Hitachi Ltd developed a technology to recover rare earth materials such as neodymium (Nd) and dysprosium (Dy) from rare-earth magnets used in the motors of hard disk drives (HDDs), the compressors of air conditioners and so forth.
The company developed equipment that separates rare-earth magnets from used products and succeeded in recovering rare earth materials from the magnets by using a new method.
The newly-developed equipment can separate and collect rare-earth magnets from about 100 products per hour, which is about eight times faster than a human worker (12 products), Hitachi said. For example, to break down HDDs, vibrations and impacts are continuously applied to them by spinning a drum-shaped machine so that screws are loosen and components are separated. Because components containing rare-earth magnets are separated, a human worker can easily collect those components by sight.
To disassemble compressors, their packages are cut by a cutting machine. Then, rotors containing rare-earth magnets are exposed by hand. After separating the rotors by using a machine dedicated to taking out a rotor, their magnetic fields are weakened by applying a resonance current that disorders the magnetization direction. Lastly, vibrations are applied to the rotors by using a machine dedicated to taking out rare-earth magnets so that rare-earth magnets are separated from them.
The rare-earth magnets collected by those methods are separated into rare earth materials and other materials such as iron by using an extraction agent. It is possible to obtain rare earth alloys by distilling the extraction agent after removing materials other than rare earth materials.
While existing extraction methods using chemical agents require waste liquid treatment, the new extraction method does not require any additional treatment, reducing environmental loads. Hitachi plans to start recycling rare earth materials in earnest in 2013 by firmly establishing the new method and calculating costs and an expected collection rate.