Quantifying the modes of occurrence of trace elements in coal

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20013442

Palmer, C A; Mroczkowski, S J; Kolker, A; Finkelman, R B; Bullock, J Jr

The modes of occurrence of trace elements in coal were determined semi-quantitatively using an integrated approach developed by the US Geological Survey. Methods to infer modes of occurrence have been quantified for up to 42 elements, including all the elements designated as potential hazardous air pollutants in the 1990 Amendments to the Clean Air Act, using a sequential leaching method followed by chemical analysis, x-ray mineralogy and micro-beam analysis of individual grains. This study summarize the findings for 16 US coal samples from the major coal producing areas of the Appalachian, Illinois and Powder River Basins. In most bituminous coals in this data set, association of As with pyrite is indicated by the fact that generally more than 50% of the As (and Fe) was leached by HNO{sub 3}. With few exceptions, more than 50% of the Be and 40% of the Cr are leached by HF, indicating an association of these elements with aluminosilicates. Generally more than 35% of the Se and 50% of the Hg is associated with disulfides. However, 95% of the Se in one Northern Appalachian cleaned coal sample and 70 to 75% of the Se in the two Powder River basin samples was not removed by leaching, indicating an organic association. In one Powder River Basin coal sample 100% of the Hg was not leached, also indicating an organic association. In the coals investigated: (1) Co, Ni, Sb, Th and U have multiple modes of occurrence; (2) more than 50% of the Mn is generally associated with the carbonates; (3) more than 55% of the Zn and Cd are associated with mono- and di-sulfides, and (4) up to 75% of the Pb is associated with mono- and di-sulfides but Pb also has significant organic associations (up to 70% in some samples).

• Research Organization: Geological Survey, Reston, VA (US)
• OSTI ID: 20013442
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ANTIMONY
ASH CONTENT
BITUMINOUS COAL
CADMIUM
COBALT
EXPERIMENTAL DATA
LEAD
MANGANESE
MULTI-ELEMENT ANALYSIS
NICKEL
PHASE STUDIES
SUBBITUMINOUS COAL
THORIUM
URANIUM
ZINC