Improved Performance of the Alkaline-Side CSEX Process for Cesium Extraction from Alkaline High-Level Waste Obtained by Characterization of the Effect of Surfactant Impurities

PDF Version Also Available for Download.

Description

Improved understanding and performance of the alkaline-side CSEX process has been obtained through the characterization of impurity effects that hinder complete stripping of cesium from the solvent. It is shown in this report that tests of the alkaline-side CSEX process conducted in the summer and fall of 1998 were complicated by the presence of common surfactant anions, undecyl- and dodecylsulfonate, as trace impurities in the two simulants tested. This conclusion was drawn from the results of a series of systematic extraction tests followed by a definitive identification by electrospray mass spectrometry (ES-MS). Based on this understanding, a straightforward preventative measure ... continued below

Physical Description

vp.

Creation Information

Delmau, L.H. November 4, 1999.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 35 times . More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Author

Sponsor

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

Improved understanding and performance of the alkaline-side CSEX process has been obtained through the characterization of impurity effects that hinder complete stripping of cesium from the solvent. It is shown in this report that tests of the alkaline-side CSEX process conducted in the summer and fall of 1998 were complicated by the presence of common surfactant anions, undecyl- and dodecylsulfonate, as trace impurities in the two simulants tested. This conclusion was drawn from the results of a series of systematic extraction tests followed by a definitive identification by electrospray mass spectrometry (ES-MS). Based on this understanding, a straightforward preventative measure involving the addition of a lipophilic tertiary amine extractant at a small concentration to the solvent is proposed and demonstrated. As part of the task ''Fission Product Solvent Extraction'' supported by the Efficient Separations and Processing Crosscutting Program within the USDOE Office of Environmental Management, the alkaline-side CSEX process has been developed for removal of radio-cesium ({sup 137}Cs) from alkaline high-level wastes stored in underground tanks at the Hanford Site and Savannah River Site (SRS). As described in a previous report, tests conducted in Fiscal Year 1998 generally demonstrated performance meeting the requirements for cesium removal from the waste to be treated at the SRS. However, discrepancies in stripping behavior were shown to arise from unidentified differences ''in the batches of waste simulant employed for testing. Various effects such as solvent impurities, kinetics, contacting method, and counting method were eliminated as possible causes of the observed discrepancies. Tests in Fiscal Year 1999 reported herein confirmed the earlier suspicion that the simulants contained lipophilic anionic impurities. Extraction tests demonstrated that the impurities could be concentrated in the solvent, and by ES-MS in the negative-ion mode it was possible to identify the harmful impurities as undecyl- and dodecylsulfonate. Subsequent tests with purchased sodium dodecylsulfonate confirmed that this surfactant could produce decreased stripping performance of the magnitude equivalent to that observed when using the simulant associated with the worse performance. With the identification of the impurity now settled, it is clear that poor stripping arises from ion-pair species in the solvent comprised of the cesium-extractant complex cation and the alkylsulfonate anion. Because the Gibbs energy of transfer of this anion and the complexation of the cesium cation by the extractant are both so favorable, the stripping of the cesium, nitrate from the solvent is correspondingly unfavorable. Thus, once the cesium associated with nitrate ion in the solvent has been stripped, further stripping of the remaining cesium in the solvent becomes inefficient. A simple remedy is the addition of a lipophilic amine such as trioctylamine to the solvent. This well-known amine extractant, once proposed for reprocessing, remains neutral and essentially inert during extraction of the alkaline waste but converts to the trioctylammonium nitrate salt on scrubbing and stripping. This lipophilic salt remains in the organic phase and allows the final traces of cesium in the solvent to be stripped by supplying the alkylsulfonate impurity in the solvent with equivalent cationic charges. Further results regarding this and other improvements to the solvent system will be described elsewhere.

Physical Description

vp.

Source

  • Other Information: PBD: 4 Nov 1999

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Report No.: ORNL/TM-1999/209
  • Grant Number: AC05-00OR22725
  • DOI: 10.2172/814457 | External Link
  • Office of Scientific & Technical Information Report Number: 814457
  • Archival Resource Key: ark:/67531/metadc735598

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • November 4, 1999

Added to The UNT Digital Library

  • Oct. 18, 2015, 6:40 p.m.

Description Last Updated

  • March 31, 2016, 1:21 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 2
Total Uses: 35

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Delmau, L.H. Improved Performance of the Alkaline-Side CSEX Process for Cesium Extraction from Alkaline High-Level Waste Obtained by Characterization of the Effect of Surfactant Impurities, report, November 4, 1999; United States. (digital.library.unt.edu/ark:/67531/metadc735598/: accessed October 19, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.