Closing the Loop: Key Role of Iron in Metal-Bearing Waste Recycling

Abstract

The role of iron in metal-bearing waste bioleaching was studied. Four various types of waste (printed circuit boards (PCBs), Ni-Cd batteries, alkaline batteries and Li-ion batteries) were treated by bioleaching using the acidophilic bacteria A. ferrooxidans and A. thiooxidans (separately or in mixture). Role of main leaching agents (Fe 3+ ions or sulphuric acid) was simulated in abiotic experiments. Results showed that oxidation abilities of Fe 3+ ions were crucial for recovery of Cu and Zn from PCBs, with the efficiencies of 88% and 100%, respectively. To recover 68% of Ni from PCBs, and 55% and 100% of Ni and Cd, respectively, from Ni-Cd batteries both oxidation action and hydrolysis of Fe 3+ were required. The importance of Fe 2+ ions as a reducing agent was showed in bioleaching of Co from Li-ion batteries and Mn from alkaline batteries. The efficiency of the processes has increased by 70% and 40% in Co and Mn bioleaching, respectively, in the presence of Fe 2+ ions. Based on the results we suggest the integrated biometallurgical model of metal-bearing waste recycling in the effort to develop zero-waste and less energy-dependent technologies.

Bio-Based Processes for Material and Energy Production from Waste Streams under Acidic Conditions

“…By controlling pH, one may stimulate required bioprocesses, e.g., methanogens hardly work below pH 6, thus other microorganisms work more efficiently when pH declines. Very low pH in metal recovery by bioleaching is fundamental for bacterial life resulting in the high efficiency of metal extractions from various resources [4]. Besides application in metal recovery, bioleaching represents an interesting tool in the environmental clean-up technology aiming to produce metal free materials (e.g., removal of metals from sewage sludge or pig manure prior to their re-use) [5,6].…”

“…Besides application in metal recovery, bioleaching represents an interesting tool in the environmental clean-up technology aiming to produce metal free materials (e.g., removal of metals from sewage sludge or pig manure prior to their re-use) [5,6]. Metal bioleaching from waste is considered a significant research area to secure critical metals for the European market and developing processes adopting circular economy principles, especially in combination with other biological processes for metal extraction from solutions such as bioaccumulation or biosorption [4,7].…”

LCD panels bioleaching with pure and mixed culture of Acidithiobacillus

“…The search for effective solutions, apart from classic mechanical, hydrometallurgical and pyrometallurgical methods, also includes biohydrometallurgical methods, using the potential of microorganisms. Biological methods are an attractive alternative, they do not require extreme parameters and offer low cost and environmentally friendly benefits (Vestola et al, 2010;Willner et al, 2015;Sedlakova-Kadukova et al, 2017). Microorganisms are capable of transforming many metals found in many valence states by catalysing redox reactions.…”

“…They can obtain the oxidizing energy both reduced sulfur compounds and the ferrous ion. There is an increasing amount of new results on the utilization of acidophilic microorganisms in the bioleaching of various types of metal-bearing wastes (Printed Circuit Boards -PCBs, Ni-Cd batteries, Li-ion batteries, spent refinery catalysts) with high efficiency of metals bioleaching (> 90%) (Sedlakova-Kadukova et al, 2017;Willner and Fornalczyk, 2013;Nagar et al, 2021), including valuable In extraction from LCD (Willner et al, 2018;Jowkar et al, 2018;Xie et al, 2019;Rezaei et al, 2018).…”

Simultaneous lithium bioleaching and bioaccumulation from lepidolite using microscopic fungus Aspergillus niger

“…Among them very promising are biotechnological methods using bioleaching as this method overcome the operational and technical problems associated with lithium recovery. Traditionally acidophilic bacteria are widely applied, however, their usage is mostly oriented on metal recovery from sulphidic ores or metal-bearing waste materials, but their utilisation in aluminosilicates is limited (Sedláková-Kaduková et al 2017). The most abundant lithium containing rocks are pegmatites with various Li minerals (Zhang et al 2018).…”