DEVELOPMENT OF HYDRODYNAMIC SOIL WASH SYSTEM USING VORTEX- BREAKDOWN SOIL WASH, HYDROCYCLONE AND INCLINED SETTLER

Abstract

 Particle size separation between sand and silt or finer particle is one of the most expected way to reduce the amount of Cesium-contaminated soil made by the accident of Fukushima Daiichi Nuclear Power Plant. We made hydrodynamic soil wash system which is composed with vortex-breakdown nozzle for soil wash, hydrocyclone and inclined settler for particle size separation. In this study, soil wash and size separation ware examined separately.

 In soil wash experiment, it can reduce radioactive material for 24% when suspend sand with oxalate solution 0.05 mol/L and though nozzle for 40 times. In separation experiment, we set 75 µm as a separation diameter. As the result, fine particle rate in coarse were down from about 25% to below 6% when flow ratio of hydrocyclone were about 30 L/min.