PARTICLE SIZE AND CRYSTAL STRUCTURE EFFECTS ON PYROLYSIS BEHAVIOR OF IRON SULFIDES IN ARGONNE PREMIUM COALS AND A MAYA PETROLEUM VACUUM RESID ASPHALTENE AS EXAMINED WITH S-XANES

摘要

Argonne Premium Coals are standards used world-wide. All of these coals contain sulfur in varying amounts. Sulfur X-ray Near Edge Absorption Spectroscopy (S-XANES) is a direct, nondestructive characterization technique that can provide valuable information of the chemical and thermal sulfur transformations that occur in geologic materials such as coals and kerogens [1,2,3]. SXANES data are processed using a third derivative analysis method that utilizes a library of model compounds and a nonlinear leastsquares regression program to curve-resolve each sample spectrum into individual sulfur species and has successfully been used to determine the behavior of pyritic sulfur in an Illinois #6 coal in the past. [4,5] In this work, the behavior of iron sulfides in an Illinois #6 (IL6) was analyzed as a function of particle size and degree of pyrolysis. The behavior of the polymorphs marcasite and pyrite (FeS2) in a coal matrix was also examined.