Bioleaching of Pyrrhotite concentrate for Ni Extraction
Discarded unattended waste slag soon becomes acidic resulting in an uncontrolled source, thereby releasing metals to the environment by a process known as Acid Mine Drainage (AMD). Traditional Pyrometallurgical methods to extract base metals from ore tailings have focused on using acid that is produced locally as a result of smelting operations, and Oxygen to accelerate this process at 250oC that helps in quantitatively extracting metals in solution and concurrently cleaning the slag. However such a process calls for significant capital expenditure in terms of heat transfer equipments like Heat exchanger as well as places a burden on the atmosphere due to emission of noxious gases such as sulphur dioxide. Furthermore, as society’s expectations for a cleaner environment increase so do the environmental regulations that push industries to invest in emission reduction and elimination of hazardous waste rejection. In this regard, our research will focus on using Bacterial mediated leaching (Bioleaching) that is aimed at improving nickel extraction efficiency from a Nickeliferous Pyrrhotite (Fe1-xS) concentrate, which is a waste stream from Vale Inco’s mining plant in Sudbury, Ontario, Canada using defined thermophilic isolates of the genus Sulfobacillus and Sulfolobus respectively. This research would be beneficial in understanding the Pyrrhotite biooxidation process while simultaneously identifying and alleviating rate limiting steps in the Bioleaching process.