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ABSTRACT<br />
Waste streams of hydrogen and helium mixtures are produced at the Kennedy<br />
Space Center during purging of the hydrogen systems and supply lines. This process is<br />
done prior to and after hydrogen servicing. The purged waste gases are lost to the<br />
atmosphere, resulting in an annual loss of 2 million and 0.1 million standard cubic meters<br />
of helium and hydrogen, respectively. Recovery of these gases will have an economic<br />
benefit. Metals, alloys, and intermetallics are known to react with hydrogen in favorable<br />
conditions; therefore, they have the possibility of serving as separating and recovery<br />
agents.<br />
In this study, Mg 2 Ni, VTiNi and LaNi 5 were studied for the separation of H 2 from<br />
He, using differential scanning calorimetry and thermal volumetric analysis. The ability<br />
of LaNi 5 to react with hydrogen reversibly at room temperature was verified, and further<br />
analysis focused on this compound. Size reduction and activation of LaNi 5 by mechanical<br />
milling was investigated using different milling parameters for the purpose of activating<br />
the material for hydrogen absorption.<br />
Because it has been shown that addition of aluminum to LaNi 5 resulted in<br />
improved hydriding and dehydriding properties, that system was studied further here. In<br />
this study, aluminum was added to LaNi 5 by mechanical milling. Hydriding properties<br />
and elemental compositions of the samples were determined afterwards. The hydrogen<br />
absorption rate and capacity were compared to that of LaNi 5 .<br />
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