Rare earths help make money

It is well known that lanthanides are widely used in the most advanced technologies, for instance in production of metal hydride batteries, the strongest permanent magnets, automobile and oil cracking catalysts etc. [1].

Constantly increasing demands together with shortage of resources lead to extremely high prices for rare earths. For that reason trading of lanthanides is a very lucrative business bringing a lot of money to the sellers.

Interesting fact is that a company involved in trading with lanthanides always withdraws some amount of rare earths from the customer. ’It is a fraud’ – you probably would say. No, it has nothing to do with a fraud. The reason is that some bank notes, euro for instance [2], contain small quantities of rare earths in a form of security inks. Therefore paying bills for lanthanide sources in cash the buyer voluntarily gives away a ’stash’ of these elements.

       Euro banknotes

Fig. 1 – Euro banknotes

 Modern bank notes have several security features: watermark, hologram, glossy stripe, perforations, security inks etc. [3]. The security inks are based on luminescent compounds that are well known in the field of document security for protection of valued papers. Such compounds are known to include for example europium, terbium, ytterbium, thulium or erbium doped materials [4].

Taking into account aforementioned information one can firmly declare that rare earths help make money in all senses.

It should be mentioned here that the application of lanthanides as components of security inks in bank notes was not always used in the struggle against counterfeiting. The former East German secret police – Stasi – used radioactive isotope of Scandium (Sc-46) to mark bank notes and documents in order to track targeted dissidents [5]. Luckily this dark side of lanthanide history came to past forever and now rare earths are used only for sustainable development.

References:

1. S. Massari, M. Ruberti. Rare earth elements as critical raw materials: focus on international markets and future strategies / Resources Policy, 38, 2013. 36-43.
2. http://www.chemheritage.org/discover/online-resources/thanks-to-chemistry/ttc_communication_counterfeiting.aspx, http://pubs.acs.org/cen/80th/print/lanthanides.html, http://www.rsc.org/chemistryworld/podcast/interactive_periodic_table_transcripts/terbium.asp
3. http://www.ecb.europa.eu/euro/html/security_features.en.html
4. K. Binnemans, C. Görller-Walrand, P. W. Nockermann, R. Van Deun. UK Patent Application GB 2410946 A. 2005; T.K. Anh, D.X. Loc, T.T. Huong et al. Luminescent nanomaterials containing rare earth ions for security printing / Int. J. Nanotechnol., Vol. 8, Nos. 3/4/5, 2011.
5. http://news.bbc.co.uk/2/hi/europe/1100317.stm

Rare Earth power game!

The United States biggest concern on the rare earth issue is based on its reliance on technology, especially for military applications. This text talks about the rare earth elements that are used in defense-related technology.

The pentagon claims that only 5% of world’s supply of rare earth is consumed by the United States Department of Defense. Yet it should be considered that for producing some of the most powerful weapons, US is completely dependent on China [1].

Two commercially available permanent magnets of rare earth elements are samarium cobalt (SmCo) magnets, and neodymium iron boron (NdFeB) magnets. SmCo is used for military technologies such as precision-guided missiles, smart bombs, and aircraft, since its magnetic strength is retained at elevated temperatures. NdFeB magnets, known as the world’s strongest permanent magnets are used for smaller and lighter defense weapon systems [2].

Rare earths used in missiles and smart bombs can provide directional capabilities. They are also used in detection devices for enemy mine detection, interrogators, underwater mines, and countermeasures. Other critical application of rare earth elements in defensive applications are laser targeting systems, range-finder lasers, radar surveillance, optical equipments and communication systems [3]. Rare earth alloys are also replacing piezoceramic materials in several devices such as Sonar transducers for submarines [4].

 

The use of rare earth elements in different of military applications are shown in figures 1-5 [2]:

1- Rare earth elements in missile guidance and control systems for controlling the direction of the missile

1- Rare earth elements in missile guidance and control systems for controlling the direction of the missile

 

2- Rare earth elements in disk drive motors installed in aircraft, tanks and control centers; in defense electronic warfare

2- Rare earth elements in disk drive motors installed in aircraft, tanks and control centers; in defense electronic warfare

3- Rare earth elements in targeting and weapon systems

3- Rare earth elements in targeting and weapon systems

4- Rare earth elements in electric motors

4- Rare earth elements in electric motors

5- Rare earth elements in electronic and communication for optical equipment and speakers.

5- Rare earth elements in electronic and communication for optical equipment and speakers.

The United States was the leader in global production of rare earths from 1960s to 1980s. Since then China has been ruling in rare earth production due to lower costs and environmental standards. In July 2010, China announced cutting rare earth mineral exports by about 72%. This could be very problematic for U.S as the biggest consumer of rare earths by imposing economic and national security risks.

 

In January 2011, three Members of Congress wrote a letter to Secretary of Defense asking for an immediate action for providing a detailed accounting of supplies of rare earth availability [2]:

“Clearly, rare earth supply limitations present a serious vulnerability to our national security. Yet early indications are the Department of Defense (DOD) has dismissed the severity of the situation to date…

As the ultimate customer, the Department has the right and responsibility to require their contractors to provide a detailed accounting of the various rare earth containing components within their weapon systems. This information should then be aggregated into an element by element overall demand for DOD. With that knowledge, DOD could compare expected supply and demand of each rare earth element with overall consumption by the Department to identify critical vulnerabilities in our supply chain. This will enable the Department to establish policies to ensure the defense supply chain has access to those materials. For example, one policy may be for the DOD to establish a limited stockpile of rare earth alloys that are in danger of supply interruption to ensure security of supply of both metals and magnets.”

 

In the same year another advisor of Department of Defense stated [5]:

“The Pentagon has been incredibly negligent…there are plenty of early warning signs that China will use its leverage over these materials as a weapon.”

 

In order to overcome the economic and military dependence of US on China, actions were needed: Stockpiling the rare earths as a short term solution; as it has been already done in South Korea and Japan [6]. Developing new mines was another solution. However it can take over 10 years until a new mine can start running efficiently. Finding materials as substitutes for rare earth metals without loss in performance was another option. Developing new technologies for refining and recycling rare earth elements was another promising alternative.

The investigations and research is still ongoing to determine who will win the rare earth power game!

 

 

 

References:

1-. Ratnam, Gopal. “Rare Earth Shortage Would Spur Pentagon to Action”. Bloomberg News, April 9, 2012.

 

2- Valerie Bailey Grasso. “Rare Earth Elements in National Defense: Background, oversight Issues, and Options for Congress” Congressional Research Service. December 23, 2013

 

3- http://www.molycorp.com/products/rare-earths-many-uses/defense-technologies/

 

4- James B. Hedrick. “Rare-Earth Industry Overview and Defense Applications” U.S. Department of the Interior and U.S. Geological Survey”. February 18, 2005

 

5- Emily Coppel “Rare Earth Metals and U.S National Security” American security project. February 1, 2011

 

6- Hounshell, Blake, “Is China Making a Rare Earth Power Play?” Foreign Policy, September 23, 2010

 

 

 

 

 

 

Additives in Neodymium Iron Boron magnets

Written by: Tom Vander Hoogerstraete

NdFeB magnets are not only build up by neodymium, iron and boron. They contain also other elements (so-called “exogens”) that slightly change the chemical or physical properties of the magnet. The presence of these elements is a drawback in chemical recycling processes because they require stable metal feeds. Mixtures of all kind of different magnets, obtained from diverse applications, are therefore not easy to recycle.

Most often, neodymium and iron are substituted by other elements to increase the coercivity, the anisotropy or the Curie temperature of the magnet. However, the addition of one element could lead to a substantial increase in one of these properties but also to a decrease in performance of one of the other magnet properties. The coercivity or coercive force (Hc) is the force of the magnet to withstand an external magnetic or electronic field. It represents the resistance of a magnet towards demagnetization. Magnetic anisotropy means that the magnetic properties of the magnet depend on the direction. And the Curie temperature (Tc) is defined as the temperature when permanent magnetism changes in induced magnetism. The magnet becomes paramagnetic above this temperature.

Neodymium is often substituted by Dysprosium (Dy), even up to 8 wt%. It is used to increase the anisotropy and the coercivity of the magnet, especially when the magnets are used at higher temperatures. Also terbium or holmium can be used, but dysprosium is a cheaper heavy rare earth and therefore more interesting. Disadvantage of Dy substitution is the reduced magnetization. Praseodymium (Pr) can be found as well in NdFeB magnets because this element is very similar to Neodymium. Therefore, the magnetic properties will change only slightly.

Cobalt (Co) is added to magnets to increase the Curie temperature. For instance, the replacement of all iron in Nd2Fe14B by Nd2Co14B increases the Curie temperature from 310 °C to 720 °C. The main disadvantage of this substitution is the decrease in coercivity. This drawback can be avoided by the addition of Aluminium (Al). This element decreases the magnetic moment and Curie temperature slightly but increases the coercivity significantly. Also small amounts of Copper (Cu) are sometimes added to increase the coercivity of the NdFeB magnets or to reduce the temperature of the eutectic neodymium rich phase during manufacturing of the magnet. This makes further processing of the magnet sometimes easier.

Gallium (Ga) is added to NdFeCoB magnets to increase the coercive force and to improve the thermal stability. Molybdenum (Mo) and Vanadium  (V) substitution increase the coercivity and the corrosion resistance of NdFeB magnets. A very small amount of Zirconium (Zr) (up to 0.1 wt%) can improve the magnetic properties of a magnet. Niobium (Nb) increases the coercivity and only slightly influences the magnetic properties.

Substitution by Silicon (Si) increases the magnetization of the magnet and also improves the squareness in the demagnetization curve. Oxygen (O) can be present as an impurity and is often introduced when the magnet is coated with a protective metal (oxide) layer.

Another point of attention is the coating of the NdFeB magnets which is crucial because NdFeB magnets have a very poor corrosion resistance. The individual grains in bonded magnets are coated with a polymer. Sintered magnets can have nickel, zinc, titanium nitride, silicon oxide or aluminium coating. Chemical recycling processes also deal with these kinds of impurities.

  (1)   M. Tanaka, T. Oki, K. Koyama, H. Narita, and T. Oishi, In Handbook on the Physics and Chemistry of Rare Earths
Including Actinides, Jean-Claude, G. Bünzli and Vitalij, Ed., Elsevier: 159-211.

  (2)   K. Binnemans, P. T. Jones, B. Blanpain, T. Van Gerven, Y. Yang, A. Walton, and M. Buchert, J. Clean. Prod., 2013, 51, 1-22.

  (3)   S. Pandian, V. Chandrasekaran, G. Markandeyulu, K. J. L. Iyer, and K. V. S. Rama Rao, J. Appl. Phys., 2002, 92, 6082-6086.

  (4)   J. M. D. Coey, Rare-Earth Iron Permanent Magnets, Clarendon Press Oxford, Oxford, 2006.

Current situation and problems of rare earth industry in China

China produces more than 90 percent of the world’s rare earth. Meanwhile, overcapacity, a low proportion of high-end products, smuggling and pollution still hamper the development of the rare earth industry. Hence, in order to try to curtail pollution and prevent over-mining, China has been cracking down on the industry for years to curb illegal mining, smuggling and environmental devastation. Subsequently, China imposed strict rare earth export quotas in 2010.

After many years of development, China has established a relatively complete R&D system, pioneered numerous technologies of international advanced levels in rare earth mining and dressing, smelting, separating, etc., and its unique mining and dressing processes and advanced separating techniques have laid a solid foundation for efficient exploitation and utilization of rare earth resources. The rare earth new materials industry has experienced steady development, and industrialization has been achieved in using rare earths to produce permanent-magnet, luminescent, hydrogen-storage, and catalytic materials, and other new materials, providing support for the restructuring and upgrading of traditional industries, and the development of emerging industries of strategic importance.

With a relatively complete industrial system armed with mining, dressing, smelting and separating technologies and incorporating equipment manufacturing, material processing and end-product utilization, China can produce over 400 kinds of rare earth products in more than 1,000 specifications. In 2011, China produced 96,900 tons of rare earth smelting separation products. Currently, China supplies over 90 percent of the global rare earth demand with 23 percent of the world’s total reserves.

After more than 50 years of excessive mining, China’s rare earth reserves have kept declining and the years of guaranteed rare earth supply have been reducing. The decline of rare earth resources in major mining areas is accelerating, as most of the original resources are depleted. In Baotou, only one-third of the original volume of rare earth resources is available in the main mining areas, and the reserve-extraction ratio of ion-absorption rare earth mines in China’s southern provinces has declined from 50 two decades ago to the present 15.

Outdated production processes and techniques in the mining, dressing, smelting and separating of rare earth ores have severely damaged surface vegetation, caused soil erosion, pollution, and acidification, and reduced or even eliminated food crop output.

Due to multiple factors, including domestic and international demand, the smuggling of rare earth products to overseas markets continues to be a problem in spite of the efforts made by China’s customs listing it as a key criminal act to crack down on.

References

1. China’s rare earth industry expands but problems persists, http://www.mining.com/chinas-rare-earth-profits-fall-98385/

2. China’s rare earth industry sees progress, challenges, http://www.globaltimes.cn/content/80252

3. Situation and policies of China’s rare earth industry. Foreign Languages Press, 2012.

4. ZHANG Shujing. Problems and countermeasures of rare earth industry in China, Canadian Social Science, Vol. 9, No. 3, 2013, 9-14.

5. REE – Rare Earth Elements and their Uses. http://geology.com/articles/rare-earth-elements/