Sherwood Plots: A Difference Between the Economics of Material Isolation in the 1950's and 2020s.

[NNadir]

Last edited Fri Apr 3, 2026, 12:56 PM - Edit history (1)

I'm writing one of my long posts (for my own edification) commenting on a recent paper on the topic of recovering cladding material from used nuclear fuel, and reference to "Sherwood Plots" popped into my head. Some years ago, I scanned Thomas Sherwood's 1959 lecture in accepting the Priestly medal for his work, which, put very succinctly, discussed what the concentration of a commodity should be, in waste or in ores, to justify its economic recovery.

This inspired me to look up the following open sourced paper, to which I'll refer, very briefly, in this post:

Karakatsanis, G.; Makropoulos, C. Resource Recovery and the Sherwood Plot. Entropy 2023, 25, 4. https://doi.org/10.3390/e25010004

From the introductory text:

The Sherwood Plot (SP) -after the Chemical Engineer Thomas K. Sherwood who originally formulated the method [1,2] is based on the core assumption that waste matrices are potential sources for the recovery of valuable materials, as an alternative to mining them from virgin ore deposits. Specifically, the original postulation of the SP depicted the relationship between the required market price of a target material to be recovered from a waste matrix and its dilution in the latter. In this context, the dilution was defined as reverse concentration at a logarithmic scale for smoothing extreme differences in scales of measurement (e.g., the comparison of very small fractions of the target material in relation to thousands of dollars of required market price). The formation of a set of coordinates by these two variables structured a map as decision support visualization for the recovery -or not- of the resource from the waste matrix [3].

Empirically, even though many target compounds or elements were found at very low concentrations (respectively very high dilutions) in waste matrices, it was still profitable to recover them due to their high natural scarcity, while others with very high concentrations were not, due to their very low market price that constituted their mining from virgin deposits to be a much more profitable solution. In any case, this rather profound macroscopic observation has deeper microeconomic extensions, affecting fundamentally the market structure and the allocation of market shares between industries operating in the recovery of the same materials, as we examine in Section 2 and Section 3.

However, the original form of the SP came with significant drawbacks. These drawbacks are the main motivation for our work that aims at reconsidering its foundations and revitalize its validity on more solid ground. The original SP form although it depicted the market price as a vital criterion for deciding to recover a material (or not), it made indirect assumptions on a unified cost of recovery between industries, which in reality differs significantly from industry to industry due to differences in technology [4], R&D programs, Intellectual Property (IP) rights (e.g., patents), learning curves and process engineering [5]. In addition, as the recovery of resources from wastes is at the core of what is called today Circular Economy (CE) -with Industrial Symbiosis (IS) being one of its major vehicles- the main quantitative issue is to implement full cost-benefit accounting. Full cost accounting means that besides the conventional industrial processing costs (e.g., capital, operational) two (2) types of environmental costs/benefits should be also included: (a) The cost/benefit of avoided pollution (e.g., in terms of CO2 emissions savings or conservation of ecosystem services value) and (b) The cost/benefit of avoided virgin resources’ consumption that leads to higher in situ availability [6,7]. In natural resource economics literature the above are considered as a natural capital consignment for future generations; also in line to the Brundtland Commission’s definition of sustainable development “Sustainable is the development that meets the needs of the present without compromising the ability of future generations to meet their own needs” with focus on intergenerational natural resource justice [8]. Such cost-accounting schemes can also be found in the standards of the European Union’s (EU) legislation on water resources [9]. Hence, under the EU’s economy’s re-structuring towards the CE, the cost and benefit of natural capital recovery and conservation is becomes a pillar of its ongoing industrial paradigm shift.

The italicized parts are so in the original.

The italicized text strikes me as making important points, particularly with respect to my bête noire, our responsibility - so readily ignored these days - to future generations.

The paper may be obscure, but it strikes me as a worthy comment. It is decidedly not true, to my mind, that economic considerations, which obscenely boil down to these days to what is cheap or perceived myopically as "cheap" (for example fossil fuels and so called "renewable energy" ) is not a justification for accepting a material or energy system.

I regard these absurd foci on "cheap" as immoral, obscenely so. What is "cheap" for us is unacceptably expensive to others.

Whence a sense of decency?

Have a nice weekend.

[GiqueCee]

1. our responsibility to future generations...

... is, indeed, too readily ignored these days. Which has prompted me, on numerous occasions of late, to mention my take on the corporatist's attitude toward future generations, to wit: "WHAT HAS POSTERITY EVER DONE FOR ME?"
The distilled essence of pathological selfishness.