Key smartphone ‘ingredients’ could soon run out

There is no adequate substitute for indium, which is used in computer and cell phone displays. Above, PET plastic coated with indium tin oxide. (Credit: Adafruit Industries/Flickr)

Some of the metals that are critical for making newer technologies—like smartphones, infrared optics, and medical imaging—may be extremely difficult to find in the coming decades, experts warn.

A new study that assesses the “criticality” of all 62 metals on the Periodic Table of Elements offers key insights into which metals will be scarce, which will exact the highest environmental costs, and which ones simply cannot be replaced as components of vital technologies.

Researchers were inspired to try to quantify the criticality of the materials—defined by the relative importance of their uses and their global availability—by sporadic shortages in the past decade of metals needed to create a wide range of high-tech products.

man enters tungsten mine in Rwanda
Above, a tungsten mine in Rwanda. (Credit: Fairphone/Flickr)

No substitutes

Many of the metals traditionally used in manufacturing, such as zinc, copper, and aluminum, show no signs of vulnerability. But other metals may be harder to obtain, says Thomas Graedel, professor of industrial ecology at Yale University.

“The metals we’ve been using for a long time probably won’t present much of a challenge. We’ve been using them for a long time because they’re pretty abundant and they are generally widespread geographically.

“But some metals that have become deployed for technology only in the last 10 or 20 years are available almost entirely as byproducts. You can’t mine specifically for them; they often exist in small quantities and are used for specialty purposes. And they don’t have any decent substitutes.”

The findings illustrate the urgency for new product designs that make it easier to reclaim materials for reuse, says Graedel, lead author of the new paper in the Proceedings of the National Academy of Sciences.

3 big risks

Criticality depends not only on geological abundance, researchers say. Other important factors include the potential for finding effective alternatives in production processes, the degree to which ore deposits are geopolitically concentrated, the state of mining technology, regulatory oversight, geopolitical initiatives, regional instabilities, and economic policies.

In order to assess the state of all metals, researchers developed a methodology that characterizes criticality in three areas: supply risk, environmental implications, and vulnerability to human-imposed supply restrictions.

  • They found that supply limits for many metals critical in the emerging electronics sector (including gallium and selenium) are the result of supply risks.
  • The environmental implications of mining and processing present the greatest challenges with platinum-group metals, gold and mercury.
  • For steel alloying elements (including chromium and niobium) and elements used in high-temperature alloys (tungsten and molybdenum), the greatest vulnerabilities are associated with supply restrictions.

Among the factors contributing to extreme criticality challenges are high geopolitical concentration of primary production—for example, 90 to 95 percent of the global supply of rare Earth metals comes from China; lack of available substitutes—there is no adequate substitute for indium, which is used in computer and cell phone displays; and political instability—a significant fraction of tantalum, used widely in electronics, comes from the war-ravaged Democratic Republic of the Congo.


The researchers also analyzed how recycling rates have evolved over the years and the degree to which different industries are able to utilize “non-virgin” sources of materials. Some materials, such as lead, are highly recycled because they are typically used in bulk.

But the relatively rare materials that have become critical in some modern electronics are far more difficult to recycle because they are used in such miniscule amounts—and can be difficult to extricate from the increasingly complex and compact new technologies.

“I think these results should send a message to product designers to spend more time thinking about what happens after their products are no longer being used,” Graedel says.

“So much of what makes the recycling of these materials difficult is their design. It seems as if it’s time to think a little bit more about the end of these beautiful products.”

Source: Yale University