ORNL Is Developing Methods to Recover Rare Earth Magnets from Used Hard Drives

Oak Ridge National Laboratory, which attempts to provide solutions to compelling problems in energy and security, has designed a patent-pending process to recover rare earth magnets made using neodymium from used hard drives.

Rare Earth Elements

Rare earth elements include the fifteen lanthanides, as illustrated in the table below, as well as scandium and yttrium.

Tabel I The lanthanides. Table courtesy of Wikipedia.

Despite what the name suggests, these elements are not rare and some of them are as abundant as copper in the earth’s crust. These elements are generally found together and it is not easy to separate them from one another.

Rare earth elements, such as neodymium, are required to make powerful magnets. Such strong magnets are widely used in computer hard drives, cell phones, MRI machines, air conditioners, wind turbines, electric and hybrid vehicles, cancer treatment drugs, nuclear reactor shielding, aircraft engines, weapons, and a lot of other industrial equipment.

The unique magnetic and conductive properties of these elements miniaturize the technologies and make them more efficient. Julie Michelle Klinger, an assistant professor of international relations at the Frederick S. Pardee School of Global Studies at Boston University, has been quoted as saying that without these elements, a smartphone would be the size of a classroom.

Rare Earth Elements and Politics

Klinger, who is an expert in the politics of development, environment, and security in Latin America and China, notes that these elements were thought to be rare when they were first discovered. However, rare earth elements are almost one-fifth of naturally occurring elements. Some of these elements are as abundant as copper and, fortunately, we do not need a large amount of them. According to Smithsonian.com, after all, oil is the blood, steel is the body, and rare earth elements are the vitamins to modern society.

Adamas Intelligence, which publishes research on metals and mining, reports that the global consumption of copper in 2014 is nearly 183 times higher than that of rare earth elements.

Dysprosium is used in electric cars. Image courtesy of Materialscientist [CC BY-SA 3.0]

According to Klinger, the main worry about rare earth elements is that only one country—China— has abundant, but limited, sources of these elements. Klinger’s research suggests that, soon after discovering rare elements and their applications, they have become enmeshed in politics and war.
As an example of the political environment around rare earth elements, after some diplomatic disputes with Japan in 2010, China reduced its rare earth elements exports by 72%. This almost doubled the price of some of these elements. Later, once again, China reduced the exports by 35% in the first half of 2011.

In order to circumvent the uncertainty of China’s export policies, in July, Honda announced a motor for hybrid vehicles which does not need heavy rare earth elements. In addition to Honda and Daido Steel, a number of other companies such as Yasukawa Electric Corp., Mitsubishi Electric Corp., and Nidec Corp. have developed rare-earth-free motors to reduce costs and reliance on China.
To keep our equipment working while not sabotaging our international relations, Klinger suggests not calling these elements rare and trying to find better ways of harvesting the rare earth elements.

Recovering Magnets from Used Hard Drives

More than 95% of the global production of neodymium is produced in countries other than the United States. To provide a solution to the scarcity problem of neodymium, scientists of ORNL resort to recovering the element from used devices. Considering the fact that hard drives are the second major use of neodymium magnets, the company targets a cost-effective recycling process of rare earth elements from this readily available source.

ORNL attempts to recover magnets from used computer hard drives. Image courtesy of ORNL.

According to Timothy McIntyre, project lead and program manager in ORNL's Electrical and Electronics Systems Research Division, 35% of used hard drives are shredded in the US because of data security concerns. Others are either sold into secondary markets or buried in the landfills. Recovering that 35% of the used drives, ORNL expects to collect nearly 1000 metric tons of magnet material per year.

To assure data security, a highly automated process is suggested. The recovery process sorts and aligns hard drives on a conveyor. A coordinate measuring machine is employed to position the drives for correct robotic disassembly. After recovering different parts such as the magnets, permalloy brackets, circuit boards, and those components made of aluminum and steel, the data storage media is automatically destroyed to ensure security.

The recovered magnets can be directly utilized by hard drive manufacturers or they can be resized and reshaped to be used in other products. It is claimed that the process can be extended to recover rare earth elements from other consumer goods such as electric motors, air conditioning systems, and more. The cost of the recovered magnets can be significantly less than that of the magnets produced by standard mining because many processing stages are eliminated and the recovered magnets are ready to be used.

The Membrane Solvent Extraction Method

Dallas-based Momentum Technologies, which is focused on the extraction of rare earth elements and other materials from hard drives, holds an exclusive licensing agreement with the Department of Energy's Critical Materials Institute to commercialize their Membrane Solvent Extraction (MSX) and High Throughput Collection Technologies.

MSX technology, which is as good as or exceeding conventional solvent extraction, is capable of recovering rare earth elements such as neodymium, europium, yttrium, terbium, and dysprosium in a single step. Solvent extraction is a general method to partially remove a substance from a solution by dissolving it in another, immiscible solvent (in which the target substance is more soluble). Compared with conventional methods, MSX requires lower energy and provides greater efficiency and process stability.

Preston Bryant, Momentum's CEO, hopes that the company will create a sustainable business model and provide a solution to the most complicated problems in the rare earth elements supply chain.