Review
Engineering, Environmental
Emmanuel Yaw Owusu-Fordjour, Xinbo Yang
Summary: Bioleaching, using microorganisms to dissolve minerals and extract Rare Earth Elements (REEs) in aqueous media, has gained attention for its potential eco-friendliness compared to other extraction methods. Mixed culture bioleaching is preferred for efficient REEs extraction, promoting closed-loop recycling and reducing supply chain issues. This literature review provides an overview of challenges, opportunities, microorganisms, mechanisms, approaches, parameters, and techno-economic considerations related to REEs bioleaching, and offers recommendations for future advancements.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Metallurgy & Metallurgical Engineering
Sabrina Hedrich, Anja Breuker, Mirko Martin, Axel Schippers
Summary: Sands from the German Baltic Sea coast are recovered as construction material and contain heavy minerals enriched with zircon, garnet, ilmenite, rutile, magnetite, and monazite. Gravity and magnetic separation can be used to concentrate the heavy minerals. Bioleaching experiments were conducted on zircon concentrates and eudialyte concentrates containing rare earth elements (REE), but the results showed limitations in the extraction of REEs from heavy minerals through bioleaching.
Article
Metallurgy & Metallurgical Engineering
Laura Castro, Helena Gomez-Alvarez, Manuel Carmona, Felisa Gonzalez, Jesus A. Munoz
Summary: The aim of this study was to investigate the solubilization of monazite and recovery of REE using Burkholderia thailandensis, and the influence of the rhamnolipids produced by the bacteria on REE mobilization. B. thailandensis grown in nutrient broth with 1% monazite (w/v) achieved a REE concentration of 8.3 mg center dot l-1 after 15 days. Rhamnolipids were produced by B. thailandensis grown in medium supplemented with 10% glycerol, and the critical micelle concentration (CMC) was determined to be 94.45 mg center dot l-1 for commercial rhamnolipids and 60.41 mg center dot l-1 for purified rhamnolipids. The maximum REE solubilization was achieved at CMC, with 9.36 mg center dot l-1 for commercial rhamnolipids and 5.13 mg center dot l-1 for rhamnolipids produced by B. thailandensis E264.
Article
Energy & Fuels
Juanjuan Ma, Shuyan Li, Jinxi Wang, Shuting Jiang, Balaji Panchal, Yuzhuang Sun
Summary: This study optimized the culture conditions and bioleaching process of Aspergillus niger for the extraction of rare earth elements (REEs) from coal fly ash (CFA). It was found that organic nitrogen sources influenced the morphology and acid production capacity of A. niger, with oxalic acid being the main acid secreted (4.05 mg/L). The initial pH value was identified as the most influential factor affecting the bioleaching process, and by optimizing it, a leaching rate of 30.91% for total REEs in CFA was achieved. The main mechanism of REEs bioleaching by A. niger from CFA was speculated to be proton exchange and organic ligand complexation.
Article
Metallurgy & Metallurgical Engineering
Luver Echeverry-Vargas, Nestor Ricardo Rojas-Reyes, Luz Marina Ocampo-Carmona
Summary: This paper investigates the leaching conditions of hydrochloric acid and sulfuric acid for the maximum extraction of cerium, lanthanum, and neodymium from a dephosphorized monazite concentrate. The experiments showed that sulfuric acid performed better in terms of extraction efficiency. The addition of hydrogen peroxide further enhanced the dissolution of rare earth elements in sulfuric acid. The recovered rare earths can be converted to oxides through precipitation with oxalic acid and subsequent calcination.
Review
Biochemistry & Molecular Biology
Laura Castro, Maria Luisa Blazquez, Felisa Gonzalez, Jesus angel Munoz
Summary: Biohydrometallurgy, a method of recovering metals through microbially mediated processes, has gained attention for extracting critical resources such as rare earth elements. The interest in rare earth elements is growing due to their applications in novel technologies and green economy, with biohydrometallurgy being used to extract resources from waste streams to support innovative mining and promote a circular economy.
Article
Metallurgy & Metallurgical Engineering
Adrian Carrillo Garcia, Mohammad Latifi, Jamal Chaouki
Summary: The study investigated the calcination process of a rare earth carbonatite ore from Niobec in Quebec, Canada, focusing on the decomposition of bastnasite and monazite. A global kinetic model was developed to represent the calcination kinetics of the whole ore based on individual calcination kinetics of the minerals nested in the ore. Initially developed for small particles, the model was later adapted to larger particle sizes by including coefficients based on physical particle size parameters.
Article
Environmental Sciences
Nathalia Luiza P. Wyatt, Vinicius C. Costa, Jefferson R. de Souza, Merisnet Ferde, Floriatan S. Costa, Jordan B. Neris, Geisamanda P. Brandao, Wesley N. Guedes, Maria Tereza W. D. Carneiro
Summary: The Brazilian coast is rich in monazite, a mineral found in beach sand deposits. This study focused on the composition of monazite sands from beaches in the State of Espirito Santo, Brazil. The concentrations of rare earth elements, thorium, and uranium were determined and found to exceed established limits, indicating an elevated radiological risk and higher risk of developing cancer compared to the world average.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Metallurgy & Metallurgical Engineering
Binyuan Gao, Min Gan, Chongran Sun, Hui Chen, Xi Liu, Qianzi Liu, Yuguang Wang, Haina Cheng, Hongbo Zhou, Zhu Chen
Summary: A cell-free cascade enzymatic process was developed to produce gluconate from low-cost rice straw as an alternative to ammonium sulfate for leaching ion-adsorption rare earth ores. Compared to fermentation, the enzymatic process showed higher yield and superior leaching efficiency. This study provides a new avenue for potentially economical production of biogenic lixiviants from renewable and cheap feedstocks.
Article
Metallurgy & Metallurgical Engineering
Raphael Cruz Alves, Marisa Nascimento, Jessica Frontino Paulino, Julio Carlos Afonso
Summary: This work focuses on processing a monazite concentrate containing iron mineral phases to recover rare earth elements, with the alkaline conversion route showing the best combined recovery and selectivity results for lanthanum and iron. Various experimental designs were used to determine the key variables for each processing route, with temperature playing a significant role in all three routes.
Article
Engineering, Chemical
Laura Castro, Helena Gomez-Alvarez, Felisa Gonzalez, Jesus A. Munoz
Summary: Rare earth elements (REE) are vital for high-tech products and their environmentally friendly recycling methods are poorly studied. In this study, Aspergillus niger CECT2807 was used to leach REE from fluorescent phosphor powder in fluorescent tubes. The bioleaching experiments showed significant REE dissolution, with Y, Eu, Ce, Tb, and La concentrations reaching 122 mg/l, 8.50 mg/l, 0.95 mg/l, 0.40 mg/l, and 1.11 mg/l, respectively, after 7 days. The residues were analyzed using SEM and XRD, confirming the biotransformation of lamp powder. Semicontinuous experiments further demonstrated increased REE dissolution rate under static conditions, with extraction of 16.5 mg of Y and 0.75 mg of Eu per gram of fluorescent lamp powder.
MINERALS ENGINEERING
(2023)
Article
Engineering, Environmental
Ghazaleh Shakiba, Roozbeh Saneie, Hadi Abdollahi, Ehsan Ebrahimi, Ali Rezaei, Mohsen Mohammadkhani
Summary: In this paper, deep eutectic solvents (DESs) were applied as a green replacement for conventional solvents in the leaching process of REEs from monazite. The DES comprised of 2ChCl:1PTSA exhibited the highest extraction efficiency.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Biotechnology & Applied Microbiology
Y. Tian, X. Hu, X. Song, A. J. Yang
Summary: This study investigates the bioleaching of rare-earth elements (REEs) from phosphate rock using Acidithiobacillus ferrooxidans for the first time, and it shows that the bioleaching process is more efficient and environmentally friendly compared to abiotic leaching. The results also suggest that bacterial contact and Fe2+ oxidation play a key role in the bioleaching process, and extracellular polymeric substances contribute to the leaching of REEs.
LETTERS IN APPLIED MICROBIOLOGY
(2022)
Article
Environmental Sciences
Radhouan El Zrelli, Jean Yves Baliteau, Lamia Yacoubi, Sylvie Castet, Michel Gregoire, Sebastien Fabre, Vivien Sarazin, Louis Daconceicao, Pierre Courjault-Rade, Lotfi Rabaoui
Summary: This study is the first to examine the behavior and industrial fluxes of rare earth elements (REE) in coastal fertilizer plants in Gabes (southeastern Tunisia), highlighting the economic losses, environmental hazards, and risks to human health associated with their wastes. The concentrations of 16 REE were assessed in various samples, showing the need for the development of a new industry to exploit REE from waste materials for environmental and economic benefits.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Spectroscopy
Ilemona C. Okeme, Peter G. Martin, Christopher Jones, Richard A. Crane, Theophilus Ojonimi, Konstantin Ignatyev, Dave Megson-Smith, Thomas B. Scott
Summary: Analysis of Nigerian simulated fly ash samples revealed high total REE content, primarily consisting of critical REE such as Nd, Eu, Tb, Dy, Y and Er. These REE were mainly associated with discrete mineral particles such as monazite, xenotime and Y-bearing zircon. Monazite particles isolated from the samples showed a core-shell structure with Ce, Nd and La enriched in the shell and U and Th enriched in the core.
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY
(2021)
Article
Geology
Tsing Bohu, Ravi R. Anand, Anna H. Kaksonen, Ignacio Gonzalez-Alvarez, Anais Pages, Ryan R. P. Noble, Melvyn J. Lintern, Samuel C. Spinks, Xuliang Zhuang
Summary: Fungi play a crucial role in metals biomineralization and biogeochemical cycling, affecting essential pedogenic processes. Geomycology, the study of fungal contributions to geological processes, has the potential to develop new approaches for mineral exploration. This study provides an overview of geomycology on supergene Au and transition metals, discussing mechanisms and potential applications in efficient mineral probing.
ORE GEOLOGY REVIEWS
(2022)
Article
Geochemistry & Geophysics
Huan Li, Elsayed Oraby, Jacques Eksteen, Tanmay Mali
Summary: This study presents a cyanide-free leaching method, glycine-ammonia leaching in the presence of permanganate, for treating low-grade and copper-bearing gold tailings. The addition of glycine, ammonia, and permanganate significantly enhanced gold and copper extractions. The solids content had no significant effect on copper extraction, while gold leaching kinetics was slightly better at lower solids content.
Article
Metallurgy & Metallurgical Engineering
Jonovan Van Yken, Ka Yu Cheng, Naomi J. Boxall, Aleksandar N. Nikoloski, Navid Moheimani, Marjorie Valix, Anna H. Kaksonen
Summary: This study evaluated a novel two-step process for biological lixiviant generation to facilitate base metals leaching from waste printed circuit boards (PCBs). The first step involved biologically oxidizing waste sulfur to produce biogenic H2SO4, while the second step involved biologically oxidizing the acidified effluent to produce ferric iron. The recovered biolixiviant was then used for base metal leaching from PCBs.
Article
Metallurgy & Metallurgical Engineering
Ka Yu Cheng, Tharanga Weerasinghe Mohottige, Maneesha P. Ginige, Anna H. Kaksonen
Summary: Alumina is produced from bauxite ore using the Bayer process, but the presence of organics in Australian bauxite ore hampers the process. Oxalate is a key organic impurity that needs to be removed from the Bayer liquor. Microbial bioreactor treatment is a promising method for oxalate removal, although current bioreactors have some limitations. This study provides an overview of biotechnical processes for treating alkaline oxalate-containing liquor and proposes perspectives for further research.
Review
Green & Sustainable Science & Technology
Shaokun Song, Maneesha P. Ginige, Ka Yu Cheng, Tianhao Qie, Christopher S. Peacock, Anna H. Kaksonen
Summary: The distribution of biogas in headspace and gas collection devices is often assumed to be identical in batch experiments for evaluating biohydrogen potential. However, this assumption has been examined for the first time and a model for biogas distribution has been developed and validated. The results showed a difference of 5% to 30% in biogas concentration between headspace and gas collection unit. This measurement error in batch experiments has led to inaccurate reporting of biohydrogen purity and negative impacts on industry operations and regulatory compliance.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Environmental Sciences
Tharanga N. Weerasinghe Mohottige, Maneesha P. Ginige, Anna H. Kaksonen, Ranjan Sarukkalige, Ka Yu Cheng
Summary: This study proposed and validated the application of a dual-chamber bioelectrochemical cell as an add-on unit for an aerobic bioreactor to facilitate reagent-free pH-correction, organics removal, and caustic recovery from alkaline and saline wastewater. The results showed that the BES concurrently removed the majority of the influent organics and reduced the pH, enabling caustic production at a lower electrical energy demand compared to conventional chlor-alkali processes. The proposed application of BES holds promise to improve the environmental sustainability of industries in managing organic impurities in alkaline and saline waste streams.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Biotechnology & Applied Microbiology
Arya van Alin, Melissa K. Corbett, Homayoun Fathollahzadeh, M. Christian Tjiam, William D. A. Rickard, Xiao Sun, Andrew Putnis, Jacques Eksteen, Anna H. Kaksonen, Elizabeth Watkin
Summary: Microbial attachment and biofilm formation of Klebsiella aerogenes on monazite and xenotime minerals were investigated. The biofilm development process was observed and divided into three distinct stages. Higher coverage of biofilm was found on the high-grade monazite ore due to its rougher surface. Also, no selective attachment or colonization towards specific mineralogy or chemical composition was detected.
MICROBIAL BIOTECHNOLOGY
(2023)
Article
Microbiology
Arya Van Alin, Melissa K. Corbett, Homayoun Fathollahzadeh, M. Christian Tjiam, Andrew Putnis, Jacques Eksteen, Anna H. Kaksonen, Elizabeth Watkin
Summary: The adsorption behavior of micro-organisms during the initial attachment stage affects biofilm formation. Factors such as available attachment area and surface properties impact microbial attachment. This study investigated the initial attachment behavior of Klebsiella aerogenes on monazite and explored the role of extracellular DNA (eDNA). The ratio of planktonic and sessile subpopulations (P:S ratio), eDNA production, surface properties, particle size, available attachment area, and initial inoculation size were tested. The results showed that attachment occurred preferentially on larger particles, and decreasing the inoculation size or increasing the available area further promoted attachment. The presence of eDNA hindered bacterial attachment by creating repulsive interaction with bacteria.
Article
Metallurgy & Metallurgical Engineering
Jonovan Van Yken, Naomi J. Boxall, Ka Yu Cheng, Aleksandar N. Nikoloski, Navid Moheimani, Anna H. Kaksonen
Summary: This study evaluated the economic feasibility of an integrated bio- and hydrometallurgical process for extracting and recovering base and precious metals from electronic waste. A preliminary techno-economic analysis was conducted to examine the potential costs and profitability of the proposed process. The findings suggest that the process is profitable under optimized conditions and can address challenges associated with e-waste processing.
Article
Engineering, Chemical
Elsayed Oraby, Huan Li, Zixian Deng, Jacques Eksteen
Summary: This study successfully recovered Ni and Co from flotation slime using an alkaline glycine-based leaching method, achieving higher extraction rates and faster leaching kinetics. Using ammonia as a pH modifier improved the leaching efficiency and resulted in higher impurity rejection.
MINERALS ENGINEERING
(2023)
Article
Engineering, Environmental
Su Yan, Ka Yu Cheng, Tsing Bohu, Christina Morris, Line Lomheim, Ivy Yang, Maneesha P. Ginige, Elizabeth Edwards, Guanyu Zheng, Lixiang Zhou, Anna H. Kaksonen
Summary: Oxidation reduction potential (ORP) feedback-control by ethanol-dosing has been proven effective in a two-stage fluidized bed reactor (FBR) process for removing selenate, nitrate, and sulfate from wastewater and recovering high-purity elemental Se. This study investigated the impact of ORP conditions on microbial community composition and found that high ORP and elevated sulfate significantly altered microbial communities in FBR1. Selenate reducers were affected by ORP above -360 mV or -440 mV, while nitrate reducers remained unaffected.
JOURNAL OF WATER PROCESS ENGINEERING
(2023)
Article
Engineering, Chemical
Elsayed Oraby, Zixian Deng, Huan Li, Jacques Eksteen
Summary: Traditional hydrometallurgical processes are unable to recover valuable metals from nickel tailings, but the proposed alkaline glycine leaching process can effectively extract nickel and cobalt from the tailings. The experimental results show that alkaline glycine-ammonia system has better leaching performance compared to ammonia alone. Furthermore, the use of resin-in-leach, grinding, increasing temperature, and controlling dissolved oxygen levels can all enhance the leaching efficiency.
MINERALS ENGINEERING
(2023)
