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U.S. Department of Energy
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Chemical de-ashing of bituminous coal by flame treatment (in German)

Technical Report ·
OSTI ID:6818008

At the Bitterfeld chromate works, unsuccessful attempts were made to purify bituminous coal by a variation of the flame-exposure treatment used to purify chrome ores. Coal slurries were made in lye solutions using from 144 to 10,000 mesh coal powders. The slurry used 2.5% NaOH and was 1:1.5 coal-to-lye solution. A major effort went into maintaining the suspension to prevent stoppage of the feed lines. This was done by a forceful blast of air up through the slurry-holding vessel. The suspension was showered through a nozzle into a mantle where the mist was mixed with a nitrogen stream. The coal-lye mist entered a tubular oven over a short-flamed hydrogen burner, to be refined in the flame. The temperature within the oven was not measured but that of the exhaust was 70/sup 0/ to 80/sup 0/C. A layer of coal was deposited on the surface inside the oven and analyses were made for the ash content at various points. Washing of the samples to remove lye and chromate impurities from other experiments preceded the analysis. The oven, which had formerly been used to research chrome ore purification, made necessary a chromate extraction step as well as the HCl wash to remove lye. The coal entering was found to have 1.04% to 1.11% ash while that near the exit had 0.85% to 0.86% ash. Coal fines which were passed on in the chimney gases contained 0.8% ash. The washes of samples, along with the possibility of air separation of various-sized particles, were thought to be the main causes for a decrease in ash content. The amount of purification by the flame treatment was considered to be negligible.

Research Organization:
I.G. Farbenindustrie, A.G., Hoechstadt (Germany)
OSTI ID:
6818008
Report Number(s):
TOM-286-33-34
Country of Publication:
United States
Language:
German