Hydrous titanium oxides as adsorbent for uranium

Hydrous titanium oxides produced in stainless steel reactors were found to exhibit better adsorption of uranium than those obtained in glass reactors. Hydrous titanium oxide manufactured from titanic solution containing Fe ion was also found to exhibit relatively high uranium adsortivity. Observation by electron microscope revealed that hydrous titanium oxide particles from glass reactors were similar in form to glass fragments, while those from stainless steel reactors and commercial titanium oxide manufacturing processes were found to be spherical in form. X-ray diffraction showed all of these hydrous titanium oxides to be of the anatase type. Diffraction charts of amorphous hydrous titanium oxides after their use in the uranium adsorption-desorption process showed some difference from charts obtained before use, while such difference was not observed in charts of crystalline hydrous titanium oxides. This suggested that these two groups of materials differed in uranium adsorption-desorption mechanism. Heating of crystalline hydrous titanium oxides to 6000C caused no significant change in their crystal structure, but they were fully transformed to anatase at 8000C, and to rutile at 1,0000C. In both thermogravimetric analysis and differential thermal analysis, these hydrous titanium oxides exhibited considerable heat absorption and weight loss due to the evaporation of water. The hydrous titanium oxide manufactured by a company in particular underwent a great loss of weight in the temperature ranges from 5500C to 7250C and from 9000C to 1,0000C. The cause was not made clear. (author)