The Mechanism Research On Preparation Of Fetialloy By Electro-Deoxidization In Molten Salt From Ilmenite Concentrate

The titanium resources in Pan zhihua is abundant, in which ilmenite concentrate (FeTiO3) is the main material of preparing titanium white and titanium-rich products. However, the content of CaO and MgO in FeTiO3in China is higher, thus make sulfuric acid process and chloride process have some restriction and will cause environment pollution. In2000, solid oxides of electro-deoxidization in molten salt (FFC) method has draw much more attention, many researchers have prepared metal or alloy successfully, such as Ti、Tb、Cr、Si、AlSi、TiV, etc. But low current efficiency of FFC process is always a main problem and has not solved. So this technology is still in basic research stage instead of industrial production, especially in the electro-deoxidation process, reaction mechanism and improvement of current efficiency have been existed controversy. In this thesis, the deoxidation process of FeTiO3cathode, the production of intermediate product(CaTiO3) and electrical conductivity of cathode were investigated by analogue computation of materials studio,monitoring mass of cathode, the contrast experimental of different molten salt and electrochemical methods. Several conclusions were shown as follows:It is considered from theoretical computation that CaTiO3structure is unstable relatively and thus to form titanium sub-dioxide further, which is the intermediate product during electrolytic process.The electrical conductivity of cathode at different sintering temperature was studied, which considered sintering temperature has a great effect on electrical conductivity of cathode. With the sintering temperature rising, connection parts between phase and phase increase, and then conductivity become better.The results of thermodynamics calculator indicate that Fe is first obtained in deoxidation process of FeTiO3, then TiO2will be reduced from high state gradually. The variation of compounds is:TiO2�'Ti3O5�'Ti2O3�'TiO�'Ti. Fe2Ti will be generated in the process and last to get FeTi.The deoxidization way of FeTiO3can be divided into two main processes. Fe is prior to be reduced and Ca2+in molten salt accesses into cathode combines with TiO2to generate CaTiO3; Secondly, TiO2and CaTiO3are further electrolyzed to generate titanium sub-oxide and get FeTi.The hydrolysis reaction of molten salt can produce CaTiO3, but the main reason of producing CaTiO3during electrolysis process is that Ca2+in molten salt inserted into cathode to combine with TiO2and electron to generate CaTiO3by electrochemical reaction.The factors of influencing the deoxidizing rate were discussed by variation of cathode mass.One is that the generation of CaTiO3after reduction of Fe, another is the electrolysis of CaTiO3.The results from cyclic voltammetry are consistent with those of AC impedance spectroscopy. Fitting parameters in equivalent circuit and considered that at low voltages, the speed of electro-deoxidation process is decided mainly through electrochemical reaction. And at high voltages, the diffusion of ion is the main controlling step of the electro-deoxidation.