Partition of metallic cations between aqueous solutions and mixed crystals of hydrated cobalt and nickel nitrates: Modelling of the influence of temperature and composition
A systematic study of the solid-liquid equilibria of the H2O-Co(NO3)2-Ni(NO3)2 ternary system enabled to define the liquidus and the solidus curves of the isotherms at 287.15 K and 313.5 K. Two widespread solid solutions, Co(1-r)Nir(NO3)2.6H2O and Ni(1-x)Cox(NO3)2.6H2O, were observed. They were formed by the substitution of Co2+ cations by Ni2+ cations in the monoclinic structure of the cobalt nitrate hexahydrate and the substitution of Ni2+ by Co2+ in the triclinic structure of the nickel nitrate hexahydrate. Two series of tie-lines for each crystallographic structure of these hexahydrates were obtained. The analyses of these tie-lines and those of the previous studies at 258.15 K and 303.15 K enabled a thermodynamic modelling of the solid-liquid equilibria within a temperature range from 258.15 K to 313.15 K. The simple equation system obtained allows to calculate the accurate composition of the mother solution, at a defined temperature, to reach the appropriate cationic ratio in the crystallised solid solution.
Compounds
#
Formula
Name
1
H2O
water
2
CoN2O6
cobalt(II) nitrate
3
N2NiO6
nickel(II) nitrate
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.