One-step ambient temperature ferrite process for treatment of acid mine drainage waters

Ori Lahav, Barak E. Morgan*, Giovanni Hearne, Richard E. Loewenthal

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

A novel approach toward the removal of iron and nonferrous metals from typical South African acid mine drainage (AMD) waters was investigated. The approach involves the controlled oxidation of ferrous-containing AMD water at ambient temperatures in the presence of magnetite seed. The resulting oxidation product is the ferrite (M132+M22+O4) magnetite (Fe3O4) which has the capacity for nonferrous metal removal by cation substitution. Mössbauer spectroscopy, x-ray diffraction, and scanning electron microscopy analyses confirmed the precipitant to be magnetite. The effects of four parameters are reported: airflow rate, seed concentration, pH, and temperature. All of these independently affect the % ferrous in the final precipitant. In all experiments, the airflow rate was found to be rate limiting with respect to the kinetics of ferrous removal. The retention time for the complete removal of 1,200 mg Fe/L was 0.3-1.6 h (corresponding to airflow rates of 0.05-0.6 L/min, respectively). The precipitant settled well and showed complete stability at pH 5. The total iron concentration in the raw effluent was always less than 1 mg/L, representing an iron removal efficiency of greater than 99.9%.

Original languageEnglish
Pages (from-to)155-161
Number of pages7
JournalJournal of Environmental Engineering, ASCE
Volume129
Issue number2
DOIs
StatePublished - Feb 2003
Externally publishedYes

Keywords

  • Acid mine water
  • Oxidation
  • Wastewater treatment

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