Application of soil size separation and micro-babble flotation for the cesium contaminated soil

As a method of remediation and recycling for the radioactive cesium contaminated soil caused by the explosion of Fukusima Daiichi Nuclear Power Plant, it is promising to apply soil size separation that can be treated in large quantities and at relatively low cost. In this study, fine size classification to separate particles under 20 μm is proposed in order to increase the concentration rate and the recycling rate. As a post-treatment technology, solid-liquid separation by microbubble flotation (MBF) was performed in order to solve the problems in sedimentation separation using a general coagulant precipitant. Since most of the target soil is derived from farmland, a combination of a foaming agent and a collector that has a wide range of effects is selected for inexperienced target mud water containing not only soil particles but also organic fine particles. It was confirmed that the target turbidity could be achieved by finely adjusting the flow rate and the amount of collector. By this combined system of fine soil size separation and MBF, it was confirmed that radioactive cesium could be concentrated in the fraction of 20 μm or less, and the possibility as a new practical volume reduction method for radioactive Cs contaminated soil was shown. (author)