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Title: Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions

Abstract

The separation of trivalent actinides and rare earths from other fission products in high-level nuclear wastes by oxalate precipitation followed by ion exchange (OPIX) was experimentally investigated using synthetic wastes and a small-scale, continuous-flow oxalic acid precipitation and solid-liquid separation system. Trivalent actinide and rare earth oxalates are relatively insoluble in 0.5 to 1.0 M HNO/sub 3/ whereas other fission product oxalates are not. The continuous-flow system consisted of one or two stirred-tank reactors in series for crystal growth. Oxalic acid and waste solutions were mixed in the first tank, with the product solid-liquid slurry leaving the second tank. Solid-liquid separation was tested by filters and by a gravity settler. The experiments determined the fraction of rare earths precipitated and separated from synthetic waste streams as a function of number of reactors, system temperature, oxalic acid concentration, liquid residence time in the process, power input to the stirred-tank reactors, and method of solid-liquid separation. The crystalline precipitate was characterized with respect to form, size, and chemical composition. These experiments are only the first step in converting a proposed chemical flowsheet into a process flowsheet suitable for large-scale remote operations at high activity levels.

Authors:
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
OSTI Identifier:
5602200
Report Number(s):
ORNL/TM-6445
TRN: 80-004949
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; AMERICIUM; ION EXCHANGE; PRECIPITATION; CURIUM; OPIX PROCESS; RADIOACTIVE WASTE PROCESSING; HIGH-LEVEL RADIOACTIVE WASTES; RARE EARTHS; FISSION PRODUCTS; FLOWSHEETS; OXALATES; OXALIC ACID; ACTINIDES; CARBOXYLIC ACID SALTS; CARBOXYLIC ACIDS; DIAGRAMS; DICARBOXYLIC ACIDS; ELEMENTS; ISOTOPES; MANAGEMENT; METALS; ORGANIC ACIDS; ORGANIC COMPOUNDS; PROCESSING; RADIOACTIVE MATERIALS; RADIOACTIVE WASTES; SEPARATION PROCESSES; TRANSPLUTONIUM ELEMENTS; TRANSURANIUM ELEMENTS; WASTE MANAGEMENT; WASTE PROCESSING; WASTES; 052001* - Nuclear Fuels- Waste Processing

Citation Formats

Forsberg, C. W. Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions. United States: N. p., 1980. Web. doi:10.2172/5602200.
Forsberg, C. W. Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions. United States. https://doi.org/10.2172/5602200
Forsberg, C. W. 1980. "Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions". United States. https://doi.org/10.2172/5602200. https://www.osti.gov/servlets/purl/5602200.
@article{osti_5602200,
title = {Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions},
author = {Forsberg, C. W.},
abstractNote = {The separation of trivalent actinides and rare earths from other fission products in high-level nuclear wastes by oxalate precipitation followed by ion exchange (OPIX) was experimentally investigated using synthetic wastes and a small-scale, continuous-flow oxalic acid precipitation and solid-liquid separation system. Trivalent actinide and rare earth oxalates are relatively insoluble in 0.5 to 1.0 M HNO/sub 3/ whereas other fission product oxalates are not. The continuous-flow system consisted of one or two stirred-tank reactors in series for crystal growth. Oxalic acid and waste solutions were mixed in the first tank, with the product solid-liquid slurry leaving the second tank. Solid-liquid separation was tested by filters and by a gravity settler. The experiments determined the fraction of rare earths precipitated and separated from synthetic waste streams as a function of number of reactors, system temperature, oxalic acid concentration, liquid residence time in the process, power input to the stirred-tank reactors, and method of solid-liquid separation. The crystalline precipitate was characterized with respect to form, size, and chemical composition. These experiments are only the first step in converting a proposed chemical flowsheet into a process flowsheet suitable for large-scale remote operations at high activity levels.},
doi = {10.2172/5602200},
url = {https://www.osti.gov/biblio/5602200}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1980},
month = {Tue Jan 01 00:00:00 EST 1980}
}