制钛过程中阴极钙钛矿的形成与阳极溢出气体间的关系（英文）
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摘要
采用FFC剑桥工艺在熔融CaCl_2中电解二氧化钛时,钙钛矿是阴极上不可避免形成的相。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3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Ti O和Ti O到Ti的脱氧。尽管分解电压低于CaCl_2,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Ti O_2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Ti_3O_5和Ti O_2之间时,在第1脱氧阶段Ti O_2和氯气的质量比为9:2到9:4。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Ti_2O的脱氧是在熔融CaCl_2中电解制备钛的主要限制性环节。从Ti O_2到Ti的总电流效率是24.07%。目前第1阶段的电流效率在22.37%～44.74%之间,第2阶段在30.18%～37.72%之间。
Perovskite is the inevitable phase formed in the cathode during electrolysis of TiO _2 in molten CaCl_2 by FFC Cambridge process.Dependency of perovskite in the cathode on gases released from the anode in the process of titanium preparation was studied.The results show that three stages are 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 closely related to gases released from the anode although the decomposition voltage is lower than that of CaCl_2.Chlorine release from the anode is due to overvoltage caused by the formation of perovskite in a short time.Amount of chlorine is dependent on the mass of TiO_2 and generation of different titanium suboxides during electrolysis process.The mass ratio of TiO_2 to chlorine is from 9:2 to 9:4 when titanium suboxides are between Ti_3O_5 and TiO at the first deoxygenation stage.The anode has no obvious consumption during chlorine release.Formation of the perovskite and deoxygenation of Ti_2O are the main limited step to prepare titanium by electrolysis process in molten CaCl _2.The total current efficiency from TiO_2 to Ti is 24.07%.The current efficiency of the first stage is between 22.37%～44.74%and the second stage is between 30.18%～37.72%.
Perovskite is the inevitable phase formed in the cathode during electrolysis of TiO _2 in molten CaCl_2 by FFC Cambridge process.Dependency of perovskite in the cathode on gases released from the anode in the process of titanium preparation was studied.The results show that three stages are 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 closely related to gases released from the anode although the decomposition voltage is lower than that of CaCl_2.Chlorine release from the anode is due to overvoltage caused by the formation of perovskite in a short time.Amount of chlorine is dependent on the mass of TiO_2 and generation of different titanium suboxides during electrolysis process.The mass ratio of TiO_2 to chlorine is from 9:2 to 9:4 when titanium suboxides are between Ti_3O_5 and TiO at the first deoxygenation stage.The anode has no obvious consumption during chlorine release.Formation of the perovskite and deoxygenation of Ti_2O are the main limited step to prepare titanium by electrolysis process in molten CaCl _2.The total current efficiency from TiO_2 to Ti is 24.07%.The current efficiency of the first stage is between 22.37%～44.74%and the second stage is between 30.18%～37.72%.
引文
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2 Wang S L,Li Y.Journal of Electroanalytical Chemistry[J],2004,571(1):37
3 Jiang K,Hu X,Ma M et al.Angewandte Chemie[J],2006,45(3):428
4 Suzuki R O,Inoue S.Metallurgical&Materials Transactions B[J],2003,34(3):287
5 Hu M,Qu Z,Bai C et al.Materials Transactions[J],2017,58(3):322
6 Wan H L,Xu B Q,Dai Y N et al.Chinese Journal of Nonferrous Metals[J],2012,22(7):2075
7 Schwandt C,Fray D J.Electrochimica Acta[J],2005,51(1):66
8 Bhagat R,Dye D,Raghunathan S L et al.Acta Materialia[J],2010,58(15):5057
9 Abdelkader A M,Kilby K T,Cox A et al.Chemical Reviews[J],2013,113(5):2863