Neutralization and Sulfidation of Acid Mine Drainage from a Mining Unit in Cerro de Pasco

Abstract

This study proposes an alternative solution to the environmental problems caused by the acidic waters of the Quiulacocha Lagoon, which discharge into the San Juan River and negatively affect the ecosystem, particularly the population of the Simón Bolívar district in the province of Pasco. A quantitative, explanatory, and experimental methodology was applied, consisting of collecting composite samples of acid mine drainage from a point in the Quiulacocha Lagoon for characterization. The physicochemical parameters were found to exceed the Maximum Permissible Limits (LMP) established in D.S. 010-2010-MINAM and the Environmental Quality Standards (ECA), Category 3, defined in D.S. 004-2017-MINAM.

For the treatment, an alkalization method using a 10% m/v lime solution was applied, followed by a sulfidation stage using a 10% m/v sodium hydrosulfide (NaSH) solution to increase the removal efficiency of iron, copper, lead, and zinc. In the alkalization stage, the results slightly exceeded environmental standards for iron, copper, and zinc, but not for lead. With the additional sulfidation stage, metal removal levels far surpassed regulatory requirements: 98.30% for iron, 99.83% for copper, 99.48% for lead, and 66.59% for zinc.

In conclusion, the waters of the Quiulacocha Lagoon contain high concentrations of heavy metals that pose serious risks to environmental and public health. The alkalization method with 10% m/v lime, combined with an additional sulfidation stage using 10% m/v NaSH, represents a viable alternative for neutralizing the acidic waters of the lagoon and preventing contamination of the San Juan River in the Simón Bolívar district, Pasco.