To meet the growing global demand for metals – while also meeting sustainability goals and reducing the environmental impacts associated with use and production of metals – requires a rethink of product design and metal recycling practices.
Theoretically, metals can be recycled almost indefinitely, thus presenting a valuable opportunity to reduce environmental degradation, energy and water use and contribute to the transition to a low-carbon, resource-efficient Green Economy.
According to UNEP, recycling requires significantly less energy per kilogramme of metal produced than primary production, and also decreases the overall local impact of mining. Recycling also slows down the need for exploiting low-grade ores – a more energy-intensive process that is likely to become more common as demand grows – and can help ward off future scarcity of certain commonly used precious metals.
The potential for recycling is enormous when the amount of electrical and electronic equipment waste being generated is considered. According to UNEP, such waste is estimated at 20 to 50 million tonnes, or three to seven kilogrammes per person, each year – and in Europe alone, the amount of such waste generated is about 12 million tonnes per year.
However, the growing complexity of products makes it difficult to extract all and reuse valuable metals due to the laws of physics and related economics. For example, a mobile phone can contain more than 40 elements, including base metals such as copper and tin and precious and platinum-group metals such as silver, gold and palladium.
“A far more sophisticated approach is urgently needed to address the challenges of recycling complex products, which contain a broad variety of interlinked metals and materials,” said UN Under-Secretary-General and UNEP Executive Director Achim Steiner. “Product designers need to ensure that materials such as rare earth metals in products ranging from solar panels and wind turbine magnets to mobile phones can still be recovered easily when they reach the end of their life.”
To boost historically low recycling rates, a global move from a Material-Centric to a Product-Centric approach, in which recycling targets specific components of a product and their complexity at its End of Life (EoL) and devises ways to separate and recover them, is essential.
Optimizing the recycling of EoL products can avoid losses in efficiency throughout the chain of recycling. The global mainstreaming of such a Product-Centric view would be a remarkable step towards efficient recycling systems, resource efficiency and a Green Economy.
Two reports were recently released the UNEP-hosted International Resource Panel: Environmental Risks and Challenges of Anthropogenic Metals Flows and Cycles provides an overview of the environmental challenges of metals and the potential contribution of recycling to mitigate them; Metal Recycling – Opportunities, Limits, Infrastructure outlines improvements required to metal recycling systems in the 21st century.
The reports issued a series of recommendations to attain a workable sustainable metals management system, including:
- Certified systems based on Best Available Technologies (BATs) and other measures increasing energy and entropy efficiency for mining as well as recycling industries have been developed and need to be applied on a global level. These techniques differ between regions, and do not necessarily need to be high technology.
- Weight-based targets hinder rather than promote recycling of the many critical elements in complex products, usually present in very low concentrations. Priorities have to be set for different metals, such as base metals, special metals, critical-technology metals, etc.
- Policy targets for recycling must account for the loss of metals due to mixing, must not exceed physical, technological and thermodynamic limits, and should not prioritize one or two metals at the inadvertent expense of others. Targets that go beyond what is thermodynamically possible are likely to fail. Policy makers can set appropriate targets from a life-cycle perspective by drawing on the expertise and tools available within the recycling industry.
- System optimization and design can further increase recycling rates and decrease environmental impacts. Product designers should take life-cycle approaches as well as metallurgical knowledge and rigorous process recycling system simulation into account when designing new products. Research and education is critically important for preserving this knowledge and for driving innovation that maximizes resource efficiency
- Policy goals for the recycling system must dovetail with economic drivers. With so many operators in the collection and recycling industry, regulation enforcement is unlikely to be sufficient by itself for determining the destination of metal-containing waste-streams.
- Primary production energy-efficiency increases can be achieved by improved process efficiency and use of waste streams (fly ash, sludge, slags, precipitates and suchlike) as sources of metals.