How Much Precious Metal In A Catalytic Converter? Part I

Perhaps the most important question is how much precious metal in a catalytic converter? At Scrap Catalyst Hub we are growing a database which we have used to illustrate* the Pt, Pd and Rh content, as well as the masses, of a population of vehicle catalytic converters. The database currently has several hundred entries, which we are using to develop a model for extracting maximum value from scrap cats.
The content of Platinum (Pt), Palladium (Pd) and Rhodium (Rh) in vehicle catalytic converters is highly variable, dependent on engine type, brand, age & geography amongst several other factors. The value of a scrap autocat is naturally related to the content of the Platinum Group Metals (PGM), although as we will outline in a forthcoming post there are a host of other factors to take into account when determining its actual value.
The data are entered into in somewhat more detail below, though in summary our catalytic converter database suggests that:
• Average monolith mass is approximately 2 lb (0.9 kg)
• Average Platinum content is 0.17 %
• Average Palladium content is 0.07 %
• Average Rhodium content is 0.03 %

The variability of the data warrants more analysis than presented here, and will be contained in the follow-up post “How Much Precious Metal is in a Catalytic Converter? Part II”, while the cash-value expected from processed cats is considered in the post “The Cash Value of Vehicle Catalytic Converter Scrap”

Monolith Mass

We’ll firstly consider the mass of the catalytic converters (Fig. 1), and to avoid any confusion this refers to the mass of the de-canned monolith (sometimes referred to as “honeycomb”) or beads, not the entire assembly. In this case we’ve chosen to use pounds (lb) as our unit of measurement; if required the conversion from kilograms (kg) is near enough 2.2046 i.e. 1kg = 2.2046 lb.

Monolith mass of catalytic converter

 

 

 

 

 

 Fig. 1 Mass distribution of individual catalyst monoliths

This distribution of the mass of individual catalytic converters in our database shows that
• the average monolith mass is around 2 lb / 0.9kg,
• mass ranges from less than around 0.5 to more than 5 lb (although we are aware of examples of greater mass)
• 75% of examples are less than 2.7 lb (yellow shaded area),
• 90% are less than 3.3 lb (pink shaded area).

Ratio of Platinum Group Metals

The ratio of Pt, Pd and Rh is highly variable between different vehicle catalytic converters, with Platinum dominating for diesel engines and Palladium for petrol engines. The following plot (Fig. 2) shows the percentage of each metal contained in individual converters. It is clear that Platinum dominates, followed by Palladium and Rhodium being least common.

PGM ratio of catalytic converter

 

 

 

 

 

Fig. 2 Proportion of PGM’s contained in individual vehicle catalytic converters
Specifically,
• Around 86% of converters contain at least some Pt
• 18% are exclusively Pt
• Around 30% contain at least some Pd
• Around 75-80% contain at least some Rh

Platinum Group Metal Content

A scatter plot of individual PGM content vs. monolith mass (Fig. 3) highlights the relative proportion of Pt, Pd and Rh (zero values excluded).

Metal and monolith in catalytic converter

 

 

 

 

 

 Fig. 3 Pt, Pd and Rh Content vs Monolith Mass (zero values excluded)
The variability of the content of Platinum, Palladium and Rhodium are shown in Fig. 4 and summarized in Table 1.

Metal content in catalytic converter

Fig. 4 Content distribution for Pt, Pd and Rh

Metal content in catalytic converter 2

 

 

 

 Table 1. Summary of Pt, Pd and Rh content in vehicle catalytic converters

For further analysis and conclusions drawn, please see the forthcoming follow-up post “How Much Precious Metal is in a Catalytic Converter? Part II”.

*We do not claim that this is a complete database of all vehicle catalytic converters, nor have any of the data been independently verified, and we cannot take responsibility for its use.