Catalytic Converters – Streets Paved with Platinum

It’s difficult to believe that something so rare and precious could literally litter our streets, but that’s the truth of it. The group of metals close to platinum, such as palladium and rhodium, are covering our streets. So what are we going to do about the wastage of these precious metals and where do they come from? One company has already set to work on collecting these metals and we’re about to explain how.

Where are the Precious Metals Coming from?

These precious metals are usually found within the catalytic converters of cars with reduced carbon emissions. The catalytic converters are fitted with a number of precious metals inside them, the job of these precious metals is to react with and remove the toxins that are spewed by the engines of cars, the precious metals also remove part of the carbon content from the exhaust fumes. As the precious metals react with the emissions the metal begins to corrode and after a period of time small parts of these metals will break away and fall out of the exhaust onto the pavement or road.

It was originally perceived as too difficult to collect these extremely fine particles from the road and it was believed that even if they could be retrieved, the process would not be cost effective. However one company, Veolia, has decided that they are going to take a chance and attempt to collect these miniscule particles by travelling the streets of London and various other cities within the UK and sweeping up the particles from the road.

How Will Veolia Achieve This?

Veolia have created a technique that combines two main stages. The first stage filters the contents of the sweepings to remove the largest particles and the second stage removes the palladium by washing the soil.

Although the palladium will only be removed in trace amounts the metal is so precious that even these traces are very valuable. In the past these metals have been considered so precious that a number of people have stolen catalytic converters just to remove the metals from them and sell them on.

Palladium was first discovered by a chemist in London called William Hyde; he named the metal after a meteor that has been discovered the year before due to the silvery white colour and the lustre of the metal.

The Process

Veolia will send out mobile units that will scour the streets sweeping up any particles that they find. These particles will then be taken back for examination where the largest objects and particles will be removed through sieving.

Smaller metallic particles are then removed through the use of magnets but aluminium is extracted separately through an eddy current separator. Once the more common metals have been removed the sweepings are placed onto a vibrating conveyor belt where twigs, plastics and grit will be taken away.

At this point only a fine grey dust will remain which is mixed with water, filtered, shaken, spun and then filtered a third time. Veolia use a special technique to remove oils from the water; they use bags filled with absorbent polymers to remove the oils safely before continuing the process.

The oil-free water will then be treated with a variety of chemicals and filtered through membranes in order to extract the platinum group metals, including palladium.

This is one of the many ways in which technology is advancing and we are creating new ways in which we can recycle our metal. Keep your eyes peeled for more information as the experiments continue. For more information on metal recycling and how you can help the environment get in touch with us at Taroni Metal, we’d be happy to hear from you.