Metal Recycling: Opportunities, Limits, Infrastructure

Last month the UN Environment Program published a report entitled Metal Recycling: Opportunities, Limits, Infrastructure. The report provides a valuable update on what has been done and what needs to be done to increase recycling of metals and metal-containing products around the world:

  • A wider, systemic, view of recycling must look at the environmental, industrial and economic factors driving recycling. Simplified approaches to recycling – specifying desired recycling outputs – will not adequately support a drive for resource efficiency.
  • For maximizing resource efficiency, a Product-Centric approach to recycling must be based on a good understanding of the physics of materials in products. This allows simultaneous consideration of the interactions, why and when they dynamically vary, and the economic value of the resulting recyclates, as well as the impact on resource conservation and environmental sustainability.
  • Stimulating the use of BAT (Best Available Technique) by certified operators raises the overall level of recycling.
  • As dictated by the Second Law of Thermodynamics, there will always be losses from a recycling system. Concepts such as ‘Closing the loop’, ‘Circular Economy’ and ‘Cradle-to-Cradle’ represent unattainable ideal conditions, but they bring systemic thinking into material-efficiency discussions, and provide an upper limit to the potential economic benefits.
  • Policy and legislation play a key role in shaping the economic incentives and guiding conditions for overall system performance. Where the economic incentives for collection of waste by private or public operators are not aligned with policy goals, significant resource volumes can be lost to illegal or informal recycling, or are simply unaccounted for, sometimes through ‘cherry picking’. This often leads to environmental problems, damaging health impacts and impacts on water or climate, as regulatory standards are ignored.
  • The best policy and legislative results are achieved by creating a level playing field that internalizes external costs.
  • Policy and legislation can improve results if it focuses on promoting BAT in recycling systems, setting up the framework for innovative business models. In some cases, this will mean providing incentives for coping with negative revenues from parts of the treatment process for end of life products. Actions increasing the willingness of product manufacturers and their customers to recycle end of life products and use recycled materials produced with BAT, can also drive the recycling market.
  • For some minor elements, the required economies of scale will only be reached through processing at a sufficiently large “central” facility. However, in order to achieve this, effective international arrangements would be required to facilitate cross-border transportation in a transparent and sustainable manner.
  • The infrastructure and knowledge for the processing of waste into recycled metal is often the same as that used for primary metal production. Therefore, the health of such production is vitally important for recycling, as a healthy balance between primary and recycled metal production fosters metallurgical systems knowledge. This balance also mitigates the cyclical nature of the primary metals industry.
  • Optimized recycling requires secure and large volumes of waste, collected (or sorted) in ways that assist its metallurgical processing. Two essential factors for successful waste collection are:
    • (i) a suitable infrastructure for collection, and
    • (ii) economic incentives for the delivery of waste to BAT operators, rather than to informal or illegal operators.
  • Where economic incentives exist, private operators often set up collection infrastructures. In some cases, public-policy intervention must help the creation or capacity building of such infrastructure, for example when setting up recycling systems for mobile phones. Where waste ends up in areas with no or poor-quality recycling, the resources are often lost.
  • For optimal recycling, the industrial-waste and End-of-Life-product streams that enter processing should be economically and physically compatible with the metal production system. Both product design and collection methods strongly affect the physical properties of a waste stream. Optimal recycling can only succeed by better physics-based Design for Resource Efficiency (DfRE). Design can then try to avoid putting metals together in a stream that cannot be separated by the BAT. Nevertheless, material linkages can make any DfRE useless, as the consumer primarily purchases product functionality.
  • Legal recycling-rate targets have two implicit weaknesses:
    • They do not differ between individual substances, but are calculated solely by weight based on an entire fraction. Hence, to achieve the targets, recovery of mass substances such as plastics, glass or steel becomes much more important than recovery of precious and special metals, which are usually only present in small amounts.
    • As the targets do not consider metallurgical steps, the high legal recycling targets pretend a recycling quality that in reality is not obtained. For instance, the EU’s End of Life Vehicles directive requires a 85% recycling rate (material and energy recovery), to be increased to 95 % by 2015. If smelting and refining are included, real recycling rates will be much lower, especially for precious and special metals.
  • It may be counter-productive to use material-based recycling-performance output standards, such as mass or percentage of a single metal in a waste stream. They can ignore the complexity of recycling and its inherent trade-off between outputs of different recycled metals from mixed waste streams. This may lead to wasting of valuable metals. For example, a system focused on increasing recycled iron output may lose valuable metals with complex links to iron, such as vanadium.
  • Research and education is critically important for preserving expert knowledge, especially of the processing of key metals, and for driving innovation that maximizes resource efficiency. Moreover, much knowledge is tacit – held and transmitted by vitally important experts who cannot be traded like a commodity – and that is lost when industry sectors are too cyclical. There is a need for disseminating the physics-based systems approach to recycling, as described in this report.
  • Market operations are significantly helped when recycling operators can estimate future needs for recycling infrastructure by quantifying the “urban orebody”, its location and waste flows.

There is much more to be found in this excellent 320 page report and many of the findings have relevance not just to metal recycling but also to recycling of many other types of material.

The report is available at

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