Honda develops process to reuse rare earth metals extracted from old NiMH batteries for new NiMH batteries for hybrid vehicles
|Honda’s process for recycling NiMH batteries. The new portion of the process is outlined in red. Click to enlarge.|
Honda Motor Co., Ltd. has established what it says it is the first process to reuse rare earth metals extracted from old nickel-metal hydride (NiMH) batteries for new nickel-metal hydride batteries for use in hybrid vehicles.
Honda has been extracting an oxide containing rare earth metals from used nickel-metal hydride batteries at the plant of Japan Metals & Chemicals Co., Ltd. (JMC). (Earlier post.) Now, by applying molten salt electrolysis to this oxide, Honda has succeeded in extracting metallized rare earth that can be used directly as negative-electrode materials for nickel-metal hydride batteries.
Such a process has been of interest for some time. For example, the German government more than 10 years ago funded a processing and feasibility study for the development of a pyrometallurgical closed-loop recycling process for metal recovery from Ni-MH batteries. (Müller and Friedrich)
The rare earth metals extracted in the Honda process have a purity of more than 99% which is as high as that of ordinary traded, newly mined rare earth metals. In addition, the new process enables the extraction of as much as above 80% of rare earth metals contained in nickel-metal hydride battery.
Under the newly established process, the extracted rare earth metals will be supplied from JMC to a battery manufacturer in early March, which will reuse them as negative-electrode materials for nickel-metal hydride batteries for hybrid vehicles.
The rare earth metals were extracted from nickel-metal hydride batteries collected from 386 Honda hybrid vehicles that were stored prior to being on sale but became unusable by the Great East Japan Earthquake.
As soon as a sufficient volume is secured, Honda will begin applying the same process and recycle rare earth metals extracted from used nickel-metal hydride batteries collected by Honda dealers through battery replacement.
Honda strives to extract rare earth metals not only from nickel-metal hydride batteries but also from various used parts to achieve the further recycling of limited and precious resources.
Tobias Müller and Bernd Friedrich (2003) Development of a new metallurgical process for closed-loop recycling of discarded Nickel- Metal hydride-Batteries. (Proceedings of EMC 2003)