Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Solubility data of the reciprocal system Ca2+, Mn2+//F-, SO42- + H2O is very important for removing fluoride or calcium ions from MnSO4 aqueous solution by CaF2(s) precipitation, however, they are unavailable from any literature up to now. In this work, solubility data for the ternary systems CaF2 + MnSO4 + H2O, CaF2 + MnF2 + H2O, MnF2 + MnSO4 + H2O and the quaternary systems CaF2 + CaSO4 + MnSO4 + H2O and CaF2 + MnF2 + MnSO4 + H2O have been elaborately measured at 298.15 K. The results showed that the CaF2(s) solubility monotonically increase with increasing MnSO4 concentration in the CaF2 + MnSO4 + H2O system, and MnSO4 imposes a stronger salt-in effect on CaF2(s) than ZnSO4 does. The CaF2(s) solubility decreases on the addition of MnF2 to in the aqueous solution, and after going through a minimum value it increases again. In the MnF2 + MnSO4 + H2O system the addition of MnSO4 results in at first decrease and then increase of the MnF2(s) solubility, similar to the MgF2(s) solubility behavior in the system MgF2 + MgSO4 + H2O. In CaSO4*2H2O(s)-saturated solution, CaF2(s) solubility increases with increasing MnSO4 concentration, but is generally lower than in pure MnSO4 aqueous solution. In MnF2(s)-saturated solution, CaF2 solubility increases with increasing MnSO4 concentration, but generally is lower than in pure MnSO4 aqueous solution. In the reciprocal system Ca2+, Mn2+//F-, SO42- CaSO4(s)*2H2O(s)-CaF2(s)-MnSO4*H2O(s), CaF2(s)-MnSO4*H2O(s)-MnF2(s). H2O exists co-saturated phase CaF2(s)-MnSO4*H2O(s) fields of and