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Microbial Processes for Treatment of e-Waste Printed Circuit Boards and Their Mechanisms for Metal(s) Solubilization
Published in Ram Chandra, R.C. Sobti, Microbes for Sustainable Development and Bioremediation, 2019
Shailesh R. Dave, Asha B. Sodha, Devayani R. Tipre
Biomining is a well-known process for extraction of metals from ore and concentrates. It is a safe, green environmentally friendly technology. However, use of this process is not well documented in e-Waste bioleaching field as compared with other disciplines, mainly because the handling of a live system is difficult as compared with chemical and mechanical treatments. The prevailing conventional e-Waste treatment methods adopted are harmful to the environment and found to be toxic to human as well as surrounding other living creatures. Biohydrotechnology seems to be safe and acceptable technique as compared with other methods of e-Waste treatments available; nevertheless, the gaps in the study still prevail and need to be connected. The major problems are that this method can tackle a small amount of e-Waste, the organisms used in the process fail to remain viable for a longer time due to the toxicity of e-Waste, and the amount of lixiviant generated is not sufficient as well as takes a longer time for the production, so there is an urgent need to focus on the development of more efficient strain, search of new strain, process optimization, scale-up of the current process for e-Waste management, and treatment. Thus, there is a need for the development of hybrid technology, which requires more attention to various interdisciplinary subjects, such as microbiology, metallurgy, engineering, and biotechnology.
Innovative Biomining
Published in Edgardo R. Donati, Heavy Metals in the Environment, 2018
Camila Castro, Edgardo R. Donati
Biomining is an applied biotechnology for mobilization of metal cations from insoluble materials such as ores and concentrates by biological oxidation and complexation processes. The general term, covers both bioleaching and biooxidation techniques, although the microbial action in both cases is the same. During a bioleaching process the valuable metal is directly solubilized, while the latter term refers to situations where microorganisms are used to remove minerals that occlude target metals which are solubilized in a second process (Donati et al., 2016; Johnson, 2014; Vera et al., 2013). Today, biomining is a well-established technology; a variety of full-scale biomining operations significantly contribute to the metals mined worldwide (Brierley and Brierley, 2013; Donati et al., 2016). But the potential of biomining is yet to be explored in the case of metal recovery from alternative resources.
Comparative studies of novel biooxidation process to low-grade sulphide gold ores
Published in Geosystem Engineering, 2022
Junmo Ahn, Jiajia Wu, Jaeheon Lee
Biomining refers to the oxidation of sulphidic whole ores or concentrates with microorganisms to recover base and precious metals (Rawlings & Johnson, 2007). Biomining in gold extractive metallurgy includes biooxidation of sulphide minerals such as pyrite when gold grains are physically locked in the mineral structure. Pyrite can be oxidized in either indirect or direct pathways in the presence of microorganisms. During indirect biooxidation, bacteria species oxidize byproducts to enhance pyrite oxidation as shown in Eq. (1) – Eq. (5) (Jiang et al., 2007; Liu et al., 2018).
Hydrometallurgical Roadmaps and Future Strategies for Recovery of Rare Earth Elements
Published in Mineral Processing and Extractive Metallurgy Review, 2023
C. Erust, M. K. Karacahan, T. Uysal
In order to reduce the direct impact of hydrometallurgical methods on the environment, combined systems can be developed by including biohydrometallurgical processes such as biooxidation, bioleaching, and biosorption, which are being tested for rare earth elements under certain operating conditions. New improvements looks like it will allow biomining to implement with other hydrometallurgical or chemical processing technologies successfully.
A Review on Bioflotation of Coal and Minerals: Classification, Mechanisms, Challenges, and Future Perspectives
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Kaveh Asgari, Qingqing Huang, Hamid Khoshdast, Ahmad Hassanzadeh
In mineral processing, microorganisms are commonly used in the form of two processes, namely ‘Biomining’ and ‘Biobeneficiation.’ The term biomining itself comprises two sub-processes, i.e. bioleaching and biooxidation. Although these terms are often used interchangeably, bioleaching refers to the processes in which an insoluble metal is dissolved, such as the conversion of metal sulfide to metal sulfate, and through which the target metal is transferred into a solution. On the other hand, biooxidation is mainly related to the bacterial decomposition of the sulfide matrix of a mineral, which encapsulates the target metal (mainly gold and silver (Natarajan 1989, 1992; Hunter et al., 1998)), releasing and facilitating the chemical extraction of the metal (Pradhan et al., 2018; Andrews 1998; Abhilash and Pandey 2013). In the latter process, the target metal does not dissolve during bacterial decomposition and then requires traditional techniques (such as cyanidation) to recover (Bosecker 1997; Zheng et al. 1998; Kuyucak 1998; Rawlings 2002; Rohwerder 2003; Olson 2003; Johnson, Grail, and Hallberg 2013; Rawlings and Johnson 2019; Moosakazemi et al. 2022). Meanwhile, biobeneficiation covers two areas including bioflotation and bioflocculation. These two can be defined as operations in which microorganisms facilitate separation selectivity by acting as reagents, collectors, and modifiers (NCBI webpage on Sulfolobus 2007). By using microorganisms as collectors, a bridge can be created between the interfacial regions of interacting microorganisms and minerals. These bioreagents affect the physicochemical properties of mineral surfaces, including the atomic and electronic compositions, acid – base characteristics, the net charge/potential, and the wettability of the surfaces (NCBI webpage on Archaeoglobus 2007). Besides, it is interesting to note that bioflotation is a green and eco-friendly technology and compared to the conventional flotation method, it has little environmental impact, while benefits from highly biodegradable substances.