Remediation of radium contaminated soil

The objective of this study is to develop a physico-chemical separation process for the removal of radium from a sample of refractory contaminated soil of Ottawa site near Chicago. The size/activity distribution showed that the activity was not uniformly distributed in all particle sizes and almost 1/2 of the Ra-226 activity was associated with finer than 5-micron size particles. The characterization analysis also resulted in dividing the soil into three size fractions at 300 and 10 micron level. A series of washing and flotation experiments showed that the +300 micron and 300 x 10 Inicron size fraction can be remediated below the regulatory level of 6 pCi/gm level using mild solution of hydrochloric acid containing sodium chloride. Also, flotation with a combination of 8-Hydroxyquinoline and Lambda ERO R 801 collectors and chemical leaching utilizing the chloride based lixiviants was found to be potentially useful for the remediation of -300 + 10 and -10 micron size fraction respectively and are currently under further investigation.