Precious metal in scrap catalytic converters

The question of how much precious metal in scrap catalytic converters is, not surprisingly, very commonly asked.

But only few (if any) of the guides and resources available give the actual content of platinum, palladium and rhodium, mostly because the information can be difficult and expensive to come by.

We discuss in more detail the quantity of precious metal in scrap catalytic converters here and here, but in this post we get a better feel for the question using simple visualisation.

Let’s first take a look at some of the properties of the precious metals in scrap catalytic converters.

Platinum, palladium and rhodium

Platinum is one of the denser metals, about 21.45 x that of water. Palladium clocks in at a bit more than half of that, at around 12.02, while rhodium is about 12.41. By way of comparison, gold is 19.32, while copper is only 8.96. Water, obviously, is 1.

The image below approximates these metals’ densities in relation to the volume of water.

Density of precious metals in scrap catalytic convertersLet’s consider this another way:

A normal matchbox like the one below would have a volume of about 22.2 cm3.

matchbox - standard
Now if this matchbox was completely filled with platinum, it would weigh around 476 g (15.3 oz*), or about the same as half a kitten.

The weights for the other metals, should they fill the matchbox, are shown in the graph below. Au, Cu and H2O are also shown, for comparison.

mass of metals - matchbox

This is all very well, but how much is this hypothetical matchbox stuffed with precious metal actually worth?

At today’s NY spot prices…

A platinum-filled matchbox would fetch over $15,000. Gold, a fraction more.
A palladium matchbox: $6,500. A bit more for rhodium.
Copper-filled: $1.20.

metal value

So now we have a feel for some of the properties and the relative value of platinum, palladium and rhodium. Next we’ll have a look at these precious metals in scrap catalytic converters.

Precious metals in scrap catalytic converters

Firstly, I want to get something out of the way. There are thousands of different catalytic converters out there, manufactured globally over decades. Their precious metal content is highly variable, both in terms of absolute quantity, and relative proportions, of platinum, palladium and rhodium. It is doubtful that anyone has precious metal content information on all (or even most) of them. So the info below is based on our data, which we have found to serve our purpose well enough.

So then, let’s have a look at this in a bit more depth.

Because Platinum Group Metals are highly effective catalysts, it doesn’t take much for them to do their job. So, tiny amounts of precious metals in catalytic converters are ‘stuck’ on a substrate (usually a cordierite structural ceramic monolith, the so-called ‘honeycomb’, though also foil or beads) in a very thin layer.

To show just how much (or little) platinum, palladium and/or rhodium is actually in your average catalytic converter, consider that a 1kg monolith will on average contain less than about 3 g total precious metal. That’s less than 0.3%.

The image below puts that in perspective: if the blue dots represent the monolith, the total amount of contained PGM will be the red dots.

average pgm in scrap cats

Put another way, if you compare the monolith to a 24 hour day, the average total precious metal content is the equivalent to about 4 minutes

So we see that there is not terribly much total platinum, palladium and rhodium in the average catalytic converter.

Going back to our example above then, how much catalytic converter scrap would you need to fill our matchbox with recovered platinum group metals?

Based on our experience and database, about 200 catalytic converters should do the trick.

But of course it is not as simple as that, because there are a whole series of costs and losses in the process of metal recovery that need to be considered. We’ll be revisiting these issues in an upcoming post, as well as our proven strategies to maximise the value of scrap catalytic converters.

 

Notes:
When we refer to oz, it always means troy ounces. 1 troy ounce = 31.1035 g.

Sometimes we refer to PGM, i.e. platinum group metals. Technically PGM include ruthenium, osmium and rubidium as well, though we of course are only interested in Pt, Pd and Rh.