Isothermal dehydration and thermal annealing of 80Br retention in neutron activated LiBrO3.H2O

Isothermal dehydration and isothermal annealing of neutron activated lithium bromate monohydrate was studied in the temperature range 100-195 degC. The fractional dehydration at 120 degC for 40 min. was observed to be 0.15 which was increased to 1.10 for the same time when the isothermal heating was carried out at 195 degC. The initial retentions of 80Br, 80mBr and 82Br in the same compound were 10.8, 19.5 and 21.5 ± 1.5% respectively. Thermal annealing at 140 degC increased the retention of 80Br isotope to 15.1%. Retention reached to 26% at 195 degC in 30 min, indicating that retention increased gradually. The retention was higher for anhydrous form than that for hydrated form. The activation energy involved for hydrated lithium bromate for isothermal annealing process is 0.34 eV whereas it is 2.01 x 10-2 eV for isothermal dehydration. An attempt is made to correlate the annealing data and the dehydration characteristics. (author). 4 refs., 4 figs., 1 tab