Determination of melanterite-rozenite and chalcanthite-bonattite equilibria by humidity measurements at 0.1 MPa

Chou, I‐Ming; Seal, Robert R.; Hemingway, Bruce S.

doi:10.2138/am-2002-0112

Cited by 75 publications

(44 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results of the present study and those of Chou et al (2002), Chou and Seal (2004), and Seal (2003a, 2003b) further confi rm the conclusion of Hemingway et al (2002) that the Gibbs free energy contribution for each water of crystallization in hydrated sulfate salts, except for the fi rst water, is about -238.0 kJ/mol. The Gibbs free energy contribution for each water of crystallization can be calculated from the experimental results of this study for Reaction 1 by the equation: Cox et al 1989), and n is the stoichiometric coeffi cient for water in the dehydration reaction.…”

Section: Discussionsupporting

confidence: 87%

“…Hydrogenetic grid for selected hydrated metal-sulfate salts. Curves for bieberite and moorhouseite are from this study, those for melanterite and rozenite, and chalcanthite and bonattite are from Chou et al (2002), those for goslarite, bianchite, and gunningite are from Chou and Seal (2005), those for epsomite, hexahydrite, and kieserite are from Chou and Seal (2003a), and those for morenosite and retgersite are from Chou and Seal (2003b). The stippled fi eld indicates the stability of bierberite, the most common Co sulfate.…”

Section: Discussionmentioning

confidence: 70%

“…A weighed amount of the starting material, typically 378 to 567 mg, was loaded into a plastic sample container (8 mm ID x 10 mm OD and 20 mm tall), which was partly immersed in a humidity-buffer solution in a glass container (17.5 mm ID × 20 mm OD and 40 mm tall) sealed by a rubber stopper. Humidity-buffer solutions are saturated solutions with well-characterized humidity variations with temperature (Greenspan 1977;Chou et al 2002). The present study used fi ve different binary aqueous buffer solutions: NaBr, KI, NaNO 3 , KBr, and KNO 3 (Fig.…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

“…Published estimates for the equilibrium relative humidity (RH) at 25 °C range from 69.8 to 74.5% for the reaction. To evaluate these data, the humidity-buffer technique (Polyanskii et al 1976;Malinin et al 1977;1979;Chou et al 2002) was used in this study to determine equilibrium constants for this reaction between 14 and 43 °C at 0.1 MPa. Reversals were obtained along fi ve humiditybuffer curves.…”

Section: Dehydration Equilibriummentioning

confidence: 99%

See 3 more Smart Citations

Acquisition and evaluation of thermodynamic data for bieberite-moorhouseite equilibria at 0.1 MPa

Chou

Seal

2005

American Mineralogist

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 70%

Section: Experimental Methods and Resultsmentioning

confidence: 99%

Section: Dehydration Equilibriummentioning

confidence: 99%

See 2 more Smart Citations

Acquisition and evaluation of thermodynamic data for bieberite-moorhouseite equilibria at 0.1 MPa

Chou

Seal

2005

American Mineralogist

View full text Add to dashboard Cite

“…In the pure system at 20 8C, the melanterite-rozenite transition occurs at 59% relative humidity ( Fig. 4; Chou et al, 2002). Solid solution affects the dehydration product.…”

Section: Mineralogymentioning

confidence: 98%

Secondary sulfate minerals associated with acid drainage in the eastern US: recycling of metals and acidity in surficial environments

et al. 2005

Self Cite

View full text Add to dashboard Cite

Weathering of metal-sulfide minerals produces suites of variably soluble efflorescent sulfate salts at a number of localities in the eastern United States. The salts, which are present on mine wastes, tailings piles, and outcrops, include minerals that incorporate heavy metals in solid solution, primarily the highly soluble members of the melanterite, rozenite, epsomite, halotrichite, and copiapite groups. The minerals were identified by a combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron-microprobe. Base-metal salts are rare at these localities, and Cu, Zn, and Co are commonly sequestered as solid solutions within Fe-and Fe-Al sulfate minerals. Salt dissolution affects the surfacewater chemistry at abandoned mines that exploited the massive sulfide deposits in the Vermont copper belt, the Mineral district of central Virginia, the Copper Basin (Ducktown) mining district of Tennessee, and where sulfide-bearing metamorphic rocks undisturbed by mining are exposed in Great Smoky Mountains National Park in North Carolina and Tennessee.Dissolution experiments on composite salt samples from three minesites and two outcrops of metamorphic rock showed that, in all cases, the pH of the leachates rapidly declined from 6.9 to b3.7, and specific conductance increased gradually over 24 h. Leachates analyzed after 24-h dissolution experiments indicated that all of the salts provided ready sources), and base metals (N1000 mg L À1 for minesites, and 2 mg L À1 for other sites). Geochemical modeling of surface waters, mine-waste leachates, and salt leachates using PHREEQC software predicted saturation in the observed ochre minerals, but significant concentration by evaporation would be needed to reach saturation in most of the sulfate salts. Periodic surface-water monitoring at Vermont minesites indicated peak annual metal loads during spring runoff. At the Virginia site, where no winter-long snowpack develops, metal loads were highest during summer months when salts were dissolved periodically by rainstorms following sustained evaporation during dry spells. areas, persist in protected areas when temperature and relative humidity are appropriate, and contribute to metal loadings and acidity in surface waters upon dissolution, thereby causing short-term perturbations in water quality. Published by Elsevier B.V.

show abstract

Practical Thermodynamic Model for Acidic Sulfate Solutions

2013

View full text Add to dashboard Cite

Determination of melanterite-rozenite and chalcanthite-bonattite equilibria by humidity measurements at 0.1 MPa

Cited by 75 publications

References 19 publications

Acquisition and evaluation of thermodynamic data for bieberite-moorhouseite equilibria at 0.1 MPa

Acquisition and evaluation of thermodynamic data for bieberite-moorhouseite equilibria at 0.1 MPa

Secondary sulfate minerals associated with acid drainage in the eastern US: recycling of metals and acidity in surficial environments

Practical Thermodynamic Model for Acidic Sulfate Solutions

Contact Info

Product

Resources

About