Resumen:
The utilization of a modified lime mortar as a binder for the stabilization/solidification of mine tailings presents a promising and sustainable solution for immobilizing potentially toxic elements found in these waste materials as compared with the use of cement mortars. The effectiveness of this modified lime mortar in avoiding the mobility of toxic elements, namely Pb and As, in mine tailings has been thus studied. Encapsulating matrices of (1:1) and (2:1) tailing waste:air lime ratios were prepared. The former showed better mechanical strengths than samples (2:1), with a more intense pozzolanic reaction. Needle-shaped C-S-H structures were identified by SEM observations. The hardened materials showed a good endurance against freeze-thaw cycles. The semi-dynamic Tank-test demonstrated the effective encapsulation of the toxic components due to the use of the lime mortars, yielding values of released Pb and As below the detection limit in all instances. Considering the cost-effectiveness, widespread availability, and ease of use, the modified lime mortar for the treatment of mine tailings can be recommended to mitigate the environmental impacts of mining activities.
