Rare Earth Elements: A Review of Production, Processing ...

Rare Earth Elements Review Section 7 – Summary, Key Findings, and Next Steps
� While environmental impacts can occur, when compared with primary processing of metals, it is
reported that controlled recycling of REEs will provide significant benefits with respect to air
emissions, groundwater protection, acidification, eutrophication, and climate protection.
� Frequently, recycling of electronics is taking place outside of the United States in developing
countries using informal processes. These informal operations can include manual dismantling,
open burning to recover metals, de-soldering of printed wiring boards over coal fires, and acid
leaching in open vessels—all with the potential for significant, adverse environmental and human
health impacts.
� The specific health effects of elevated concentrations of REEs in the environment from mining
and processing REE-containing ores are not well understood. From the limited literature review,
it appears that most available epidemiological data are for mixtures of REEs rather than
individual elements. These data indicate that pulmonary toxicity of REEs in humans may be a
concern. Additionally, as referenced in Section 6, the larger, lighter (i.e., smaller atomic number),
and less soluble ions have been observed to deposit primarily in the liver, while the smaller,
heavier (i.e., larger atomic number), and more soluble ions are similar in ionic radius to divalent
calcium and distribute primarily to bone.
7.3 Suggested Next Steps
Suggested next steps that could provide the additional information necessary to fill current knowledge
gaps and support future decision-making efforts include the following:
1. Conduct technology review(s) of wastewater treatment (including an evaluation of the
environmental impacts) for REE mining and processing operations. Following the technology
review, efforts could focus on technology development to address gaps identified in the review.
2. Conduct sustainability studies focused on urban mining in the United States to include
information on REEs (and other high-value materials) contained in products, the value of those
materials, methods for reclaiming or recycling the materials, and the environmental impacts from
all steps. Such studies could take a life-cycle approach and include topics such as design of
products to make recycling easier.
3. Support research focused on determining the technical and economic barriers to recycling of
certain rare earths. Following determination of the barriers, explore options for
reducing/eliminating the barriers, including technology research, development, and
environmental impact studies.
4. Expand upon the information provided in this report and develop a system understanding for all
elements associated with REE mining, processing, and recycling that have the potential for
environmental or health impacts. Use this information to perform regional environmental
evaluations of locations where REE mines, processing facilities, and recyclers are likely to be
developed to determine the potential for environmental and health impacts that could occur. Use
the results to plan and prioritize research, regional technical support, and regulatory efforts.
5. Conduct a more complete review of the health, biomonitoring, and ecological impacts literature—
to include a comparison of the references cited in health background documents to the
preliminary literature search results presented in this document—to ensure all available studies
are included.
6. Support additional human health toxicity and ecological impact studies on specific REEs and then
use this information to conduct risk assessments related to REE mining, processing, and
recycling.
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