Solubility of Gypsum in MSO₄ Solutions (M = Mg, Mn, Co, Ni, Cu, Zn) at 298.15 K and 313.15 K

Abstract

The search for literature data in the ternary systems M 2+ , Ca 2+ + SO 4 2-+ H 2 O (M ) Mg, Mn, Co, Ni, Cu, Zn) revealed a lack of data. A reason might be the difficulties of Ca analysis at high concentrated bivalent metal solutions. The solubility of gypsum was determined in MSO 4 solutions (M ) Mg, Mn, Co, Ni, Cu, Zn) over a broad concentration range at T ) 298.15 K and T ) 313.15 K. With increasing magnesium and heavy metal sulfate, respectively, the gypsum solubility decreases to a minimum and rises afterward to a maximum at about 1.2 mol MSO 4 /kg. Above that concentration, the solubility of gypsum decreases again until saturation with MSO 4 . At both temperatures and in the whole concentration range, no double salt formation was noticed. With increasing temperature, the solubility of gypsum increases also.

Solubility phenomena involving CaSO4 in hydrometallurgical processes concerning heavy metals

“…A good deal of gypsum solubility data [24,26,27,29,30] has been reported in the ternary CaSO 4 + ZnSO 4 + H 2 O system (see Fig. 7 increasing H 2 SO 4 concentrations in the temperature range 298-368 K and concentration range 0.3-0.8 mol kg -1 , Farrah et al [34] reported the inverse, as shown in Fig.…”

“…Most of the reported solubility data [22][23][24][25][26][27] for the CaSO 4 + CuSO 4 + H 2 O system concerns gypsum (Fig. 4).…”

“…Later solubility data [25][26][27] for gypsum were determined by volumetric analysis, and atomic absorption spectroscopy may also be unreliable. Wollmann and Voigt [24] applied inductively coupled plasma-optical emission spectroscopy (ICP-OES) to analyze calcium contents and set the equilibrium time from 11 to 50 d, and their reported solubility data for gypsum at 298. 15 Dutrizac and Kuiper [28] studied the solubility behavior of gypsum and anhydrite in quite typical Cu-electrolyte solutions in the temperature range 298-368 K, as shown in Figs.…”

“…There are many solubility reports [24,35,36] While Azimi and Papangelakis [36] reported the solubility of anhydrite in the CaSO 4 + NiSO 4 + H 2 O system at 150 and 175 °C (see Fig. 14), data near 100 °C are still unknown, and they are necessary for control of the purification process by crystallization.…”

Solid–liquid phase equilibria in the system K2SO4–MgSO4–H2O at 318K

“…The system MgSO 4 -CaSO 4 -H 2 O was examined by us recently at 298 K and 313 K [10]. In this paper, we report new phase equilibrium data for the system K 2 SO 4 -MgSO 4 -H 2 O with particular emphasis on the picromerite-leonite transition.…”