Applying a Thermodynamic Model to the Non‐Stoichiometric Precipitation of Barium Sulfate

Vicum, Lars; Mazzotti, Marco; Bałdyga, J.

doi:10.1002/ceat.200390050

Cited by 56 publications

(75 citation statements)

References 12 publications

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“…The theoretical supersaturation level that could be achieved in the system is very high. However, because of a very short induction period the actual X cannot exceed the threshold value over which the nucleation rate surpasses the mixing velocity, so that X is limited by crystal precipitation (Sö hnel and Mullin, 1987;Philips et al, 1999;Kile et al, 2000;Vicum et al, 2003;Schwarzer and Peukert, 2004). As a result the first nucleating particles grow while further nuclei are simultaneously generated.…”

Section: Discussionmentioning

confidence: 99%

Kinetics of crystal nucleation in ionic solutions: Electrostatics and hydration forces

Kowacz

Prieto

Putnis

2010

Geochimica et Cosmochimica Acta

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The heat of precipitation, the mean crystal size and the broadness of crystal size distribution of barium sulfate precipitating in aqueous solutions of different background electrolytes (KCl, NaCl, LiCl, NaBr or NaF), was shown to vary at constant thermodynamic driving force (supersaturation) and constant ionic strength depending on the salt present in solution. The relative inversion in the effect of respective background ions on the characteristics of barite precipitate was observed between two studied supersaturation (X) and ionic strength (IS) conditions. The crystal size variance (b 2 ) increased in the presence of background electrolytes in the order LiCl < NaCl < KCl at X = 10 3.33 and IS = 0.03 M and KCl < NaCl < LiCl at X = 10 3.77 and IS = 0.09 M. At a given X and IS the respective size of barite crystals decreased with increasing b 2 in chloride salts of different cations and remained constant in sodium salts of different anions.We suggest that ionic salts affect the kinetics of barite nucleation and growth due to their influence on water of solvation and bulk solvent structure. This idea is consistent with the hypothesis that the kinetic barrier for barium sulfate nucleation depends on the frequency of water exchange around respective building units that can be modified by additives present in solution. In electrolyte solution the relative switchover between long range electrostatic interactions and short range hydration forces, which influence the dynamics of solvent exchange between an ion solvation shell and bulk fluid, results in the observed inversion in the effect of differently hydrated salts on nucleation rates and the resulting precipitate characteristics.

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Section: Discussionmentioning

confidence: 99%

Kinetics of crystal nucleation in ionic solutions: Electrostatics and hydration forces

Kowacz

Prieto

Putnis

2010

Geochimica et Cosmochimica Acta

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“…The kinetics of nucleation (increase in particle number n) and growth (change in particle size d) can be described by experimentally derived empirical correlations [6,7,10,[18][19][20].…”

Section: Kinetic Approachesmentioning

confidence: 99%

Optimization of a Continuous Precipitation Process to Produce Nanoscale BaSO4

Pieper

Aman

Hintz

et al. 2011

Chem. Eng. Technol.

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The effect of supersaturation, reaction temperature, and mixing intensity on particle size was investigated. Sterical stabilization of barium sulfate suspensions was applied to prevent formation of agglomerates. This allowed a reactant ratio of 1:1, thus maximizing product yield. The local supersaturation is strongly affected by the mixing intensity that can be characterized by Reynolds numbers. The significant decrease in particle size was observed by increasing the Reynolds number from 600 to 8000. A higher reactant concentration leads to a higher degree of supersaturation, and finer particles are precipitated. The particle size can be reduced with increasing reactant concentration. The degree of supersaturation increases with temperature reduction, i.e., the particle size will be reduced at low temperature. In addition, nucleation and growth kinetics are changed in a way that reduces the particle size. The optimized lab-scale process is capable of producing over 1 kg h -1 of nanoscaled BaSO 4 with a median diameter of 75 nm.

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“…According to this small solubility, applying some thermodynamic model was done to explain the precipitation of some insoluble salts [8]. The molar volumes (V M ) for (CC) in mixed EtOH-H 2 O were calculated by dividing the molecular weight by the exact solution densities and their values are tabulated in Table (3).…”

Section: Resultsmentioning

confidence: 99%

Solubility and Solvation Parameters of Calcium Carbonate in Mixed Ethanol-water Mixtures at 301.15 K

Gomaa¹

2012

SCIT

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The molar solubility of calcium carbonate (CC) in mixed ethanol (ETOH)-water solvents was measured at 301.15 K. From the molar solubilities, the solvation parameters, activity coefficients, solubility products, free energies of solvation and transfer free energies for interaction of (CC) from water as reference solvent to mixed (EtOH-H 2 O) solvents were evaluated. All the salvation parameters were discussed.

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Applying a Thermodynamic Model to the Non‐Stoichiometric Precipitation of Barium Sulfate

Cited by 56 publications

References 12 publications

Kinetics of crystal nucleation in ionic solutions: Electrostatics and hydration forces

Kinetics of crystal nucleation in ionic solutions: Electrostatics and hydration forces

Optimization of a Continuous Precipitation Process to Produce Nanoscale BaSO4

Solubility and Solvation Parameters of Calcium Carbonate in Mixed Ethanol-water Mixtures at 301.15 K

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