Phase Equilibria in a System Formed by Potassium Oxalates and Citrates

The authors study the effect different factors (having a seed of a certain phase, mixing, and period of holding while preparing the initial heterogeneous mixtures, acidity) have on the conditions of crystallization of solid phases from solutions in the K+, H+||C2O $$_{4}^{{2 - }}$$ (abbr. Ox2–), and C6H5O $$_{7}^{{3 - }}$$ (abbr. Cit3−)–H2O systems. The solubilities of salts of potassium hydrocitrate K2HC6H5O7 (K2HCit) and potassium hydrooxalate KHC2O4 (KHOx) with pH 2.5–5 are determined at 298.15 K (25°C) in the 10–40 wt % and 0–20 wt % ranges of concentrations, respectively. Areas of the crystallization of salts of KH2Cit⋅2H2O, K2HCit⋅0.5H2O, KHOx, 2K2Ox⋅H2Ox⋅2H2O, and K2Ox⋅H2O are identified.