Extraction Of Metals In Coal With Dimethylsulfoxide Based Solvents

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ISBN 13 :
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Download or read book Solvent Extractions of Illinois No. 6 Coal written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The usual abilities of amine solvents, especially EDA, were recognized many years ago. Some recent work has dealt with solvents mixtures. What we think is new is the idea that amines have a chemical as well as a physical action and the finding that DMSO assists the action of EDA, at least partly because it increases the swelling of the coal. The EDA + DMSO combination is more effective than the EDA + pyridine combination. The results with solvent combinations in Table 1 bring out the separate physical and chemical effects of solvents and the effects of longer reaction time and higher temperature when chemical reaction is involved. The primary amines are the best solvents, the smallest and strong base, EDA, being best. Benzylamine and 2-phenethylamine are next best among those tested, with solvent properties closely proportional to their nitrogen contents. Without unusual precautions to exclude air during 1 to 18-hour extractions at 100°C, the EDA/DMSO combination extracted more material than EDA alone. We ascribe the higher rate of exraction by the mixed solvent to the greater swelling of the insoluble material. The difference is not due to oxidation by DMSO. Increasing the temperature and duration of extraction with DMSO alone does not increase by much the amount of coal dissolved and the advantage of DMSO added to EDA decreases with longer reaction times. That 50% of Illinois No. 6 coal can now be dissolved at 100°C to give a solute mostly soluble in pyridine and an extracted coal with much less crosslinking (higher swelling ratio) than pyridine-extracted coal provides a new and exceptional opportunity to investigate the structure of coal that has never been heated above 100°C since it was mined.