The Leachability of Heavy Metals from Alkali-Activated Fly Ash and Blast Furnace Slag Matrices

Abstract:

The ability of alkali-activated materials (AAMs) to fix and immobilize heavy metals was investigated. Two raw materials were used to prepare alkali-activated matrices – high-temperature fly ash and blast furnace slag (BFS). NaOH served as an alkaline activator. Two heavy metals (Mn, Ni) were added in different amounts to find out the influence of dosage of heavy metal on the mechanical properties of the matrices and the leachability. Leachability was measured as concentration of heavy metals in leachates (ČSN EN 12457-4) by inductively coupled plasma/optical emission spectrometry (ICP/OES). Structure of prepared matrices was characterized by scanning electron microscopy (SEM). Increasing of addition of heavy metals led to decrease of mechanical properties of matrices. The leaching tests showed, that both matrices can immobilize Mn and Ni in dosages of 0.1 – 2,5%. Higher dosages caused deterioration of the matrices and increased the leachability. After alkali activation both heavy metals were transformed into the form of insoluble salts.

• Periodical: Materials Science Forum (Volume 851)
• Pages: 141-146
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.851.141
• Online since: April 2016
• Authors: Jan Koplík*, Miroslava Smolková, Jakub Tkacz
• Keywords: Alkaline Activation, Blast Furnace Slag, Fly Ash, Leachability

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