Sustainability assessment of rare earth elements (REEs) beneficiation in the
mining industry and use in materials development
Linda Omodara,1 Satu Pitkäaho1, Kati Oravisjärvi,2 and Riitta L. Keiski1
1- Environmental and Chemical Engineering Research Group (ECE), Faculty of Technology, P.O. Box 4300, FI-90014 University of Oulu, Finland.
2-. Pyhäsalmi Mine Oy, P.O.Box 51 FI-86801 Pyhäsalmi FINLAND
[email protected]
Background
Sustainability Assessment
REEs belong to a class of metals known as critical metals. Critical metals have their title
because of their huge importance globally making the demand for them high. Typically
REE substitutes are not readily available, they have a low recycling rate and they are at
risk of low supply.
Recovery of REEs are of two forms e.g. recycling of REEs from end-of-life consumer
goods containing REEs (primary focus of most researches) and flows from industrial
process residues containing REEs, (lesser focus).
The aim of sustainability assessment is to guide decision makers in determining what
actions to take and what actions to forego in order to attain a sustainable society.
The goal of this research is to demonstrate that sustainability assessment of the
potential recovery routes of REE can lead to a sustainable beneficiation process of REEs.
Sustainability assessment is needed in all stages of REEs’ life cycle.
Sustainability assessment was done using a questionnaire based on SAT. Scores of -1, 0, 1
were allocated to each question based on the assumption that a process can have a
positive, negative or no impact. The environmental, economic and social aspects of each
principle were evaluated in parallel. Spider charts were plotted using the results derived
from the sustainability assessment questionnaire, in this case three routes were
compared and the resulting charts are illustrated in Figure 3. Figure 4 illustrates the
sustainability assessment flow sequence.
Figure 1.Three Pillars of Sustainability
Objectives
The objectives of this research is to demonstrate that sustainability assessment of the
potential recovery routes of REE and critical metals can lead to a sustainable beneficiation
process of these metals and that sustainability assessment is needed in any industry
responsible for the production and processing of materials.
Figure 3 Spider charts illustrating
assessment
environmental, social and economic sustainability
Methods
The sustainability assessment tool (SAT) (Figure 2) utilized in this research has been
derived from a combination of indicators obtained from Green Chemistry (GC), Global
Reporting Initiatives-Mining and Metal Sector supplement (GRI-MMS), Life Cycle
Assessment (LCA), Towards Sustainable Mining (TSM) and Seven Questions to
Sustainability (7QS). The result obtained from the SAT tool will be used as a guide to
provide substitutes to critical metals currently being exploited for the production
purposes and also to substitute primary materials with secondary materials.
7QS
Figure 2. Sustainability Assessment Tool (SAT)
Spider Chart
Conclusion
GRIMMS
SAT
Result
Figure 4 Sustainability Assessment Flow Sequence
GC
TSM
Questionnaire
LCA
Recycling, reuse, recovery and substitution of REEs offer interesting possibilities for
industry from economic, environmental and social points of view. Sustainability
assessment is needed in all stages of REEs life cycle from its extraction, beneficiation,
usage, end-of-life and disposal phase. However, there are no tools in existence that
completely and satisfactorily addresses this stages. Such a tool would be useful also for
researchers studying and developing new production processes. In our current societal
interest on critical metals, such a tool would be needed, to assess social, environmental
and economic sustainability of products and processes.
Acknowledgement
The work was carried out with the financial support of Renlund Foundation, and
Advanced Materials Doctoral Programme at the University of Oulu Graduate
School (ADMA-DP/UniOGS).