REE used in magnet

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Rare Earth Elements Used in Magnet An Increasingly important use of REE is in permanent magnets. This application was first developed in the 1960s when samarium alloyed with cobalt was used. By the mid-1980s neodymium-lron- boron magnets had been developed and have now largely replaced samarium-cobalt magnets, except in high temperature applications, Neodymlum-lron-boron magnets possess a magnetic energy of up to 2.5 times greater than the samarium-cobalt versions. In addition the principal constituent is iron (84.4 per cent) which is significantly cheaper and more abundant than cobalt. Permanent magnets account for approximately 38 per cent of the REE market by value and 21 per cent by volume. Because neodymium magnets are more powerful than alternatives, they provide improved performance for a smaller size which has led to many miniaturized applications. Tiny neodymium magnets are used in the speakers in earphones for consumer devices such as MP3 players, as well as in numerous other high performance speakers. This results in smaller, lighter devices with improved performance. Permanent magnets are also used in hard disk and DVD drives. The voice coil motor which controls the arm that reads and writes information onto the disk uses a neodymium-based magnet which gives improved control allowing thinner tracks and more data storage. Neodymium-iron-boron magnets are important in many 'green', carbon reducing technologies. It is estimated that wind turbines use in the range of 0.6-1.0 tone of neodymium magnets per megawatt, Of which approximately 30 per cent is REE. In wind turbines electricity is generated in an alternator when magnets pass wire coils. One factor which determines the amount of electricity generated is the strength of the magnets used. The stronger the magnets, the higher the current generated, so strong neodymium magnets make considerably better alternators. Neodymium magnets are essential for hybrid cars such as the Toyota Prius. Hybrid cars reduce fossil fuel consumption by combining a petrol engine, battery-powered electric motors and brakes that capture energy during breaking. It has been suggested that the Prius is the largest consumer of REE of any individual product with each electric motor in a Prius requiring one kilogram of neodymium. The use of REE magnets has the potential to increase the energy efficiency of many appliances. For example use of REE magnets in air conditioning systems can reduce power consumption by up to 50 per cent whilst retaining the same level of performance. Dysprosium and terbium are also used in magnets. Many magnets tend to lose their magnetism as they heat up, but the addition of dysprosium or terbium prevents this from happening at high temperatures.