Key process parameters to modify the porosity of cerium dioxide microspheres formed in the internal gelation process

Hunt, Rodney Dale; Collins, Jack Lee; Reif, Tyler J.; Cowell, Brian Spencer; Johnson, Jared A.

doi:10.1016/j.jnucmat.2017.08.007

Title: Key process parameters to modify the porosity of cerium dioxide microspheres formed in the internal gelation process

Full Record
Other Related Research

Abstract

Recently, an internal gelation study demonstrated that the use of heated urea and hexamethylenetetramine can have a pronounced impact on the porosity and sintering characteristics of cerium dioxide (CeO₂) microspheres. This effort has identified process variables that can significantly change the initial porosity of the CeO₂ microspheres with slight modifications. A relatively small difference in the sample preparation of cerium ammonium nitrate and ammonium hydroxide solution had a large reproducible impact on the porosity and slow pour density of the produced microspheres. Increases in the gelation temperature as small as 0.5 K also produced a noticeable increase in the slow pour density. If the gelation temperature was increased too high, the use of the heated hexamethylenetetramine and urea was no longer observed to be effective in increasing the porosity of the CeO₂ microspheres. In conclusion, the final process variable was the amount of dispersing agent, Span™ 80, which can increase the slow pour density and produce significantly smaller microspheres.

Authors:

Hunt, Rodney Dale ^[1]; Collins, Jack Lee ^[1]; Reif, Tyler J. ^[1]; Cowell, Brian Spencer ^[1]; Johnson, Jared A. ^[1]

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Publication Date:: Fri Aug 04 00:00:00 EDT 2017

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1423099

Alternate Identifier(s):: OSTI ID: 1549842

Grant/Contract Number:: AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Nuclear Materials

Additional Journal Information:: Journal Volume: 495; Journal Issue: C; Journal ID: ISSN 0022-3115

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; Cerium oxide spheres; Internal gelation

Citation Formats


                    Hunt, Rodney Dale, Collins, Jack Lee, Reif, Tyler J., Cowell, Brian Spencer, and Johnson, Jared A. Key process parameters to modify the porosity of cerium dioxide microspheres formed in the internal gelation process.  United States: N. p., 2017. 
Web.  doi:10.1016/j.jnucmat.2017.08.007.

Copy to clipboard


                    Hunt, Rodney Dale, Collins, Jack Lee, Reif, Tyler J., Cowell, Brian Spencer, & Johnson, Jared A. Key process parameters to modify the porosity of cerium dioxide microspheres formed in the internal gelation process.  United States.  https://doi.org/10.1016/j.jnucmat.2017.08.007

Copy to clipboard


                    Hunt, Rodney Dale, Collins, Jack Lee, Reif, Tyler J., Cowell, Brian Spencer, and Johnson, Jared A. Fri .  
"Key process parameters to modify the porosity of cerium dioxide microspheres formed in the internal gelation process".  United States.  https://doi.org/10.1016/j.jnucmat.2017.08.007.  https://www.osti.gov/servlets/purl/1423099.

Copy to clipboard


                    
@article{osti_1423099,

  title        = {Key process parameters to modify the porosity of cerium dioxide microspheres formed in the internal gelation process},

  author       = {Hunt, Rodney Dale and Collins, Jack Lee and Reif, Tyler J. and Cowell, Brian Spencer and Johnson, Jared A.},

  abstractNote = {Recently, an internal gelation study demonstrated that the use of heated urea and hexamethylenetetramine can have a pronounced impact on the porosity and sintering characteristics of cerium dioxide (CeO2) microspheres. This effort has identified process variables that can significantly change the initial porosity of the CeO2 microspheres with slight modifications. A relatively small difference in the sample preparation of cerium ammonium nitrate and ammonium hydroxide solution had a large reproducible impact on the porosity and slow pour density of the produced microspheres. Increases in the gelation temperature as small as 0.5 K also produced a noticeable increase in the slow pour density. If the gelation temperature was increased too high, the use of the heated hexamethylenetetramine and urea was no longer observed to be effective in increasing the porosity of the CeO2 microspheres. In conclusion, the final process variable was the amount of dispersing agent, Span™ 80, which can increase the slow pour density and produce significantly smaller microspheres.},

  doi          = {10.1016/j.jnucmat.2017.08.007},

  journal      = {Journal of Nuclear Materials},

  number       = C,

  volume       = 495,

  place        = {United States},

  year         = {Fri Aug 04 00:00:00 EDT 2017},

  month        = {Fri Aug 04 00:00:00 EDT 2017}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (Publisher)

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1016/j.jnucmat.2017.08.007

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 4 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Use of boiled hexamethylenetetramine and urea to increase the porosity of cerium dioxide microspheres formed in the internal gelation process

Journal Article Hunt, R. D. ; Collins, J. L. ; Cowell, B. S. - Journal of Nuclear Materials

Cerium dioxide (CeO₂) is a commonly used simulant for plutonium dioxide and for plutonium (Pu) in a mixed uranium (U) and Pu oxide [(U, Pu)O₂] in nuclear fuel development. This effort developed CeO₂ microspheres with different porosities and diameters for use in a crush-strength study. The internal gelation technique has produced CeO₂ microspheres with limited initial porosity. When an equal molar solution of urea and hexamethylenetetramine (HMTA) is gently boiling for 1 hr and used in the gelation process, the crystallite size and porosity of mixed U and thorium oxide microspheres and the (U, Pu)O₂ microspheres increased significantly. In thismore »« less
Cited by 7
https://doi.org/10.1016/j.jnucmat.2017.04.061

Full Text Available
Production of cerium dioxide microspheres by an internal gelation sol–gel method

Journal Article Katalenich, Jeffrey A. - Journal of Sol-Gel Science and Technology

An internal gelation sol-gel technique was used to prepare cerium dioxide microspheres with uniform diameters near 100 µm. In this process, chilled aqueous solutions containing cerium, hexamethylenetetramine (HMTA), and urea are transformed into a solid gel by heat addition and are subsequently washed, dried, and sintered to produce pure cerium dioxide. Cerous nitrate and ceric ammonium nitrate solutions were compared for their usefulness in microsphere production. Gelation experiments were performed with both cerous nitrate and ceric ammonium nitrate to determine desirable concentrations of cerium, HMTA, and urea in feed solutions as well as the necessary quantity of ammonium hydroxide addedmore »« less
https://doi.org/10.1007/s10971-017-4345-8
Key properties of mixed cerium and zirconium microspheres prepared by the internal gelation process with previously boiled HMTA and urea

Journal Article Hunt, Rodney Dale ; Collins, Jack Lee ; Choi, Jae-Soon - Ceramics International

The internal gelation process using previously boiled hexamethylenetetramine-urea was used in exploratory study to produce CeO₂–ZrO₂ microspheres, which can serve as a simulant for ceramic transuranic fuel particles and as a viable three-way catalyst. The calcined CeO₂ and ZrO₂ microspheres with Barrett–Joyner–Halenda (BJH) pore size and volumes of 8–10 nm and 0.19–0.20 mL/g, respectively, had many more surface cracks than their relatively smooth CeO₂–ZrO₂ counterparts even though the BJH pore sizes and volumes of mixed oxide spheres were lower at 3 nm and 0.11–0.12 mL/g, respectively. The Brunauer–Emmett–Teller (BET) surface areas for the CeO₂ and ZrO₂ microspheres were 74 andmore »« less
https://doi.org/10.1016/j.ceramint.2021.05.042

Full Text Available
Determination of Ideal Broth Formulations Needed to Prepare Hydrous Cerium Oxide Microspheres via the Internal Gelation Process

Technical Report Collins, Jack Lee ; Chi, Anthony

A simple test tube methodology was used to determine optimum process parameters for preparing hydrous cerium oxide microspheres via the internal gelation process.1 Broth formulations of cerium ammonium nitrate [(NH4)2Ce(NO3)6], hexamethylenetetramine, and urea were found that can be used to prepare hydrous cerium oxide gel spheres in the temperature range of 60 to 90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations to be able to equate the test-tube gelation times to actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broth formulations.
https://doi.org/10.2172/947141

Full Text Available
Production of 75–150 µm and <75 µm of cerium dioxide microspheres in high yield and throughput using the internal gelation process

Journal Article Hunt, Rodney D. ; Collins, Jack L. ; Johnson, Jared A. ; ... - Annals of Nuclear Energy (Oxford)

Hundreds of grams of calcined cerium dioxide (CeO₂) microspheres were produced in this paper using the internal gelation process with a focus on 75–150 µm and <75 µm diameter sizes. To achieve these small sizes, a modified internal gelation system was employed, which utilized a two-fluid nozzle, two static mixers for turbulent flow, and 2-ethyl-1-hexanol as the medium for gel formation at 333–338 K. This effort generated over 400 g of 75–150 µm and 300 g of <75 µm CeO₂ microspheres. The typical product yields for the 75–150 µm and <75 µm microspheres that were collected and processed were 72more »« less
Cited by 10
https://doi.org/10.1016/j.anucene.2017.03.010

Full Text Available

Similar Records