Publications
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Abstract
As global demand for petrochemical products increases and competes for finite oil resources currently exploited as an energy source, the need for the energy mix to include renewable generation is ever more acute. Naturally abundant solar, wind, geothermal and tidal energy can be used to generate electricity using renewable technologies; however, a major barrier to this is the availability of materials required to manufacture. One group of metals, commonly known as Rare Earth Elements (REE) are frequently contained as functional materials in renewable technologies including solar cells. A reliable and sustainable supply of REE is therefore critical for renewable energy generation.
REE comprise seventeen chemical elements, the fifteen lanthanides plus scandium and yttrium. Despite their name, rare earth elements are abundant in the Earth's crust; however, REE are typically widely dispersed and found in low concentrations that are not economically exploitable. Global demand for REE is increasing exponentially due to their use in a plethora of consumables and industrial applications together with increasing demand from rapidly industrialising countries. Current uses for REE include: permanent magnets, batteries, catalysts, computer memory and lighting to name but a fraction. Global supply of REE originates from very few countries, mainly China, who provide over 90% of the global supply and have recently implemented export restrictions including quotas and taxes. Many factors currently limit the supply of REE. Environmentally damaging extraction processes combined with competition for land-use mean that there are many restrictions on mining operations around the world. As relatively high-grade deposits become exhausted and lower-grade deposits are exploited, the energy demand for extraction increases. Sometimes REE are deposited as trace elements within other commercially extracted minerals; here the REE are a commercial by-product of the primary ore extraction. Therefore, the supply of REE extracted in this manner fluctuates depending upon extraction of the primary ore. Long lead-times to set up new mining operations mean that increased REE demand cannot be quickly met, leading to a significant time-lag between variation in demand and the reaction of supply. Global demand is growing but supplies are not guaranteed therefore prices are rising sharply and will continue do so. There is rarely a simple substitution of REE for another material. Less than 1% of REE are currently recycled. Recycling REE reduces consumption of energy, chemicals and reduces emissions in the primary processing chain. Most recycling processes have a high net-benefit concerning air emissions, groundwater protection, acidification, eutrophication and climate protection. A more efficient option than recycling is the remanufacture of components and products that contain REE. This research investigates the current and future use of REE and their application in technologies such as renewable energies. The aim is to facilitate a sustainable supply of REE for manufacturers through the use of strategies such as the reuse, refurbishment, remanufacture and recycling of components and materials.
SMART authors: James Colwill , Liam Gardner