26 Sep 2018

Authors:

  • ALEX DRAK, ROI ZAKEN PORAT AND TOMER EFRAT | IDE Technologies | Kadima, Israel
  • MARCO KERSTHOLT AND GERARD VAN HOUWELINGEN | Royal Haskoning DHV | Amersfoort, the Netherlands

Abstract: (Acid) mine drainage ((A)MD) is a big problem for the mining industry. The formation of (Acid) mine drainage is caused by the oxidation of sulphide minerals which, depending on the buffer capacity of the rocks, leads to either highly acidic, metal-rich water with high sulphate content or neutral/slightly acidic water with moderate metal content and high sulphate concentration. Both types of (A)MD have high sulphate concentration and high scaling potential, predominantly of gypsum. Sulphate is considered a more significant long-term water quality issue for mining operations, and its control levels are based primarily on secondary drinking water recommendations of approximately 500 mg/L. Two methodologies are mainly used, stand-alone or in combination, to remove sulphate from acid mine water: membrane separation or salt precipitation, for example formation of gypsum. Conventional membrane separation systems, as a solution for sulphate removal from acid mine wastewater, have several drawbacks that limit the maximum possible system recovery, and even prevent their use in these applications. Conventional membrane systems will also encounter operational challenges when required to handle variable feed quality and variable recoveries, as well as at high supersaturation conditions of calcium sulphate (CaSO4). A recently developed MaxH2O DESALTER technology overcomes these limitations, making it the perfect solution for treating acid mine wastewater...

Keywords: Acid mine wastewater treatment, MaxH2O DESALTER, reverse osmosis, Crystalactor® technology, calcium sulphate precipitation, brine management.