Surface Properties of NaOH Treated Coals

摘要

Surface properties of alkali-treated Illinois and Wyodak coals were studied using gravimetric, mass spectrometric, and calorimetric techniques. The results were compared with similar studies of untreated coals. The treatment increased H sub 2 O sorption and the heats of immersion in water but reduced sorption of N sub 2 and CO sub 2 . These observations were explained in terms of a flexible coal structure, the interstices of which may be closed by the NaOH treatment and may be accessible only by sorption of polar vapors. H sub 2 O and CO sub 2 were the major species evolved in outgassing. Most of the H sub 2 O was physically adsorbed, but some was liberated with CO sub 2 as the product of mineral decomposition. (ERA citation 04:055980)