Sulfur Fractions and Distribution of Carbon, Nitrogen, and Phosphorus in Profiles of Coal Mines

Abstract

AbstractAnalysis of samples of four profiles, two containing calcareous shale and two acid shale, from a coal mine in Iowa showed that the total S content of the coal seam under acid shale ranged from 9 to 10% and of the coal under calcareous shale was about 5%. Zinc‐HCl‐reducible S always exceeded the Raney Ni‐reducible S in all the samples studied. With the exception of one coal sample under acid shale that contained an appreciable amount of sulfide S, all the shale and coal samples contained small amounts of sulfide S. The shale samples generally contained greater amounts of pyrite S (52–85%) than did the coal samples (35–63%). Pyrite S was significantly correlated with total S in the shale (r = 0.95**) and coal (r = 0.93**) samples studied.Other results indicated that total N values were much lower in the overburden materials (0.01–0.13%) than in the coal samples (0.65–0.81%). Total P content was the greatest in the shale samples. The coal seam under acid shale contained greater P concentrations, with the organic P fraction exceeding the inorganic P, than did the coal seam under the calcareous shale, where the amounts of organic and inorganic P fractions were similar. The sulfur fractions in the various horizons of the four profiles studied and the relationships among organic C, N, and P are discussed.