Coal electron microprobe analysis

Table 17.3 Representative electron microprobe analysis of arsenopyrite and pyrite from southwestern Guizhou Province coal...

Table V. Electron Microprobe Analysis on Organic Maceral (Vitrinite) Level of Raw and Leached Coals and of Residues After Extraction by HC1 and HN0. a...

In our work, the removal of organic sulfur from coal was followed by the ASTM procedure. In addition, the fate of iron and sulfur was assessed by a series of extraction experiments with analysis of the solid residues and the liquid extracts by conventional chemical methods. Finally, an instrumental method based on electron microprobe X-ray analysis was used for the direct determination of organic sulfur in the organic coal matrix (18, 19). The analytical results from the different... 

Modes of occurrence of the elements in coal can be determined using a variety of procedures. Perhaps the most effective method is the use of scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX). This method can detect and analyze minerals as small as 1 pm in diameter (Figure 14). The SEM-EDX also provides useful information on the textural relationships of the minerals. Other microbeam techniques, such as the electron microprobe analyzer, ion microprobe, laser mass analyzer, and transmission electron microscopy, have also been used to determine modes of occurrence of elements in coal. 

Figure 17. Wavelength-dispersive electron microprobe image of arsenic concentration in within a coal sample from the Black Warrior basin of Alabama. Brighter colors show areas with higher arsenic concentrations and reveal the oscillatory zonation of arsenic in pyrite. Black is coal. White arrows indicate cell lumens in the host coal that are filled with epigenetic pyrite. The labeled points are microprobe analysis sites (values in weight percent) HSI=4.38%As, HS2=4.45%As, HS3=3.97% A.s, CSI=0.40%As, CS2=0.33%As.

Direct determination of inorganic elements associated with macerals and lithotypes was based on an electron microprobe study of coal microcomponents (3 ) using energy dispersive x-ray analysis to determine the presence of elements and their ratios as well as variation at three locations in the Beulah-Zap seam. 

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