Rare earth elements (REE) include the lanthanide series elements (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) plus Sc and Y. Currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to LED light bulbs and wind turbines. This article summarizes the occurrence of these metals in the Earth's crust, their mineralogy, different types of deposits both on land and oceans from the standpoint of the new data with more examples from the Indian subcontinent. In addition to their utility to understand the formation of the major Earth reservoirs, multi-faceted updates on the applications of REE in agriculture and medicine including new emerging ones are presented. Environmental hazards including human health issues due to REE mining and large-scale dumping of e-waste containing significant concentrations of REE are summarized. New strategies for the future supply of REE including recent developments in the extraction of REE from coal fired ash and recycling from e-waste are presented. Recent developments in individual REE separation technologies in both metallurgical and recycling operations have been highlighted. An outline of the analytical methods for their precise and accurate determinations required in all these studies, such as, X-ray fluorescence spectrometry (XRF), laser induced breakdown spectroscopy (LIBS), instrumental neutron activation analysis (INAA), inductively coupled plasma optical emission spectrometry (ICP-OES), glow discharge mass spectrometry (GD-MS), inductively coupled plasma mass spectrometry (including ICP-MS, ICP-TOF-MS, HR-ICP-MS with laser ablation as well as solution nebulization) and other instrumental techniques, in different types of materials are presented.

Rare earth elements:A review of applications, occurrence, exploration, analysis, recycling, and environmental impact

A review on Life Cycle Assessment, Life Cycle Energy Assessment and Life Cycle Carbon Emissions Assessment on buildings

Decarbonization of electricity generation can support climate-change mitigation and presents an opportunity to address pollution resulting from fossil-fuel combustion. Generally, renewable technologies require higher initial investments in infrastructure than fossil-based power systems. To assess the tradeoffs of increased up-front emissions and reduced operational emissions, we present, to our knowledge, the first global, integrated life-cycle assessment (LCA) of long-term, wide-scale implementation of electricity generation from renewable sources (i.e., photovoltaic and solar thermal, wind, and hydropower) and of carbon dioxide capture and storage for fossil power generation. We compare emissions causing particulate matter exposure, freshwater ecotoxicity, freshwater eutrophication, and climate change for the climate-change-mitigation (BLUE Map) and business-as-usual (Baseline) scenarios of the International Energy Agency up to 2050. We use a vintage stock model to conduct an LCA of newly installed capacity year-by-year for each region, thus accounting for changes in the energy mix used to manufacture future power plants. Under the Baseline scenario, emissions of air and water pollutants more than double whereas the low-carbon technologies introduced in the BLUE Map scenario allow a doubling of electricity supply while stabilizing or even reducing pollution. Material requirements per unit generation for low-carbon technologies can be higher than for conventional fossil generation: 11-40 times more copper for photovoltaic systems and 6-14 times more iron for wind power plants. However, only two years of current global copper and one year of iron production will suffice to build a low-carbon energy system capable of supplying the world's electricity needs in 2050.

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Integrated life-cycle assessment of electricity-supply scenarios confirms global environmental benefit of low-carbon technologies.

Principles of Corporate Finance - 4/E

We have assembled extensive information on the cradle-to-gate environmental burdens of 63 metals in their major use forms, and illustrated the interconnectedness of metal production systems. Related cumulative energy use, global warming potential, human health implications and ecosystem damage are estimated by metal life cycle stage (i.e., mining, purification, and refining). For some elements, these are the first life cycle estimates of environmental impacts reported in the literature. We show that, if compared on a per kilogram basis, the platinum group metals and gold display the highest environmental burdens, while many of the major industrial metals (e.g., iron, manganese, titanium) are found at the lower end of the environmental impacts scale. If compared on the basis of their global annual production in 2008, iron and aluminum display the largest impacts, and thallium and tellurium the lowest. With the exception of a few metals, environmental impacts of the majority of elements are dominated by the purification and refining stages in which metals are transformed from a concentrate into their metallic form. Out of the 63 metals investigated, 42 metals are obtained as co-products in multi output processes. We test the sensitivity of varying allocation rationales, in which the environmental burden are allocated to the various metal and mineral products, on the overall results. Monte-Carlo simulation is applied to further investigate the stability of our results. This analysis is the most comprehensive life cycle comparison of metals to date and allows for the first time a complete bottom-up estimate of life cycle impacts of the metals and mining sector globally. We estimate global direct and indirect greenhouse gas emissions in 2008 at 3.4 Gt CO2-eq per year and primary energy use at 49 EJ per year (9.5% of global use), and report the shares for all metals to both impact categories.

http://philip.nuss.me/wp-content/uploads/2014_SA_LCA-of-Metals_PLoSOne.pdf

Life Cycle Assessment of Metals: A Scientific Synthesis

Energy and greenhouse gas impacts of mining and mineral processing operations

Rare earths are used in the renewable energy technologies such as wind turbines, batteries, catalysts and electric cars. Current mining, processing and sustainability aspects have been described in this paper. Rare earth availability is undergoing a temporary decline due mainly to quotas being imposed by the Chinese government on export and action taken against illegal mining operations. The reduction in availability coupled with increasing demand has led to increased prices for rare earths. Although the prices have come down recently, this situation is likely to be volatile until material becomes available from new sources or formerly closed mines are reopened. Although the number of identified deposits in the world is close to a thousand, there are only a handful of actual operating mines. Prominent currently operating mines are Bayan Obo in China, Mountain Pass in the US and recently opened Mount Weld in Australia. The major contributor to the total greenhouse gas (GHG) footprint of rare earth processing is hydrochloric acid (ca. 38%), followed by steam use (32%) and electricity (12%). Life cycle based water and energy consumption is significantly higher compared with other metals.

Rare Earth Elements: Overview of Mining, Mineralogy, Uses, Sustainability and Environmental Impact

Rare earth elements (REE) are indispensable to infrastructure, technology, and modern lifestyles, which has led to an increasing demand for these elements. The current global rare earth oxides (REO) market is dominated by Chinese production, which peaked in 2006 at 133,000 tonnes REO per year, accounting for some 97.1% of global production, causing concern about the long-term supply of REE resources. Although the REE consist of 17 individual elements (15 lanthanides plus scandium and yttrium) that are hosted by numerous types of mineralization, the relatively modest scale of the global REE mining sector has limited our knowledge of REE mineral resources and mineralizing systems compared to metals such as copper and iron, which are produced in much larger quantities.

In order to quantitatively analyze the mineralogy, concentrations, and geologic types of REE deposits, we compiled a global dataset of REE mineral resources based on the most recently available data (2013–2014). This compilation yields minimum global contained total rare earth oxides plus yttrium oxide (TREO + Y) resources of 619.5 Mt split between 267 deposits. Deposits with available grade and tonnage data (260 of the 267 deposits in our database) contain some 88,483 Mt of mineral resources at an average concentration of 0.63% TREO + Y, hosting 553.7 Mt TREO + Y. Of the 267 total deposits in our database, some 160 have mineral resources reported using statutory mining codes (e.g., JORC, NI43-101, SAMREC), with the remaining 107 projects having CRIRSCO-noncompliant mineral resources that are based on information available in the industry literature and peer-reviewed scientific articles.

Approximately 51.4% of global REO resources are hosted by carbonatite deposits, and bastnasite, monazite, and xenotime are the three most significant REE minerals, accounting for >90% of the total resources within our database. In terms of REE resources by individual country, China dominates currently known TREO + Y resources (268.1 Mt), accounting for 43% of the global REO resources within our database, with Australia, Russia, Canada, and Brazil having 64.5, 62.3, 48.3, and 47.1 Mt of contained TREO + Y resources, respectively. Some 84.3 Mt TREO + Y is hosted within tailings (dominated by tailings from Bayan Obo but with smaller resources at Palabora, Steenkampskraal, and Mary Kathleen) and 12.4 Mt TREO + Y is hosted by monazite within heavy mineral sands projects, illustrating the potential for REO production from resources other than traditional hard-rock mining.

Global REE resources are dominated by the light REE, having an average light REO (LREO; La-Gd) to heavy REO (Tb-Lu and Y) ratio of 13:1. These REE deposits contain an average of 81 ppm Th and 127 ppm U, indicating that radioactive waste associated with REE extraction and refining could be a concern. Modeling the 2012 global production figures of 110 kt TREO + Y combined with an assumed 5% annual growth in REE demand indicates that known REE resources could sustain production until 2100 and that geologic scarcity is not an immediate problem. This suggests that other issues such as environmental, economic, and social factors will strongly influence the development of REE resources.

Nawshad Haque

Papers

Energy and greenhouse gas impacts of mining and mineral processing operations

Rare Earth Elements: Overview of Mining, Mineralogy, Uses, Sustainability and Environmental Impact

A Detailed Assessment of Global Rare Earth Element Resources: Opportunities and Challenges

Using sustainability reporting to assess the environmental footprint of copper mining

Using life cycle assessment to evaluate some environmental impacts of gold production