Observation of a Layer Structure in Ti-U-O System

Abstract

It is well known that hydrous titanium oxides are useful as an inorganic adsorbent for uranium resources in seawater. In this work, it was found that a characteristic layer structure appears when the Ti-U coprecipitates formed by the addition of aqueous ammonia to the nitric acid/sulfuric acid solution are heated in an 8%H₂-92%Ar reducing atmosphere at a relatively low temperature (around 350°C). The formation of this layer structure and the phase transformation which proceeds in air with time were examined by means of X-ray diffraction analysis, magnetic susceptibility measurement, X-ray photoelectron spectroscopy, thermogravimetry etc. These results are considered to suggest that the layer structure is formed by the occupation of uranium (probably as uranyl units) between the layers in the titanium oxide crystal.