Wealth of Minerals Could Be 'Mined' By Recycling Gadgets
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Usage of rare earth minerals by gigagrams (Gg).
CREDIT: Xiaoyue Du and T. E. Graedel |
Recycling the hidden treasure in old smartphones, tablets and laptops could help feed the world's growing appetite for rare earth minerals. A new study finds that the amount of such economically and technologically vital minerals already in use is four times bigger than what is mined each year.
So-called "urban mining" or recycling may ease U.S. dependence on China, which produces 97 percent of the world's rare earth mineral supply and has begun cutting back on exports because of its own needs. It could even offset a "significant part" of any future mining from natural deposits, according to Yale University researchers.
Recycling the minerals looks most likely for metallurgical applications, automobile catalysts, and magnets in wind turbines and automobiles, where the minerals exist in larger quantities, said Xiaoyue Du, a Ph.D. candidate in forestry and environmental studies at Yale University. But Du added that many recycling challenges remain even for the most widely-used applications.
"Because the rare earths are used in a small amount mixed with other metals or materials, it's very hard and costly to separate them, for example, in the cell phones," Du told InnovationNewsDaily.
The Yale study came up with the first global estimate of the amount of rare earth minerals already in use, as opposed to the amount in the ground or mined each year. Rare earth minerals already in use totaled about 485,000 tons in 2007, or four times the amount mined in the same year. [INFOGRAPHIC: Energy-Critical Elements to Watch ]
Where do the minerals go
Manufacturers in the U.S., Japan and China use most of the rare earth minerals currently produced. The three countries accounted for 90 percent of worldwide manufacturing that used rare earth minerals in 2006, and so the Yale study took their figures as substitutes for the global estimate.
The most widely used minerals included lanthanum, cerium, neodymium and praseodymium. That "big four" group also made up the lion's share of rare earth minerals used by all the different manufacturing sectors.
Serious recycling could start with the largest in-use stocks of rare earth minerals found in metallurgy metal-working that uses rare earth minerals as chemicals to remove impurities found in iron and steel. Some countries already recover neodymium and praseodymium from metallurgy.
The second-highest amount in use is found in the computers, where magnets made from rare earth minerals help stabilize the spinning computer hard drives. The third-highest amount is found in automobile catalytic converters that cut down on car emissions.
Stretching supplies
One of the Yale study authors previously talked about the need to recycle during the American Association for the Advancement of Science (AAAS) conference in Washington, D.C. But he also cautioned that any urban mining would have to wait until the applications using rare earth minerals wore out.
"Recycling will not make a major contribution in the next few decades, because it doesn't all go into cell phones," said Thomas Graedal, an industrial ecologist at Yale University. "Some goes into decades-long use in wind turbines or hybrid car batteries, and we won't get them back immediately."
The lifetimes range from one year for compact fluorescent bulbs to 10 years for computers, flat panel displays and audio systems, according to the latest study. They can go as high as 20 years for wind turbines and 30 years when used as additives for metal alloys.
Still, recycling could help stretch the supply for tech-hungry consumers such as the U.S., Japan, South Korea and Europe. Some researchers have also begun searching for substitutes to replace rare earth minerals, such as the neodymium used in powerful magnets.
Still digging
Most production since 1995 has come from seven rare earth mines in China and one mine in Mountain Pass, Calif., and new mines around the world won't start up until at least 2014.
The U.S. is sitting on vast deposits of rare earth minerals, but lacks the expensive refineries needed to process the minerals. It may require 15 years for the country to build its own independent supply chain for the minerals, according to industry estimates in a 2010 report by the U.S. Government Accountability Office.
Yale's study detailed in the March online issue of the journal Environmental Science & Technology coincided with renewed action from U.S. lawmakers. On March 31, Rep. Hank Johnson (D-Ga.) introduced the Resource Assessment of Rare Earths (RARE) Act of 2011.
The proposal asks the U.S. Geological Survey to run a three-year global assessment of rare earth minerals. That ranges from assessing likely undiscovered deposits to figuring out the complete rare earths supply chain from mining to manufacturing.
"Without secure access to rare earth elements, we will be unable to lead the world in clean tech," Johnson said in a statement. "The RARE Act will dramatically advance our ability to access rare earths worldwide."
You can follow InnovationNewsDaily Senior Writer Jeremy Hsu on Twitter @ScienceHsu.
