A Review on Bioflotation of Coal and Minerals: Classification, Mechanisms, Challenges, and Future Perspectives

ABSTRACT

Today, with the ever-increasing concerns about the widespread environmental impact of the mining industry, the movement of the mineral processing sectors, which heavily rely on various chemical and petroleum-origin reagents, to the green industry is imperative. Due to the advantages biotechnological approaches provide, bioprocessing is considered a benign alternative to conventional mineral processing techniques. Recent fundamental research works have directed the attention to the development of biotechnology and using microorganisms in the new field of biobeneficiation, especially bioflotation. The current review categorizes bioflotation methods into direct and indirect processes giving an in-depth insight into their concepts. Furthermore, this study provides a comprehensive review of research on different aspects of bioflotation, such as the effects of operating (mainly solid content and pH) and biotechnological parameters, potential mechanisms, and unexplored points, but from different, and practical viewpoints. Recent studies were summarized by categorizing microorganisms based on their wall structures, and growth temperature. It was disclosed based on the literature data that the nutritional requirement of variant microorganisms was only chemolithotroph. Further, the conducted researches in investigating optimum conditions for maximization of contact angle and adhesion forces to reach the maximum recovery were reviewed. In addition, existing problems and challenges of this field were investigated and it was found that economic barriers and obscurities were the main obstacles of industrial application in mining and mineral processing industries. Finally, new perspectives and suggestions were presented to shed light on future research and help to solve the challenges currently facing its application.

KEYWORDS:

• Coal
• sulfide minerals
• direct and indirect bioflotation
• mechanisms
• biosurfactant

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

Conceptualization, K.A., H.K.; Methodology, K.A., H.K. and A.H.; Original draft preparation: K.A., H.K.; Writing, reviewing and editing, K.A., Q.H., H.K. and A.H.; Investigation, K.A., Q.H., H.K. and A.H.