Open AccessPhase Equilibria and Phase Diagrams for the Ternary Aqueous System Containing Lithium, Sodium, and Pentaborate Ions at 298.15 and 323.15 K and 101.325 kPa
Author(s) -
Panpan Li,
Kaiyu Zhao,
Shangqing Chen,
Jiayin Hu,
Yafei Guo,
Mingli Li,
Ji Duo
Publication year - 2019
Publication title -
journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.436
H-Index - 50
eISSN - 2090-9063
pISSN - 2090-9071
DOI - 10.1155/2019/1541508
Subject(s) - chemistry , phase diagram , eutectic system , aqueous solution , ternary numeral system , ternary operation , solubility , dissolution , thermodynamics , isothermal process , lithium (medication) , phase (matter) , sodium , electrolyte , crystallization , ion , inorganic chemistry , crystallography , microstructure , organic chemistry , medicine , physics , electrode , endocrinology , computer science , programming language
Phase equilibria and phase diagrams for the ternary aqueous system containing lithium, sodium, and pentaborate ions at 298.15 and 323.15 K and 101.325 kPa were investigated by the methods of isothermal dissolution equilibrium. From the experimental data, the phase diagrams and the diagrams of physicochemical properties versus composition of lithium pentaborate in the equilibrium systems were plotted, respectively. The phase diagrams of the ternary system LiB 5 O 8 + NaB 5 O 8 + H 2 O at two temperatures contain one invariant point, two univariant curves, and two crystallization regions corresponding to sodium pentaborate pentahydrate (NaB 5 O 8 ·5H 2 O) and lithium pentaborate pentahydrate (LiB 5 O 8 ·5H 2 O). Due to the different dissolution behaviors of pentaborate salts in the aqueous systems, the component of LiB 5 O 8 has a relatively strong effect on the solubility of NaB 5 O 8 . It was found that this system belongs to a simple eutectic type at two temperatures, and neither double salts nor solid solutions were formed. The densities and refractive indices in the ternary system at 298.15 and 323.15 K are as similar as changing regularly with the increase of LiB 5 O 8 concentration. On the basis of empirical equations of the density and refractive index in electrolytes, the calculated values of density and refractive index agreed well with the experimental values at two temperatures.