Ronald P May

US Patent:

55737382, Nov 12, 1996

Filed:

Jul 8, 1994

Appl. No.:

8/272193

Inventors:

Jonathan K. Ma - Henderson NV
Andrea W. Chow - Los Altos CA
Scott A. Ranger - St. George UT
David W. Peters - West Cliffe CO
Ronald F. May - Las Vegas NV

Assignee:

Lockheed Martin Corporation - Bethesda MD

International Classification:

C01G 4300

US Classification:

423 20

Abstract:

Soil, contaminated with radioactive material such as uranium, is treated to remove the radioactive contaminant. The soil is first pre-processed to remove and clean oversized particles for release back to the environment as recovered soil. Pre-processing also includes removal of metallic uranium from the soil by gravimetric separation for off-site disposal. An aqueous slurry is formed from the pre-processed feed which is fed to a mechanical separation device. Particles greater than 10 mesh are crushed to provide a uniform feed slurry. The slurry is processed in an aqueous leaching solution of sulfuric acid, hydrogen peroxide and iron to remove uranium. Particulate matter is removed from the acidic slurry; the remaining fine particulate matter is then submitted to a second-stage leaching to remove residual uranium. Uranium is recovered from the combined leaching solutions by either a two-stage precipitation process or by passage over an ion-exchange material. The process utilizes a closed loop system for process water which is reclaimed, clarified, and recirculated for reuse.