EQ3NR, a computer program for geochemical aqueous speciation-solubility calculations: Theoretical manual, user`s guide, and related documentation (Version 7.0); Part 3

EQ3NR is an aqueous solution speciation-solubility modeling code. It is part of the EQ3/6 software package for geochemical modeling. It computes the thermodynamic state of an aqueous solution by determining the distribution of chemical species, including simple ions, ion pairs, and complexes, using standard state thermodynamic data and various equations which describe the thermodynamic activity coefficients of these species. The input to the code describes the aqueous solution in terms of analytical data, including total (analytical) concentrations of dissolved components and such other parameters as the pH, pHCl, Eh, pe, and oxygen fugacity. The input may also include a desired electrical balancing adjustment and various constraints which impose equilibrium with special pure minerals, solid solution end-member components (of specified mole fractions), and gases (of specified fugacities). The code evaluates the degree of disequilibrium in terms of the saturation index (SI = 1og Q/K) and the thermodynamic affinity (A = {minus}2.303 RT log Q/K) for various reactions, such as mineral dissolution or oxidation-reduction in the aqueous solution itself. Individual values of Eh, pe, oxygen fugacity, and Ah (redox affinity) are computed for aqueous redox couples. Equilibrium fugacities are computed for gas species. The code is highly flexible in dealing with various parameters as either model inputs or outputs. The user can specify modification or substitution of equilibrium constants at run time by using options on the input file.

[1]  D. Langmuir,et al.  Activity coefficients of MgCOo3 and CaSOo4 ion pairs as a function of ionic strength , 1976 .

[2]  Kenneth S. Pitzer,et al.  A thermodynamic model for aqueous solutions of liquid-like density , 1987 .

[3]  H. Helgeson,et al.  Summary and critique of the thermodynamic properties of rock forming minerals , 1978 .

[4]  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 .

[5]  P. B. Barton,et al.  Fluid-Mineral Equilibria in Hydrothermal Systems , 1984 .

[6]  C. Monnin.  An ion interaction model for the volumetric properties of natural waters: Density of the solution and partial molal volumes of electrolytes to high concentrations at 25°C , 1989 .

[7]  K. Pitzer,et al.  Volume changes for mixing the major sea salts: Equations valid to ionic strength 3.0 and temperature 95°C , 1989 .

[8]  R. Bates,et al.  An approach to conventional scales of ionic activity for the standardization of ion-selective electrodes , 1974 .

[9]  Y. Kharaka,et al.  Aliphatic Acid Anions in Oil-Field Waters--Implications for Origin of Natural Gas , 1978 .

[10]  R. Mesmer.  Comments on “a new approach to measuring pH in brines and other concentrated electrolytes” by K.G. Knauss T.J. Wolery, and K.J. Jackson , 1991 .

[11]  J. B. Rapp,et al.  Short chain aliphatic acid anions in oil field waters and their contribution to the measured alkalinity , 1975 .

[12]  D. Nordstrom,et al.  Fluorite solubility equilibria in selected geothermal waters , 1977 .

[13]  R. Bassett,et al.  Chemical modeling of aqueous systems : an overview , 1990 .

[14]  K. Knauss,et al.  A new approach to measuring pH in brines and other concentrated electrolytes , 1990 .

[15]  R. Mesmer,et al.  Isopiestic studies of aqueous solutions at elevated temperatures VIII. The alkali-metal sulfates , 1986 .

[16]  D. Macinnes.  THE ACTIVITIES OF THE IONS OF STRONG ELECTROLYTES. , 1919 .

[17]  F. Millero.  The use of the specific interaction model to estimate the partial molal volumes of electrolytes in seawater , 1977 .

[18]  R. Bates.  Ion activity scales for use with selective ion-sensitive electrodes , 1973 .

[19]  W. L. Marshall,et al.  Amorphous silica solubilities IV. Behavior in pure water and aqueous sodium chloride, sodium sulfate, magnesium chloride, and magnesium sulfate solutions up to 350°C , 1982 .

[20]  P. Brimblecombe,et al.  Solubility of volatile electrolytes in multicomponent solutions with atmospheric applications , 1990 .

[21]  K. Knauss,et al.  Dependence of albite dissolution kinetics on ph and time at 25°c and 70°c , 1986 .

[22]  F. Millero,et al.  Use of Pitzer's equations to determine the media effect on the formation of lead chloro complexes , 1984 .

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

[24]  D. Bradley,et al.  Extension of the specific interaction model to include gas solubilities in high temperature brines , 1985 .

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

[26]  K. Knauss,et al.  Reply to Comment by R.E. Mesmer on “a new approach to measuring pH in brines and other concentrated electrolytes” , 1991 .

[27]  D. D. Runnells,et al.  Ground Water Redox Reactions: An Analysis of Equilibrium State Applied to Eh Measurements and Geochemical Modeling , 1984, Science.

[28]  E. Merino.  Internal consistency of a water analysis and uncertainty of the calculated distribution of aqueous species at 25°C , 1979 .

[29]  H. Helgeson,et al.  Theoretical prediction of thermodynamic properties of aqueous electrolytes at high pressures and temperatures. III. Equation of state for aqueous species at infinite dilution , 1976 .

[30]  J. Hostettler.  Electrode electrons, aqueous electrons, and redox potentials in natural waters , 1984 .

[31]  R. Spencer.  The prediction of mineral solubilities in natural waters : A chemical equilibrium model for the Na-KCa-Mg-ClS 04-Hz 0 system at temperatures below 25 OC * , 2022 .

[32]  W. Stumm,et al.  Redox Equilibria and Measurements of Potentials in the Aquatic Environment , 1967 .

[33]  M. Whitfield.  39.—Progress towards a Chemical Model for Sea Water. , 1972 .

[34]  Kenneth S. Pitzer,et al.  Thermodynamics of electrolytes. IV. Activity and osmotic coefficients for mixed electrolytes , 1974 .

[35]  H. Helgeson,et al.  Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures , 1974 .

[36]  H. Helgeson,et al.  Theoretical prediction of the thermodynamic behavior of aqueous electrolytes by high pressures and temperatures; IV, Calculation of activity coefficients, osmotic coefficients, and apparent molal and standard and relative partial molal properties to 600 degrees C and 5kb , 1981 .

[37]  T. Wolery,et al.  Calculation of equilibrium distributions of chemical species in aqueous solutions by means of monotone sequences , 1975 .

[38]  D. L. Parkhurst,et al.  Application of the Pitzer equations to the PHREEQE geochemical model , 1990 .

[39]  Thomas A. Jones,et al.  Calculation of mass transfer in geochemical processes involving aqueous solutions , 1970 .

[40]  S. H. Storey,et al.  The computation of chemical equilibria , 1970 .

[41]  John H. Weare,et al.  The prediction of borate mineral equilibria in natural waters: Application to Searles Lake, California , 1986 .

[42]  K. Pitzer,et al.  Model for aqueous electrolyte mixtures for systems extending from dilute solutions fo fused salts , 1990 .

[43]  K. Pitzer,et al.  Heat capacity and other thermodynamic properties of Na2SO4(aq) in hydrothermal solutions and the solubilities of sodium sulfate minerals in the system Na-Cl-SO4-OH-H2O to 300°C , 1988 .

[44]  D. Langmuir,et al.  Techniques of Estimating Thermodynamic Properties for Some Aqueous Complexes of Geochemical Interest , 1979 .

[45]  James W. Johnson,et al.  Critical phenomena in hydrothermal systems; state, thermodynamic, electrostatic, and transport properties of H 2 O in the critical region , 1991 .

[46]  E. Busenberg.  The products of the interaction of feldspars with aqueous solutions at 25°C , 1978 .

[47]  Kenneth S. Pitzer,et al.  Thermodynamics of electrolytes. III. Activity and osmotic coefficients for 2–2 electrolytes , 1974 .

[48]  I. Parsons.  Elementary Thermodynamics for Geologists , 1977, Mineralogical Magazine.

[49]  E. C. Beutner.  Slaty cleavage and related strain in Martinsburg Slate, Delaware Water Gap, New Jersey , 1978 .

[50]  P. Brimblecombe,et al.  Solubility of ammonia in pure aqueous and multicomponent solutions , 1989 .

[51]  D. Laxen,et al.  Comparison of filtration techniques for size distribution in freshwaters , 1982 .

[52]  Everett L. Shock,et al.  Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: Correlation algorithms for ionic species and equation of state predictions to 5 kb and 1000°C , 1988 .

[53]  D. Thorstenson.  Equilibrium distribution of small organic molecules in natural waters , 1970 .

[54]  H. Haung.  Estimation of Pitzer's ion interaction parameters for electrolytes involved in complex formation using a chemical equilibrium model , 1989 .

[55]  R. Garrels,et al.  Solutions, Minerals and Equilibria , 1965 .

[56]  D. L. Peck,et al.  The concept of electron activity and its relation to redox potentials in aqueous geochemical systems , 1984 .

[57]  William L. Bourcier,et al.  Current status of the EQ3/ 6 software package for geochemical modeling , 1990 .

[58]  T. J. Wolery,et al.  EQPT, a data file preprocessor for the EQ3/6 software package: User`s guide and related documentation (Version 7.0); Part 2 , 1992 .

[59]  Kenneth S. Pitzer,et al.  Thermodynamics of concentrated electrolyte mixtures and the prediction of mineral solubilities to high temperatures for mixtures in the system Na-K-Mg-Cl-SO4-OH-H2O , 1987 .

[60]  Hans Wanner,et al.  Chemical thermodynamics of uranium , 1992 .

[61]  J. Schott,et al.  Determination of the solubility products of sodium carbonate minerals and an application to trona deposition in Lake Magadi (Kenya) , 1984 .

[62]  M. Paabo,et al.  Activity Standards for Ion-Selective Electrodes , 1971 .

[63]  K. Pitzer,et al.  Thermodynamics of electrolytes. VI. Weak electrolytes including H3PO4 , 1976 .

[64]  K. Pitzer,et al.  Thermodynamics of electrolytes. 8. High-temperature properties, including enthalpy and heat capacity, with application to sodium chloride , 1977 .

[65]  H. Helgeson,et al.  Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures; I, Summary of the thermodynamic/electrostatic properties of the solvent , 1974 .

[66]  James W. Ball,et al.  A Comparison of Computerized Chemical Models for Equilibrium Calculations in Aqueous Systems , 1979 .

[67]  S. Ben-Yaakov,et al.  Independent estimate of the pH of Dead Sea brine , 1977 .

[68]  Anil Kumar,et al.  Prediction of densities of concentrated brines by Pitzer theory , 1986 .

[69]  R. Garrels,et al.  A chemical model for sea water at 25 degrees C and one atmosphere total pressure , 1962 .

[70]  R. N. Roy,et al.  The thermodynamics of aqueous borate solutions I. Mixtures of boric acid with sodium or potassium borate and chloride , 1987 .

[71]  A. Truesdell.  THE ADVANTAGE OF USING pE RATHER THAN Eh IN REDOX EQUILIBRIUM CALCULATIONS1 , 1968 .

[72]  H. Helgeson,et al.  Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures; revised equations of state for the standard partial molal properties of ions and electrolytes , 1988 .

[73]  J. W. Ball,et al.  Redox Equilibria of Iron in Acid Mine Waters , 1979 .

[74]  David L. Parkhurst,et al.  A computer program incorporating Pitzer's equations for calculation of geochemical reactions in brines , 1988 .

[75]  E. Oelkers,et al.  SUPCRT92: a software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions from 1 to 5000 bar and 0 to 1000 ° C , 1992 .

[76]  T. J. Wolery,et al.  EQ3/6, a software package for geochemical modeling of aqueous systems: Package overview and installation guide (Version 7.0) , 1992 .

[77]  T. J. Wolery.  On the thermodynamic framework of solutions (with special reference to aqueous electrolyte solutions) , 1990 .

[78]  Jerry P. Greenberg,et al.  The prediction of mineral solubilities in natural waters: A chemical equilibrium model for the Na-K-Ca-Cl-SO4-H2O system to high concentration from 0 to 250°C , 1989 .

[79]  H. Helgeson.  Thermodynamics of complex dissociation in aqueous solution at elevated temperatures , 1967 .

[80]  Everett L. Shock,et al.  Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: Standard partial molal properties of organic species , 1990 .

[81]  E. Oelkers,et al.  Calculation of the thermodynamic properties of aqueous species at high pressures and temperatures. Effective electrostatic radii, dissociation constants and standard partial molal properties to 1000 °C and 5 kbar , 1992 .

[82]  H. Helgeson,et al.  Thermodynamics of hydrothermal systems at elevated temperatures and pressures , 1969 .

[83]  Y. Marcus.  The activities of potassium chloride and of water in Dead Sea brine , 1977 .

[84]  Y. Tardy,et al.  A method of estimating the Gibbs energies of formation of layer silicates , 1974 .

[85]  James W. Ball,et al.  WATEQ2—A Computerized Chemical Model for Trace and Major Element Speciation and Mineral Equilibria of Natural Waters , 1979 .