THERMAL DECOMPOSITION OF URANYL SULFATE Submitted as a thesis to Faculty of The Graduate School of Arts and Sciences of the University of Cincinnati in partial fulfillment of the Requirements for the Degree of Master of Science in Chemistry

摘要

The thermal decomposition of uranyl sulfate to U308 was investigated by means of differential thermal analysis (DTA) and both isothermal and non-isothermal thermogravimetric analysis (TGA), with the following results:nDehydration of U02S04 3H20, the usual commercial form, occurs in three steps, with the intermediate formation of the dehydrate and the monohydrate. Anhydrous uranyl sulfate may be conveniently prepared by calcining the hydrate to constant weight at 450-500 in air.nUranyl sulfate undergoes an enantiotropic transition at 755. The high-temperature form, previously unreported, is designated as /3-U02S04.nDecomposition of U02S04 to U308, oxides of sulfur, and oxygen was observed over a tem¬perature range of 690-830. The decomposition is reversible and the decomposition tempera¬ture varies with atmosphere. In air, calcining to constant weight at 750 yields stoichiometric.