THERMODYNAMIC ANALYSIS OF THE CHEMICAL-REACTIONS OF ZIRCONIUM WITH AQUEOUS-SOLUTIONS

An appraisal was made of existing experimental data on the thermodynam ic characteristics (DELTAH(f,298)0, DELTAG(f,298)0, S298(0)) of Zr, Zr O2, and Zr(OH)4, the aqua ions, and the mononuclear and polynuclear hy droxo complexes of Zr(IV). For a series of forms on which there is no information empirical methods of evaluation were used. As a result a c omplete thermodynamically consistent system of thermal constants was o btained. Some results from modeling and computer calculation of the ho mo- and heterogeneous equilibria in the ranges of T = 298-623 K, pH298 (0) = -1 to 14, and [Zr] = 10(-9)-10(-1) mole/kg (for the homogeneous systems) are given.