Japanese team recovers rare metals using microwave oven

November 27, 2017

Yonezawa, Yamagata Pref.- A team of researchers of Japan's Yamagata University has developed a simple method to recover rare metals from automotive exhaust gas treatment systems using a home-use microwave oven.

The method, if put into practice, will drastically save time and costs to recover the metals.

Exhaust fume treatment systems employ honeycomb-structured tubes containing catalysts sprayed with particles of rare metals, such as platinum and palladium, in order to remove harmful substances from exhaust gases.

About one gram of platinum is used in each system, according to the team.

In vehicle recycling, catalysts are usually crushed into small fragments at special facilities and rare metals are separated from other substances.

The new method makes it unnecessary to break catalysts.

Under the method, a honeycomb structure into which acid has been injected is exposed to microwaves in an oven for tens of seconds. This process produces a rare metal solution.

When reductants are added to the liquid, the metals are obtained in powder form, the team said, adding that this process is also facilitated by microwave exposure.

Under conventional methods, it takes about 27 hours to make a rare metal solution and recover the metals from a one-square-centimeter piece of a catalyst. But the new method requires only up to 10 minutes.

"With a microwave oven that anybody can operate easily, I hope to put (the new method) into practical use," said research team member Masatoshi Endo, associate professor at Yamagata University. Jiji Press