熔盐电解法制备高钛铁合金

Preparation of High Titanium Ferroalloy by Molten Salt Electrolysis from Mixture of TiO_2 and Ilmenite

采用电化学还原法,温度为900℃,在CaCl2熔盐中以烧结的TiO2与钛铁矿混合物(Ti∶Fe=1∶1原子比)为阴极,石墨棒为阳极,制备出了高钛铁合金。探讨了混合物烧结后的相组成变化及高钛铁合金的合金化历程。实验结果表明,混合物烧结后,TiO2由锐钛矿结构转变为金红石结构,钛铁矿转化为热力学稳定的Fe2TiO5。钛铁矿的晶体结构由烧结前的三方晶系经950℃以上烧结后,转变为斜方晶系的Fe2 TiO5。制备出的高钛铁中铁钛含量分别为:77.19%和9.68%(质量分数)。其合金化历程为:TiO2先生成CaTiO3,然后继续脱氧还原为金属钛;钛铁矿优先还原出金属铁,然后与生成的金属钛发生合金化反应生成钛铁合金。表明熔盐电解TiO2与钛铁矿的混合物是一条制备高钛铁合金的新途径。优化电解条件提高电流效率可进一步提高电解速度,得到质量更高的高钛铁合金。

High titanium ferroalloy was prepared by electro-deoxidization method.Using CaCl2 molten as electrolyte,sintered TiO2 and ilmenite mixed oxides pallets as cathode,graphite rod as anode,the pallets were electrolyzed at 900 ℃,3.1 V for 6,8 and 12 h.The phase structure of mixture of TiO2＋ilmenite after 950 ℃ sintered and mechanism of electro-deoxidization of the mixture was studied.The result showed that after 950 ℃ sintered,the structure of the TiO2 was transformed from anatase to rutile,and the ilmenite was transformed from thermodynamic stable phase Fe2TiO5,which crystal structure was monoclinec.The contents of Ti and Fe of produced high titanium ferroalloy was 77.19% and 9.68%（mass fraction） separately.The mechanism of electro-deoxidization of mixture of TiO2 and ilmenite in the molten salt was that TiO2 formed CaTiO3 firstly,then CaTiO3 was reducted to Ti.The deoxidizing of ilmenite generate Fe priority,once Ti metal was formed,the two kinds of metal soluted each other to form high titanium ferroalloy.Thus,molten salt electrolysis was a new way to produce high titanium ferroalloy from the mixture of TiO2 and ilmenite.Optimizing the electrolytic technology conditions to improve the efficiency of the electric current and increase the rate of the electrolysis,so high quality high titanium ferroalloy can be produced by molten salt electrolysis.