Recycling rare

Here are electronics parts from old computers. Recycling the rare-earth metals in these parts might help meet demand for these highly valued materials.

Adam Smigielski/iStock/Getty Images Plus

By Erin Wayman

May 4, 2023 at 6:30 am

Our modern lives depend on metals known as rare earths. Unfortunately, these elements are so widely used and popular that someday soon we may not have enough of them to meet society's needs.

Because of their special properties, these 17 metals have become crucial to high-performing computer screens, cell phones and other electronics. Compact fluorescent lamps use them. So do medical-imaging machines, lasers, high-power magnets, fiber optics and pigments. They’re even in rechargeable electric car batteries. These elements are also a gateway to a climate-friendly low- or zero-carbon future.

In 2021, the world mined 280,000 metric tons of rare earths. That's roughly 32 times as much as in the mid-1950s. By 2040, experts estimate we’ll need up to seven times as much as we use today.

There are no good substitutes for most of the jobs that rare earths do. So satisfying our appetite for these metals won't be easy. They are not found in rich deposits. So miners must excavate huge amounts of ore to get them. Then companies must use a mix of physical and chemical processes to concentrate the metals and separate them out.

Those processes use lots of energy. They’re also dirty and use toxic chemicals. Another concern: China is nearly the only place where these metals are mined and processed. Right now, for instance, the whole United States has just one active rare-earths mine.

All of this explains why researchers are looking to recycle these metals. Recycling is "going to play a very important and central role," says Ikenna Nlebedim. He's a materials scientist at the Department of Energy's Critical Materials Institute. (It's run by Ames National Laboratory in Iowa.)

Within 10 years, Nlebedim says, recycling could meet up to one fourth of the need for rare earths. If true, he says, that would be "huge."

In the United States and Europe, it's standard to recycle from 15 to 70 percent of high-use metals, such as steel. Yet today, only about 1 percent of the rare earths in old products get recycled, notes Simon Jowitt. A geologist, he works at the University of Nevada, Las Vegas.

"Copper wiring can be recycled into more copper wiring. Steel can just be recycled into more steel," he says. But a lot of rare-earth products are "not very recyclable."

Why? Often they have been blended with other metals. Separating them out again can be very hard. In some ways, recycling rare earths from tossed-out items is about as challenging as extracting them from ore and processing them.

Rare-earth recycling tends to use hazardous chemicals, such as hydrochloric acid. It also uses a lot of heat — and thus a lot of energy. And that effort may only recover a tiny amount of metal. A computer's hard-disk drive, for instance, might contain just a few grams (less than an ounce) of rare-earth metals. Some products might have just a thousandth as much.

But scientists are trying to develop better recycling approaches to reduce the need for mining more of these metals.

One approach recruits microbes. Gluconobacter bacteria naturally produce organic acids. These acids can pull rare earths — such as lanthanum and cerium — from used catalysts or from the glowing phosphors that make fluorescent lights glow. The bacterial acids are less harmful to the environment than other metal-leaching acids, says Yoshiko Fujita. She's a biogeochemist at Idaho National Laboratory in Idaho Falls.

In experiments, those bacterial acids recover only about a quarter to half of the rare earths from catalysts and phosphors. That's not as good as hydrochloric acid, which in some cases can extract up to 99 percent. But the bio-based approach might still be worth the effort, Fujita and her team report.

Other bacteria can also help extract rare earths. A few years ago, researchers discovered that some microbes produce a protein that can grab onto rare earths. This protein can separate rare earths from each other — such as neodymium from the dysprosium used in many magnets. Such a system might avoid the need for many toxic solvents. And the waste left from this process will biodegrade.

Another new technique uses copper salts — not acids — to pull rare earths from discarded magnets. Neodymium-iron-boron (NIB) magnets are the single biggest user of rare earths. Rare earths make up almost one-third of these magnets by weight. Within seven years, recycling the neodymium from NIB magnets in U.S. hard-disk drives could meet about 5 percent of the world's demand for this metal (outside of China).

Nlebedim led a team that developed a technique that uses copper salts to leach rare earths from magnets in shredded electronics. The process has also been used on leftovers from the making of magnets. There, it could recover 90 to 98 percent of the rare earths. The extracted metals are pure enough to make new magnets, Nlebedim's team has shown. Their process could also be better for the climate. Compared with one of the main ways rare earths are mined and processed in China, the copper-salt method has less than half its carbon footprint.

An Iowa company called TdVib has just built a pilot plant to use this copper-salt process. It aims to produce two tons of rare-earth oxides per month. It will recycle rare earths from old hard disk drives from data centers.

Noveon Magnetics is a company in San Marcos, Texas. It's already making recycled NIB magnets. After demagnetizing and cleaning discarded magnets, it mills the metal into a powder. That powder is used to make new magnets. Here, there's no need to first extract and separate the rare earths. The final product can be more than 99 percent recycled magnet.

Compared with the usual way of making NIB magnets, this method cuts energy use by about 90 percent, researchers reported in a 2016 paper. Noveon also estimates that it only releases about half as much carbon dioxide, a greenhouse gas.

Many communities have programs to collect metal, paper or glass for recycling. Nothing like that exists for collecting trashed products that contain rare earths, says Fujita, at the Idaho National Laboratory. Before rare-earth recycling can begin, you’ll have to get to those bits that contain the valued metals.

Apple has launched efforts to recycle some of its electronics. Its Daisy robot can dismantle iPhones. And last year, Apple announced a pair of robots — Taz and Dave — that aid in the recycling of rare earths. Taz can gather magnet-containing modules that are typically lost during the shredding of electronics. Dave can recover magnets from another part of the iPhones.

Still, it would be a lot easier if companies just designed products in a way that made recycling easy, Fujita says.

But no matter how good recycling gets, Jowitt sees no getting around a need to boost mining efforts. Society's hunger for rare earths is just too big — and growing. He does agree, however, that recycling is needed. "Better we try and extract what we can," he says, "rather than just dumping it in the landfill."

bacteria: (adj. bacterial) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms (such as plants and animals). Bacteria are one of the three domains of life on Earth.

biodegradable: Adjective for something that is able to break down into simpler materials, based on the activity of microbes. This usually occurs in the presence of water, sunlight or other conditions that help nurture those organisms.

biogeochemist: Someone who studies processes that cycle (or eventually deposit) pure elements or chemical compounds (including minerals) between living species and nonliving aspects (such as rock or soil or water) of an ecosystem. This field of study is known as biogeochemistry.

carbon dioxide: (or CO2) A colorless, odorless gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they’ve eaten. Carbon dioxide also is released when organic matter burns (including fossil fuels like oil or gas). Carbon dioxide acts as a greenhouse gas, trapping heat in Earth's atmosphere. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.

carbon footprint: A popular term for measuring the global warming potential of various products or processes. Their carbon footprint translates to the amount of some greenhouse gas — usually carbon dioxide — that something releases per unit of time or per quantity of product.

catalyst: (v. catalyze) A substance that helps a chemical reaction to proceed faster. Examples include enzymes and elements such as platinum and iridium.

climate: The weather conditions that typically exist in one area, in general, or over a long period.

colleague: Someone who works with another; a co-worker or team member.

data center: A facility that holds computing hardware, such as servers, routers, switches and firewalls. It also will house equipment to support that hardware, including air conditioning and backup power supplies. Such a center ranges in size from part of a room to one or more dedicated buildings. These centers can house what it takes to make a "cloud" that makes possible cloud computing.

develop: To emerge or to make come into being, either naturally or through human intervention, such as by manufacturing.

electronics: Devices that are powered by electricity but whose properties are controlled by the semiconductors or other circuitry that channel or gate the movement of electric charges.

element: A building block of some larger structure. (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.

excavate: (n. excavation) To dig something out of soil or rock (such as dinosaur bones); to remove the inner part of something to make a hole (cavity) within it.

extract: (v.) To separate one chemical (or component of something) from a complex mix. (noun) A substance, often in concentrated form, that has been removed from some source material. Extracts are often taken from plants (such as spearmint or lavender), flowers and buds (such as roses and cloves), fruit (such as lemons and oranges) or seeds and nuts (such as almonds and pistachios). Such extracts, sometimes used in cooking, often have very strong scents or flavors.

fiber optics: The use of thin, flexible fibers of glass (known as optical fibers) or other transparent solids to transmit light signals, chiefly for telecommunications.

fluorescent: (v. fluoresce) Adjective for something that is capable of absorbing and reemitting light. That reemitted light is known as fluorescence.

greenhouse gas: A gas that contributes to the greenhouse effect by absorbing heat. Carbon dioxide is one example of a greenhouse gas.

leach: (in geology and chemistry) The process by which water (often in the form of rain) removes soluble minerals or other chemicals from a solid, such as rock, or from sand, soil, bones, trash or ash.

magnet: A material that usually contains iron and whose atoms are arranged so they attract certain metals.

materials scientist: A researcher who studies how the atomic and molecular structure of a material is related to its overall properties. Materials scientists can design new materials or analyze existing ones. Their analyses of a material's overall properties (such as density, strength and melting point) can help engineers and other researchers select materials that are best suited to a new application.

metal: Something that conducts electricity well, tends to be shiny (reflective) and is malleable (meaning it can be reshaped with heat and not too much force or pressure).

microbe: Short for microorganism. A living thing that is too small to see with the unaided eye, including bacteria, some fungi and many other organisms such as amoebas. Most consist of a single cell.

microscopic: An adjective for things too small to be seen by the unaided eye. It takes a microscope to view objects this small, such as bacteria or other one-celled organisms.

module: A set of standardized parts or independent units used to assemble a more complex structure. The module could be used to create a "prefabricated" home or furniture — or even a spacecraft.

neodymium: A chemical element which appears as a soft, silvery metal when it is pure. It is found in some minerals, and can be used to trace the source of mineral grains carried long distances by water or wind. Its scientific symbol is Nd.

optics: Having to do with vision or what can be seen.

ore: A naturally formed rock or mineral that contains a metal that can be extracted for some new use.

organic: (in chemistry) An adjective that indicates something is carbon-containing; also a term that relates to the basic chemicals that make up living organisms. (in agriculture) Farm products grown without the use of non-natural and potentially toxic chemicals, such as pesticides.

oxide: A compound made by combining one or more elements with oxygen. Rust is an oxide; so is water.

phosphor: A synthetic chemical that glows when excited by electrons. It typically is used (often in combination with others) to coat LEDs, fluorescent lamps or cathode-ray tubes to produce a desired color of light.

physical: (adj.) A term for things that exist in the real world, as opposed to in memories or the imagination. It can also refer to properties of materials that are due to their size and non-chemical interactions (such as when one block slams with force into another).

pigment: A material, like the natural colorings in skin, that alter the light reflected off of an object or transmitted through it. The overall color of a pigment typically depends on which wavelengths of visible light it absorbs and which ones it reflects. For example, a red pigment tends to reflect red wavelengths of light very well and typically absorbs other colors. Pigment also is the term for chemicals that manufacturers use to tint paint.

protein: A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Antibodies, hemoglobin and enzymes are all examples of proteins. Medicines frequently work by latching onto proteins.

radioactive: An adjective that describes unstable elements, such as certain forms (isotopes) of uranium and plutonium. Such elements are said to be unstable because their nucleus sheds energy that is carried away by photons and/or and often one or more subatomic particles. This emission of energy is by a process known as radioactive decay.

rare earths: (in Earth science) These are a group of metal elements that tend to be soft, bendable and chemically reactive.

recycle: To find new uses for something — or parts of something — that might otherwise be discarded, or treated as waste.

salt: A compound made by combining an acid with a base (in a reaction that also creates water). The ocean contains many different salts — collectively called "sea salt." Common table salt is a made of sodium and chlorine.

solvent: A material (usually a liquid) used to dissolve some other material into a solution.

system: A network of parts that together work to achieve some function. For instance, the blood, vessels and heart are primary components of the human body's circulatory system. Similarly, trains, platforms, tracks, roadway signals and overpasses are among the potential components of a nation's railway system. System can even be applied to the processes or ideas that are part of some method or ordered set of procedures for getting a task done.

toxic: Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.

Journal:​ ​​ Y. Fujita, S.K. McCall and D. Ginosar. Recycling rare earths: Perspectives and recent advances. MRS Bulletin. Vol. 47, March 2022, p. 283. doi: 10.1557/s43577-022-00301-w.

Journal:​ S.M. Jowitt. Mineral economics of the rare-earth elements. MRS Bulletin. Vol. 47, March 2022, p. 276. doi: 10.1557/s43577-022-00289-3.

Journal:​ N.A. Chowdhury et al. Sustainable recycling of rare-earth elements from NdFeB magnet swarf: Techno-economic and environmental perspectives. ACS Sustainable Chemistry & Engineering. Published online November 17, 2021. doi.org: 10.1021/acssuschemeng.1c05965.

Journal:​ H. Jin et al. Bioleaching of rare earth elements from industrial waste materials using agricultural wastes. ACS Sustainable Chemistry & Engineering. Published online August 20, 2019. doi: 10.1021/acssuschemeng.9b02584.

Journal:​ H. Jin et al. Comparative life cycle assessment of NdFeB magnets: Virgin production versus magnet-to-magnet recycling. Procedia CIRP. Published online July 27, 2016. doi: 10.1016/j.procir.2016.03.013.

Journal:​ M. Zakotnik et al. Analysis of energy usage in Nd-Fe-B magnet to magnet recycling. Environmental Technology & Innovation. Vol. 5, April 2016, p. 117. doi: 10.1016/j.eti.2016.01.002.

Erin Wayman is the magazine managing editor at Science News. She has a master's degree in biological anthropology from the University of California, Davis and a master's degree in science writing from Johns Hopkins University.

Free educator resources are available for this article. Register to access:

Already Registered? Enter your e-mail address above.

Readability Score: 8