Improved Uranium Recovery from the Process Streams in an Electroplating Facility

Abstract

AbstractCylindrical uranium slugs are used as irradiation targets in the production reactors at the Savannah River Plant. These slugs are first chemically etched, nickel plated, encased in aluminum, inspected, and individually pressure tested. An improved process was developed to recover the uranium from the acidic etching streams by controlling pH and the PO4 to U ratio so that the precipitation of the uranium as hydrogen uranyl phosphate was maximized. Bench scale tests demonstrated that the recovery of uranium could be increased to greater than 99.9% (vs. the current level of about 95% recovery). The recommended changes involved the addition of process effluent “hold” tanks. The addition of the various process streams to the neutralization/precipitation tank could therefore be controlled to maintain a consistent ratio of uranyl nitrate and phosphoric acid. Also, it was determined that a strong caustic solution (resulting from the dissolution of rejected aluminum slugs) could be utilized to neutralize the nitric and phosphoric acid solutions. The buffering action of the aluminum in the “caustic recovery solution” would reduce the sensitivity of the hydrogen uranyl phosphate precipitation to the phosphate ion concentration.