Comparison of dissolution under oxic acid drainage conditions for eight sedimentary and hydrothermal pyrite samples |
| |
| Authors: | Ran Liu Amy L Wolfe David A Dzombak Brian W Stewart Rosemary C Capo |
| |
| Institution: | (1) Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA;(2) Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, PA 15260, USA;(3) Present address: ARRO Consulting, Inc., 270 Granite Run Drive, Lancaster, PA 17601, USA |
| |
| Abstract: | The abiotic oxidative dissolution behaviors of eight natural pyrite samples, five sedimentary and three hydrothermal, from
various geological environments were compared under oxic conditions at pH 3 and 6 in a highly controlled batch reactor dissolution
system. The three sedimentary pyrite samples associated with coal had greater specific surface areas and also exhibited greater
apparent dissolution rates and extent than the other two sedimentary and three hydrothermal samples under both pH conditions.
However, after normalizing for surface area, the dissolution rate constants for the different pyrite samples were similar;
the greatest difference was between the two non-coal sedimentary pyrite samples. Pyrite morphology and the presence of trace
metals could contribute to the differences in dissolution behavior as reflected in the normalized dissolution rates. The sulfur:iron
ratio observed in the aqueous solution at pH 3 increased with time, but was always less than 2.0 (predicted from the stoichiometry
of dissolution) for all the pyrite samples during the 24-h experimental duration. This can be explained by the disproportionation
dissociation of thiosulfate, an initial product of pyrite dissolution, to elemental sulfur and sulfate which does not occur
in a 1:1 ratio. The results of this work indicate the importance of extracting and using the specific pyrite(s) relevant to
particular mining areas in order to understand pyrite dissolution rates and the influence of environmental conditions on those
rates. |
| |
| Keywords: | Pyrite Sedimentary Oxidative dissolution Trace metal contents Semiconducting properties |
| 本文献已被 SpringerLink 等数据库收录！ |
|
