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