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F.T. Dulong

Publications and source records attributed to F.T. Dulong.

25 records · Page 2Linked to original sources
USGS1984

Oxidation of pyrite in coal to magnetite

When bituminous coal is heated in an inert atmosphere (He) containing small amounts of oxygen at 393–455 °C, pyrite (FeS 2 ) in coal is partially converted to magnetite (Fe 3 0 4 ). The maximum amount of Fe 3 0 4 formed during the time of heating corresponds to 5–20% of the total pyrite present, depending on the coal sample. The magnetite forms as an outer crust on the pyrite grains. The fact that the magnetic properties of the pyrite grains are substantially increased by the magnetite crust suggests that pyrite can be separated from coal by use of a low magnetic field. In a laboratory test, 75% removal is obtained by means of a 500 Oe magnet on three samples, and 60% on a fourth sample.

Fuel↗
USGS1984

Semi-quantitative ion microprobe mass analyses of mineral-rich particles from the upper freeport coal

An ion microprobe mass analyzer (IMMA) has been used to analyze semi-quantitatively mineral-rich coal particles from two separate facies of the Upper Freeport coal bed. Accuracy is estimated to be ∓ 20% for those elements making up more than 0.1 wt.% of the particles and ∓ 50% for elements making up less than 0.1 wt.%. Using IMMA data, we found statistically significant differences between the two samples for five (Fe, Ca, Mn, Li, Ce) of the 25 elements detected. For Li and Mn the differences between the mineral-rich particles within samples were similar to differences found between samples on a whole-coal basis. For Ca and Fe, the differences are attributed to different modes of occurrence, and for Ce, the differences are probably due to an irregular distribution of an inorganic phase. We conclude that the IMMA can be used to obtain semi-quantitative data that may provide insight into the distribution and mode of occurrence of some of the elements in coal.

International Journal of Coal Geology↗
USGS1983

RECENT DEVELOPMENTS ON THE ORIGIN OF MINERAL MATTER IN COAL.

This study attempts to quantify some of the various origins of mineral matter. Data developed for the Upper Freeport coal bed indicates that mineral matter other than pyrite and calcite is primarily derived from the vegetal matter that ultimately became coal. Cathodoluminesence was used to verify that the quartz in the Upper Freeport coal is dominantly authigenic and not detrital in origin. Sulfur variability in coal beds of the central Appalachian Basin was investigated stratagraphically.

Conference Paper↗
USGS1983

SUBMICROSCOPIC ( less than 1 mu m) MINERAL CONTENTS OF VITRINITES IN SELECTED BITUMINOUS COAL BEDS.

An important aspect of the petrographic description of coal is the characterization of coal quality, including chemical attributes. For geologic investigations, data on the concentrations, distribution, and modes of occurrence of minor and trace elements provide a basis for reconstructing the probable geochemical environment of the swamp material that was converted into peat, and the geochemical conditions that prevailed during and subsequent to coalification. We have been using electron (EPMA) and proton (PIXE) microprobe analytical methods to obtain data on the chemical characteristics of specific coal constituents in their original associations within coal samples. The present study is aimed at evaluation of the nature of mineral occurrences and heterogeneous elemental concentrations within vitrinites. Vitrinites are usually the most abundant, and therefore most important, maceral group in bituminous coal. 8 refs.

Conference Paper↗
USGS1982

Geologic factors that control mineral matter in coal

Elements other than organically derived and bound C, H, N, O, and S constitute mineral matter in coal. Mineral matter may consist of discrete minerals such as calcite, quartz, clays, and pyrite, and/or organic compounds that contain organically bonded elements such as Ca and CI. Processes that may affect the association and content of mineral matter are operable from the initial peat-forming stage to the time of utilization of the coal. However, the objective of this paper is to discuss some of the various geologic processes that may influence content and associations in unmined coal.

Book chapter↗