Enhanced Selective Leaching of Chromium from Radioactive Sludges--Lynntech, Inc., 7610 Eastmark Drive, Suite 202, College Station, TX 77840-4023; 979-693-0017
Dr. Jinseong Kim, Principal Investigator
Mr. Oliver J. Murphy, Business Official
DOE Grant No. DE-FG03-99ER82817
Amount: $683,605

Techniques are needed for the safe and cost-effective remediation of radioactive wastes stored in more than 300 underground storage tanks at Department of Energy sites. The presence of chromium materials in the waste sludge is a major problem because it has a relatively large impact on the volume of high level waste (HLW) when vitrified. The cost of vitrification and storage could be substantially reduced by effectively separating chromium from the HLW using a selective oxidant combined with an enhanced selective oxidation process to reduce the amount of chromium in these wastes. This project will develop a selective oxidative alkaline leaching (ESOAL) process to accomplish this removal. In Phase I, the process was tested with simulant waste and shown to be capable of removing chromium species from complex sludges with a 100 percent efficiency in a short operation time. Efficiencies and removal rates were substantially better than other processes such as caustic leaching and conventional oxidative leaching. The ESOAL process was also successful in the co-dissolution of non-radioactive species (with a corresponding high reduction of sludge mass) with no dissolution of strontium, an important radioactive species found in underground storage tanks. In Phase II, the process will be optimized and tested with several sludge simulants as well as with actual waste from the Hanford site. A scaled-up automated process will then be developed and tested.

Commercial Applications and Other Benefits as described by the awardee: Besides its application to the remediation of nuclear waste, this process could be applied to the treatment of many wastewaters, such as from the dye, electroplating, and pharmaceutical industries as well as municipal sewage.