Optimization of Electric Field Assisted Mining Process Applied to Rare Earths in Soils

Pires, Carolina Mocelin Gomes; Pereira, Jucélio Tomás; Ribeiro, Alexandra B.; Ponte, Haroldo de Araújo; Ponte, Maria José Jerônimo de Santana

doi:10.3390/app11146316

Cited by 5 publications

(2 citation statements)

References 43 publications

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“…The core of EKM applies an electric field to drive and control ion migration unidirectionally, coupled with gravity, pressure, and concentration to promote the infiltration of leaching agents in soil [15]. Though EKM has advantages including low environmental pollution and economic cost [16,17], the technology is still in its early stages. Many significant working mechanisms, particularly the soil conductivity mechanism that is regarded as the prerequisite of EKM technology, have not been well understood.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Rare Earth Elements from Ion-Adsorption Deposits Using Electrokinetic Technology: The Soil Conductivity Mechanism Study

Kang,

Ling,

Liang

et al. 2024

Minerals

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Rare earth elements (REEs) are essential raw materials for modern industries but mining them has caused severe environmental issues, particularly the recovery of heavy REEs (HREEs) from ion-adsorption deposits (IADs). Very recently, an emerging technology, electrokinetic mining (EKM), has been proposed for the green and efficient recovery of REEs from IADs. However, the conduction mechanism of the weathering crust soil, which is also a prerequisite for EKM, remains unclear, making the EKM process unpredictable. Here, we systematically investigated the conductivity of weathering crust soil in the presence of light REEs (LREEs, i.e., La3+ and Sm3+) and HREEs (Er3+ and Y3+), respectively. Results suggested that the voltage was dynamically and spatially redistributed by the movement of REEs and water during EKM, and the conventional assumption of the linear distribution of voltage leads to an inaccurate description of soil voltage. We proposed an improved Archie’s equation by coupling the mechanisms of liquid phase and solid-liquid interface conduction, which can predict soil conductivity more precisely. Moreover, the extended Archie’s equation is able to recalculate the voltage distribution at distinct times and spaces well during EKM. More importantly, the water content in field-scale weathered-crust soils can be retrieved by the newly proposed Archie’s equation, which helps optimize the leaching wells and improve the recovery rate of REE. This study focuses on the conduction mechanism of weathering crust soil, which provides a theoretical basis for better use of the EKM technology and promotes mining efficiency fundamentally.

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Section: Introductionmentioning

confidence: 99%

Recovery of Rare Earth Elements from Ion-Adsorption Deposits Using Electrokinetic Technology: The Soil Conductivity Mechanism Study

Kang,

Ling,

Liang

et al. 2024

Minerals

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“…Electrokinetic transport is a synergy among electromigration, electroosmosis, and electrophoresis [35][36][37]. Additionally, flow and solute-transport processes in actual weathering crust are coupled with electrolysis and geochemical reactions, which further increases the complexity of modeling [29,30].…”

Section: Introductionmentioning

confidence: 99%

Transport Model of Rare Earth Elements in Weathering Crusts during Electrokinetic Mining

Wang,

Ling,

Liang

et al. 2024

Minerals

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Electrokinetic mining (EKM) is a novel method for rare earth element (REE) mining that can achieve green and efficient recovery of REEs. However, as yet, there is no accurate model for describing the electrokinetic transport of REEs in weathering crusts, and this hinders the wider application of EKM. The conventional model fails to capture the microscale transport physics occurring in the nanochannels that exist ubiquitously in weathering crusts. Consequently, the existing models cannot distinguish the mobilities of different REEs. Here, we report a new model for a more faithful description of the electrokinetic transport of REEs in weathering crusts that considers the ionic size, which has previously been neglected. We reveal that the electrokinetic transport of heavy REEs (HREEs) is faster than that of light REEs (LREEs) in weathering crusts, which is contrary to the predictions of conventional models. Our model was validated experimentally by measurements of the electrokinetic transport of two LREEs (La and Sm) and an HREE (Er) in weathering crusts. The speed of electrokinetic transport follows the order Er > Sm > La. Our findings suggest that the ionic size is a non-negligible factor affecting the electrokinetic transport of REEs in weathering crusts containing nanochannels. This work offers a constitutive model to describe the electrokinetic transport of REEs in weathering crusts, which promotes both theoretical developments and practical applications of EKM.

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Extracting light rare earth elements by applying electric field assisted mining technique

Pires,

Ponte,

Grassi

et al. 2023

Minerals Engineering

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Optimization of Electric Field Assisted Mining Process Applied to Rare Earths in Soils

Cited by 5 publications

References 43 publications

Recovery of Rare Earth Elements from Ion-Adsorption Deposits Using Electrokinetic Technology: The Soil Conductivity Mechanism Study

Recovery of Rare Earth Elements from Ion-Adsorption Deposits Using Electrokinetic Technology: The Soil Conductivity Mechanism Study

Transport Model of Rare Earth Elements in Weathering Crusts during Electrokinetic Mining

Extracting light rare earth elements by applying electric field assisted mining technique

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