制钛过程中阴极钙钛矿的形成与阳极溢出气体间的关系

采用FFC剑桥工艺在熔融CaCl₂中电解二氧化钛时,钙钛矿是阴极上不可避免形成的相。本文研究了在制备钛的过程中,阴极钙钛矿的形成与阳极释放气体的关系。结果表明,阴极上相的形成主要有三个阶段,包括钙钛矿的形成、钙钛矿的脱氧及钛的低价氧化物脱氧为TiO、和TiO到Ti的脱氧。尽管分解电压低于CaCl₂,但阴极形成的钙钛矿与从阳极释放的气体密切相关。由于短时间内钙钛矿的形成造成过电压,因而阳极释放出氯气,氯气的量取决于TiO₂和电解过程中产生的不同低价钛的量。当钛的低价氧化物介于Ti₃O₅和TiO₂之间时,在第一脱氧阶段TiO₂和氯的质量比为9：2到46：2。在氯气释放的过程中阳极没有明显的消耗。钙钛矿的形成和Ti₂O的脱氧是在熔融CaCl₂中电解制备钛的主要限制性环节。从TiO₂到Ti的总电流效率是24.07％。目前第一阶段的电流效率在22.37％~44.74％之间,第二阶段在30.18％~37.72％之间。

Dependency of gases released from the anode on perovskite formed in the cathode in the process of the preparation of titanium

Perovskite is the inevitable phase formed in the cathode during electrolysis of TiO₂ in molten CaCl₂ by FFC Cambridge process. Dependency of perovskite in the cathode on gases released from the anode in the process of the preparation of titanium is studied. The results show that three stages is obtained based on the phases formed in the cathode including formation of perovskite, deoxygenation from perovskite and titanium suboxides to TiO and deoxygenation from TiO to Ti . Perovskite formed in the cathode is close related with gases released from the anode although the decomposition voltage is lower than that of CaCl₂. Chlorine releases from the anode due to overvoltage which is caused by the formation of perovskite in a short time. Amount of chlorine is depended on the mass of TiO₂ and generation of different titanium suboxides during electrolysis process. The mass ratio of TiO₂ and chlorine is from 9:2 to 46:2 when titanium suboxides are between Ti₃O₅ and TiO at the first deoxygenantion stage. The anode is no obvious consumption during chlorine releases. Formation of the perovskite and deoxygenation of Ti₂O are the main limited step to prepare titanium by electrolysis process in molten CaCl₂. The total current efficency from TiO₂ to Ti is 24.07%. The current efficiency of the first stage is between 22.37% and 44.74% and the second stage is between 30.18% and 37.72%.