Method for the recovery of actinide elements from nuclear reactor waste

Patent · Sun Dec 31 23:00:00 EST 1978

OSTI ID:863392

Horwitz, E Philip ^[1]; Delphin, Walter H ^[2]; Mason, George W ^[3]

---

1. Elmhurst, IL
2. Woodridge, IL
3. Clarendon Hills, IL

A process for partitioning and recovering actinide values from acidic waste solutions resulting from reprocessing of irradiated nuclear fuels by adding hydroxylammonium nitrate and hydrazine to the waste solution to adjust the valence of the neptunium and plutonium values in the solution to the +4 oxidation state, thus forming a feed solution and contacting the feed solution with an extractant of dihexoxyethyl phosphoric acid in an organic diluent whereby the actinide values, most of the rare earth values and some fission product values are taken up by the extractant. Separation is achieved by contacting the loaded extractant with two aqueous strip solutions, a nitric acid solution to selectively strip the americium, curium and rare earth values and an oxalate solution of tetramethylammonium hydrogen oxalate and oxalic acid or trimethylammonium hydrogen oxalate to selectively strip the neptunium, plutonium and fission product values. Uranium values remain in the extractant and may be recovered with a phosphoric acid strip. The neptunium and plutonium values are recovered from the oxalate by adding sufficient nitric acid to destroy the complexing ability of the oxalate, forming a second feed, and contacting the second feed with a second extractant of tricaprylmethylammonium nitrate in an inert diluent whereby the neptunium and plutonium values are selectively extracted. The values are recovered from the extractant with formic acid.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4162230
• OSTI ID: 863392
• Country of Publication: United States
• Language: English

Related Subjects

/252/423/976/
ability
achieved
acid
acid solution
acidic
actinide
actinide elements
actinide values
adding
adding sufficient
adjust
americium
ammonium nitrate
aqueous
aqueous strip
complexing
contacting
curium
destroy
dihexoxyethyl
diluent
earth
earth values
elements
extractant
extracted
feed
feed solution
fission
fission product
formic
formic acid
forming
fuels
hydrazine
hydrogen
hydroxylammonium
hydroxylammonium nitrate
inert
irradiated
irradiated nuclear
loaded
method
neptunium
nitrate
nitric
nitric acid
nuclear
nuclear fuel
nuclear fuels
nuclear reactor
organic
oxalate
oxalic
oxalic acid
oxidation
partitioning
phosphoric
phosphoric acid
plutonium
plutonium values
process
product
product values
rare
rare earth
reactor
reactor waste
recovered
recovering
recovering actinide
recovery
remain
reprocessing
resulting
selectively
selectively extract
separation
solution
solutions
solutions resulting
strip
strip solution
sufficient
tetramethylammonium
tricaprylmethylammonium
trimethylammonium
uranium
uranium values
valence
values
waste
waste solution
waste solutions
whereby