Integrated bioleaching-electrometallurgy for copper recovery - A critical review

Abstract

The recovery of copper from secondary waste resources (e.g. electronic wastes, slag, fly-ash, sludge and spent catalysts) via oxidative and reductive bioleaching becomes a running trend and a potential alternative to limited metal supply. The motive of this review is to ponder over recycling of secondary waste towards the circular economy to reduce environmental risks as well as to increase the economic profitability of the mining industry. The biochemistry of iron/sulfur minerals, bacteria–mineral interactions and adaptive behavior allowing the acidophiles to survive are among the key parameters to be optimized during the bio recovery of copper. The use of OMICS approaches such as genomics, proteomics , transcriptomics and metabolomics is also crucial to elucidate a comprehensive view of the bioleaching communities, their mechanisms and interactions with minerals. This handy information can act as a boon to develop potential strains by adopting synthetic biology and antiviral CRISPR-Cas9 technologies to efficiently control the bioleaching process. Furthermore, some of these recent discoveries to design bioelectrochemical system (BES) and to achieve higher rate of metal recovery are discussed. Finally, the objective of this study is to narrow the gap between fundamental and applied research to fully address scientific, technological and economic challenges and bottlenecks of bioleaching process in general and BES in particular. • Bioleaching is a boom for metal recovery from metallurgical waste. • Impact of mineral biochemistry on process performance is given. • Role of OMICS and synthetic biology to improve process efficiency are identified. • Bioelectrochemical system is a promising technology for metal recovery. • Investigations to reduce investment costs of bioleaching process are discussed.