The United States of America As Represented by the United States

Siemens Power Corporation, Inc.

Advanced Nuclear Fuels Corporation

Jerry A Partridge

Ronald E Lerch

Gail P Bosuego

Jack B Kendall

Richard A Hermens

A method for removing low levels of heavy metal from chemical/industrial waste streams containing interfering anions which typically form strong complexes with heavy metals such as uranium utilizes an ion exchange resin having amino-phosphonic functional groups which selectively capture the heavy metal from the chemical waste stream in an efficient manner such that the amount of heavy metal in the waste stream is reduced to sub-ppm levels. After capture, the resin is treated with a sequestering agent, such as a solution of ammonium fluoride or ammonium sulfate, which releases the heavy metal from the resin. The resin is then regenerated with a sodium solution and returned to service. Utilizing ion exchange and a resin containing amino-phosphonic functional groups allows removal of heavy metal to a level of less than or equal to 0.1 ppm which is a substantial reduction in view of the presence of significant quantities of complexing anions in the waste stream.

Method for removing a heavy metal from a waste stream

For the recovery of uranium from a solution in which the uranium is in valence (VI), a solution is formed containing ammonium (NH.sub.4.sup.+), fluoride (F.sup.-) and sodium hydrosulfite (Na.sub.2 S.sub.2 O.sub.4). This forms a precipitate (NaNH.sub.4 UF.sub.6), a previously unreported compound. It can be dissolved in an aqueous solution of nitric acid, aluminum nitrate nonahydrate, Al(NO.sub.3).sub.3.9H.sub.2 O, or a mixture of the two. This produces uranyl nitrate hexahydrate, which can be purified by processes conventionally used for that purpose.

Recovery of uranium from solutions

Mercuric nitrate-nitric acid scrub solutions containing radioiodine may be reduced in volume without excessive loss of volatile iodine. The use of concentrated nitric acid during an evaporation process oxidizes the mercury-iodide complex to a less volatile mercuric iodate precipitate.

Mercuric iodate precipitation from radioiodine-containing off-gas

The invention relates to chemical etching process for reclaiming contaminated equipment wherein a reduction-oxidation system is included in a solution of nitric acid to contact the metal to be decontaminated and effect reduction of the reduction-oxidation system, and includes disposing a pair of electrodes in the reduced solution to permit passage of an electrical current between said electrodes and effect oxidation of the reduction-oxidation system to thereby regenerate the solution and provide decontaminated equipment that is essentially radioactive contamination-free.

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Richland, WA, United States of America

Jerry A Partridge