Development of Continuous Process for Separation of Cesium (Stable Isotope)

February 20, 2012

 JNC Corporation (head office: Chiyoda-ku, Tokyo, President: Michio Morita) has developed a continuous process for separation of cesium (stable isotope), targeted at cesium-contaminated water.
In the release last December, the process was based on a batch separation technology on a laboratory scale. The technology has further been advanced to practical application to allow continuous separation of cesium on a bench scale, bearing in mind the treatment of contaminated water in the nuclear power plant struck by the Great East Japan Earthquake.

 According to the newly developed technology, ferrocyanide and iron chloride are added to cesium-contaminated water, and allowed to become weakly alkaline to form a cesium complex magnet. Then, cesium is removed and recovered by a simple process of applying a drum-type magnetic separation unit as the major equipment for separating the complex magnet.
The features of this technology are to allow prompt and high-volume treatment of contaminated water and to allow reduction of waste volume by continuously removing and recovering the complex magnet using magnetism by remote control.

 In the bench scale test using 20 liters of aqueous solution having a cesium concentration of 10 to 200 ppm, the reaction time was 3 minutes for completing formation of the cesium complex magnet, and magnetic separation of the magnet from the contaminated water could be achieved at a treatment speed of 4 liters per minute. The test was successfully conducted, and resulted in removing 99.5% or more of cesium and reducing the waste volume to 1/200 of the contaminated water. The scale-up of the process is easy, and a process allowing treatment of 20 m3 of cesium-contaminated water per hour is being devised.

 This technology can be widely applied. For example, the technology may be applied to contaminated water or the like produced upon washing radioactively-contaminated soil or rubble, in addition to the case of removing cesium from the contaminated water in the nuclear power plant.

 In the days ahead, we will continue examination toward practical application by performing demonstration tests using test machines of various scales so as to apply the technology not only to the treatment of contaminated water resulting from the Great East Japan Earthquake, but also to treatment and monitoring any and all radioactive cesium-contaminated water.

[Diagram of Drum-Type Magnetic Separation Unit]