condition for the existence of two kinds of carbonaceous materials. Furthermore, the same assertion should be valid in the application of DTA to the analyses of solid materials in general.
ACKNOWLEDGMENT The authors acknowledge helpful discussions with G. Adler, C. R. Krishna, and D. J. Metz and a critical review by D. J. Metz. We also thank W. M. Reams for performing the x-ray diffraction analyses. LITERATURE CITED (1)T. V. Rode and A. A. Balandin, J. Gen. Chem. USSR. (Engl. Trans/.),28, 2937 (1958). (2)A. A. Balandin, froc. Second lnt. Gong. Cafal., Paris, 1135-1157, (1960). (3)T. Honda, T. Saito, and Y. Horiguchi, J. Carbon (Jpn), 72, 14 (1973).
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RECEIVEDfor review March 15,1976. Accepted June 25,1976. This work was performed under the auspices of the Office of Molecular Sciences, Division of Physical Research, US.Energy Research and Development Administration,Washington, D.C.
Determination of Aluminum in Bulk iron Ore Samples by Neutron Activation Analysis Mihai Borsaru* and Ralph J. Holmes CSIRO Division of Mineral Physics, P.O. Box 124, Port Melbourne, Victoria 3207,Australia
Neutron activation analysis has been applied to the determination of aluminum in 25-kg iron ore samples at -6-mm particle slze. By measuring the thermal and epithermal neutron fluxes reflected by the samples durlng irradiatlon, an accuracy of better than 4~0.3% (95% confidence Intervals) was achieved for alumina concentrations between 1 and 6%. Ore samples should be dried to
