MODELING OF DISSOLUTION OF OXIDE PHASES ZIRCONIUM AND HAFNIUM IN ACID SOLUTIONS

The article presents the results of the study of the dissolution kinetics of hydrated zirconium and hafnium dioxides. Experimental dependences characterizing the kinetic regularities of the process were obtained by potentiometric titration of dioxide suspensions in acidified aqueous solutions of potassium chloride. The constants of acid-base equilibria at the dioxide/solution interface were calculated, taking into account which the obtained data were interpreted. The staged nature of the dissolution process was established by modeling and comparative analysis of experimental and theoretical curves. It was shown that the dissolution of dioxides occurs with the formation of intermediate adsorption complexes.