Low-temperature ashing of lignite using an oxygen plasma.
Proc N.D. Acad Sci 1971 Jan; 24:119-124
Many processes utilizing lignite or other fossil fuels are concerned with the chemical and mineralogical composition of the ash. In an effort to better understand the original condition of the inorganic components in the fuel, a low-temperature oxidation unit was used to ash lignite. In this way temperature-sensitive structures are preserved. Carbonaceous material is oxidized with "active" oxygen generated in a microwave discharge under reduced pressure. The addition of a small quantity of nitrogen catalyzes the formation of active oxygen at temperatures below 60 deg c, as determined by a thermometer inserted in a well in the reactive chamber. The low- temperature ash was analyzed by x-ray diffraction and found to differ considerably from a corresponding high-temperature ash in that sodium occurred mainly as carbonate-sulfate in the latter and as nitrate in the former.
OP; Journal Article
Proceedings of the North Dakota Academy of Science