Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, December 31, 1993 [report]

F.M. Doyle
1993 unpublished
RESEARCH OBJECTIVES The objective of thisresearch is to developa mechanistic understanding of the oxidation of coaland coalpyrite, and to correlate the intrinsic physicaland chemical properties of theseminerals, along with changesresulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The results will provide fundamental insight into oxidation, in term of the bulk and surface chemistry, the microstructure, and the semiconductor
more » ... miconductor properties of the pyrite. During the thirteenth quarter, wet oxidation tests were done on coal samples from the Pennsylvania State Coal Bank. As-received and oxidized coal samples were studied by Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy to detect functional groups that might be responsible for changing the hydrophobicity of coal smnples. EXPERIMENTALMETHODS AND RESULTS a.-Sample Characterization Coals with different rank and sulfur content, obtained from the Pennsylvania State Coal Bank, were studied. Table I shows the proximate and sulfur analysis of the coals studied. b.-Wet Oxidation Studies Coal samples from the Pennsylvania State Coal Bank were oxidized for 5 hours at room temperature using 10% H202 at pH 1.0, 1.0 M HNO 3 or 0.05 M Fe2(SO4)3 at pH 1.0. Details of the experimental procedure used in the wet oxidation tests were provided in our September 30, 1993 report, along with results of ion-exchange analysis and film flotation tests on as-received and oxidized coal samples. Table II shows the weight percentage of carboxylic and phenolic group oxygen generated by oxidation with different treatments, as determined by ion-exchange. DRIFt spectroscopic analysis was done on as-received and oxidized samples to identify different functionalities directly, to supplement the information on carboxylic and phenolic groups obtained indirectly by ion-exchange methods. The procedure for DRIFT analysis was reported in our June 30, 1993 report. TECHNICAL PROGRESS REPORT (December 31,1993) O _ 7" I RESEARCH OBJECTIVES The objective of thisresearchis to develop a mechanisticunderstanding of the oxidationof coal and coalpyrite,and to correlatethe intrinsic physicaland chemical propertiesof these minerals,along with changes resultingfrom oxidation,with those surfaceproperties thatinfluencethe behavior in physicalcleaningprocesses.The results willprovide fundamental insight intooxidation, in term of the bulk and surfacechemistry, the microstructure, and thesemiconductorproperties of thepyrite. DE-FG22-90PC90287
doi:10.2172/10143817 fatcat:urmr7dk7hfdkvic4tgzml27j64