Category: Emissions Control
Subject: PGM loading and recycling rates in autocatalysts
What proportion of cars have had autocatalysts fitted to them in the EU, US and Japan over time (1995 to date)?
What has the PGM loading in grams of the average autocatalyst been over time in the EU, US and Japan?
What proportion of autocatalysts in the EU, US and Japan are recycled and have been recycled over time?
A large proportion of new light duty vehicles sold in the European Union, Japan and the United States have been required to be fitted with catalysts in the period 1995 to date. Gasoline vehicles sold in Europe have required emissions control catalysts since 1993 while diesel vehicles sold in Europe have required emissions control catalysts since 2001. In the United States, all new gasoline cars sold have been fitted with catalysts since the 1975 model year, and light duty diesel vehicles since 2007. In Japan, gasoline vehicles have been fitted with catalysts since the mid-1970s and diesel vehicles since 2002. Vehicles produced in the EU, USA and Japan for export could have been fitted with catalysts before the above dates, depending on their destination.
The catalyst formulation and loading used will vary greatly from one vehicle to another, based on the engine's control strategy, the relevant emissions control legislation, the engine's size and where the catalyst is positioned on the car. The worldwide average platinum group metal content is around 4-5 grams per car, but the range is very wide - from 1 g on microcars to 15 g or more for large, powerful vehicles. Most gasoline-fuelled vehicles use a combination of palladium and rhodium as the catalytic metals, but a number also use platinum. Something like seven times as much palladium as rhodium is estimated to be used for autocatalyst applications globally. By contrast, in diesel vehicles, although the catalyst loading and catalyst size vary greatly, the metal formulation varies little, being mainly based on platinum or platinum-palladium. Platinum is easily the most efficient metal for reducing emissions from the oxygen-rich exhaust of the diesel engine.
In 2011 over 80% of the pgm in US light duty scrap vehicle autocatalysts were recycled, while over 60% of the pgm contained in European and Japanese end-of-life vehicle autocatalysts were recovered. Recovery rates have grown over the past 30 years as collection networks have become more efficient and as more vehicles fitted with catalysts have been scrapped. Data on the volume of pgms recovered from autocatalysts in 2011 can be seen in: http://www.platinum.matthey.com/uploaded_files/PT_2012/recycling.pdf
Answer posted 23rd July 2012
Submitted by: Peter Lowery
Affiliation: Investec AM
Answered by: Jonathan Butler
Affiliation: Publications Manager, Johnson Matthey Precious Metals Marketing