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Union Showa Develops Method of Stable Solidification of Insoluble Ferrocyanide

Union Showa K.K.
Showa Denko K.K.
 July 26, 2012

Union Showa K.K., a joint venture between Showa Denko K.K. (Minato-Ku, Tokyo, Japan) and UOP LLC (Des Plaines, Illinois, U.S.A), has successfully developed a new method of stable solidification of insoluble ferrocyanide widely used to remove radioactive cesium (Cs) in contaminated water generated by the accident at Fukushima Daiichi Nuclear Power Plant, which was triggered by the Tsunami disaster hit across much of northern Japan in March 2011.

Insoluble ferrocyanide has high Cs selectivity over other elements and maintains high adsorbing volume capacity even in high salt water concentration of cooling water without losing adsorbent rate. However, insoluble ferrocyanide will be easily decomposed by heat and release radioactive Cs into the air. Insoluble ferrocyanide also releases toxic cyanogen gas in a reducing atmosphere. Therefore, an innovative method of heat solidification has been sought to solve the problem.

Union Showa, under the guidance of Professor Mimura of Tohoku University, has successfully established a new method of stable solidification by heat treating mixture of used ferrocyanide and zeolite under a non-reducing atmosphere in which vaporized Cs by thermal decomposition of insoluble ferrocyanide is trapped again on the high surface area of zeolite. Such zeolite can be vitrified by heating at high temperature to contain radioactive Cs for long-term storage.

Union Showa represents UOP IONSIV(TM) Selective Media successfully used to remove radiation from water at Fukushima Daiichi Nuclear Power Plant and Three Mile Island in the U.S.A. Union Showa also manufactures and develops various Ion Exchangers at its Yokkaichi Plant, Mie Prefecture for nuclear waste remediation.

The new method can be applied to manufacture prefixed hybrid media of ferrocyanide and zeolite. Union Showa has already developed hybrid media with ferrocyanide to simultaneously remove Strontium or Cobalt with Cs.

Details of the method will be presented at a seminar of the Processing and Recycle Technology Division and at an annual meeting of Atomic Energy Society of Japan scheduled for coming August and September respectively.

For more information, contact:
Union Showa K.K. (Phone: 81-3-5427-0567)