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The United States of America As Represented by the United States

Molten Metal Technology, Inc.

Robert S Eby

Michael J Stephenson

Paul A Haas

Thomas H Hamilton

Deborah H Andrews

The present invention provides a method for varying and controlling the chemical composition and physical properties of the uranium oxide solids produced by the thermal conversion of UF.sub.6. The method allows the production of predominantly UO.sub.2, U.sub.3 O.sub.8, or UO.sub.3 interchangeably from the same reactor simply by controlling the hydrogen and oxygen contents of the feed relative to uranium. The temperature profile of the thermal reactor is established by specifying the preheat of the feed prior to mixing, the feed composition, and the reactor wall temperature to thus vary and control the physical properties of the resulting solids according to the end use of the uranium product.

Method for the control of the composition and physical properties of

The invention is a UF.sub.6 -recovery process of the kind in which a stream of substantially pure gaseous UF.sub.6 is directed through an externally chilled desublimer to convert the UF.sub.6 directly to an annular solid ring adhering to the interior wall of the desublimer. After accumulation of a desired amount of solid UF.sub.6, the desublimer is heated to liquefy the solid. Subsequently, the liquid is recovered from the desublimer. It has been found that during the heating operation the desublimer is subjected to excessive mechanical stresses. In addition, it has been found that the incorporation of a very small percentage of relatively noncondensable, nonreactive gas (e.g., nitrogen) in the UF.sub.6 input to the desublimer effects significant decreases in the stresses generated during the subsequent melting operation. This modification to the process provides valuable advantages in terms of reduced hazard, lower operating costs for the desublimer, and increased service life for the desublimer and its auxiliaries. The new process is especially suitable for the recovery of enriched UF.sub.6 from high-speed UF.sub.6 gas-centrifuge cascades.

UF.sub.6 -Recovery process utilizing desublimation

This invention is an improved gas-absorption process for the recovery of a desired component from a feed-gas mixture containing the same. In the preferred form of the invention, the process operations are conducted in a closed-loop system including a gas-liquid contacting column having upper, intermediate, and lower contacting zones. A liquid absorbent for the desired component is circulated through the loop, being passed downwardly through the column, regenerated, withdrawn from a reboiler, and then recycled to the column. A novel technique is employed to concentrate the desired component in a narrow section of the intermediate zone. This technique comprises maintaining the temperature of the liquid-phase input to the intermediate zone at a sufficiently lower value than that of the gas-phase input to the zone to effect condensation of a major part of the absorbent-vapor upflow to the section. This establishes a steep temperature gradient in the section. The stripping factors below this section are selected to ensure that virtually all of the gases in the downflowing absorbent from the section are desorbed. The stripping factors above the section are selected to ensure re-dissolution of the desired component but not the less-soluble diluent gases. As a result, a peak concentration of the desired component is established in the section, and gas rich in that component can be withdrawn therefrom. The new process provides important advantages. The chief advantage is that the process operations can be conducted in a single column in which the contacting zones operate at essentially the same pressure.

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Oak Ridge, TN, United States of America

Robert S Eby