Dissolution of cerium oxide in sulfuric acid

The dissolution behavior of CeO2 in sulfuric acid was examined using a batch reactor with various acid concentrations (8-14 M) at different temperatures (75-130°C). The dissolution of CeO2 was slow and it took more than 3 days to dissolve 4 mmol of a CeO2 powder completely in 100 mL of 12 M sulfuric acid at 90°C. The dissolution rate increased with increases in the temperature and the sulfuric acid concentration. The dissolution rate could be expressed by a shrinking sphere kinetics model. The variation of the dissolution rate constant with temperature obeyed the Arrhenius equation with the activation energy of 120 kJ mol-1. The reaction rate constant was a function of the acid concentration as C6.5. © Springer 2011.