No abstract

No abstract

No abstract

No abstract

The metal mining of certain minerals is associated with the generation of acid mine drainage waters and effluents containing cyanides that can have long-term negative impacts on waterways and biodiversity. Obtaining valuable components from those effluents would improve the resource efficiency and the environmental performance of mining. This paper reviews the main separation processes cited in literature for the purification of real acid mine drainage waters and cyanide tailings, and for the recovery of heavy metals and cyanides from those effluents. The processes used are adsorption and membrane technology to obtain valuable compounds from acid mine drainage waters and ion-exchange, acidification-volatilization-reneutralization, sulphidization-acidification-recycling-thickening and membrane technology from cyanide tailings. Further, the use of the 12 green engineering principles for improving the environmental performance of the purification techniques is debated. This work indicates that the energy and chemical consumption and the formation of waste are the main environmental disadvantages of the purification and recovery techniques. This paper concludes that the limitations may be overcome by improving the efficiency of the processes and by using renewable energy and material. The benefits of conducting the purification and recovery techniques utilizing hybrid processes are also pointed out.