Patent Number: 046541730
Section: claims

1. A process for the removal of technetium values from a nuclear waste solution which contains an initial, Tc-99, concentration in the range of about 2.5.times.10.sup.-5 to 1.times.10.sup.-4 molar, comprising the steps of (1) contacting said solution with a precipitation agent that contributes to said solution an amount of tetraphenylphosphonium cation sufficient to precipitate at least a portion of said technetium values out of said waste solution as an insoluble pertechnetate salt precipitate and then  (2) separating said pertechnetate salt precipitate from said waste solution. 2. A process according to claim 1, wherein said precipitating agent comprises a water soluble tetraphenylphosphonium salt. 3. A process according to claim 2, wherein said salt is a water soluble tetraphenylphosphonium halide salt. 4. A process according to claim 2, wherein said precipitating agent comprises at least one compound selected from the group consisting of tetraphenylphosphonium chloride and tetraphenylphosphonium hydroxide. 5. A process according to claim 1, wherein said portion of said technetium values precipitated out of said waste solution ranges between at least 90% and about 96%. 6. A process according to claim 1, wherein step (2) comprises removing said pertechnetate salt precipitate from said waste solution by filtering. 7. A process according to claim 1, wherein said waste solution has a sodium ion concentration of at least 5.6 molar. 8. A process according to claim 1, further comprising prior to step (2) the step of concentrating said precipitate. 9. A process according to claim 8, wherein concentration of said precipitate is effected by cross-flow filtration. 10. A process according to claim 1, wherein said amount of tetraphenylphosphonium cation is between about 7.times.10.sup.-4 and 2.times.10.sup.-3 molar.