Rare Earths
The Korea Electric Power Corporation (KEPCO) announced on Aug. 20 that it has developed a source technology to extract more than 90 percent of the lithium, a rare high-value metal, contained in coal ash generated in coal-fired power plants, and completed the applications for domestic and international patents.
KEPCO said that the new technology means that since it can extract the raw material from coal ash created in the process of coal-fired electricity generation, which is widely used in the world, it is a high-efficiency source technology.
The existing technology to extract lithium from coal ash using carbon dioxide is still in the research phase worldwide, but its extraction rate is only 10 percent. However, KEPCO’s process technology can extract more using microwaves. There are between 50 and 280 milligrams of lithium per kilogram of coal ash.
In Korea, about 57 million tons of coal ash are currently buried in power plant landfills, and around 7.9 million more tons of coal ash is generated from coal-fired power plants every year.
Other rare earth metals, such as yttrium and neodymium, core raw materials of LEDs and permanent magnets, are also concentrated in coal ash.
Based on the source technology, KEPCO is currently developing additional technologies to produce lithium carbonate with more than 95 percent purity, which can be commercially used, and to simultaneously extract rare earth metals from coal ash.