Abstract
Phase equilibria were studied at temperatures 475–520°C and a pressure to 130 MPa in the ternary system Na2SO4–NaCl–H2O with boundary binary subsystems of two types. In type 1 subsystems (the NaCl–H2O subsystem in this work), there are no critical phenomena in saturated solutions. Type 2 subsystems (the Na2SO4–H2O subsystem in this work) have terminal critical points p (G = L – \({S_{N{a_2}S{O_4}}}\)) and Q (L1 = L2 – \({S_{N{a_2}S{O_4}}}\)). It was shown that the ternary system contains two regions of three-phase equilibria ((G–L–S) and (L1–L2–S)), divided by a two-phase fluid region (F – \({S_{N{a_2}S{O_4}}}\)), and two types of monovariant critical curves ((G = L – \({S_{N{a_2}S{O_4}}}\)) and (L1 = L2 – \({S_{N{a_2}S{O_4}}}\))). With increasing temperature, these three-phase regions approach each other until the two-phase fluid equilibrium vanishes and the monovariant critical curves meet at a binary homogeneous critical point (G = L–S ⇔ L1 = L2 – \({S_{N{a_2}S{O_4}}}\)) at a maximal temperature of ~495°C and a pressure of ~75 MPa.
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Original Russian Text © M.A. Urusova, V.M. Valyashko, 2017, published in Zhurnal Neorganicheskoi Khimii, 2017, Vol. 62, No. 6, pp. 856–867.
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Urusova, M.A., Valyashko, V.M. Na2SO4–NaCl–H2O system with a binary homogeneous critical point: Phase equilibria at 475–520°C and to 130 MPa. Russ. J. Inorg. Chem. 62, 843–853 (2017). https://doi.org/10.1134/S0036023617060250
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DOI: https://doi.org/10.1134/S0036023617060250