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U.S. Department of Energy
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Wet grinding versus dry grinding for deep cleaning ultrafine coal by flotation. Technical progress report

Technical Report ·
OSTI ID:6187879

Laboratory froth flotation tests were conducted with dry- and wet-ground minus-400-mesh coal to determine the effect of grinding methods on clean coal recovery and product grade. A laboratory air-classifying impact mill was used for the dry grinding, and a stirred ball mill (attritor) was used for the wet grinding. Products of as near the same size distribution as possible were prepared by each method, i.e., nominal minus 27 micrometers (..mu..m) with a mean particle size of 10 to 12 ..mu..m. The test results show that the dry-ground coal is more floatable (i.e., greater weight-percent recoveries were obtained at any given reagent dosage), but the wet-ground coal provides substantially lower ash products at equivalent yield. For example, the dry-ground coal yielded about 20 wt % to over 80 wt % froth product with frother reagent dosages of 0.1 to 0.5 pound per ton of dry solids (lb/ton), respectively, and the product ash contents ranged from 2.0 to 4.0%. The wet-ground coal, on the other hand, yielded about 25 wt % to a little over 70 wt % froth product with frother reagent dosages of 0.2 to 0.5 lb/ton, respectively, and the product ash contents ranged from about 1.5 to 2.0%. 4 figures, 2 tables.

Research Organization:
USDOE Pittsburgh Energy Technology Center, PA
OSTI ID:
6187879
Report Number(s):
DOE/PETC/TR-84/10; ON: DE84017086
Country of Publication:
United States
Language:
English