Opening Remarks 

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1:05 - 1:25 p.m.

Critical Raw Materials; European Perspectives and Solutions Including Environmental Impact​

Stéphane Pepin, ENA

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In Europe since 2008 is an ever growing awareness on the dependency the EU has on all kind of materials necessary for a modern economy. In order to reduce this dependency, the EU set up a list of so-called critical materials mainly existing of Li and REE's. Furthermore, policies have been developed to decrease this dependence such as the recent European Critical Material Acts of March 2023. They promote new policies and developments such as recycling of these materials as well as the development of an EU based mining industry for these types of materials. One of the options is to look into current waste streams to assess whether they consist of relevant amounts of interesting materials. The Act requires Member States to step up efforts to recover critical raw materials from waste products and mining waste.  In our presentation we will go into a number of relevant waste streams as well as potential technologies by which the generally low concentrations of Li, REE's or other critical materials can be economically feasible retrieved. The potential and environmental constraints of landfill mining will also be discussed. Moreover, also the environmental impact will be discussed as well as management options for the remainder of the separation step.​

Coauthors: Rob Wiegers (IBR Consult/ENA​)
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1:25 - 1:45 p.m.

Unconventional Sources of Critical Minerals – Opportunities for Recovery from Mined Materials in the Copper and Gold Mining Environment

Jeff Gillow, Arcadis

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Climate safe energy technologies have increased demand for certain metals and rare earths. These include electric vehicles and wind turbines, photovoltaics, and advanced defense systems.  Conventional ore deposits for many of these elements are limited. The USGS has designated these elements as critical minerals, due to the supply chain risk.  
Unconventional sources of critical minerals include mined materials at operating and closed copper and gold mines. For example, rhenium, selenium, and tellurium are often concentrated in porphyry copper deposits, along with rare earth elements including neodymium and praseodymium. Energy-critical elements are associated with gold deposits in alkaline igneous rock, including tellurium and indium, element for PVs.  
The challenges for harnessing these unconventional sources include identifying their presence and form and developing processes for their recovery. Water treatment systems operate at many of these mines and include lime (high density sludge) and membrane (nanofiltration or reverse osmosis) plants. Opportunities for recovery of critical minerals begin with these systems, with the addition of processes that recover and concentrate select critical minerals. This may include selective pH adjustment to precipitate dissolved rare earth elements, along with separation of these from a complex mine water matrix. Other approaches include nanofiltration to reject multivalent cations into a brine stream for further processing.  
Benefits to current operations associated with critical mineral recovery include an additional revenue stream to help offset mine environmental management costs and waste minimization through selective recovery of elements that currently are managed as wastes within the operations. In this presentation we review the occurrence of critical minerals in mined materials and process engineering approaches to recovery in the context of operating mines, and mines undergoing reclamation. The promise of unconventional resources of critical minerals is being realized today and these resources have a significant role to play in meeting supply chain demand.​

Coauthors: Shannon Ulrich (Arcadis), Courtney Lenzo (Arcadis), Gabriella Rincon (Arcadis), Justin Provolt (Arcadis​)
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1:45 - 2:05 p.m.

Recovering Critical Minerals from the Phosphate Fertilizers Could Reduce their Accumulated Concentration Levels in the Agricultural Soils​

Chandra Tummala, Wayne State University

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Phosphate fertilizers are the main source for the accumulation and enrichment of many metals in agricultural soils, including rare-earth element (lanthanides plus yttrium and scandium) and radionuclides such as uranium and thorium. In the last two decades, REEs were added to the phosphate fertilizers in China as an additive to improve the crop productivity.  Although REEs may be somewhat beneficial, they can easily accumulate to levels that produce negative effects such as bioaccumulation in crops. Consumption of these REE accumulated plant products could result in the toxication of human health.  
Our research investigates the potential to recovery valuable metals from phosphate rock fertilizer before applying the phosphate to agricultural fields. This could result in lower metal accumulation in the soil while providing some additional supply of REEs and other elements.  
Little research has been conducted in evaluating and separating the REEs from commercially available phosphate fertilizers. In this study, we have evaluated the REE concentration levels in three phosphate fertilizers produced in the different locations across the United States. Laboratory scale experiments were conducted to determine the concentrations and metal extractability from the samples to help develop a method to effectively extract and separate the REEs from the phosphate fertilizers. Total digestion results show that total REE concentrations in the phosphate fertilizers varied from 300 to 1200 mg REE/kg fertilizer, which compares favorably to other unconventional REE feedstocks such as coal fly ash. Kinetics and leaching experiments showed extremely fast extraction kinetics, with most REEs being extracted within 10 minutes at HCl concentrations between 1.5 and 3M. XRD results showed that REEs were  separated from the leachate through co-precipitation with calcium chloride. 

Coauthors: Sai Praneeth (Wayne State University), Mohammed Dardona (Wayne State University), Sanjay Mohanty (University of California, Los Angeles), Timothy Dittrich (Wayne State University)
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2:05 - 2:25 p.m.

Selective Separation and Extraction of Rare Earth Elements (REEs) from Acidic Solutions by Using Novel N, N, N′, N′-tetraoctyl diglycolamide (TODGA) Grafted Organosilica Media

Venkata Sai Praneeth Doranadula, Department of Civil and Environmental Engineering, Wayne State University

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Rare earth elements (REEs), a group of lanthanides plus scandium and yttrium, are widely used in various applications ranging from magnets to satellites, and due to geopolitical situations, demand for REEs is rising ͂ 5% annually. Even though many REE extraction/separation techniques such as liquid-liquid, solid-liquid, and supported liquids have been reported, solid-liquid extraction has shown to have potential advantages due to its selectivity, ease of scalability, and reusability.  N, N, N′, N′- tetraoctyl diglycolamide (TODGA) is a tridentate ligand that has been used mostly in solvent extraction for the separation of actinides and lanthanides from high-level radioactive waste but has not been explored for the potential for attachment to a solid support to be used in separations of individual lanthanides from mixed acid solutions. In this study, an organosilica solid support was impregnated with TODGA to make a new sorbent media. The resultant media were used in absorption studies to see the selectivity and recovery of 17 elements (REE + Sc+ Y+ Th) under various conditions such as nitric acid molarity, dosage, kinetics, and isotherms. REE adsorption significantly increased from 1.26 mg/g to 10 mg/g in 0.01 M and 15.9 M nitric acid, respectively. The media also demonstrates high selectivity towards heavy REE (Dy to Lu) with little or no sorption of lighter REE (Ce to Gd). The media showed a similar selectivity toward heavy REE at all the dosages tested (1.5 g/L to 5 g/L). The media in packed-column studies also confirms the same selectivity towards REEs and potential separation. Pre- and post-sorption characterization were also studied on the media by using SEM-EDS, ATR, and XPS to explore the possible mechanisms. 

Coauthors: Ahmed K. Sakr (Department of Civil and Environmental Engineering, Wayne State University), Chandra Tummala (Department of Civil and Environmental Engineering, Wayne State University), Matthew J. Allen (Department of Chemistry, Wayne State University), Timothy M. Dittrich (Department of Civil and Environmental Engineering, Wayne State University)
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2:25 - 2:45 p.m.

Radio and Chemo Toxicity from Exposure to Uranium and Related metals: A Case Study of Mrima Hill​ 

Pamella Kageliza Kilavi, Technical University of Kenya/University of Nairobi

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Mrima Hill is a carbonatite-alkaline intrusion rich in Nb and REE, critical metals for industrialization. These metals coexist with U, Th, Pb, and Cd, among others. However, exposure to these metals is a global health concern. This study sought to evaluate the human health risk from exposure to U, Th, Cd, and As in topsoils sampled from the environs of Mrima Hill, a prospecting Nb and REE mine. ICP-MS was used to evaluate the samples' concentration of Nb, REE, U, Th, Cd, and As. The US EPA model embedded in the EnviroPRA Monte Carlo simulation package was used to assess the chemo toxicity from exposure to  U, Pb, Cd, and As via dermal and ingestion pathways, while  RESRAD OFFSITE code was used to model the dose and cancer risk from exposure to U, Th, and their progenies. The mean concentrations in mg/kg of Nb, Th, U, Pb, Cd, and As were 291 ± 20.3, 115 ± 2.32, 12.1 ± 0.25, 47.2 ±1.2, and 167 ± 4.12, respectively. The non-cancer risk from dermal exposure to the metals in the soil was below the threshold value of 1, while the non-cancer risk from the ingestion pathway was 1.67, with As contributing a value of 1.42 to the non-cancer risk value. The population was also more prone to cancer risk from exposure to As since its cancer risk value from soil ingestion was 1.99E-04, and the cancer risk from dermal exposure value was 2.87E-05. The RESRAD OFFSITE model showed that the external dose of gamma and beta radiation from 228Ra and 228Th was higher than the internal exposure from incidental ingestion of soil and inhalation of dust. The cancer risk value was slightly above the recommended regulatory limit of 10-4 due to external exposure, thus having a negligible effect on human health.

Coauthors: Ian Muchai Kaniu (University of Nairobi); Jayanti P Patel (Technical University of Kenya); Iyabo T Usman (University of Witwatersrand)
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Posters and Vendor Exhibit

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3:15 - 3:35 p.m. 

Challenges and Opportunities to Promote Circularity in Mining

Horst Monken-Fernandes, International Atomic Energy Agency

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Challenges and Opportunities to Promote Circularity in Mining

Many industrial operations use or process materials containing natural radionuclides, whose activity concentrations can be significantly modified (concentrated) in residues, waste and effluents generated by the particular process. A structured framework for the possible valorisation of these residues is needed so that valorisation can be done in a safe and cost-effective way while addressing concern on the part of different stakeholders due to the presence of natural radionuclides. A particular attribute of these residues is that the in some cases their quantities can be very large, measurable in hundreds of millions of tonnes produced per year. Over time this has led to legacy accumulations of billions of tonnes of residues disposed on land, the land itself being lost to productive use.

In the context of the linear economy the production logic is one-way: take – process – dispose, meaning that the end-of-life plan for all residues is disposal. By doing this, the advantage from processing and reuse of these residues with inherent economic value is lost. Likewise, high costs of disposal and ongoing monitoring of such residues, including loss of land to productive purposes are unnecessarily incurred and/or imposed on future generations to bear — so-called negative externalities. Disposal of potentially usable secondary resources adds to the already intense pressure put on primary natural resources, which at current rates of consumption are predicted to result in the exhaustion of many critical resources and raw materials, sometime in the near future.

The IAEA-led Conference NORM2020 heard that in recent years, the emphasis on creating sustainable economic growth has led a range of NORM (Naturally Occurring Radioactive Material) related industries to make substantial efforts to find residue/waste prevention and recycling solutions. Successful examples of NORM residues recycling can be found in agriculture, as soil amendment, in construction or in the metal processing industry. But disposal of high volumes of NORM residue as wastes remains the default in many countries, in part due to unacceptable concentration of radionuclides and other substances they contain, in part because technology is yet to be developed so as to economically reprocess such residues and put them to beneficial use, but also because of unduly restrictive regulations. In this context, the IAEA-NORM2020 Conference pointed out that the adoption of the concept of circular economy to the NORM related industries could represent a step forward in the sustainable management of NORM residues, in line with the UN SDGs, notably SDG12. Some MS have already revised their regulatory and policy approaches to NORM residues and use, recategorizing these materials as usable. Case studies documenting the success of such changes are multiplying, showing substantial combinations of social, economic, and environmental benefits.

The purpose of this presentation is to provide an overview of case studies, success stories and lessons learned concerning the international state-of-the-art residue and waste valorisation technologies relevant to NORM.
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3:35 - 3:55 p.m.

Critical Minerals and TENORM; How Do Permitting Reform and Executive Branch Actions Address Radioactivity?​ 

Philip Egidi, U.S. Environmental Protection Agency​ 

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After 40 years of globalization and just-in-time supply chain approaches to many aspects of U.S. manufacturing, it has now been recognized that free-market policies offshoring our talent, funding, and sources of some items, including critical minerals, may have created economic and security risks for the U.S. The ongoing and evolving policies of the U.S. with respect to climate change are causing major changes to the needs of certain critical minerals, particularly for electric car batteries and components of wind turbines. There are also numerous defense needs that can be impacted from a disruption in supplies. To counter these challenges there have been multiple Executive Orders, allocations of funding under the Defense Production Act, and movement in Congress on permitting reform. These actions are all subject to political interference and as such, things can change rapidly. One aspect of permitting reform that is not being highlighted is the reality that many critical minerals are associated with natural radioactivity. When the ores are harvested, the radioactivity in the U.S. is called technologically-enhanced naturally occurring radioactive material (TENORM). Since TENORM is largely regulated by the States with little federal guidance, licensing and permitting of these projects can be difficult to achieve, particularly if there is a lack of forethought in the environmental review process. This talk will review actions taken to date and their potential impact, if any, on licensing of radioactive materials and their residuals in the critical minerals space. After 40 years of globalization and just-in-time supply chain approaches to many aspects of U.S. manufacturing, it has now been recognized that free-market policies offshoring our talent, funding, and sources of some items, including critical minerals, may have created economic and security risks for the U.S. The ongoing and evolving policies of the U.S. with respect to climate change are causing major changes to the needs of certain critical minerals, particularly for electric car batteries and components of wind turbines. There are also numerous defense needs that can be impacted from a disruption in supplies. To counter these challenges there have been multiple Executive Orders, allocations of funding under the Defense Production Act, and movement in Congress on permitting reform. These actions are all subject to political interference and as such, things can change rapidly. One aspect of permitting reform that is not being highlighted is the reality that many critical minerals are associated with natural radioactivity. When the ores are harvested, the radioactivity in the U.S. is called technologically-enhanced naturally occurring radioactive material (TENORM). Since TENORM is largely regulated by the States with little federal guidance, licensing and permitting of these projects can be difficult to achieve, particularly if there is a lack of forethought in the environmental review process. This talk will review actions taken to date and their potential impact, if any, on licensing of radioactive materials and their residuals in the critical minerals space.
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3:55 - 5:00 p.m.

Panel Discussion: Promises, Challenges, and Risks in the Search for Critical Materials

Panelists and conference participants are invited to engage in discussion of key issues associated with critical minerals development. Topics include, but are not limited to, lessons-learned from past environmental legacies of mining; managing environmental effects of existing and new mining/extraction technologies; balancing economic drivers with environmental and social/ethical concerns; and policy and regulatory changes needed to support sustainable development. 

Panelists: Natalie Byrd (University of Manchester), Rob Wiegers (IBR Consult/ENA), Philip Egidi (U.S. Environmental Protection Agency)

Facilitators: Horst Monken Fernandes (International Atomic Energy Agency), Stéphane Pepin (ENA) 

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