Mitsui Mining new autocatalyst uses silver, not platinum

TOKYO, April 23 (Reuters) - Mitsui Mining and Smelting Co Ltd (5706.T: Quote, Profile, Research, Stock Buzz) said on Wednesday it has developed a new catalyst for diesel engine cars that replaces the use of platinum with silver, a less conventional but much cheaper metal.

"Silver will totally replace platinum in this new autocatalyst that we've developed," a company spokesman said.

By substituting platinum with silver, the cost of precious metals in the production of autocatalysts, which clean car exhaust fumes, would be cut by more than 90 percent, the company said.

Spot silver <XAG=> is currently trading at around $17.70 an ounce, compared with platinum <XPT=> at around $2,030.

The spokesman said Japan, Europe and the United States are all planning to impose tighter rules on exhaust emissions for heavy-duty vehicles, such as those used in construction and farming, from 2012.

"We hope that this catalyst will be used in diesel engines for those vehicles, and this is the market we are targeting," he said.

Platinum specialist Johnson Matthey Plc said last November that platinum demand from automakers for catalytic converters would climb 2.3 percent to 4.24 million ounces in 2007 on the back of robust sales of light-duty diesel vehicles in Europe.

Platinum and its sister metal palladium are employed in varying amounts in autocatalysts to filter out carbon monoxide and particulate emissions. (Reporting by Miho Yoshikawa)