LITHIUM, LITHIUM EVERYWHERE

ENVIRONMENT

TOKYO-Heavily dependent on imported raw materials, Japan has consistently sought ways of synthesizing or producing inputs at home. The latest chapter in Japan's drive for self-sufficiency is being written at Saga University, where researchers are perfecting techniques for extracting commercial quantities of lithium from seawater. Lithium is used widely by industry, consumers, and in medicine. It powers electric cars and laptops, is used in telescopes and ceramics, and to treat manic-depressive disorders. The versatile substance is extracted from igneous rocks, which Japan imports from countries such as Australia and China.

Lithium "is very promising as a next-generation energy source," notes Kazuharu Yoshizuka, a professor of environmental engineering at the University of Kitakyushu, who is collaborating on the project. "When you consider that two thirds of the Earth is seawater, the amount of [available] lithium is immense."

The Japanese have been thwarted so far by the fact that lithium concentrations in seawater are extremely low, requiring vast quantities of seawater to be processed to harvest even minute quantities. Saga University's lithium chloride haul, obtained from forcing seawater through manganese dioxide crystals which adsorb the lithium, has been a mere gram a day. Still, Yoshizuka reckons technology to efficiently recover lithium from seawater is not far off. -LUCY CRAFT

Copyright American Society for Engineering Education Sep 2004
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