ABSTRACT

This work reports the stability and solubility of nesquehonite in several salts (NaCl, NH4Cl, MgCl2, and KCl) over the temperature range of (15 to 35) deg C. The needle-like nesquehonite used in this work was prepared by the reaction of analytical pure MgCl2 with Na2CO3. The concentration investigated for all salts was up to 4 mol *dm-3 NaCl, 3.5 mol *dm-3 NH4Cl, 4 mol *dm-3 MgCl2, and 1.0 mol *dm-3 KCl at ambient temperature. The solubility of nesquehonite in pure water was found to decrease with temperature within the temperature range in which nesquehonite is the stable phase. In NaCl solutions, the solubility of nesquehonite initially increases to a maximum value and then decreases gradually with an increase of the common salt concentration. It was further found that the addition of MgCl2, NH4Cl, or KCl causes the solubility of nesquehonite to increase due apparently to complexation. XRD and SEM examination of the equilibrated solids showed that nesquehonite is stable in pure water up to 50 deg C, but its stability region becomes smaller in concentrated brines.

Compounds

#	Formula	Name
1	CH6MgO6	nesquehonite
2	Cl2Mg	magnesium chloride
3	ClH4N	ammonium chloride (NH4Cl)
4	ClNa	sodium chloride
5	ClK	potassium chloride
6	H2O	water

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.
Type	Compound-#	Property	Variable	Constraint	Phase	Method	#Points
POMD	6 1	Molality, mol/kg ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid Crystal - 1	gravimetric method	12
POMD	4 6 1	Molality, mol/kg - 1 ; Liquid	Temperature, K; Liquid Solvent: Amount concentration (molarity), mol/dm3 - 4; Liquid	Pressure, kPa; Liquid	Liquid Crystal - 1	gravimetric method	36
POMD	6 3 1	Molality, mol/kg - 1 ; Liquid	Temperature, K; Liquid Solvent: Amount concentration (molarity), mol/dm3 - 6; Liquid	Pressure, kPa; Liquid	Liquid Crystal - 1	gravimetric method	33
POMD	6 2 1	Molality, mol/kg - 1 ; Liquid	Temperature, K; Liquid Solvent: Amount concentration (molarity), mol/dm3 - 6; Liquid	Pressure, kPa; Liquid	Liquid Crystal - 1	gravimetric method	36
POMD	5 6 1	Molality, mol/kg - 1 ; Liquid	Solvent: Amount concentration (molarity), mol/dm3 - 6; Liquid	Temperature, K; Liquid Pressure, kPa; Liquid	Liquid Crystal - 1	gravimetric method	12

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

Solubility and Stability of Nesquehonite MgCO3*3H2O) in NaCl, KCl, MgCl2, and NH4Cl Solutions

Dong, M.[Mei], Cheng, W.[Wenting], Li, Z.[Zhibao], Demopoulos, G. P.[George P.]

ABSTRACT