Rare Earth Oxides

Ford Motor Co. is turning to an obscure set of rare earth oxides (REOs) in an effort to drive down cost and conserve the amount of precious metals in the catalytic converters of its cars and trucks.

By utilizing greater amounts of REOs — including lanthanum, cerium, praseodymium and neodymium — to optimize the reactivity of catalyst precious metals such as palladium, platinum and rhodium, the auto maker has reduced its overall precious-metal use in North American gasoline-fueled vehicles about 40% over the past two years, says Ford Technical Fellow Haren Gandhi.

Ford now is focused on extending its precious-metal reduction crusade globally — including emerging markets in Asia/Pacific and South America, where emissions standards have yet to mature.

The auto maker's drive to find material savings in catalyst technologies is nothing new. In 1997, Ford partnered in a joint venture with China's State Science and Technology Commission to build a low-cost converter for that country using rare earth oxides.

Ford also is looking to eliminate the use of platinum from its diesel catalysts because diesels are expected to continue to penetrate most markets in the world.

The oxides, which really are not rare, enhance catalytic activity within the catalyst as well as extending the life of the component, while allowing Ford to pack its converters with a small concentration of expensive precious metals.

A 37-year Ford veteran, Gandhi oversees a pair of departments for the auto maker. They include chemical engineering and the Emissions and Fuel Economy Core Team — both of which, he says, are critical in helping the company save money and the planet at the same time.

When platinum became too expensive, Gandhi is credited with spearheading research that allowed Ford to move toward cheaper palladium. As palladium costs heated up, he turned to rare earths.

Ford is finding the REOs actually are improving the performance and longevity of catalytic converters — which account for most of the precious metals found in an automobile.

The auto industry bought 2.6 million lbs. (73,708 kg) of platinum for use in auto catalysts in 2003 — worth $1.8 billion, according to catalyst-maker Johnson Matthey plc.

The reduction of precious metals in automotive use could spell a significant decline in demand, especially if global auto makers hone the rare-earth innovation. Gandhi estimates competitors could catch on to Ford's reduction strategy within three to four years.

It also would go a long way in reducing the cost of catalysts, while helping auto makers to meet world emissions standards, such as Euro III that began its phase-in in 2000, and the Partial Zero Emission Vehicle standards proposed by California's Air Resources Board for phase-in starting in the '09 model year.

New federal Tier II and California Low-Emissions Vehicle II emissions standards also require auto makers to warrant catalysts for 120,000 miles (195,000 km).

Prices of palladium, platinum and rhodium currently run about $215, $850 and $1,125 per ounce (28 g), respectively, Johnson Matthey says. The price of rhodium has doubled vs. year-ago, while platinum has jumped about 20% and palladium has remained flat.

Auto makers are the largest end users in the volatile precious metals market annually, consuming between 40% and 86% of the world's entire market for such metals, according to data by Johnson Matthey, which publishes periodic journals devoted to the subject.

The auto industry is on pace to spend more than $3.5 billion annually on precious metals for catalysts this year, alone, and Johnson Matthey expects that number to increase as auto production and emissions standards are tightened.

REOs, like precious metals, are found in ample supply in China, performance developer AMR Technologies says.

They help work to cut precious-metal content by either strengthening or weakening chemical interactions within the catalyst, thereby ensuring “that we absolutely…use to the minimum extent necessary the precious metals to get the job done,” Gandhi says.

Demand for rare earths — which are a late-blooming group of elements (about 15 in all) on the periodic table known as the Lanthanide Series and only recently exploited by the industry — is expected to grow at the rate of 3%-5% annually over the next three years, AMR says.

Such elements are prized for their unique individual chemical and physical properties.

Says Gandhi: “Rare earth oxides are the group of metal oxides, which, in combination with precious metals, allows us to retain the high sensitivity of precious metals and the thermal durability,” without forcing Ford to overload catalysts with unnecessary amounts of precious metals to ensure long-term performance in the face of potential thermal damage.

He also says the work has allowed the auto maker to more precisely place precious metals on ceramic, in addition to helping refine its cold-start strategy.

“Once we figured out how to improve the thermal stability, (the former) precious metal requirement became unnecessary, and that's the basis for this significant reduction in precious metals,” he says.