Washing of mining waste is a widespread practice to stabilize and minimize the impact of such waste. Depending on the chemical composition of wastes, washing is carried out using different compounds, ranged from industrial water to washing with hydrogen sulfide, NaHS, Ca(HS)2, or other precipitators and metal chelators compounds. LAR-2~R is a reagent composed mainly by citric acid (and other organic acids), which is a well-known siderophore, able to be applied as leaching agent to enhancing metal recovery from mineral matrices. It is equivalent in its effectiveness to sulfuric acid, but having the advantage of being an easily degradable organic acid in harmless components that minimize its environmental risks. The present work evaluates the effect of washing mining wastes with the LAR-2~R reagent from a dump from leaching plant in Chile. The experimental design contemplated two stages: (i) simulations of an in-situ wash with the LAR-2~R reagent, and (ii) simulations of rainfall on previously washed wastes. In-situ washing was treated using three concentrations of LAR-2~R (0, 5 and 15 g/L of LAR-2~R). After LAR-2~R washing application, treated wastes were subsequently washed with water (1 or 2 washes with water). Finally, rains of different intensity were simulated on the treated wastes to study the influence of the treatments on the metals mobility during rainfall events. The results indicate that washing with LAR-2~R produces a greater dissolution of metallic values of interest than when washing them with water. Moreover, a direct relationship is observed between the concentration of LAR-2~R and the recovery of Cu and Fe after treatment. On the other hand, the washing treatment is effective in reducing the mobility of the metals contained in the waste under rainfall events of medium to high intensity.
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