The current uncertainty in the global supply of rare earth elements (REEs) necessitates the development of novel extraction technologies that utilize a variety of REE source materials. Herein, we examined the techno-economic performance of integrating a biosorption approach into a large-scale process for producing salable total rare earth oxides (TREOs) from various feedstocks. An airlift bioreactor is proposed to carry out a biosorption process mediated by bioengineered rare earth-adsorbing bacteria. Techno-economic assessments were compared for three distinctive categories of REE feedstocks requiring different pre-processing steps. Key parameters identified that affect profitability include REE concentration, composition of the feedstock, and costs of feedstock pretreatment and waste management. Among the 11 specific feedstocks investigated, coal ash from the Appalachian Basin was projected to be the most profitable, largely due to its high-value REE content. Its cost breakdown includes pre-processing (leaching primarily, 77.1%), biosorption (19.4%), and oxalic acid precipitation and TREO roasting (3.5%). Surprisingly, biosorption from the high-grade Bull Hill REE ore is less profitable due to high material cost and low production revenue. Overall, our results confirmed that the application of biosorption to low-grade feedstocks for REE recovery is economically viable.

Soil chemistry, soil extracts, biochar challenge data. This dataset is not publicly accessible because: First author organization owns the data. It can be accessed through the following means: Contact first author. Format: Excel Spreadsheet. This dataset is associated with the following publication: Ippolito, J., T. Ducey, K.A. Spokas, K. Trippe, and M. Johnson. A biochar selection method for remediating heavy metal contaminated mine tailings. International Journal of Environmental Science and Technology. Springer, Heidelburg, GERMANY, 05621-9, (2024).

An important consideration for the process design is cell immobilization-enabled flow-through operation. Large-scale biosorption relies on cells that are immobilized on a supporting substrate and used to 'attract' metal ions. Cell immobilization allows easy separation of the feed solution and REEs that are attached to the cell surface. It also allows continuous operation without the need of energy-intensive centrifugation or filtration. Lightweight, high surface area, low cost (~$200/m3) high-density polyethylene (HDPE) plastic disks are used as cell carriers for biofilm formation.

We summarized the FY17 and part of FY18 results of the analysis of the effect of several parameters (e.g., total dissolved solids, specific competing metals, pH, and temperature) on REE recovery from geothermal brine in a manuscript that was submitted to Environmental Science & Technology. In this manuscript, we investigate biosorption as a potential means of recovering REEs from geothermal fluids, a low-grade but abundant REE source. We have previously engineered E. coli to express lanthanide binding tags (LBTs) on the cell surface and the resulting strain showed an increase in both REE adsorption capacity and selectivity. Here we examined how REE adsorption by the engineered E. coli is affected by various geochemical factors relevant to geothermal fluids, including total dissolved solids (TDS), temperature, pH, and the presence of competing trace metals.

We summarized the FY17 and part of FY18 results of the analysis of the effect of several parameters (e.g., total dissolved solids, specific competing metals, pH, and temperature) on REE recovery from geothermal brine in a manuscript that was submitted to Environmental Science & Technology. In this manuscript, we investigate biosorption as a potential means of recovering REEs from geothermal fluids, a low-grade but abundant REE source. We have previously engineered E. coli to express lanthanide binding tags (LBTs) on the cell surface and the resulting strain showed an increase in both REE adsorption capacity and selectivity. Here we examined how REE adsorption by the engineered E. coli is affected by various geochemical factors relevant to geothermal fluids, including total dissolved solids (TDS), temperature, pH, and the presence of competing trace metals.

This data describes rare earth element adsorption onto E. coli cells engineered to express a lanthanide binding tag (LBT). We used a Great Salt Lake synthetic solution as the background matrix with Tb added to 1-10,000 ppb, concentrations much lower than the competing ions present. Our results showed that Tb binds to LBT, even in the presence of high concentrations of competing metals. We also tested REE adsorption at elevated temperatures (up to 100 degrees Celsius), and observed that Tb adsorption increases with temperature of to 70 degrees Celsius, and then remains constant until 100 degrees Celsius. Data analyses were performed using an ICP-MS at UCSC.

Description of a conceptual commercial process to remove rare earth elements (REEs) from geothermal brine, based on a small-scale laboratory experiment to load, strip, and regenerate a ligand-based media used to adsorb REEs from a simulated brine doped with known mineral concentrations.

Data describes the impact of biochar amendments on soil lead bioaccessibility. It contains the raw soil bioaccessibility information. This dataset is associated with the following publication: Plunkett, S., C. Eckley, T. Luxton, and M. Johnson. The effects of biochar and redox conditions on soil Pb bioaccessibility to people and waterfowl. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, USA, 294: 133675, (2022).

Heavy rare earth elements are essential in renewable energy and high-tech products. Some natural rare earth element (REE) deposits exhibit heavy rare earth element (HREE) enrichment from < 10% to ~85% of the REE budget (Williams-Jones et al., 2015). Controls on REE fractionation in hydrothermal systems are imposed by (1) changes in the relative stability of REE aqueous complexes with temperature (Migdisov et al., 2016) and (2) incorporation or rejection of REE by crystalline structures. Also, the REEs are invariably found as solid solutions but not as pure minerals. REE and yttrium (Y) sulphate complexes are some of the most stable REE and Y aqueous species in hydrothermal fluids (Migdisov and William-Jones, 2008, 2016; Guan et al., 2022) and may be responsible for REE transport and deposition in sediment-hosted deposits. Within the unconformity-related deposits, REEs are hosted mostly by xenotime ((Y,Dy,Er,Tb,Yb)PO4) and minor florencite ((La,Ce)Al3(PO4)2(OH)6) (Nazari-Dehkordi et al., 2019). Modelling the stability of xenotime in the H-O-Cl-(±F)-S-P aqueous system is critical for understanding HREE enrichment in this mineral system. We use a newly derived thermodynamic dataset depos for REESO4+ and REE(SO4)2‑ aqueous complexes to generate stability diagrams illustrating mechanisms of REE transport and deposition in the above deposits. Sulphate REE complexes may dominate even in chloride-rich brines and facilitate REE mobilization in acid oxidizing environments. Previously Nazari-Dehkordi et al. (2019) proposed an ore genesis model involving the mixing of discrete hydrothermal fluids that separately carried REE + yttrium and phosphorus. The speciation model that includes sulphate complexes expands this scenario; a process resulting in fluid neutralization or reduction will also promote precipitation of xenotime enriched in HREEs. This Abstract was submitted/presented to the 2022 Specialist Group in Geochemistry, Mineralogy and Petrology (SGGMP) Conference 7-11 November (https://gsasggmp.wixsite.com/home/biennial-conference-2021)

This reference database in RIS format contains all of the references that were collected as part of our retrospective analysis of geothermal mineral recovery (REE and Li) activities and domestic resource assessment. The outputs detail the chemistry and molecular processes used in lithium recovery from geothermal brines. The articles included include information about the study including more information on geothermal brines and the technologies used for recovering lithium from geothermal brines.