Mössbauer study of the effect of acidic treatment on iron minerals during the demineralization of coals

Abstract

Mössbauer spectroscopy was used to determine the iron-containing minerals that remained in two different Spanish subbituminous coals after acidic treatments. Spectra were taken before and after treatments of both coals with HCl and HCl followed by HF. Pyrite, jarosite and Fe2+-clay were the main iron mineral constituents of the untreated samples. After the treatments significant changes in the relative concentration of these species were noticed. The weakness of the used demineralization procedures is discussed.