How Much Precious Metal In A Catalytic Converter? Part II

We continue the series looking at how much precious metal in catalytic converters. In Part I we graphically depicted the variability of Platinum, Palladium and Rhodium content, as well as monolith masses, of vehicle catalytic converters based on our database* of several hundred different models.

In this post we will expand on the analysis to look at total contained PGMs for individual catalytic converters*, as well as introduce the “Platinum equivalent” metric for analysing data. The cash-value expected from processed cats is considered in the post “The Cash Value of Catalytic Converter Scrap”.

Total PGM Content

A simple arithmetic treatment of the total grade (i.e. percentage contained) of Pt + Pd + Rh gives a distribution as in Fig. 1.

PGM content catalytic converter

 

 

 

 

 

Fig. 1 Total PGM grade % distribution.
This translates into a total mass of precious metals contained in individual catalytic converters as per the distribution in Fig. 2. (Mass unit: 1 troy oz. = 31.103 g approx.)

Total PGMs catalytic converters

 

 

 

 

 

Fig. 2 Total contained PGM (troy ounces).

Importantly, this is what we refer to as the “in-situ” metal content, to differentiate from the “paid” metal content which the basis for determining a value for any particular converter, and which will be detailed in a subsequent post.

While instructive, a ‘total PGM content’ measure is not wholly suited to analysing or comparing value of different models of catalytic converter. The variability of both the content (as seen in Part I) and value of Pt, Pd and Rh makes direct comparison difficult, so we have borrowed the mining-industry concept of metal equivalents to deal with this.

Platinum Equivalent Content

For the current purpose, the in-situ Pt-equivalent is a normalisation of the data based only on individual metal content and market price. In essence, it ‘converts’ Pd and Rh grade (%) to a comparable Pt percentage which is then considered the overall grade %. This is a simplification of a broader concept to illustrate a comparison of in-situ metal content only, and is not a measure of cash-value. Valuation will be covered in later posts, where treatment and refining costs, losses, penalties and paid metal rates among others will be included to estimate a value.

Table 1 is a comparison of the in-situ total PGM content (above) and the Pt-equivalent data, while Fig. 3 is a plot of Pt-Equivalent% vs. monolith mass.

Platinum equivalent catalytic converters

 

 

 

Table 1. In-situ Total PGM and Pt Equivalent content.

Platinum equivalent monolith mass catalytic converters

 

 

 

 

 

 

Fig. 3 Pt-Equivalent vs Monolith Mass

Since the Pt-Equivalent is partly based on price data (the above in Fig. 3 is 30 May 2015 prices) it is an economic measure and therefore variable.

Join us for forthcoming posts where we will be looking at valuing scrap catalytic converters.


*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.

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.

Maximising the cash return of your scrap catalytic converters

The appeal for recycling scrapped catalytic converters from end-of-life vehicles (amongst other industrial sources) is easy to understand. This is largely because of the general perception that Platinum Group Metal (PGM) content is a high value and easily accessible resource.

Considering the high number of vehicles scrapped each year this is not surprising.Consequently, the autocat recycling market a competitive and rather crowded space.  

There is currently a well-established route from vehicle-breakers and scrapyards through any number of intermediaries until the PGMs are finally recovered at smelters and refineries. Some consider this to be the most efficient route for autocat recycling. But, this pyramid-shaped supply chain generally means a significant loss of value, particularly for those at the base of the supply chain.

As a result, we propose new and better way to get the most value from scrap cats. Follow us as we analyse the scrap catalyst market from all angles, including

• How much precious metal do scrap cats contain?
• What are autocats really worth?
• What is their recycling pathway?
• How are the PGM’s recovered?

In addition, we will be considering the PGM market, including

• Platinum, Palladium and Rhodium prices
• Supply / producers and demand / consumers
• Market history & outlook