Release of Zn, Ni, Cu, SO42- and CrO42- as a function of pH from cement-based stabilized/solidified refinery oily sludge and ash from incineration of oily sludge

Athanasios K. Karamalidis, Evangelos A. Voudrias

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A framework for the evaluation of leaching behavior of inorganic constituents from stabilized/solidified refinery oily sludge and ash produced from incineration of oily sludge with cement was employed. Metal and anion release as a function of pH was investigated. The leaching test consisted of multiple parallel extractions at pH range from 2 to 12. Remarkably good immobilization >98% was observed for metals of solidified ash at pH > 6 and >93% of solidified oily sludge at pH > 7. Sulfate leaching was high at pH range 2-12. The leaching behavior of metals and anions was simulated by VMINTEQ. The calculations showed that leaching behavior of Zn, Ni and Cu was controlled by chemical equilibrium and surface complexation onto ferrihydrite, at the pH range 2-12. The dominant solid phases that controlled metal leachability were metal hydroxides. The dominant mechanism that described sulfate leaching was found to be chemical equilibrium. Sulfate and also chromate leachability was controlled by Ettringite and Cr(VI)Ettringite as the major minerals affecting their release.

Original languageEnglish (US)
Pages (from-to)591-606
Number of pages16
JournalJournal of Hazardous Materials
Issue number3
StatePublished - Mar 22 2007


All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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