Presentation Title

Uranium Abatement Pellets' Robustness Enhanced By Slow Dehydration

Start Date

November 2016

End Date

November 2016

Location

HUB 302-#10

Type of Presentation

Poster

Abstract

Geologic and anthropogenic activities in the Four Corners region have contaminated potable water sources on the Navajo Nation with heavy metals, especially uranium. Due to clays cation exchange capabilities, ceramic clay pellets were made to purify contaminated waters. Both clay and water are essential for pellet fabrication; variations in clay and water ratios effect robustness, a critical component for safe disposal. The Instron 5800 compression test produces the robustness indicator. For the study, 3 reference clays and 2 regional clays are utilized; Wyoming, Arizona, Texas, Gallup and Berino New Mexico, respectively. Initial hydration of the clays is essential to allow orientation of clay platelets. Subsequently, pellet dehydration is necessary. However, excess water exiting the pellet rapidly during the dehydration process causes micro-fractures, thus compromising robustness. Conversely, it is hypothesized that excess water will make a more robust pellet when maximum inter-platelet interaction are allowed. To avoid fractures, a slow dehydration process was designed. Pellets were made in a 40:60 Gallup soil to DD water ratio. An enclosed system was used for slow dehydration, and it was monitored every 24 hours. The system uses the pellets’ own water to create constant water vapor pressure; which retards the rate of dehydration. The pellets did not visibly crack or micro-fracture; moreover extremely robust pellets were produced exceeding 3,500 psi compression strength. Pellet robustness verification is a key fabrication facet which we now understand. Robustness studies to ensure safe disposal will be extended to the other reference and regional clays proven to abate uranium.

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Nov 12th, 4:00 PM Nov 12th, 5:00 PM

Uranium Abatement Pellets' Robustness Enhanced By Slow Dehydration

HUB 302-#10

Geologic and anthropogenic activities in the Four Corners region have contaminated potable water sources on the Navajo Nation with heavy metals, especially uranium. Due to clays cation exchange capabilities, ceramic clay pellets were made to purify contaminated waters. Both clay and water are essential for pellet fabrication; variations in clay and water ratios effect robustness, a critical component for safe disposal. The Instron 5800 compression test produces the robustness indicator. For the study, 3 reference clays and 2 regional clays are utilized; Wyoming, Arizona, Texas, Gallup and Berino New Mexico, respectively. Initial hydration of the clays is essential to allow orientation of clay platelets. Subsequently, pellet dehydration is necessary. However, excess water exiting the pellet rapidly during the dehydration process causes micro-fractures, thus compromising robustness. Conversely, it is hypothesized that excess water will make a more robust pellet when maximum inter-platelet interaction are allowed. To avoid fractures, a slow dehydration process was designed. Pellets were made in a 40:60 Gallup soil to DD water ratio. An enclosed system was used for slow dehydration, and it was monitored every 24 hours. The system uses the pellets’ own water to create constant water vapor pressure; which retards the rate of dehydration. The pellets did not visibly crack or micro-fracture; moreover extremely robust pellets were produced exceeding 3,500 psi compression strength. Pellet robustness verification is a key fabrication facet which we now understand. Robustness studies to ensure safe disposal will be extended to the other reference and regional clays proven to abate uranium.