Temporal Solubility Trends of Aluminum and Iron Leached from Coal Spoils and Contaminated Soil Materials
- A. D. Karathanasis *,
- Y. L. Thompson and
- V. P. Evangelou
Column leaching experiments were conducted over a period of 5 mo on selected spoil, soil, and sediment samples collected from acid mine watersheds with low buffering capacity in Kentucky. Evaluation of effluent compositions over time suggested that at different stages of leaching these samples may release different levels of Al and Fe. These levels appeared to be controlled by the solubility of characteristic sequences of basic Al-sulfate, Al-hydroxide, and alumino-silicate minerals, or Fe-sulfate and Fe-hydroxide minerals, which are sample specific. Jurbanite-jurbanite, jurbanite-alunite, and jurbanite-alunite-microcrystalline gibbsite appeared to be the dominant mineral sequences controlling the solubility of Al. Similarly, the jarosite-amorphous Fe(OH)3 and amorphous Fe(OH)3-goethite sequences appeared to control the solubility of Fe. Alternating water saturation and desaturation cycles appeared to cause more drastic changes in the above relationships than different flow rates simulating rain events of different intensity. The findings suggest that understanding temporal relationships among the sequence of mineral phases controlling Al and Fe solubility is essential for realistic modeling of Al and Fe release into aquifers.
Contribution from the Dep. of Agronomy, Univ. of Kentucky, Agric. Exp. Stn., Lexington, KY 40546. Journal Paper no. 88-3-309.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .