January 20, 2016
Research group led by Kanagawa University Faculty of Science Professor Hisao Hori succeeds in high-efficiency separation and collection of rare metal rhenium from water!
●Rhenium (Re) is a rare metal used in aircraft engines, turbines for thermal power generation, etc.
●The process for manufacturing rhenium from minerals or waste matter involves separating and collecting perrhenate ions (ReO4–) dissolved in water, which is traditionally performed through repeated heat concentration and cooling of a solution (recrystallization), but the high energy cost and low collection rate are problematic.
●A research group led by Kanagawa University Faculty of Science Professor Hisao Hori was the first in the world to successfully collect almost all perrhenate ions from water (rhenium atom collection rate: 95%), without producing wastewater with high concentrations of nitrogen or the like. This was achieved by adding 2-propanol and acetone to a perrhenate ion solution and converting it to insoluble rhenium (IV) oxide and rhenium (VI) oxide by irradiating it with light.
Rhenium (Re) is a rare metal that demonstrates superior heat resistance, but it is the scarcest among 47 rare metal elements, and there is a little concern over its supply—for example, in 2007-2008, Kazakhstan ceased exporting it. Rhenium is expensive, even for a rare metal—not only because of its scarcity, but also because of low manufacturing efficiency. Traditionally, this metal is obtained by collecting perrhenate ions (ReO4–) in water from rhenium(VII) oxide (Re2O7) in molybdenite (molybdenum ore) roasting gas, then repeatedly recrystallizing it by means of heat concentration and cooling. The resulting precipitate is manufactured by igniting it in a hydrogen stream, but since ReO4– salts are readily soluble in water across the entire pH range, the collection rate is low and the energy costs are high, which is problematic.
In this research project, the team succeeded in collecting almost all ReO4–in water (collection rate: 95%—value obtained by dividing the number of rhenium atoms contained in the precipitate by the number of rhenium atoms present in the water before reaction, based on ICP emission spectroscopy) as insoluble rhenium (IV) oxide (ReO2) and rhenium (VI) oxide (ReO3) precipitate using the simple technique of adding the inexpensive reagents 2-propanol and acetone to ReO4–dissolved in water, then irradiating it with UV-visible light.
(Photo: Photoreaction testing)
Using this method, it is also possible to selectively collect only rhenium components from solution in which they co-exist with molybdenum components.
The method was published in Separation and Purification Technology, a separation engineering journal published by Elsevier:
H. Hori, Y. Yoshimura, T. Otsu, K. Kume, Y. Mitsumori, S. Kutsuna, K. Koike, Efficient photochemical recovery of rhenium from aqueous solutions,,http://dx.doi.org/10.1016/j.seppur.2015.10.007.
The results were achieved with support from a Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research and the MEXT-Supported Program for the Strategic Research Foundation at Private Universities. In addition, the team received assistance with analysis of reaction products from Dr. Kazuhide Koike, Senior Researcher, and Dr. Shuzo Kutsuna, Chief Senior Researcher, at the Environmental Management Research Institute of the National Institute of Advanced Industrial Science and Technology (AIST) .
Professor Hisao Hori (Ph.D., Engineering)
[ Affiliation ]
Department of Chemistry, Faculty of Science
Fields of Specialization
Environmental chemistry; decomposition, detoxification, and recovery of environmentally hazardous substances
[ Background ]
April 2010-present: Professor, Department of Chemistry, Faculty of Science, Kanagawa University
April 2015-present: Visiting Researcher, Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (concurrent position)
April 2010-March 2015: Visiting Researcher, Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (concurrent position)
May 2004-March 2010: Research Group Leader, Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology
April 2001-April 2004: Senior Researcher, Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology
1997-1998: Visiting Researcher, Max-Planck-Institut für Kohlenforschung, Germany (and Science and Technology Agency long-term overseas researcher)
October 1994-March 2001: Senior Researcher, Ministry of International Trade and Industry, Agency of Industrial Science and Technology, National Institute for Resources and Environment
April 1993-September 1994: Researcher, Ministry of International Trade and Industry, Agency of Industrial Science and Technology, National Institute for Resources and Environment
April 1990-March 1993: Researcher, Toshiba Research & Development Center
March 1990: Completed Doctorate of Engineering in applied chemistry from Keio University Graduate School of Science and Technology (Ph.D., Engineering)
[ Awards ]
May 2007: 15th Chemical and Bio-Technology Tsukuba Prize (Tsukuba Foundation for Chemical and Bio-Technology) for “Development of Reaction System for Decomposition/Detoxification of Environmentally Persistent Organic Fluorine Compounds”
Contact for Inquiries about this Research
Hisao Hori (Professor, Department of Chemistry, Faculty of Science, Kanagawa University)
Tel: +81-(0)463-59-4111 (Operator), ext. 2844
Hiratsuka Research Support Department, Research Support Division, Kanagawa University
Tel: +81-(0)463-59-4111 (Operator)
Public Relations Department, Public Relations Division, Kanagawa University
Tel: +81-(0)45-481-5661 (Operator)