RT Journal Article
T1 Field multi-step limestone and MgO passive system to treat acid mine drainage with high metal concentrations
A1 Caraballo Monge, Manuel Antonio
A1 Rötting, Tobías S.
A1 Macías Suárez, Francisco
A1 Nieto Liñán, José Miguel
A1 Ayora, Carlos
AB Passive treatment systems have become one of the most sustainable and feasible ways of remediating acid mine drainage (AMD). However, conventional treatments show early clogging of the porosity or/and coating of the reactive grains when high acidity and metal concentrations are treated. The performance of fine-grained reagents dispersed in a high porosity matrix of wood shavings was tested as an alternative to overcome these durability problems. The system consisted of two tanks of 3 m3 filled with limestone sand and wood shavings, and one tank of 1 m3 with caustic magnesia powder and wood shavings, separated by several oxidation cascades and decantation ponds. The system treated about 1.5 m3/day of AMD containing an average of 360 mg/L Fe, 120 mg/L Al, 390 mg/L Zn, 10 mg/L Cu, 300 μg/L As and 140 μg/L Pb, a mean pH of 3.08 and a net acidity of 2500 mg/L as CaCO3 equivalent. The water reached pH 5 and 6 in the first and second limestone tanks, respectively (suitable to remove trivalent metals); and pH 8–9 in the MgO tank (suitable to remove divalent metals). After 9 months of operation, the system achieved an average removal of 100% Al, Cu, As, Pb, more than 70% Fe, about 25% Zn and 80% acidity. Goethite, schwertmannite, hydrobasaluminite, amorphous Al(OH)3 and gypsum were the main precipitates in the two limestone tanks. Precipitation of divalent metals (Fe (II), Zn, and traces of Cd, Ni and Co) were complete inside the third tank of MgO, but preferential flow along the walls was responsible for its low treatment performance. Goethite, gypsum, Zn-schulenbergite and sauconite are the crystalline solid phases identified in the MgO tank.
PB Elsevier
SN 0883-2927
YR 2009
FD 2009-09
LK https://hdl.handle.net/10272/23143
UL https://hdl.handle.net/10272/23143
LA eng
NO Caraballo, M. A., Rötting, T. S., Macías, F., Nieto, J. M., & Ayora, C. (2009). Field multi-step limestone and MgO passive system to treat acid mine drainage with high metal concentrations. In Applied Geochemistry (Vol. 24, Issue 12, pp. 2301–2311). Elsevier BV. https://doi.org/10.1016/j.apgeochem.2009.09.007
NO We gratefully acknowledge Mari Paz Martín, Rafael Carrasco and María José Ruíz (Central Research Services of the University of Huelva) for assistance in XRD and chemical analysis. This study was funded by the Spanish Government projects CTM2006-28151-E/TECNO and CTM2007-66724-/TECNO. M.A.C. was financially supported by the Spanish Government with a FPU PhD fellowship. We would also like to thank Anne Thompson and David Vaughan (Guest editors) and two anonymous reviewers for their comments that significantly improved the quality of this paper.
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026