阴极结构对SOM法制备金属钽的影响

Effect of Cathode Structure on Reduction of Ta_2O_5 Using SOM Process

在CaCl2熔盐中,利用固体氧离子膜(SOM)法电解还原Ta2O5直接制备金属钽。研究了成形压力与烧结温度对阴极形貌及孔隙率的影响,进而获得阴极微结构对产物形貌及氧含量的影响规律。结果表明:阴极片的颗粒尺寸和孔隙率大小是影响电解还原的重要因素;Ta2O5片的孔隙率随着成形压力的增大、烧结温度的升高明显降低;孔隙率大,有利于电解还原的进行,产物颗粒尺寸大;孔隙率小,会导致阴极产物形成致密的金属外层;在成形压力为4MPa经1150℃烧结2h或6MPa经1100℃烧结2h条件下,阴极反应活性良好,电解产物氧含量低。

Tantalum was prepared by solid oxygen-ion membrane （SOM） process from Ta2O5 directly in molten flux CaCI2 system. The micro-structural features and the porosities of the Ta2O5 pellets prepared at different pressures and sintered at different temperatures were investigated, and then the effect laws of the cathode microstructure on product morphology and oxygen contents were obtained. The results show that the particle size of cathode pellets and porosities are importance factors for the electrochemical reduction process. The porosities of the Ta2O5 pellets decrease remarkably as the pressure and sintering temperature increase. High porosity can enhance the rate of deoxidization and obtain bigger particle products; contrarily, a compact outer layer of metal tantalum is formed. When the Ta2O5 pellets are pressed at 4 MPa and sintered at 1150 ℃ for 2 h （or pressed at 6 MPa and sintered at 1100 ℃ for 2 h）, electrolysis reaction activity is good and electrolytic products have low oxygen content.