Thermodynamic investigation of the CaOAl2O3CaSO4H2O system at 25°C and the influence of Na2O

Abstract The CaOAl2O3CaSO4H2O system at 25°C has been investigated by calculations on the equilibrium solubility surfaces of AH3, C3AH6, CH, C 6 A S 3 H x , C 4 A S H x and gypsum. The results are in good agreement with the previous experimental data and make it possible to define the hydrates in equilibrium with aqueous solutions of varying compositions. Solid-aqueous equilibria are very sensitive to the presence in the systems of additional ions such as sodium.

[1]  Calcium hydrocarboaluminate, carbonate, alumina gel and hydrated aluminates solubility diagram calculated in equilibrium with CO2g and with Naaq+ ions , 1983 .

[2]  F. Hanic,et al.  Phase relations in the subsystem C4A3SCSH2CHH2O of the system CaOAl2O3CSH2O referred to hydration of sulphoaluminate cement , 1989 .

[3]  F. Glasser,et al.  The reaction between cement and natural waters containing dissolved carbon dioxide , 1992 .

[4]  M. García-Vargas,et al.  Determination of total carbonate by ligand exchange , 1990 .

[5]  E. T. Carlson,et al.  Some Observations on the Calcium Aluminate Carbonate Hydrates , 1960, Journal of research of the National Bureau of Standards. Section A, Physics and chemistry.

[6]  David L. Parkhurst,et al.  Phreeqe--A Computer Program for Geochemical Calculations , 1980 .

[7]  H. A. Berman,et al.  Heat of Formation of Calcium Aluminate Monocarbonate at 25 °C , 1961, Journal of research of the National Bureau of Standards. Section A, Physics and chemistry.

[8]  R. Fischer,et al.  Reinvestigation of the system C4A.nH2O C4A.Co2.nH2O , 1982 .

[9]  S. Sahu,et al.  Stability of calcium sulphoaluminate hydrates in water solutions with various pH values , 1991 .

[10]  H.-J. Kuzel,et al.  Solid solution of ettringites part I: incorporation of OH− and CO32- in 3CaO.A12O3.32H2O , 1990 .

[11]  L. N. Plummer,et al.  The solubilities of calcite, aragonite and vaterite in CO2-H2O solutions between 0 and 90°C, and an evaluation of the aqueous model for the system CaCO3-CO2-H2O , 1982 .

[12]  K. Pitzer,et al.  Thermodynamics of electrolytes. II. Activity and osmotic coefficients for strong electrolytes with one or both ions univalent , 1973 .

[13]  F. Jones.  The Quinary System CaO–Al2O3–CaSO4–K2O–H2O (1 per cent KOH) at 25°C , 1944 .

[14]  S. Ito,et al.  Formation and carbonation of C-S-H in water , 1985 .

[15]  F. Jones.  The quaternary system CaO—Al2O3—CaSO4—H2O at 25° C , 1939 .

[16]  J. Grandet,et al.  Etude de la formation du monocarboaluminate de calcium hydrate au contact d'un granulat calcaire dans une pate de ciment portland , 1980 .

[17]  M. Murât,et al.  Stabilite thermodynamique des phases dans le systeme CaOAl2O3CO2H2O , 1985 .

[18]  E. Preßler,et al.  Solubility of Ca(OH)2 and CaSO4.2H2O in Dilute Alkali Solutions , 1947 .

[19]  Kenneth S. Pitzer,et al.  Thermodynamics of electrolytes. I. Theoretical basis and general equations , 1973 .

[20]  F. Jones.  The Quaternary System CaO–Al2O3–CaSO4–H2O at 25°C. Equilibria with Crystalline Al2O3–3H2O, Alumina Gel, and Solid Solution. , 1944 .

[21]  D. Damidot,et al.  Thermodynamic investigation of the CaOAl2O3CaSO4H2O system at 50°C and 85°C , 1992 .

[22]  N. Møller,et al.  The prediction of mineral solubilities in natural waters: The Na-K-Mg-Ca-H-Cl-SO4-OH-HCO3-CO3-CO2-H2O system to high ionic strengths at 25°C , 1984 .

[23]  V. Lach,et al.  Long-term carbonization of the phases 3CaO.Al2O3.6H2O and 3CaO.Al2O3.SiO2.4H2 , 1972 .