Gas-chromatographic determination of free and combined carbon in uranium carbide

Abstract

A gas-chromatographic method is described for the determination of combined and total carbon in uranium carbide. The free carbon present in the sample is obtained by difference. The uranium carbide sample is heated in oxygen to 500‡ C and 1000‡ C by induction and the CO2 formed is separated and measured with a thermal conductivity detector. The values obtained at 500‡ C and 1000‡ C represent respectively the combined and total carbon contents. The entire analysis is completed in less than 10 min. The carbon present in the combined form in 10 aliquots of a uranium carbide sample has been found to be 4.76±0.02% and the total carbon was found to be 4.98 + 0.09%. The difference of 0.22% represents free carbon. The free carbon content was determined independently by the HCl dissolution method on 3 aliquots of the same uranium carbide sample and a value of 0.22±0.02% was obtained. The combustion patterns of uranium carbide and mixtures of U3O8 and carbon have been obtained, which give evidence to the completion of combustion of combined carbon at 500‡ C without affecting the free carbon and the completion of combustion of free carbon at 1000‡ C.