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Show 11 sulfide form. Se and Ni have been reported to have organic associations (4, 7), but the data in this study are not comprehensive enough to make any definite assertions for organic associations, except that it may be argued that Se, having the highest concentration removed by ammonium acetate, may have partly an organic association. To summarize these trace metal associations, Table 4 lists the different associations of the trace metals being analyzed here, based in part on the characterization data above and on information obtained from the literature. Partitioning of Trace Metals The partitioning of trace metals was ascertained by determining the fraction in which the different trace metal species were collected. Metals that are not vaporized during gasification remain in the residual ash and are collected in the size fraction greater than 1 1J.Ill. Metals that are vaporized but condense in the system are collected in the submicron fraction. Metals such as Se and Hg, which may not condense in the system but remain in a vapor state, will escape the multicyclone system and will be collected in the impinger train. Several runs were made in the PDTF varying pressure, gas temperature, and OIC ratio. Average closures for the seven trace metals are given in Table 5. A slight enrichment Element As Cd Cr Hg Ni Pb Se TABLE 4 Trace Metal Associations Associations Pyrite, other sulfides, arsenates Sulfides, clays Clays, organic compounds Pyrite, other sulfides Pyrite, clays, organic compounds Pyrite, other sulfides, clays Pyrite, other sulfides, organic compounds, sulfate |