Abstract:In order to achieve long-term stability and reliability of the covered uranium mill tailings(UMTs) pond beach face, simulation studies were carried out applying a self-made experimental instrument of radon exhalation for soil overburden on the beach, aiming at a UMTs pond in humid location of southern China, to verify radon adsorption performance of calcium lignosulfonate(CaLS) through adsorption experiments. Experiments on enhanced radon retarding performance of CaLS-stabilized red clay were carried out. Effect of CaLS-stabilized red clay as soil overburden for radon retardation on the beach surface of the UMTs pond was studied, and the strength characteristics of CaLS-stabilized red clay was studied. The results show that CaLS has some radon adsorption properties. The radon retardation rate of 6 mass percent and 8 mass percent CaLS content is 9 percent and 12 percent respectively higher than that of red clay cover without CaLS. The strength of CaLS-stabilized red clay is enhanced within 0-6 mass percent content and slightly reduced between 6-8 mass percent, but the strength of soil is enhanced overall by the effect of CaLS.