Leaching behavior of carbon-14 contained in portland cement

Abstract

MCC-1 static leaching experiments were carried out for a cementitious waste form in distilled water for up to 64 days at 5°C and 20°C in order to examine the leaching behavior of carbon-14. The complicated leaching behavior of carbon-14, meaning that the leached carbon-14 activity did not increase with (time) 0.5, was attributable to the precipitation of calcite and the formation of colloidal particles in leachates, which were mainly dependent on the pH value and calcium concentration of leachate. The normalized elemental mass loss of carbon-14 was about 7.5 × 10 −4 g/cm 2 at 20°C for 64 days, which was lower than those of cement constitute elements such as calcium, sodium and aluminum. Especially, the leach rate of aqueous carbon-14 was lower than that of carbon-14 in the suspended leachate by a factor of about 10.