| Titre : | Effect of Mg2+ ions on the nucleation kinetics of calcium sulfate in concentrated calcium chloride solutions (2010) |
| Auteurs : | Baohong Guan, Auteur ; Liuchun Yang, Auteur ; Zhongbiao Wu, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 49 N° 12, Juin 2010) |
| Article en page(s) : | pp. 5569–5574 |
| Note générale : | Chemical engineering |
| Langues : | Anglais |
| Tags : | Metastable calcium sulfate hemihydrate Nucleation kinetics |
| Résumé : | The precipitation kinetics of the metastable calcium sulfate hemihydrate (HH) from aqueous solutions has seldom been addressed. For the first time, the nucleation kinetics of calcium sulfate (probably in α-HH form) in concentrated CaCl2 solutions at 90 °C and the effect of Mg2+ ions were investigated by spontaneous precipitation experiments and a turbidity monitoring method. The results indicate that, at a moderate supersaturation with respect to calcium sulfate, Mg2+ ions retard the nucleation with 0.01 M Mg2+ ions showing the strongest effect; at a higher supersaturation, the inhibition effect decreases when the concentration of Mg2+ ions increases from 0.001 to 0.10 M, and 0.20 M Mg2+ ions show a promoting effect on the precipitation. The interfacial tension values increase with the concentration of Mg2+ ions, resulting in a decrease in nucleation rate in Mg2+ ion-containing solutions compared to Mg2+ ion-free solutions. This may indicate an involvement of Mg2+ ions in the surface reaction during calcium sulfate precipitation. |
| En ligne : | http://pubs.acs.org/doi/abs/10.1021/ie902022b |
