Phase equilibria in the system CaO—Al2O3—B2O3—H2O at 23 ± 1°C

Abstract

Phase equilibria in the four-component system CaO—Al2O3—B2O3—H20 at 23 ± 1°C have been investigated. Data obtained experimentally were used to construct a phase diagram showing the stability regions of the sohd phases Ca(OH)2, Al(OH)3, the ternary hydrate 3CaO·Al2O3·6H2O, and the two quaternary hydrates, 6CaO·Al2O3·2B2O3·39H2O and 4CaO·Al2O3·½B2O3·12H2O. Theoretical calculations were also performed using the speciation program PhreeqC, which gave results that were in close agreement with those obtained experimentally. From this study, the solubility products (PKsp) for 6CaO·Al2O3·2B2O3·39H2O and 4CaO·Al2O3·½B2O3·12H2O were determined to be 44·23 and 28·51, respectively.