Leaching of uranium and Ra-226 from low-level radioactive waste from Port Hope, Ontario

Uranium and radium were leached from a low-lever radioactive soil sample ne utralized with limestone from Port Hope, ON, in single stage and multistage leaching tests. The leachants used were alkaline EDTA, sodium citrate, sod ium potassium tartrate, acidic ferric chloride, hydrochloric acid, nitric a cid and hydrochloric or nitric acid plus boric acid mixtures. All leaching tests except the two-stage acid teachings proved ineffective in yielding le ach residues with low residual Ra-226 concentrations of < 100 pCi/g. Leachi ng with 4 mol/L HNO3 in the first stage followed by treatment with 4 mol/L HNO3 plus 0.05 mol/L boric acid in the second stage proved effective and ga ve a leach residue with 85 pCi/g Ra-226 and 16 ppm uranium.