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Hydrophobic character of pretreated coal surfaces

Conference · · Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States)
OSTI ID:5955079
Increased hydrophobicity and hence the flotability of coals of different rank has been observed for CO/sub 2/ pretreatment and/or controlled thermal pretreatment. DRIFT- and ATR-FTIR and XPS techniques have been used to determine the surface chemical characteristics in order to evaluate coal hydrophobicity. These results agree very well with those determined by traditional methods. The enhanced hydrophobicity of CO/sub 2/-treated coal is attributed to the high specific affinity of coal for CO/sub 2/ which results in the displacement of pore water and hydration water by CO/sub 2/ and on pressure release leads to nanobubble formation at the coal surface in aqueous suspension. Increased hydrophobicity of lignite by thermal treatment arises from the removal of pore water, hydration water and some organic OH functional groups as well as the diffusion of volatile matter to the surface and the reorientation of surface functional groups.
Research Organization:
Univ. of Utah, Salt Lake City (USA)
DOE Contract Number:
FG22-85PC80530
OSTI ID:
5955079
Report Number(s):
CONF-8809271-
Conference Information:
Journal Name: Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States) Journal Volume: 33:4
Country of Publication:
United States
Language:
English