Application of magnesium oxide for metal removal in mine water treatment

In this study low-grade magnesium oxide (MgO) produced by calcinations of natural magnesite was used in mine water treatment using a laboratory-column device. The treatment of mine water from the abandoned Osor mine (NE Spain) with MgO showed the removal of metals from both mine water and tailing leachates. The PHREEQC numerical code and the Geochemist’s Workbench code (GWB) were used to evaluate the speciation of dissolved constituents and calculate the saturation state of the effluents. The analysis of the treated mine water showed the removal of As (from 1.59 to 0.31 µg/L), Cd (from 1.98 to <0.05 µg/L), Co (from 19.1 to <0.03 µg/L), F (from 2730 to 200 µg/L), Mn (from 841 to 0.6 µg/L), Ni (from 17.9 to <2 µg/L, U (from 9.16 to 0.08 µg/L), and Zn (from 2900 to 68.5 µg/L). Pb was also removed (from 98 to 35.2 µg/L) in the treatment of contaminated leachates from the mine waste. The mixing of MgO and water at room temperature may promote the formation of a stabilizing agent composed of hydroxides, carbonates, and magnesium-silicate-hydrates (MSH), which may remove Cd, Zn, and similar metals by sorption on MSH, substitution on the MSH lattice, and precipitation or co-precipitation with some of the hydrated phases.
This research was funded by the Catalan Agency for the Administration of University and Research Grants (AGAUR), grant number SGR2009. Besides, the research was supported by the Consolidated Research Group on Economic and Environmental Geology and Hydrology (Universitat Politècnica de Catalunya-University of Barcelona).
Peer Reviewed
Objectius de Desenvolupament Sostenible::6 - Aigua Neta i Sanejament::6.3 - Per a 2030, millorar la qualitat de l’aigua mitjançant la reducció de la contaminació, l’eliminació dels abocaments i la reducció al mínim de la descàrrega de materials i productes químics perillosos, la reducció a la meitat del percentatge d’aigües residuals sense tractar, i un augment substancial a escala mundial del reciclat i de la reutilització en condicions de seguretat
Objectius de Desenvolupament Sostenible::6 - Aigua Neta i Sanejament
Postprint (published version)