Innovative Routes for Acid Mine Drainage (AMD) Valorization

In the aftermath of intensive mining, the generation of acid mine drainage (AMD) has been an issue of prime concern to national, regional, and international scientific and water care communities. Elevated concentrations of Al, Fe, Mn, and sulfate, among other contaminants, dominate AMD. This makes AMD a viable source of valuable metals and minerals. Lately, recovery of metals from AMD has been intensively pursue, albeit, with minimal success. Ongoing research has been widespread due to the need for effective, efficient, and working solutions that aims to responds to increasingly stringent environmental regulations. Drainages from mining activities are being considered in a fresh light with a prime attempt of them being beneficiated through the recovery and synthesis of valuable minerals. To achieve that, different approaches and techniques are used to recover valuable minerals with a wide range of industrial applications. A series of laboratory, pilot, and industrial scale technologies have been employed for the treatment of AMD with value recovery, beneficiation, and material synthesis. Despite a wide range of available AMD treatment technologies, secondary sludge, which is complex, heterogeneous, and highly mineralized, require innovative approaches to harness value and advance the concept of circular economy. The need for sustainable and economic viable AMD treatment approaches has led to much focus on clean water reclamation, reuse, and recovery. Systematically, this chapter underscores (i) the composition of AMD, (ii) environmental and ecotoxicological impacts, (iii) developed remediation techniques, (iv) valorization routes, and (v) a case study in South Africa. Different configurations and approaches for the treatment of AMD with an option of acquiring valuable secondary minerals have been reported as well. Furthermore, the employment of membrane technology for AMD treatment has been emphasized. The advantages and disadvantages of individual approaches and their synergistic products were also discussed. Overall, this chapter gives insights to various routes for AMD valorization and how they can respond to circular economy. Future perspective and research avenues were also discussed.