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Optimization of the Graphitization Process at Age-1

Published online by Cambridge University Press:  18 July 2016

Mojmír Němec*
Affiliation:
Department for Chemistry and Biochemistry, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland Laboratory of Ion Beam Physics, HPK, Schafmattstrasse 20, CH-8093 Zürich, Switzerland Department of Nuclear Chemistry, Czech Technical University, in Prague, Brehova 7, 115 19 Prague 1, Czech Republic
Lukas Wacker
Affiliation:
Laboratory of Ion Beam Physics, HPK, Schafmattstrasse 20, CH-8093 Zürich, Switzerland
Heinz Gäggeler
Affiliation:
Department for Chemistry and Biochemistry, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
*
Corresponding author. Email: mojmir.nemec@fjfi.cvut.cz
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Abstract

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The reaction conditions for the graphitization of CO2 with hydrogen were optimized for a fast production of high-quality carbon samples for accelerator mass spectrometry (AMS) measurement. The iron catalyst in use is first oxidized by heating with air to remove possible carbon and other impurities and then after evacuation reduced back to iron with hydrogen in several flushing steps to remove any iron oxide. The optimum conditions for a fast graphitization reaction were experimentally determined by changing the reaction temperatures and the H2/CO2 ratio. The resulting graphite samples were measured by AMS to find the smallest isotopic changes (δ13C) at a minimum of molecular fragment formation (13CH current). The improvements are based on thermodynamic data and are explained with Baur-Glaessner diagrams.

Type
Sample Preparation
Copyright
Copyright © 2010 by the Arizona Board of Regents on behalf of the University of Arizona 

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