US EPA

2065840 

Technical Report 

Recycle of nitric acid and aluminum nitrate 

Napier, J 

1991 

NTIS/02976684_a 

GRA and I 

GRA and I 

The Oak Ridge Y-12 Plant is located in Oak Ridge, Tennessee, and is owned by the US Department of Energy (USDOE) and is managed by Martin Marietta Energy Systems, Inc. One of the plant's programs is purification and recycle of non-irradiated enriched uranium. A unit operation in the uranium recycle process is solvent extraction of the removal if impurities. For this operation, some of the recycle uranium is dissolved in nitric acid which is then solvent extracted. Two types of acidic nitrate wastes are generated from the extraction process; one of which is a dilute nitric acid waste, called condensate, which is produced from several evaporation operations. This waste may contain up to 10 wt % nitric acid with trace amounts of impurities such as organic carbon, chlorides and fluorides. The acid must be concentrated to 30 or more wt % and the impurities require removal before the nitric acid can be reused in the plant. A second waste, called raffinate, is also produced from the extraction processes. The raffinate waste contains high levels (more than 10 wt %) of aluminum nitrate which is used in the extraction process. It also contains most of the impurities extracted from the uranium. Most of the impurities must leave the extraction process in either the condensate or raffinate stream. In the early 1950's, four unlined waste ponds were constructed to receive the acidic wastes from the extraction process. In the early 1970's, a decision was made to develop and install processes, to recover as much acid and aluminum nitrate as practical from the wastes generated by the solvent extraction processes. The remaining wastes which could not be recycled would be treated to remove the environmentally objectionable compounds. A later decision in the early 1980's was made to develop and install in-situ treatment processes for the liquid wastes in the four ponds and for similar wastes that might be generated in the future. 60 figs. (ERA citation 16:016373)