| 摘要 |
PURPOSE:To safely produce gaseous nitrogen trifluoride at an excellent current efficiency by specifying the longitudinal size of any one of the electrodes positioned downward from the bottom end of a diaphragm of the electrolytic cell for producing the gaseous NF3 by a fused salt electrolysis method. CONSTITUTION:The front end of either an anode 5 or cathode 6 is positioned at 100 to 1000mm downward from the bottom end of the diaphragm 10 which isolates the two electrodes and the front end of the other is positioned at >=100mm downward from the bottom end of the diaphragm 10. Although the electrode of only the part downward from the bottom end of the diaphragm 10 plays the role of an electrode, the part positioned downward from the bottom end of the shorter length does not produce the gas and does not play the role of an electrode if the longitudinal lengths of the two electrodes vary. The distribution of the current density of the electrodes increases and the current efficiency degrades drastically when the positions of the front ends of the both electrodes exceed 1000mm from the bottom end. In addition, the gaseous H2 generated in the cathode 6 is liable to intrude into the gaseous NF3 generated in the anode 5, by which the danger of explosion is generated. |
