Thermodynamic evaluation and optimization of the (Ca+C+O+S) system

Lindberg, Daniel; Chartrand, Patrice

doi:10.1016/j.jct.2009.04.018

Cited by 28 publications

(40 citation statements)

References 55 publications

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“…There is some uncertainty in the thermodynamic properties of these Ca compounds. A recent assessment of the Ca‐C‐O‐S system by Lindberg and Chartrand () suggests different stabilities for CaS and CaC 2 than evaluated in earlier compilations. Using their assessed thermodynamic data, we find activities of CaC 2 very similar to those of CaS in the circumstellar envelopes (CSEs).…”

Section: Discussionmentioning

confidence: 83%

Sulfur in presolar silicon carbide grains from asymptotic giant branch stars

Hoppe

Lodders²,

Fujiya

2015

Meteorit & Planetary Scien

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We studied 14 presolar SiC mainstream grains for C-, Si-, and S-isotopic compositions and S elemental abundances. Ten grains have low levels of S contamination and CI chondrite-normalized S/Si ratios between 2x10(-5) and 2x10(-4). All grains have S-isotopic compositions compatible within 2 sigma of solar values. Their mean S isotope composition deviates from solar by at most a few percent, and is consistent with values observed for the carbon star IRC+10216, believed to be a representative source star of the grains, and the interstellar medium. The isotopic data are also consistent with stellar model predictions of low-mass asymptotic giant branch (AGB) stars. In a S-33 versus S-34 plot the data fit along a line with a slope of 1.8 +/- 0.7, suggesting imprints from galactic chemical evolution. The observed S abundances are lower than expected from equilibrium condensation of CaS in solid solution with SiC under pressure and temperature conditions inferred from the abundances of more refractory elements in SiC. Calcium to S abundance ratios are generally above unity, contrary to expectations for stoichiometric CaS solution in the grains, possibly due to condensation of CaC2 into SiC. We observed a correlation between Mg and S abundances suggesting solid solution of MgS in SiC. The low abundances of S in mainstream grains support the view that the significantly higher abundances of excess S-32 found in some Type AB SiC grains are the result of insitu decay of radioactive Si-32 from born-again AGB stars that condensed into AB grains

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Section: Discussionmentioning

confidence: 83%

Sulfur in presolar silicon carbide grains from asymptotic giant branch stars

Hoppe

Lodders²,

Fujiya

2015

Meteorit & Planetary Scien

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“…In the oxy-thermal carbide furnace, the occurrence of each reaction depends on the temperature and pressure. The thermodynamic property data of the substances in the furnace are listed in Table 1, which are compiled from several references [31][32][33] after evaluation in Guo's work [18] and Li's work [22]. , , .…”

Section: Thermodynamic Equilibrium Of the Reaction Systemmentioning

confidence: 99%

Heterogeneous Phases Reaction Equilibrium in an Oxy-Thermal Carbide Furnace

et al. 2020

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This work focuses on revealing the chemical reaction equilibrium behaviors of gas–liquid–solid heterogeneous phases in an oxy-thermal carbide furnace. From a CaC2 formation mechanism investigation, it was determined that a one-step mechanism occurs when there is an excess of C and a high CO partial pressure, which inhibits the formation of Ca in the system, and a two-step mechanism occurs when there is insufficient C and a low CO partial pressure, which promotes the formation of Ca. Based on the calculated results of the equilibrium compositions at 100 kPa and different temperature conditions, the chemical reaction equilibrium behaviors of gas–liquid–solid heterogeneous phases in an oxy-thermal carbide furnace were analyzed at conditions of excess C and insufficient C.

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“…The standard FactSage Ò databases have already been shown to be insufficiently accurate for the high initial P 2 O 5 content in apatite, and access is therefore required to a proprietary database [22]. Thermodynamic evaluations have been published in the literature on a number of binaries applicable to the experimental system [20,[23][24][25] forming a potential basis for more detailed future thermodynamic evaluations.…”

Section: Phosphorus Extraction Experiments Backgroundmentioning

confidence: 99%

Pyrometallurgical Treatment of Apatite Concentrate with the Objective of Rare Earth Element Recovery: Part II

Kennedy

Sun

Yurramendi

et al. 2017

J. Sustain. Metall.

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Apatite, Ca 5 (PO 4 ) 3 F, is a useful raw material for the production of both elemental phosphorus and phosphoric acid, and the mine tailings present at LuossavaaraKiirunavaara AB (LKAB) in Kiruna, Sweden, represent a significant potential European source of apatite if upgraded to a concentrate. In the present study, pilot apatite concentrate made from the LKAB tailings has been pyrometallurgically treated using carbon to extract phosphorus without fluxing at temperatures exceeding 1800°C, with the ultimate objective of recovery of rare earth elements (REEs) from the resulting slag/residue phases. Experimental behavior has been modeled using equilibrium thermodynamic predictions performed using HSC Ò . A process is proposed, and mass-energy balance presented, for the simultaneous production of P 4 and CaC 2 (ultimately for acetylene, C 2 H 2 , and PVC production) from apatite, producing a lime residue significantly enriched in REEs. Possible implications to kiln-based processing of apatite are also discussed.

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Thermodynamic evaluation and optimization of the (Ca+C+O+S) system

Cited by 28 publications

References 55 publications

Sulfur in presolar silicon carbide grains from asymptotic giant branch stars

Sulfur in presolar silicon carbide grains from asymptotic giant branch stars

Heterogeneous Phases Reaction Equilibrium in an Oxy-Thermal Carbide Furnace

Pyrometallurgical Treatment of Apatite Concentrate with the Objective of Rare Earth Element Recovery: Part II

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