A critical review on natural surfactants and their potential for sustainable mineral flotation

The transition of the mineral processing sectors, which depend mainly on various petroleum-origin chemicals, to the green industry based on the production of greener materials and the reduction of carbon footprints, is mandatory due to the growing concerns regarding the extensive environmental impact of the mining industry. In this context, biological ore beneficiation is spurring increasing interest from scientists and industrials. The latest scientific developments in bio-metallurgy have allowed it to exploit biotechnologies in the flotation process as a novel/cleaner approach for separating gangue materials from valuables minerals. Current fundamental research projects have focused on the progress of biotechnology and the employment of biopolymers, microorganisms, and their metabolites, as well as plant-derived biosurfactants in the emerging field of bioprocessing, particularly bioflotation. Almost all studies on flotation have focused on chemical and physical parameters, and the role of natural biosurfactants remains little explored. This review presents a thorough understanding of the bioflotation concept by assessing previous research on several elements of bioflotation, including the impacts of biotechnology and operating factors (pH, biomass, and biosurfactants concentration), probable mechanisms, and unexplored areas, but from various pragmatic viewpoints. Recent studies are summarized by categorizing microorganisms, plants, and biopolymers based on their bioflotation performances. Furthermore, the most recent research investigations on biological flotation of specific minerals (salt-type sulphide and oxide) are reviewed. Finally, critical challenges of bioflotation are discussed, and novel perspectives are provided to contribute to solving the difficulties faced in its implementation.