Differential Scanning Calorimetry of Minerals of the Dolomite-Ferroan-Dolomite-Ankerite Series in Flowing Carbon Dioxide

J. V. Dubrawski and S. St. J. Warne
BHP Central Research Laboratories, PO Box 188, Wallsend, NSW 2287, Australia
Department of Geology, University of Newcastle, Shortland, NSW 2308, Australia

Abstract: The dolomite-ferroan-dolomite-ankerite series of carbonate minerals has been investigated in flowing carbon dioxide using high-temperature DSC. Decomposition products were analysed by X-ray diffraction. The minerals studied included dolomite containing no iron, and members substituted by iron in the molar ratio range of 0.082 to 0.49. Complete resolution of the three main endothermic features was observed and enthalpy values ΔH, determined from each. The individual and total enthalpy values showed a linear dependence upon the Fe and Mg content of the members across the series. A decrease in the enthalpy of decomposition occurs with increasing Fe content. The effect of Fe substitution was readily observed and the estimated limit of detection is less than 1% FeO. Accuracy of the measurements was limited by the purity of the minerals themselves.

Keywords: dolomite • ferroan dolomite • ankerite • differential scanning calorimetry • X-ray diffraction • carbon dioxide

Mineralogical Magazine; December 1988 v. 52; no. 368; p. 627-635; DOI: 10.1180/minmag.1988.052.368.07
© 1988, The Mineralogical Society
Mineralogical Society (www.minersoc.org)