Effects of Aliphatic Alcohols on Solubility, Physicochemical Properties, and Morphology of Calcium Sulfate Dihydrate (Gypsum) in Aqueous Sodium Chloride Solution at 35 °C

Abstract

The effect of addition of aliphatic alcohols (methanol, ethanol, and isopropyl alcohol) on the dissolution characteristics of calcium sulfate dihydrate (gypsum, CaSO4·2H2O) in brines has been studied at 35 °C. Addition of alcohols decreased the dissolution of CaSO4·2H2O in aqueous NaCl solutions significantly and also shifted its solubility maximum toward a lower concentration of NaCl. We have also recorded the density (ρ) and speed of sound (u) for the quaternary systems (CaSO4·2H2O + NaCl + alcohols + H2O) at 35 °C. Using primary data, we derived the isentropic compressibility (κS) of the solutions. The experimentally determined physical and derived properties have been correlated using polynomial or linear fits using the method of least-squares. The crystal growth behavior and morphology of gypsum cocrystallized with NaCl crystals from different solutions has also been examined. Alcohol additives seem to be an environmentally friendly, low-cost additive to decrease the solubility of gypsum in aqueous systems with or without NaCl.

Solubility and Physical Properties of Calcium Sulfate Dihydrate in NaCl and Glycerol Aqueous Solution at 303.15, 323.15, and 343.15 K

“…Wu et al , researched the solubility of calcium sulfate dihydrate and α-calcium sulfate hemihydrate in Ca-Mg-K chloride salt solubility at 348.15 to 371.0 K, which provides better theoretical data for the conversion between gypsum and calcium sulfate hemihydrate. However, the dissolution behavior of calcium sulfate dihydrate in organic solvent/salt/H 2 O solution is rarely studied. − The organic solvent has little corrosive effect on the equipment and has a dipole property, which can combine with water molecules and plays a good role in preventing the formation of natural gas hydrate. Because adding an organic solvent will change the solubility and crystal morphology of calcium sulfate, therefore, the solubility of calcium sulfate in organic solvent/salt/H 2 O solution needs to be studied comprehensively.…”

Solubility Measurement and Modeling of Eszopiclone in Four Binary Solvents

“…The solubility of a substance in different solvent or solvent mixtures could be influenced by several factors, such as the Coulombic force, viscosity, dielectric constant, and polarization force. − The increase of solubility in the above binary solvent mixtures might be caused by a complex hydrogen-bond effect with the additive water . In the crystallization process, the MSZW (metastable zone width) might change with increasing solubility resulting from adding water, which was the key kinetic parameter, and would affect the nucleation , and growth , step of crystallization. Furthermore, the morphology , and particle properties of the crystal production might be improved.…”

Effect of Cu2+ on the nucleation kinetics and crystallization of rod-shaped CaSO4·2H2O in aqueous solution

“…The nucleation and growth rates of the DH crystal are determined by its equilibrium solubility (C*), and according to several previous reports, [44][45][46][47] the value of C* in this system can be measured by a seeded growth equilibration method and the data are displayed in Table 3. The C* value of saturated gypsum solution can be increased effectively by the introduction of Cu 2+ , and as the concentration of Cu 2+ increases, the C* value is increased gradually.…”