Abstract
Low-grade ores, tailings, and solid wastes contain small amounts of valuable heavy metals. Improper disposal of these substancesresults in the waste of resources and contamination of soil or groundwater. Accordingly, the treatment and recycling of low-grade ores, tailings, and solid wastes attracted much attention recently. Bioelectrochemical system, an innovative technology for the removal and recovery of heavy metals, has been further developed and applied in recent years. In the current study, the low-grade chalcopyrite was bioleached with the assistance of microbial fuel cells. Copper extraction along with electricity generation from the low-grade chalcopyrite was achieved in the column bioleaching process assisted by MFCs. Results showed that after 197days bioleaching of low-grade chalcopyrite, 423.9mg copper was extracted from 200g low-grade chalcopyrite and the average coulomb production reached 1.75 C/d. The introduction of MFCs into bioleaching processes promoted the copper extraction efficiency by 2.7 times (3.62% vs. 1.33%), mainly via promoting ferrous oxidation, reducing ORP, and stimulating bacterial growth. This work provides a feasible method for the treatment and recycling of low-grade ores, tailings, and solid wastes. But balancing energy consumption of aeration and circulation frequency and chemical consumption of acid to improve the copper extraction efficiency need further investigation.
Highlights
Copper is one of the most common heavy metals and an essential raw material for many industries due to its inexpensive and excellent in performance
Copper extraction along with electricity generation from the low-grade chalcopyrite were achieved in the column bioleaching process assisted by microbial fuel cells (MFCs)
Results showed that after 197 days bioleaching of low-grade chalcopyrite, 423.9 mg copper was extracted from 200 g low-grade chalcopyrite and the average coulomb production reached 1.75 C/d
Summary
Copper is one of the most common heavy metals and an essential raw material for many industries due to its inexpensive and excellent in performance. Traditional copper extraction technologies such as pyrometallurgy and hydrometallurgy have the disadvantages of high energy consumption and large environmental pollution. Attention has been given to bioleaching due to the processes of it was clean (Ma et al, 2021; Sun et al, 2021). By mechanochemically activated (Cao et al, 2020), regulating factors (Khoshkhoo et al, 2017; Wang et al, 2014), and introducing additives (Yang et al, 2020; Ma et al, 2017; Koleini et al, 2011) to improve copper extraction. High ore heap bioleaching and in-situ bioleaching need to solve the problem of insufficient electron acceptors inside the mine heap through aeration, which increases energy consumption (Huang et al, 2019). The current challenge is to develop new technologies to solve these defects
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