The Evaluation of Solidifying Performance of Heavy Metal Waste Using Cementitious Materials (2)

Fujita, Hideki*; Harasawa, Shuichi*

Some of radioactive waste generated from JNC's facilities contain the poisonous substances such as lead and mercury. In order to establish an appropriate method of the treatment of these heavy metals, solidification performance was evaluated using cementitious materials. The results are summarized below:1. The test of stabilization process of mercuryThe conversion process from mercury to the powdery mercury sulfide(red) was examined. It was confirmed that the conversion was possible using the liquid phase reaction at 80C by the addition of sulfur powder with the NaOH solution. 2. The fabrication and evaluation of solidified wastes (1) solidification test of the lead wasteAs for the elution ratio of lead, it had obtained the better result (0.06 mg/L) at the case of solidification of sulfide lead 30mass% packed in the total solidified waste by using Highly Fly-ash contained Silicafume Cement (HFSC) than standard value(0.3mg/L) at Regulations of Waste Management and Public Cleansing Law. Additionally, it was confirmed the using admixture of the inorganic reducing agent such as the Iron (II) chloride tetrahydrate deceased the elution ratio of lead to the under limit of measurement (0.01 mg/L) at the case of solidification of sulfide lead 30 mass% packed in the total solidified waste by using Low Alkalinity Cement contained calcium sulpho-aluminate (LAC). (2)solidification test of the mercury waste Four types of solidified waste were fabricated with different binder. It was confirmed one-axis compressive strength for all solidified waste to pass the technical standards 15kg/cm2 (1.5 Mpa) for homogeneously solidified waste as the Low-level Radioactive Waste Disposal Center in Aomori Prefecture, and the elution ratio of mercury, it had obtained the result for all solidified waste to pass the standard value (0.005 mg/L) at Regulations of Waste Management and Public Cleansing Law.