Abstract
In this study, the feasibility of zinc recovery from a mining residue is shown by employing Aspergillus niger. Different mediums such as sucrose, molasses, potato peels and sawdust passed through sieve no. 16 were tested. Moreover, although it is clear that the citric and oxalic acid generated by fungi could be an important leaching agent acting in the solubilisation of the used minerals, other products of metabolism could be involved. Maximum solubilisation of 49, 2·3 and 6% were achieved for zinc, lead and iron respectively for the case of bioleaching when Aspergillus niger grown on a glucose medium. The relatively high recovery of zinc and low recovery of iron and lead could be due to selectivity of zinc for leaching by Aspergillus niger. However, further research is required to increase the recovery of zinc from low grade zinc minerals. It is obvious that the bioleaching process represents a lower ecological potential risk and that even with a lower final yield, the economical cost of such a process would be more attractive.
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