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Title: Solubility Model for Ferrous Iron Hydroxide, Hibbingite, Siderite, and Chukanovite in High Saline Solutions of Sodium Chloride, Sodium Sulfate, and Sodium Carbonate

Here, a solubility model is presented for ferrous iron hydroxide (Fe(OH) 2(s)), hibbingite (Fe 2Cl(OH) 3(s)), siderite (FeCO 3(s)), and chukanovite (Fe 2CO 3(OH) 2(s)). The Pitzer activity coefficient equation was utilized in developing the model to account for the excess free energies of aqueous species in the background solutions of high ionic strength. Solubility limiting minerals were analyzed before and after experiments using X-ray diffraction. Formation of Fe(OH) 2(s) was observed in the experiments that were initiated with Fe 2Cl(OH) 3(s) in Na 2SO 4 solution. Coexistence of siderite and chukanovite was observed in the experiments in Na 2CO 3 + NaCl solutions. Two equilibrium constants that had been reported by us for the dissolution of Fe(OH) 2(s) and Fe 2Cl(OH) 3(s) (Nemer et al.) were rederived in this paper, using newer thermodynamic data selected from the literature to maintain internal consistency of the series of our data analyses in preparation, including this paper. Three additional equilibrium constants for the following reactions were determined in this paper: dissolution of siderite and chukanovite and dissociation of the aqueous species Fe(CO 3) 2 –2. Five Pitzer interaction parameters were derived in this paper: β (0), β (1), and C φ parametersmore » for the species pair Fe +2/SO 4 –2; β (0) and β (1) parameters for the species pair Na+/Fe(CO3)2–2. Our model predicts that, among the four inorganic ferrous iron minerals, siderite is the stable mineral in two WIPP-related brines (WIPP: Waste Isolation Pilot Plant), i.e., GWB and ERDA6 (Brush and Domski), and the electrochemical equilibrium between elemental iron and siderite provides a low oxygen fugacity (10 –91.2 atm) that can keep the actinides at their lowest oxidation states. (Nemer et al., Brush and Domski; references numbered 1 and 2 in the main text).« less
Authors:
 [1] ;  [1] ;  [1] ; ORCiD logo [1]
  1. Sandia National Labs., Carlsbad, NM (United States)
Publication Date:
Report Number(s):
SAND-2017-12502J
Journal ID: ISSN 2472-3452; 658816; TRN: US1800204
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
ACS Earth and Space Chemistry
Additional Journal Information:
Journal Volume: 1; Journal Issue: 10; Journal ID: ISSN 2472-3452
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; chukanovite; ferrous iron hydroxide; hibbingite; internal consistency of thermodynamic database; Pitzer activity coefficient equation; siderite; speciation
OSTI Identifier:
1411232

Kim, Sungtae, Marrs, Cassandra, Nemer, Martin, and Jang, Jay Je-Hun. Solubility Model for Ferrous Iron Hydroxide, Hibbingite, Siderite, and Chukanovite in High Saline Solutions of Sodium Chloride, Sodium Sulfate, and Sodium Carbonate. United States: N. p., Web. doi:10.1021/acsearthspacechem.7b00065.
Kim, Sungtae, Marrs, Cassandra, Nemer, Martin, & Jang, Jay Je-Hun. Solubility Model for Ferrous Iron Hydroxide, Hibbingite, Siderite, and Chukanovite in High Saline Solutions of Sodium Chloride, Sodium Sulfate, and Sodium Carbonate. United States. doi:10.1021/acsearthspacechem.7b00065.
Kim, Sungtae, Marrs, Cassandra, Nemer, Martin, and Jang, Jay Je-Hun. 2017. "Solubility Model for Ferrous Iron Hydroxide, Hibbingite, Siderite, and Chukanovite in High Saline Solutions of Sodium Chloride, Sodium Sulfate, and Sodium Carbonate". United States. doi:10.1021/acsearthspacechem.7b00065.
@article{osti_1411232,
title = {Solubility Model for Ferrous Iron Hydroxide, Hibbingite, Siderite, and Chukanovite in High Saline Solutions of Sodium Chloride, Sodium Sulfate, and Sodium Carbonate},
author = {Kim, Sungtae and Marrs, Cassandra and Nemer, Martin and Jang, Jay Je-Hun},
abstractNote = {Here, a solubility model is presented for ferrous iron hydroxide (Fe(OH)2(s)), hibbingite (Fe2Cl(OH)3(s)), siderite (FeCO3(s)), and chukanovite (Fe2CO3(OH)2(s)). The Pitzer activity coefficient equation was utilized in developing the model to account for the excess free energies of aqueous species in the background solutions of high ionic strength. Solubility limiting minerals were analyzed before and after experiments using X-ray diffraction. Formation of Fe(OH)2(s) was observed in the experiments that were initiated with Fe2Cl(OH)3(s) in Na2SO4 solution. Coexistence of siderite and chukanovite was observed in the experiments in Na2CO3 + NaCl solutions. Two equilibrium constants that had been reported by us for the dissolution of Fe(OH)2(s) and Fe2Cl(OH)3(s) (Nemer et al.) were rederived in this paper, using newer thermodynamic data selected from the literature to maintain internal consistency of the series of our data analyses in preparation, including this paper. Three additional equilibrium constants for the following reactions were determined in this paper: dissolution of siderite and chukanovite and dissociation of the aqueous species Fe(CO3)2–2. Five Pitzer interaction parameters were derived in this paper: β(0), β(1), and Cφ parameters for the species pair Fe+2/SO4–2; β(0) and β(1) parameters for the species pair Na+/Fe(CO3)2–2. Our model predicts that, among the four inorganic ferrous iron minerals, siderite is the stable mineral in two WIPP-related brines (WIPP: Waste Isolation Pilot Plant), i.e., GWB and ERDA6 (Brush and Domski), and the electrochemical equilibrium between elemental iron and siderite provides a low oxygen fugacity (10–91.2 atm) that can keep the actinides at their lowest oxidation states. (Nemer et al., Brush and Domski; references numbered 1 and 2 in the main text).},
doi = {10.1021/acsearthspacechem.7b00065},
journal = {ACS Earth and Space Chemistry},
number = 10,
volume = 1,
place = {United States},
year = {2017},
month = {11}
}