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An Investigation on the Influence of EAF Slag Particle Size on AMD Neutralization Behavior in Static and Dynamic Slag Leaching Systems

Alizadeh, A ; Sharif University of Technology | 2015

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  1. Type of Document: Article
  2. DOI: 10.1007/s10230-014-0302-8
  3. Publisher: Springer Verlag , 2015
  4. Abstract:
  5. Steel slag, which contains basic oxides capable of generating high levels of alkalinity, may be used in leaching beds or leaching channels to neutralize acid mine drainage (AMD). In the present study, electric arc furnace (EAF) slag from the Pasargad Steel Complex was used to investigate the influence of slag particle size on AMD treatment. Three slag samples with different particle size distributions (coarse, mixed, fine) were prepared. Slag composition, pH variation, level of alkalinity, and specific surface area were measured and the surfaces of the slag particles was examined by scanning electron microscopy. In both dynamic and static leaching tests, there proved to be three stages: an initial high pH, alkalinity digestion-exhaustion, and low pH. Depletion of fine particles and precipitation of Fe, Al, and Mn hydroxides on particle surfaces were critical factors in how the alkalinity in the slag was exhausted during the second stage. SEM images suggest that metal precipitates prevented the AMD from reaching the slag surface and hence its neutralization potential was reduced. We also found that finely-ground slag produced a higher initial pH in the leachate but that after 60 leaching cycles, the pH value dropped below that of the coarse slag. A mixed sample demonstrated an initial high pH and a moderate pH after the 60th cycle, which verified greater potential for long-term alkalinity generation than the well-sorted slag
  6. Keywords:
  7. Acid mine drainage ; Alkalinity generation ; Leaching process ; pH ; Steelmaking slag
  8. Source: Mine Water and the Environment ; Volume 34, Issue 2 , 2015 , Pages 204-212 ; 10259112 (ISSN)
  9. URL: http://link.springer.com/article/10.1007/s10230-014-0302-8