aluminum,finds a fluoride molten salt system that has a certain dissolving ability for TiO2,and explores the feasibility of directly electrolyzing TiO2 on solid cathodes and liquid cathodes to prepare metallic titanium.The main research contents and conclusions are as follows:(1)In the NaF-K2TiF6 system,when the molar ratio is 1.5:1,the system has a relatively suitable primary crystal temperature and TiO2 solubility.The liquidus and solubility are 762℃ and 6wt%,respectively.The solubility of titanium dioxide fully meets the needs of electrolysis.The dissolution of TiO2 in the molten salt system is mainly in chemical form,and a new complex K2NaTiOF5 is formed after dissolution.The dissolution of a small amount of TiO2 will reduce the initial crystallization temperature of the molten salt system.(2)Through thermodynamic calculations,it is found that in the NaF-K2TiF6 system and the NaF-Na2TiF6 system,the reduction of titanium proceeds step by step in theory,and the titanium ion in the form of oxide is compared with the titanium ion in the form of fluoride Easier to be restored.(3)Through exploring the cathode process of titanium ions in different molten salt electrolysis systems,it is found that in the NaF-K2TiF6 electrolyte system,the deposition of titanium ions is carried out in two steps:TiF62-+e-→TiF63-;Ti3++e-→Ti.Using metallic zinc as a liquid cathode can achieve depolarization to a certain extent.In the NaF-K2TiF6 electrolyte system,the application of different external voltages will change the control steps of the deposition of titanium ions on the cathode.(4)Through the double-electrode constant current electrolysis experiment under different molten salt electrolyte systems and different experimental conditions,it is found that the current density,electrolysis temperature and electrolysis time will all have a certain impact on the electrolysis process.When the current density is 0.87A/cm2,the electrolysis temperature is 790℃,the pole distance is 1.5cm,stainless steel is used as the cathode,and graphite is used as the anode.After 3 hours of electrolysis,the cathode product can detect elemental titanium,and the microscopic morphology of the cathode product is in the form of small particles Exist and mixed with a certain amount of molten salt.(5)In the double-cell electrolysis experiment with zinc as the cathode,the electrolyte composition remained basically unchanged before and after electrolysis,the consumed titanium dioxide and the dissolved titanium dioxide basically reached a dynamic balance,and the presence of titanium was detected in the zinc matrix of the cathode product.At the same time,KZnF3 is generated during the electrolysis process,which causes a certain degree of consumption of zinc.