Preparation Of Ni And LaNi₅ By FFC Cambridge Process

FFC Cambridge process, a new technique which has a short route, low energy consumption and no environmental influence is proposed for preparation of Ni and LaNi5 powders by direct electrolytic deoxidization NiO or NiO and La2O3(Ni: La = 5: 1).NiO or NiO and La2O3 powders are compacted into pellets, sintered and used as cathode. High-density graphite is used as anode. Electrolysis is performed in CaCl2 or CaCl2-NaCl and the change of current during electrolysis is recorded. Composition of pellet is analyzed by XRD. Morphology of pellet is analyzed by SEM. Porosities of pellet are measured on the Archimedes' law.The influences of compact pressure, sintering temperature, sintering time, electrolytic temperature, electrolytic time and cell voltage on morphology and electrolysis process are studied. Results show that the optimal conditions are: NiO pellets are compacted at 10MPa, when sintered at 900℃for 8h and electrolyzed under 2.5V in CaCl2 at 850℃for 8h. Mechanisms on preparation of Ni under cell voltages higher and lower than the theoretical decomposition potential of NiO are discussed. Current efficiency is 36.7% and energy consumption is 7711.2 kW·h·t-1Ni for preparation of Ni from NiO under the optimal conditions.Based on the above, the influences of compact pressure, sintering temperature, cell voltage and electrolytic time on preparation of LaNi5 from NiO-La2O3 are studied. Results show that the optimal conditions are: NiO-La2O3 pellets are compacted at 30MPa, when sintered at 850℃for 5h and electrolyzed under 3.1V in CaCl2-NaCl at 850℃for 36h. Charge-discharge performances of products prepared under the optimal conditions are investigated. The mechanism on preparation of LaNi5 is discussed. Current efficiency is 7.65% and energy consumption is 26678.1 kW·h·t-1 LaNi5 for preparation of LaNi5 from NiO-La2O3 under the optimal conditions.