Factors Influencing the Direct Electrochemical Reduction of Nb_2O_5 Pellets to Nb Metal in Molten Chloride Salts

作     者：D.Sri Maha Vishnu N.Sanil K.S.Mohandas K.Nagarajan 

作者机构：Chemistry GroupIndira Gandhi Centre for Atomic Research Materials Chemistry GroupDepartment of Materials Science and MetallurgyUniversity of Cambridge 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2017年第30卷第3期

页      面：218-227页

核心收录：

学科分类：080603[工学-有色金属冶金] 08[工学] 0806[工学-冶金工程] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0703[理学-化学] 0811[工学-控制科学与工程] 

基　　金：financial assistance from IGCAR  Department of Atomic Energy India 

主　　题：Fray-Farthing-Chen （FFC） Cambridge process Electrochemical reduction Open porosity Niobium pentoxide Calcium chloride 

摘      要：Powder compacted and sintered Nb205 pellets were cathodically polarised against graphite anode in calcium chloride melt at 1173 K to study the influence of various factors on the electrochemical reduction of the oxide. The parameters were; duration and temperature of electrolysis, open porosity of pellets, nature of anode, mode of electrolysis and configuration of the oxide cathode. The experiments were also conducted in KC1, KC1-25 tool% CaC12 and NaC1 melts to understand the effect of melt composition on the electroreduction. Different Ca-Nb-O and Nb-O intermediates were found in the pellets electrolysed for different durations of time in CaC12 melt which eventually reduced to Nb. The current efficiency of the process decreased with increasing duration of electrolysis. Decrease in electrolysis temperature from 1 173 to 1073 K led to the decrease in the rate of reduction of the oxide pellets. Pellets with high open porosity reduced faster. Carbon contamination of the melt was relatively less when pyrolytic graphite was used as anode. Of all the melts studied, the reduction was found to be better in calcium chloride melt, that too when alumina crucible was used as container of the melt.