This blog article is fully based on the study by Poncelet et al. titled “Losses and lifetimes of metals in the economy,” ¹which helps us learn more about:

Metal Loss Distribution: Understanding how losses are distributed across production, fabrication, use, waste management, and recycling phases.
Production and Fabrication: Exploring substantial losses faced during production and fabrication, especially for specialty and certain ferrous and non-ferrous metals.
Use Phase Impact: Examining the minimal losses during usage, with exceptions in dissipative applications, particularly affecting specialty metals.
Waste Management and Recycling: Unveiling how waste management and recycling contribute to the largest share of cumulative losses, emphasizing the need for enhanced recycling practices.

Metals are essential for economic growth, but their increasing consumption is raising sustainability concerns.

As technological advancements continue, the demand for metals intensify as well, pressuring metal stocks and prompting western nations to identify certain commodities with supply risks that threaten their economies.

For example, more than 30 metals and minerals are considered critical raw materials by the European Union²and the United States³as part of an integral prioritization approach to secure regional supply strategies.

Given the critical importance of these metals, how effectively are they being managed over their lifecycles? → Insights from a Nature Sustainability study offer valuable perspectives.

In a recent article, researchers modeled the fate of 61 extracted metals through a life-cycle lens to identify areas where losses are likely to occur. The results showed that ferrous metals have the longest lifetimes, averaging 150 years, followed by precious, non-ferrous, and specialty metals.

Loss per Life-cycle Phase

The distribution of losses among different life-cycle phases includes production, fabrication and manufacturing, use, waste management, and recycling.

Production

Only a few metals are targeted for extraction during metal production because they are economically valuable. In contrast, others are ignored, leading to non-targeted metals being thrown away or used in low-value materials. This happens less often with widely-used metals like ferrous and non-ferrous metals, but it is a big problem for specialty metals like vanadium and osmium.

Precious metals and rare earth elements also experience significant losses during production. Over 95% of the extracted amount is lost during production for some metals, like arsenic and tellurium. Additionally, from 2015 to 2019, around 25% of extracted specialty metals were lost during production, compared to 17% for precious metals, 15% for non-ferrous metals, and 13% for ferrous metals. For example, 0.22 billion tons of iron is lost during production out of the 1.7 billion tons that are extracted.

Fabrication and Manufacturing

Regarding fabrication and manufacturing, it is observed that for 34 out of 61 metals, the cumulative losses are the lowest.

For iron, the losses are negligible, and for precious metals, they account for less than 1% of the cumulative losses (0.35 kt). However, the losses become comparatively more significant for specialty metals and ferrous metals other than iron, with cumulative losses of 4% (0.6Mt and 3Mt, respectively), and non-ferrous metals, with cumulative losses of 6% (9Mt).

Since most specialty metals go through a single life cycle, their cumulative losses during fabrication and manufacturing are lower than those of other metals.

Use Phase

Most metals have negligible losses during the use phase. For ferrous metals, use phase losses account for around 2% of total losses by weight, with 30Mt (10% when excluding iron) being lost.

Precious metals also have minimal losses during use, with only approximately 2% (700 tons) lost. However, non-ferrous metals have higher losses during the use phase, with 7% (10Mt) of total losses being lost. The use phase contributes significantly to losses for specialty metals, with 31% (5Mt, mostly barium) being lost.

Dissipative applications, such as oil and gas well-drilling muds and artisanal gold mining, are major contributors to use phase losses for some metals. For instance, oil and gas well-drilling muds account for around 80% of the demand for barium and 30% of the demand for strontium.

Other dissipative applications include:

Agricultural products
Fluid cracking catalysts that are used in the petroleum industry
Deoxidization and desulfurization agents for steel production

Nevertheless, involuntary losses may also occur during the use phase, such as zinc-containing car tires, tungsten carbides used in cutting tools wearing off, and metals exposed to the outdoor environment corroding.

These losses are expected to remain mostly in the environment, unlike landfilled materials that are under human supervision to some extent.

Waste Management and Recycling

Waste management and recycling account for the largest share of cumulative losses over time for 43 metals, representing approximately 85% of losses for ferrous metals (1.5Gt, including 1.47Gt of iron), 80% for precious metals (30kt), 71% for non-ferrous metals (98Mt), and 40% for specialty metals (6Mt).

Although metals that undergo multiple life cycles due to efficient collection and recycling channels are lost over longer periods, waste management remains the primary cause of their losses over time, including metals like aluminum, copper, gold, iron, and platinum.

Despite closed-loop recycling for some valuable metals used in industrial and jewelry applications, the recovery of metals from the collection and sorting seldom exceeds 90%, which is less favorable compared to the yields of fabrication and manufacturing.

Furthermore, recycling losses may occur during the remelting of alloys as different metals accumulate in dusts (e.g., zinc) and slags (e.g., chromium and vanadium) or end up as contaminants in large-magnitude streams (e.g., copper in steel flows).

The metals that suffer the most significant losses during recycling processes are those widely used in ferrous alloys (e.g., chromium, iron, manganese, molybdenum, and niobium), aluminum, and zinc, with the latter being used to protect steel from corrosion, representing half of its use. These losses are greatest for ferrous metals (26% of their cumulative losses) and lower for non-ferrous (8%), precious (2%), and specialty metals (0.4%).

Closing the Loop

Waste management and recycling are crucial in reducing the cumulative losses of metals over time. Despite the efficient collection and recycling channels for some metals, recycling losses still occur and may lead to contamination or lower yields during remelting.

The metals that undergo multiple life cycles are still lost over longer periods due to waste management, with aluminum, copper, gold, iron, and platinum being the primary metals affected. Ferrous alloys, aluminum, and zinc experience the most significant losses during recycling processes, with ferrous metals being the most affected.

To reduce these losses, there is a need to improve sorting and recycling practices, design longer-lasting products, and enhance waste management practices. These actions will promote a circular economy strategy that can help prolong the lifetimes of metals in the economy, increase their value for humans, reduce possible environmental impacts, and mitigate potential supply risks for future generations.

Works Cited

¹ Poncelet, et al. “Losses and lifetimes of metals in the economy.” Nature Sustainability, vol. 5, no. August 2022, 2022, pp. 717–726. nature.com, https://doi.org/10.1038/s41893-022-00895-8.

² European Council. “Critical raw materials act - Consilium.” Consilium.europa.eu, https://www.consilium.europa.eu/en/infographics/critical-raw-materials/. Accessed 23 April 2024.

³ Dombrovskis, Valdis. “EU-US Critical Minerals Agreement.” European Commission, 14 June 2023, https://ec.europa.eu/commission/presscorner/detail/en/IP_23_3214. Accessed 23 April 2024.