THERMODYNAMIC AND ELECTROCHEMICAL-BEHAVIOR OF NICKEL IN MOLTEN LI2CO3-NA2CO3 MODIFIED BY ADDITION OF CALCIUM-CARBONATE

The thermodynamic and electrochemical behavior of nickel species are i nvestigated in Li + Na carbonate eutectic containing different amounts of calcium carbonate. NiO dissolution is predicted theoretically, and its solubility is determined experimentally by an electrochemical tec hnique under P(CO2) = 1 atm. The addition of calcium increases the mel t basicity and reduces the NiO solubility significantly. Chemical inse rtion and electrochemical intercalation of alkali ions (mostly Li+) in the NiO lattice are analyzed in Li + Na and Li + Na + Ca carbonate me lts under P(CO2) = 0.1 atm + P(O-2) = 0.9 atm + P(CO2) = 0.3 atm + P(O -2) = 0.14 atm by potentiometry, voltammetry and SEM spectroscopy. (C) 1998 Elsevier Science S.A. All rights reserved.