On the geochemistry of strontium in Bulgarian coals
1989; Elsevier BV; Volume: 74; Issue: 3-4 Linguagem: Inglês
10.1016/0009-2541(89)90037-5
ISSN1872-6836
AutoresGreta M. Eskenazy, Ekaterina Minčeva,
Tópico(s)Metal Extraction and Bioleaching
ResumoSr geochemistry in coal has been studied on the basis of its distribution in 457 samples of coal, coaly shales and mineral interlayers from several Bulgarian coal deposits. Model experiments were also carried out. The analysed Sr contents are lower than the average values for coals. Only the Burgas deposit is enriched in Sr due to marine influence. The coal lithotypes liptain, vitrain, xylain and fusain are usually enriched in Sr as compared to the whole samples from which they were separated. Sr occurs in both organic (Srorg) and inorganic (Srinorg) forms. The relation to organic matter is demonstrated by: (1) Sr enrichment in low-ash coals and in lighter specific gravity fractions; (2) leaching of Sr bound to humic acids by treatment with 2% NaOH; (3) sorption experiments on xylain at pH 4-5.5 - up to 92% of Sr in solution was taken up by the sorbents; a mechanism of cation exchange as well as formation of metallo-organic complexes is proposed. Host minerals of Srinorg are aragonite, gypsum, calcite and feldspar. The highest Srinorg content is related to aragonite.
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