Bioleaching of Rare Earth Elements: Perspectives from Mineral Characteristics and Microbial Species

Abstract

Bioleaching exhibits high potential for the processing of low-grade complex mineral resources. With the development of the economy and an increase in demand, rare earth elements (REEs) in secondary resources, such as phosphogypsum, red mud and coal-related resources, are gaining more and more attention. In this review, the bioleaching performance of diverse microorganisms is summarized and compared for primary (mainly monazite) and secondary REE resources, based on publications from the past decade. The mineral characteristics of these REE resources are different, as they can be found in phosphate, sulfate, or silicate forms. Correspondingly, microbial species suitable for use in bioleaching differ. The most efficient bioleaching microbe for monazite is Paecilomyces sp., while Acidianus manzaensis is effective in processing red mud. Acidophilic sulfur oxidizers are suitable for processing acidic phosphogypsum. Acidithiobacillus thiooxidans could recover a significant amount of REEs from coal fly ash. In particular, monazite has a high REE content but extremely low bioleaching efficiency compared to that of secondary resources, supporting the understanding that bioleaching approaches are more competitive for minerals with low REE contents. Overall, great progress has been made over the last decade, as considerable REE recovery rates have been achieved, and the main metabolites of microbes were identified. However, numerous challenges still exist. Future efforts should focus on improving biorecovery efficiency, reducing the cost of cell-culture media, and exploring the interaction mechanism between cells and minerals, with an emphasis on mineralogical phase transformations and the molecular regulation mechanisms inside cells during the bioleaching process.

Microbial recovery of rare earth elements from various waste sources: a mini review with emphasis on microalgae

“…REEs occur in various forms as phosphates, sulphates, or silicates in these primary resources. Secondary REE resources typically comprise wastes like phosphogypsum, red mud, coal-related resources, and WEEE (Fathollahzadeh et al 2019 ; Shi et al 2023 ). Traditional extraction methods often involve the use of harsh chemicals and can have significant environmental impacts.…”

Possibilities of Managing Waste Iron Sorbent FFH after CO2 Capture as an Element of a Circular Economy

“…At an even lower pH of pH 1.0-3.0, the formation of sulfuric acid allows the solubilization of metals. It has been found that low pH does not negatively affect the growth and metabolism of A. thiooxidans and A. ferrooxidans [26][27][28]. The cultivation of bioleaching bacteria was carried out at a temperature of 20 • C. The optimal temperature for the growth of acidic bacteria A. thiooxidans and A. ferrooxidans is 30 • C [26][27][28].…”

“…It has been found that low pH does not negatively affect the growth and metabolism of A. thiooxidans and A. ferrooxidans [26][27][28]. The cultivation of bioleaching bacteria was carried out at a temperature of 20 • C. The optimal temperature for the growth of acidic bacteria A. thiooxidans and A. ferrooxidans is 30 • C [26][27][28]. Lowering the culture temperature resulted from the assumption of reducing energy demand (thermal energy) during the cultivation of bioleaching bacteria.…”

Bioleaching of Mine Tailings by Mesophilic: Acidithiobacillus spp., Leptospirillum ferrooxidans, and Thermophilic: Sulfobacillus thermosulfidooxidans Cultures with the Addition of Ag+ Additive

“…The advantages of processing waste from the existing mine tailings are availability and large amounts of input materials. However, as the defined waste raw materials are often characterised by lower concentrations of metals, it is essential to choose suitable processing procedures for the mentioned materials to achieve high yields of metals and to meet the environmental and economic aspects of the process for the subsequent introduction of the technology into operational conditions [4][5][6].…”