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用电化学还原法从固体TiO2中提取金属钛是一种流程较短,成本较低的新工艺。通过改变电解时间,用SEM,EDS,XRD等方法分析电解产物的结构及组成变化来研究电化学还原法制备金属钛的反应历程及反应机制。XRD分析结果表明TiO2电化学还原过程是由高价氧化物向低价氧化物逐步进行的。在电解12 h的情况下,还原产物的变化情况如下:TiO2——Ti10O19+Ti4O7+CaTiO3(Magnéli相)——Ti3O5+Ti2O3+CaTiO3——TiO+CaTiO3——Ti+TiO——Ti。对阴极产物断面的SEM分析结果表明,随着电解时间的延长,电解产物的内层由致密变得疏松,并出现相互连通的多孔结构;颗粒不断长大,其外形趋于光滑;内外层结构逐渐均匀。电解12 h后,得到金属钛,氧含量是0.28%。反应过程中出现的CaTiO3是由熔盐中饱和的CaO与电极表面未还原的钛的氧化物反应形成的;在TiO2的电化学还原过程中,氧的离子化机制和钙热还原机制是同时存在的。
Electrochemical reduction of titanium from solid TiO2 is a shorter process, lower cost of new technology. By changing the electrolysis time, the structure and composition of the electrolysis products were analyzed by SEM, EDS, XRD and other methods to study the reaction process and reaction mechanism of the preparation of titanium metal by electrochemical reduction. The results of XRD analysis show that the electrochemical reduction of TiO2 proceeds step by step from higher oxide to lower oxide. In the case of electrolysis for 12 h, the changes of the reduction products are as follows: TiO2 - Ti10O19 + Ti4O7 + CaTiO3 (Magnéli phase) - Ti3O5 + Ti2O3 + CaTiO3 - TiO + CaTiO3 - Ti + TiO - Ti. SEM analysis of the cross section of the cathode product showed that the inner layer of the electrolysis product became loose by the densification and appeared the interconnected porous structure with the extension of the electrolysis time. The particles continued to grow and their appearance tended to be smooth. The inner and outer layer structure Gradually uniform. After electrolysis for 12 h, titanium metal was obtained and the oxygen content was 0.28%. CaTiO3 appeared during the reaction was formed by the reaction of saturated CaO in the molten salt with the unreduced titanium oxide on the surface of the electrode. During the electrochemical reduction of TiO2, the ionization mechanism of oxygen and the mechanism of calcium thermal reduction coexist of.