Stefka Tepavitcharova

Solubility and Crystallization in the System MgCl2–MgSO4–H2O at 50 and 75°C

The system MgCl2–MgSO4–H2O has been investigated experimentally and modeled thermodynamically according to the Pitzer method at 50 and 75°C. It was found that, even when seemingly all requirements for reaching the stable thermodynamic equilibrium are fulfilled, the crystallization of higher hydrates as metastable phases is possible, and cannot be avoided in each crystallization field of a stable lower hydrate of magnesium sulfate. Crystallization of MgSO4 · x H2O (x = 1, 4, 6) and MgCl2 · 6 H2O at 50°C and of MgSO4 · H2O and MgCl2 · 6 H2O at 75°C as stable phases has been observed. Three metastable crystallization fields of MgSO4 · x H2O (x = 4, 6, 7) have been detected at 50°C and two of MgSO4 · x H2O (x = 4, 6) at 75°C. The results obtained and the contradictions existing in the literature with respect to the solubility and the crystallizing solid phases are discussed in terms of the crystal structures.

IUPAC-NIST Solubility Data Series. 73. Metal and Ammonium Formate Systems

This volume reviews the metal and ammonium formate solubility data published up to 1995. So far as the editors are aware, all the solubility data published during this period have been reviewed. Preference has been given to data published in numerical form. Data that appeared only in graphical form may not appear in this volume. In each section the metal atoms are arranged in the order (group) in which they appear in the Periodic Table. Metal formates are crystalline solids having some interesting chemical and physical properties. Several of these salts are important because they have nonlinear optical properties. Specific examples are: LiCHO2⋅H2O (3), NaCHO2 (4), Sr(CHO2)2, and Sr(CHO2)2⋅2H2O, Ba(CHO2)2, formates of Sc, Y and the rare earth elements having the general formula Me(CHO2)3⋅nH2O (where Me=Sc, Y, La, Ce, Pr, Nd, Sm…Lu) and some double salts and mixed salts such as NaCd(CHO2)3, BaCd(CHO2)4⋅2H2O and Li0.9Na0.1CHO2. Some metal formates have useful electric or magnetic characteristics. Thus, Cu(CH...

Chemical speciation in mining affected waters: the case study of Asarel-Medet mine

The inorganic chemical species in Maresh and Luda Yana rivers affected by the Cu– Mo Asarel-Medet mine, Bulgaria were determined during a low-flow and a high-flow period. The mining activities, the weathering and the oxidation processes strongly influenced the physicochemical processes in the whole water system. The main pollution source was a small lake receiving the acid effluents of the mining activities. High levels of SO42 − , Cu, Mg, Al, Mn and Fe were determined at the mining polluted and affected stations. Cu2 +  and CuCO30 species (1:1) were present in the reference waters and Cu2 +  and CuSO40 species (1:1) in the polluted and affected waters; Cu2 +  species was dominating downstream. Me2 +  followed by

Sea-water solubility phase diagram. Application to an extractive process

\rm{MeSO}_{4}^{\kern3pt{0}}

Pyro- and ferroelectric properties of nGly.MeCl2.2H20 (Me = Mn, Co; n = 1, 2)

(Me = Mn, Zn, Cd and Pb),

Chemical speciation of inorganic pollutants in river–estuary–sea water systems

\rm{PbCO}_{3}^{\kern3pt{0}}

Mg- and Zn-modified calcium phosphates prepared by biomimetic precipitation and subsequent treatment at high temperature

and

Chemical speciation in natural and brine sea waters

\rm{PbHCO}_{3}^{\kern3pt{+}}

The double salt RbCl · NiCl2 · 2H2O

species as well as

Chemical speciation in fresh, saline and hyper-saline waters

\rm{Fe(OH)}_{2}^{\kern3pt{+}}