The rare earth elements are a group of seventeen metals with physical and chemical characteristics that have made them highly sought after industrial materials. Two rare earth metals, neodymium and samarium, have powerful magnetic properties; to make the strongest magnets rare earth elements are alloyed with other metals.
Neodymium is combined with cobalt and iron to produce neodymium magnets, and samarium magnets contain an alloy of samarium and cobalt. Because of their characteristic combination of lightweight coupled with strong magnetic energy, rare earth magnets are used for applications where low cost, low bulk and high magnetic strength are important considerations. A neodymium magnet can produce a magnetic field of 1.2 teslas and is capable of lifting a thousand times its own weight; a samarium magnet produces a less strong magnetic field but has the advantage of a higher Curie point and is useful in equipment and machinery that operate at high temperatures.
Rare earth magnets are used in a wide variety of applications. They are increasingly used as components of miniaturized devices such as the micro-mechanisms used in biomedical fields. Mass-produced consumer electronic products such as toys, video players, headphones and computer disk drives contain rare earth magnets, as do the magnetic resonance imaging scanners used in medical diagnostics. Permanent magnet motors using rare earth magnets power electric and hybrid vehicles. There is a need in the energy industry for powerful coils and motors, and permanent magnet motors are employed in wind turbines and other heavy machinery for generating electrical power.
The rare earth metals, which tend to occur together in deposits, are found all over the world and, although uncommon, are as abundant as many familiar metals such as copper and zinc. Deposits of rare earth metals are usually in low concentrations that are uneconomical to exploit; in addition, recovering and isolating rare earth elements are challenging activities involving complex chemical and metallurgical processes. As suppliers of low-cost permanent magnets rare earth industries in China have come to dominate global markets in recent years.
Over 95 percent of the world’s supplies of rare earth metals are mined and refined in Southern China, Inner Mongolia and Tibet. Extracting and refining rare earth elements in those regions created heavy pollution; since 2010 China has changed its policy on rare earth industries, and has introduced export restrictions and tariff increases. These changes resulted in panic buying of rare earth products and a rapid escalation in prices of rare earth magnets in the global markets.
In moves to secure supplies that are sourced away from China, exploration for rare earth deposits has been renewed, and mines and refineries in India that were closed while prices were low are being reopened. Researchers in Japan are now actively involved in developing technologies to recycle rare earth metals from scrapped electronic products. As a source of materials for producing strong permanent magnets rare earth metal recycling is a practical and sustainable solution.
Rare earth magnets, despite their name are really not all that uncommon. The are actually just as plentiful as tin or lead is. As these magnets tend to break and chip easily, as well as corrode, they are generally plated or coated so that they are protected before they can be used. Corrosion protection can be provided by tin plating, or coating with epoxy resin, nickel, zinc or gold. Other rare earth materials,lanthanide for example, are able to be magnetized, however, they must be kept below room temperature to be magnetic.
Rare earth magnets come in two varieties, samarium-cobalt and neodymium. The stronger magnetic field is provided by neodymium which are used in a wide variety of consumer products including aircraft, self-powered flashlights, computer hard drives, cordless tools, LCD TVs, speakers, toys for children, and medical equipment. Neodymium magnets have become progressively less expensive since their invention in the 1980s. Developed in the 1970s, samarium-cobalt magnets have a weaker magnetic field.
One should not underestimate the strength of these rare earth magnets. Serious injuries can be caused by pinching if body parts become trapped between these magnets if they are any larger than a few centimeters or more. They actually have enough strength, even, to shatter bone. Injury can also be caused by flying chipped pieces of the magnets if they are kept too close to each other. As with any magnetic material, demagnetizing effects apply. If kept too close to credit cards, ID cards or computer hard drives, the stored information has the potential of being erased.
A recent discovery in magnetism in 2010 made in Twin Cities Minnesota by materials physicists has uncovered a magnetic material with 18% more magnetism than the current limit. Computer manufacturers have the potential of creating hard drives capable of containing more information by utilizing this new magnetic material.
Another application of rare earth magnets is in electric and hybrid vehicles. Which, due to the rising price of fossil fuels, are becoming popular items. The typical electric car contains somewhere around ten pounds of rare earth materials. The demand for such magnets around the world is somewhere between around fifty thousand and fifty-five thousand tons yearly. About 97 percent of the world's current rare earth magnets are currently owned by china. A combined effort of the U.S. And Japan has begun to even this number out through the recycling of appliances as well as the extraction of rare earth magnets from uranium.
Clean energy sources have been found to be reliant on these rare earth magnets and thus have become a very profitable commodity for investment though there is no public trade associated with the majority of trading companies. They are also applied in the U.S. defense program, rare earth magnets are required in many modern weapons for proper function. It has actually become a national security issue to preserve the rare earth material industry. There is a worldwide understanding of the necessity to preserve the steady supply of these materials from mines, as our would relies on them for technology and security.
