Lepidolite Extraction Solid By-product: Mitigation of Thallium Leaching and Utilization of Radiogenic Strontium Isotopes as a Tracer

Lepidolite Extraction Solid By-product: Mitigation of Thallium Leaching and Utilization of Radiogenic Strontium Isotopes as a Tracer

Journal: Environmental Advances
Issue: Volume 3, April 2021
Authors: Thai T. Phan a, Leah Fulton a, John Ulkem a, Steve Aiken b, Amber Blackwell b, Joe Walsh c, Peter Walker c, Fereidoun Rezanezhad d

a
Department of Earth and Environmental Sciences, University of Waterloo
b Knight Piésold Ltd.
c Lepidico Ltd.
d Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo

Abstract
The emerging growth of lithium-ion battery usage necessitates the development of unconventional resources for battery grade lithium carbonate. Extraction of lithium from micas such as lepidolite produces several marketable by-products as well as a silt-sized gypsum rich blended residue containing elevated level of thallium (Tl). The goal of this study was to assess the alternative use of the blended residue as fill material for mine reclamation.

Bulk elemental analysis and shake flask extraction of the blended residue showed that radionuclide and heavy metal levels of the solid blended residue and its leachate were within the guidelines for soil and its leachates. However, Tl concentration (24.7 ± 0.9 mg/kg), possibly in the forms of water-soluble salts in the blended residue, was much higher than the general level of Tl in naturally uncontaminated soil ( < 1 mg/kg). Thus, the efficiency of four easily accessible amendments (peat, clay, biochar, and topsoil) in mitigating the release of Tl was evaluated using a modified SPLP procedure. In addition, the usefulness of radiogenic Sr isotopes ( 87 Sr/ 86 Sr) as a tracer of the leachate plumes derived from the blended residue was assessed. Results from SPLP experiments showed that Tl was released from the blended residue under a wide range of pH values, especially under acidic conditions.

Mixing proportions of the blended residue and amendment (1:9 or 1:1) did not appreciably affect the high Tl removal efficiencies (68 – 89%) of clay, biochar, and topsoil. While mixing time did not affect the Tl removal efficiencies of clay and topsoil, Tl removal efficiency of biochar proportionally increased with mixing time and was at the highest value (~95%) among four amendments, if the mixing time was at least 7 days. Peat was not an effective amendment because its acidity possibly enhanced the release of Tl. The 87 Sr/ 86 Sr ratios in leachates of the blended residue (0.792 – 0.810) and its amendment mixtures were significantly higher than those in surface and groundwaters, soil leachates, and coal mine drainage. Thus, when the blended residue is used as fill material for mine reclamation, 87 Sr/ 86 Sr can be a powerful naturally occurring tracer in distinguishing Tl from the blended residue from other major sources of Tl in the environment. Overall, this study recommends clay and soils as the most promising amendments in mitigating the release of Tl in well-drained systems, and biochar for poor drainage conditions.

 

Download the full paper.

Download

Recent Insights

November 2024
Design of a Co-disposal Facility for Thickened Tailings and Potentially Acid-generating Waste Rock
November 2024
Compaction Sensitivity in Tailings Stack Infiltration Modeling: Unsaturated Properties Uncertainty Analysis
November 2024
Volumes of Dam Material Mobilized by Erosion During Tailings Dam Failure Events
October 2024
Estudio de rotura de una presa de jales en la zona centro-norte de México
September 2024
Influence of Pre-Existing Mobilized Zones on B3 Cave Propagation and Initial Subsidence at the New Afton Mine
September 2024
Importance of Indigenous Community Engagement related to ARD/ML and Long-Term Water Quality
September 2024
Effective Assessment of ARD/ML Potential for Non-Mining Infrastructure Projects
August 2024
CESA Aon Engineering Excellence Awards 2024: Kikagati Hydropower Plant
July 2024
Interview: Mario Lazo Emparanza, Regional Manager, Knight Piésold Chile
July 2024
Visionary Leadership: Driving Engineering Excellence in Africa with Vishal Haripersad
June 2024
Concept Feasibility and Predicted Behavior of Mining a Rock Tower with Drill-and-Blast Undermining Using Dynamic Three-Dimensional Discontinuum Numerical Models
June 2024
Estimating Shear Stress within a Clay Foundation Using the Burgers-Creep Model
June 2024
Laboratory Study of Manganese Mining Overburden Mixed with Lime as a Paving Subbase Layer
May 2024
Knight Piésold: Ensuring African Excellence in the DRC
May 2024
Wild Coast N2 Highway Project Taking Shape
May 2024
Interview: Guillermo Barreda, Gerente General, Knight Piésold Perú
April 2024
Risk Mitigation through Design Optimization Utilizing Seasonal Effects under Arctic Conditions at the Amaruq Mine
April 2024
Synthetic Rock Mass Modeling of Progressive Unravelling and Overall Slope Stability Using the Discrete Element Method
April 2024
Operational Slope Stability Risk Management for Large Open Pits at the Mount Milligan Mine – A Case Study
April 2024
Risk and Informed Approach to TSF Design and Operation