Rare earth element distribution in the acetic acid soluble fraction of combusted coals: Its implication as a proxy for the original coal-forming plants

Abstract

The precise concentrations of rare earth elements (REEs) in Japanese Ashibetsu and Taiheiyo coals, in Indonesian Ambalut coal, and in Australian boghead coal have been determined, in order to compare the REE contents of the coals with those of plants and also to obtain further knowledge of the original plants from which these coals were formed. By leaching the coals after ashing using a 10% acetic acid solution, each coal sample was separated into two fractions: an acetic acid soluble fraction, and an acetic acid insoluble fraction. Our results show that three different types of chondritenormalized REE patterns are observed in the acetic acid soluble fraction of these coals. The acetic acid soluble fractions of the Ashibetsu, the Taiheiyo, and some of the Ambalut coals showed REE patterns identical to those of peat vegetation. Those of other Ambalut coals showed an REE pattern that was similar to that of tree trunks. The boghead coal showed a different REE pattern that was similar to algae, an origin that is also suggested from a maceral study. The REE patterns of the acetic acid soluble fraction can therefore be a useful proxy for determining the original plants that formed the coals.

Origin and fluxes of atmospheric REE entering an ombrotrophic peat bog in Black Forest (SW Germany): Evidence from snow, lichens and mosses

“…The peat profile from EGR also shows an increase of REE concentrations that corresponds to the beginning of the industrial period and increasing deposition of dust. Unlike soil-grown plants (Fu et al, 2001), peat mosses (Sphagnum) and grass (Carex) do not show a Ce anomaly in their REE patterns (Akagi et al, 2002;Fu et al, 2004). This is in agreement with a simple thermodynamic model (Akagi and Masuda, 1998) showing no possible formation of Ce anomaly at the low pH and E H found in peat bogs.…”

Rare Earth Elements of Orzeskie Beds of South-West Part Upper Silesian Coal Basin (Poland) / Pierwiastki Ziem Rzadkich Z Pokładów Węgla Warstw Orzeskich Południowo-Zachodniej Części Gzw (Polska)

“…In hard coal, phosphate minerals, clay minerals and certain sulfides may act as potential REE carriers (Finkelman, 1982;Vassilev & Vasileva, 1996, 1997Ward et al, 1999;Ward, 2002;Willet et al, 2000;Worrall & Pearson, 2001;Yang & Zhou, 2001;Zhang et al, 2002). However, other studies have indicated that REE in coal may form a compound both with the organic and non-organic substance (Finkelman, 1982;Palmer et al, 1990;Schatzel & Stewart, 2003;Fu et al, 2004). The research of rare earth elements in coal has also indicated that HREE are characterized by a higher affinity with the organic substance of coal that the LREE (Eskenazy, 1987a, b;Dai et al, 2008Dai et al, , 2012.…”

“…Rare earth elements in coal may provide information on the genesis and forming conditions of coal (Fu et al, 2004). The REE concentration in hard coal is variable and depends on its petrographic and mineral composition as well as the chemical properties (Smołka-Danielowska, 2010;Vassilev & Vassileva, 1996;Ward, 1999;Schatzel & Stewart, 2003;Pires & Querol, 2004;Zhang et al, 2004).…”