Studies in the system MgO-SiO 2 -CO 2 -H 2 O (II); the activity-product constant of magnesite

Christ, C. L.; Hostetler, P. B.

doi:10.2475/ajs.268.5.439

Cited by 94 publications

(52 citation statements)

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“…One of the first authors publishing a comprehensive study of the MgO-CO 2 -H 2 O system, Langmuir (1965), therefore concluded magnesite to be unstable below 60 • C at a partial pressure of CO 2 of 1 bar. Numerous later studies have since disproved this assertion, showing magnesite to be the most stable carbonate at all temperatures and partial pressures of CO 2 (e.g., Christ and Hostetle, 1970;Kittrick and Peryea, 1986). The earlier conclusion about a greater stability of the hydrated forms of Mg-carbonate, hydromagnesite, nesquehonite, lansfordite and artinite, at lower temperatures, is now considered to be an artifact due to kinetic inhibitions in the formation of magnesite.…”

Section: The Mg-carbonate Systemmentioning

confidence: 85%

Precipitation in the Mg-carbonate system—effects of temperature and CO2 pressure

Hänchen

Prigiobbe

Baciocchi

et al. 2008

Chemical Engineering Science

441

391

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Section: The Mg-carbonate Systemmentioning

confidence: 85%

Precipitation in the Mg-carbonate system—effects of temperature and CO2 pressure

Hänchen

Prigiobbe

Baciocchi

et al. 2008

Chemical Engineering Science

441

391

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“…One other data point, by Bär, 134 requires caution because it refers to "precipitated MgCO 3 " with a solubility almost ten times higher than a magnesite sample. One data point of Christ and Hostetler 144 did not show equilibrium, and is discarded a priori, leaving 15 data points. The data are shown in Table 15.…”

Section: Analytical Methods Used For Dissolved Magnesium Determinationmentioning

confidence: 99%

IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 1. Introduction, Be and Mg

Visscher

Vanderdeelen

Königsberger

et al. 2012

Journal of Physical and Chemical Reference Data

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The alkaline earth carbonates are an important class of minerals. This volume compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1, the present paper, outlines the procedure adopted in this volume in detail, and presents the beryllium and magnesium carbonates. For the minerals magnesite (MgCO 3 ), nesquehonite (MgCO 3 Á3H 2 O), and lansfordite (MgCO 3 Á5H 2 O), a critical evaluation is presented based on curve fits to empirical and=or thermodynamic models. Useful side products of the compilation and evaluation of the data outlined in the introduction are new relationships for the Henry constant of CO 2 with Sechenov parameters, and for various equilibria in the aqueous phase including the dissociation constants of CO 2 (aq) and the stability constant of the ion pair MCO 0 3 ðaqÞ (M ¼ alkaline earth metal). Thermodynamic data of the alkaline earth carbonates consistent with two thermodynamic model variants are proposed. The model variant that describes the Mg 2þ ÀHCO À 3 ion interaction with Pitzer parameters was more consistent with the solubility data and with other thermodynamic data than the model variant that described the interaction with a stability constant.

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“…The solubility products required in the solubility domain calculations were the same as those used above, along with log K sp values for MgCO 3 ·3H 2 O and Mg 5 (OH) 2 (CO 3 ) 4 ·4H 2 O of −5.59 and −30.2, respectively (Langmuir, 1965). Previous investigations have indicated that the formation of MgCO 3 ·3H 2 O and Mg 5 (OH) 2 (CO 3 ) 4 ·4H 2 O are highly metastable with respect to Mg(OH) 2 , and depend on the CO 3 2− :OH − ratio (Christ and Hostetler, 1970;Langmuir, 1965). It was also shown that the system was mainly kinetically controlled and that MgCO 3 ·3H 2 O occurred over a very narrow pH stability region, with transformation to Mg 5 (OH) 2 (CO 3 ) 4 ·4H 2 O occurring readily (Langmuir, 1965).…”

Section: Solubility Domains In the Presence Of Mg 2+mentioning

confidence: 96%

Heavy Metals in Wastewater: The Effect of Electrolyte Composition on the Precipitation of Cadmium(II) Using Lime and Magnesia

Lin

Burns

Lawrance

2005

Water Air Soil Pollut

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The effect of effluent composition on the efficiency of hydroxide precipitation of Cd(II), using both lime and magnesia as precipitants, has been modelled by the solubility domain approach in order to provide wastewater effluent treatment limits, and has been experimentally validated. Common anionic species such as Cl − , SO 4 2− and CO 3 2− have been treated. Solubility domain calculations were based on those phases that were found to determine metal solubility for systems representing the upper and lower limits of potential effluent chemical compositions. The isolated phases were found to resemble their mineralized counterparts, although in several cases exhibited a lower degree of structural order. Experimentally determined Cd(II) solubilities were generally encompassed within the calculated solubility domains, indicating that solubility domain predictions provide effluent treatment quality assurance ranges for the hydroxide precipitation process. The formation of gypsum (CaSO 4 ·2H 2 O) and calcite (CaCO 3 ) at higher SO 4 2− and CO 3 2− concentrations as secondary precipitates using lime as the precipitant, and the hydroxy-sulfate Mg 2 (OH) 2 SO 4 ·xH 2 O, nesquehonite (MgCO 3 ·4H 2 O), hydromagnesite [Mg 5 (OH) 2 (CO 3 ) 4 ·4H 2 O] and brucite [Mg(OH) 2 ] when employing magnesia was shown to have little effect on the observed residual Cd(II) solubility, although Mg(OH) 2 did promote β-Cd(OH) 2 formation in the Mg 2+ -containing Cd(II)/Cl − and Cd(II)/SO 4 2− systems.

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Studies in the system MgO-SiO 2 -CO 2 -H 2 O (II); the activity-product constant of magnesite

Cited by 94 publications

References 0 publications

Precipitation in the Mg-carbonate system—effects of temperature and CO2 pressure

Precipitation in the Mg-carbonate system—effects of temperature and CO2 pressure

IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 1. Introduction, Be and Mg

Heavy Metals in Wastewater: The Effect of Electrolyte Composition on the Precipitation of Cadmium(II) Using Lime and Magnesia

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