Collect. Czech. Chem. Commun. 1995, 60, 2107-2111

Study of the Conversion of CaSO4 to CaCO3 within the CaSO4 + Na2CO3 = CaCO3 + Na2SO4 Four-Component Water-Salt System

Dimitar Trendafelov, Christomir Christov, Christo Balarew and Aneta Karapetkova

Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria


The Pitzer ion-interaction model was employed to predict the conversion in the title quaternary water-salt system. The thermodynamic solubility products (Ks0) were determined and the conversion of CaSO4 to CaCO3 in the CaSO4 + Na2CO3 = CaCO3 + Na2SO4 system was predicted. The standard molar Gibbs free energyrG0 of the conversion reaction was calculated to be -23.62 kJ mol-1. A 98% degree of conversion of CaSO4 was achieved by using calcium sulfate isolated from sea salt production waste brines. Suitable conditions were found for obtaining CaCO3 exhibiting a high dispersity and whiteness.