Steel slag in acid mine drainage treatment and control
Steel slags are composed of calcium alumino-silicate oxides. Most slags have a sandy texture, but others have a silty texture and give a fine, powdery feel. Neutralization potentials of steel slags range from 45 to 78%, which make them candidates for neutralizing the acidity in acid mine drainage. Analysis of total metal content in Mingo Junction steel slab shows high concentrations of aluminum, chromium, iron, manganese, and titanium. Upon leaching this slag with water, the leachate had a pH of 11.7 and n alkalinity of 1,450 mg/L as CaCO{sub 3} equivalent. In general, steel slag yielded more alkalinity than equal weights of limestone (500 to 1,500 mg/L compared to 60 to 80 mg/L) during leaching studies. Leaching the slag with water and a weak sulfuric acid solution showed that the metals contained in the slag were not readily leachable since these metals were found at low concentrations in the leachate. When different amounts of slag were mixed with an acid-producing coal refuse and then leached with water, pH values of the leachate varied between 3.5 and 7.3. Slightly elevated levels of selenium, nickel, manganese, and possibly iron were found in leachates of refuse/slag mixtures compared to refuse alone. Due to slag's high availability in some areas and low cost, steel slags show potential as an acid-neutralizing material for coal refuse and acid-producing spoils, and for treating acid mine drainage directly. If slag is to be used as an alkaline amendment, it must be added in sufficient quantities to ensure nonacid conditions now and in the future, since under acid conditions some metals may become available. Steel slag can also be used as a liming material for soils. The most promising use for steel slag is as a source of alkalinity to fresh waters that may subsequently encounter acid mine drainage, such as alkaline leach beds or limestone sand applications to headwater streams.
- Research Organization:
- West Virginia Univ., Morgantown, WV (US)
- OSTI ID:
- 20026853
- Resource Relation:
- Conference: 16th annual national meeting of the American Society for Surface Mining and Reclamation, Scottsdale, AZ (US), 08/13/1999--08/19/1999; Other Information: PBD: [1999]; Related Information: In: Mining and reclamation for the next millennium. Proceedings of the 16th annual national meeting of the American Society for Surface Mining and Reclamation, by Bengson, S.A.; Bland, D.M. [eds.], 745 pages.
- Country of Publication:
- United States
- Language:
- English
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