Bio-Beneficiation: Relevance to Mineral Processing

The increasing demand for various minerals and the limited high-grade mineral resources, concerning economic and environmental issues, has led to increasing research attention to the bio-beneficiation of low-grade mineral resources. Bio-beneficiation can be defined as employing microorganisms (including bacteria, fungi, algae, and yeast) in mineral processing and related industries. The high potential of microorganisms and their metabolites, especially extracellular polymeric substances (EPS), has been substantiated in bio-beneficiation processes. The bio-beneficiation is generally divided into two main categories: including bioflotation and bioflocculation. The bioflotation uses the microorganisms and their products (such as biomass and EPS) as flotation reagents. Microorganisms and their biomass can be applied as collectors, depressants, dispersants, and frothers in minerals floatation. Bioflocculation is another application of biotechnology in minerals processing. Almost all mineral processing techniques should be carried out in a wet environment. Therefore, dewatering and water recycling are essential steps in mineral processing plants. Microorganisms can be used as flocculants to decrease the dewatering time or minerals separation with high efficiency. Comprehensive information about flocculation, classification of flocculants, and the application of EPS as bioflocculant for selective bioflocculation of different minerals are provided in this chapter. The mechanism of the bioflocculation process and the effect of different parameters on the bioflocculation of various minerals have been investigated. Moreover, recent research on the application of bioflocculation in the selective separation or removal of minerals using different types of microorganisms has been briefly reviewed. Employing microorganisms for both bioflotation and bioflocculation can be a great strategy to save the environment and decrease process costs.