Treatment of Percolate from Metal Sulfide Mine Tailings with a Permeable Reactive Barrier of Transformed Red Mud

• Published in: Water environment research 2010-04, Vol.82 (4), p.319-327
• Main Authors: Zijlstra, J.J.P., Dessì, R., Peretti, R., Zucca, A.
• Format: Article
• Language: English
• Subjects: acid rock drainage; Aluminum; Arsenic; Chelating Agents - chemistry; column leaching; Electrical resistivity; Field study; Industrial Waste; Leaching; Lead; Mine waste; Mining; Mud; permeable reactive barrier; Pollution; Quartz; Sulfates; Sulfides - chemistry; Tailings; transformed red mud pellet; Waste Disposal, Fluid - methods; Zinc
• ISSN: 1061-4303; 1554-7531
• DOI: 10.2175/106143009X12487095236432

Metal sulfide tailings of the Sardinian (Italy) abandoned Baccu Locci arsenic mine show high concentrations of aluminum, arsenic, cadmium, copper, manganese, lead, and zinc in acid percolate (pH = 4) and have been classified as "dangerous waste." This paper shows that the release of toxic metals can be strongly reduced when the tailings are placed on a reactive permeable bed (7 wt %) of porous, alkaline pellets of transformed red mud (TRM). During a laboratory percolation test, two columns with 80 kg of waste, of which one contained a bottom layer of TRM pellets, were each alimented with 600 L of de-ionized water. Comparing pH, electroconductivity, metal, and sulfate concentrations of collected percolate from both columns demonstrates efficient neutralization (pH = 7.4) and removal of metals (80 to 99%) for the column with the permeable reactive bottom layer.