(Special session/Open call for public) Current trend of countermeasures against excavated rock/soil contamination and acid mine drainage

[2K0601-06-01] An advanced passivation technique of sulfide minerals towards sustainable management of acid mine drainage

○Ilhwan - Park¹, Sanghee Jeon¹, Mayumi Ito¹, Naoki Hiroyoshi¹ (1. Hokkaido University)

Chairman:Shingo TOMIYAMA (Hokkaido University)

Keywords:Acid mine drainage, Microencapsulation, Passivation, Surface-protective coatings, Acid-generating minerals

Acid mine drainage (AMD), an acidic effluent with elevated concentrations of heavy metals, is often generated by the oxidation of sulfide minerals in tailings storage facilities (TSFs). If released to the environment without appropriate treatments, AMD could seriously damage the surrounding water bodies, soil and sediment systems, and ecosystems. To remediate AMD, the most commonly used technique is chemical neutralization. Although neutralization-based remediation is very effective, it has two critical drawbacks: (1) high operating costs due to the continuous input of chemicals and energy until AMD formation is ceased, and (2) disposal of huge amounts of bulky and hazardous sludge produced by the treatment. Because of these drawbacks, an alternative strategy called microencapsulation that directly passivate sulfide minerals by coating them with surface-protective layers has been proposed in recent years. Once acid-generating minerals (e.g., arsenopyrite, pyrite, etc.) are covered with surface-protective layers, AMD formation will be suppressed because of coatings that limit the reaction between minerals and water/oxygen/microorganisms. In this study, recent advances in microencapsulation techniques for passivating sulfide minerals are introduced.