CHARACTERIZATION OF MERTA ROAD LIGNITE AND DECOMPOSITIONAL STUDY OF ITS PYRITE USING MOSSBAUER-SPECTROSCOPY

57Fe Mössbauer spectroscopic studies at room temperature were performed on tertiary lignite samples from the Merta Road deposit: first, to determine qualitatively pyrite and any other iron-bearing minerals present; and second, to understand the thermal decomposition behaviour of these pyrites and compare it with known data on high rank coals. In this first Mössbauer spectroscopic study on pyrite in lignite, it is concluded that decomposition differs markedly from that observed for high rank coals. In lignite, decomposition starts at relatively low temperatures; a new Fe2+ component with 2.55 mm s-1 QS and 1.34 mm s-1 IS values, analogous to some sulphate minerals, is present below 400 °C, but disappears from the spectrum of a sample preheated at 500 °C. © 1990.