Development of sustainable method for metal recovery from old flotation tailings (Majdanpek, Serbia) using Aspergillus niger fungus

Abstract

The accumulation of mine tailings in the mining area of Majdanpek represents a serious environmental problem. A strong impetus for the development of sustainable methods for the recovery of metals from mine tailings is given by the importance of heavy metal recovery and the economic benefits of precious and base metals. Currently, researchers are working to develop metals recovery from tailings through bioleaching, which is a more sustainable method compared to traditional metallurgical methods. Biotechnologies for leaching heavy metals from old flotation tailings (Majdanpek, Serbia) with fungus Aspergillus niger (A. niger) are discussed in this paper. The subject of this research is iron ions, since the tailings are the richest in this metal. With a simple bioleaching process, which is based on the cultivation of A. niger in the basic growth medium and then challenging it with tailings, 5% iron was released in 35 days. The transformation of mine tailings morphology was also confirmed by optical microscopy. Processes by which A. niger extracts metals from tailings include acidolysis, complexation, alkaloysis and biosorption. Also, in addition to metabolites, these fungi produce spores and mycelium that can destroy material and transform it to the soil. Given that Serbia is abundant with agricultural waste, as well as waste from the food industry, in future studies cheap waste should be used as an energy input source for A. niger and transformation of tailings.