The leaching behavior of borate waste glass SL-1

Vitrification is an attractive approach for treatment of the berate waste f rom nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the berate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been invest igated. Compared to the HLW-glass, the network structure of SL-1 glass is w eak. It was found that the ion-exchange reactions dominated the glass corro sion process with water in low temperature leaching conditions (less than o r equal to 70 degrees C). The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching con ditions (> 70 degrees C). There was a peak in leach rate at about 70 degree s C and a valley at about 110 degrees C. The surface layer thickness was ab out 25 mu m (MCC-1, 90 degrees C for 28 days in deionized water). Na was al most totally depleted in the surface layer. At low temperature, the glass c orrosion increases with leaching time. The glass corrosion remains about co nstant with leaching time at 90 degrees C. The surface layer formed at 90 d egrees C is protective, which is less porous than the surface layer formed at 40 and 70 degrees C. (C) 1999 Elsevier Science Ltd. All rights reserved.