The Energy Requirement of Metal Processing and the Nuclear Option.

[NNadir]

Last edited Sat Jan 27, 2018, 08:42 AM - Edit history (2)

For my money, the most interesting, and possibly the most challenging thinker on the topic of energy in our age is Vaclav Smil.

I first became aware of him when I was thinking about the subject of catalytic nitrogen fixation and kept finding references in scientific papers on modern development of catalysts to his outstanding book on the history and development of this process on which our food supply is now entirely dependent, Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production.

I have read few books as thought provoking as this.

It is only possible to go through a small subset of Smil's writings and still have a life, but to the extent I have over the years, and whenever I have, I've been impressed with his vast knowledge of industrial processes, their interface with energy, and his associated stark realism, and if nothing else, they are stark.

Recently while reflecting on Richard Feynman's 1959 lecture, "There's Room at the Bottom" which predicted the information age and the nanotechnology age which has come to pass, I was inspired to refer to the book where I first encountered it - it's in the appendix - the Second Edition of Bradley Fahlman's wonderful text Materials Chemistry - and I found myself wandering to Chapter 3 in the book which is entitled "Metals."

Reading through sections of it I was reminded of one of Smil's writings that has really troubled me for years and challenged my technological thinking - and by the way I don't always agree with Smil but one has to think very deeply if one wants to seriously disagree with many of his profound insights - specifically, this one from 2009: The Iron Age & Coal-based Coke: A Neglected Case of Fossil-fuel Dependence.

(It comes from a "Free Market" blog, and I assure you that I am in no way a "free marketeer," since I am more inclined to think about sustainability, the very long term, as opposed to the psychology of our short term amoral generation of fools and "economic realities" that some people put forth, usually as I encounter them with the fraudulent statements that "solar energy is cheaper than grid energy," or "renewables are the fastest growing source of energy capacity." )

However much Smil and I may disagree on political economics however, I am certainly not in the mainstream of my political party, the Democratic Party - inasmuch as I think that the magical thinking that betting the future of the planetary atmosphere on wind and solar energy is at best wasteful and at worst tragic - I certainly agree with the introduction of his writing on the iron age:

As an old-fashioned scientist, I prefer hard engineering realities to all those interminably vacuous and poorly informed policy “debates” that feature energy self-sufficiency (even Saudis import!), sustainability (at what spatial and temporal scales?), stakeholders (are not we all, in a global economy?) and green economy (but are not we still burning some 9 billion tonnes of carbon annually?).

High regard for facts and low regard for wishful thinking has forced me to deal repeatedly with many energy illusions–if not outright delusions–and to point out many complications and difficulties to be encountered during an inevitably lengthy transition from an overwhelmingly fossil-fueled world to economies drawing a substantial share of their primary energies from renewable sources.

I personally believe that the only sustainable form of energy is the cleanest and safest form of energy, nuclear energy. This is not, by the way, a statement that nuclear energy is without risk or that it is or has proved to be always harmless - clearly it hasn't - but my words contain the relational suffix "-est," cleanest, safest. It is merely a statement that nuclear energy is superior to all other options in energy.

Smil's point in the referenced article is that we must have coal because we must have steel.

I, by contrast, have convinced myself that nuclear energy should do everything. Am I engaged in the wishful thinking about which Smil is ever ready to challenge.

Steel...steel...steel...

If you want to get a feel for what's involved in steel, you should head out to Bethlehem, Pennsylvania and tour the steel stacks from the abandoned post industrial facility that used to be the chief plant for the defunct company Bethlehem Steel. The city of Bethlehem was left with this rotting hulk, and with wonderful creativity managed to turn it into a sort of industrial museum that also functions as an arts and music center. One can walk along a catwalk along side the towering retorts with nice little posters on industrial history, including comments on the immigrants who came to work there, and see where the steel for the Empire State Building, the Golden Gate Bridge, and the overwhelming majority of the "liberty ships" that won World War II was made.

It's a worthy afternoon, and if you go in summer, you can catch a nice evening concert on the surrounding grounds.

From Fahlman's book, on the subject of steel processing:

It is estimated that iron constitutes 90% of all applications that involve metals. Hence, it is not surprising that the purification and post-processing for iron is the most widely practiced. The most primitive method that was used in the nineteenth century to purify iron from its ore is called bloomery. This method used pure carbon in the form of charcoal to reduce the metal (Eq. 2). In this process, the temperature is not sufficient to completely melt the iron, so a spongy mass consisting of iron and silicates are formed. Through heat/hammering treatments, the silicates mix into the iron lattice, creating wrought iron. This form of iron was used exclusively by early blacksmiths, since the heating of wrought iron yields a malleable, bendable, and extremely easy compound to work with. Most modern applications for metallic iron are steel related, exploiting its high hardness, ductility and tensile strength. Figure 3.3 shows a flowchart for the various procedures that are used for modern steelmaking. The first step uses a blast furnace [3] that is comprised of a massive, refractory-lined steel column wherein pelletized iron ore, charcoal, and calcium sources (from limestone and dolomite) are poured into the top, and a large jet of pre-heated (ca. 1,050_C) air is blown in from the bottom. As mixing of the components occurs at various temperature regimes, the various oxides present in the ore are reduced to metallic iron. From the coolest – hottest portions of the blast oven, corresponding to the highest – lowest regions, respectively, the following oxides are reduced (Figure 3.4):

1. 500–600C: 1.Hematite (Fe2O3)
2. 600–900C: Magnetite (Fe3O4)
3. 900–1,100_C: Wustite (FeO)
4. >1,100_C : FeO0.5

Since iron ore is largely comprised of aluminosilicate minerals, a byproduct is also formed within the blast furnace, known as slag (ca. 30–40 wt.% SiO2, 5–10 wt.% Al2O3, 35–45 wt.% CaO, 5–15 wt.% MgO, and 5–10 wt.% CaS).
It should be noted that it takes 6–8 h for the native iron ore to descend toward the bottom of the blast furnace, but only ca. 8 s for the pre-heated air to reach the top of the furnace. Oftentimes, a fused solid known as sinter is also added to the blast furnace, which is comprised of fine particulates of iron ore, coke, limestone and other steel plant waste materials that contain iron. The reducing agent within the blast furnace (coke) is comprised of 90–93% carbon, and is formed by heating coal to remove the volatile components such as oil and tar. The coke is ignited at the bottom of the blast furnace immediately upon contact with the air blast; since there is excess carbon in the furnace, the active reducing species is CO rather than CO2.

You get the idea...

Further text refers to the removal of sulfur from the pig iron, using calcium oxide, "burnt lime," itself requiring a huge investment in heat for manufacture at 1400C and then transferring the molten metal using a ladle to the "BOF," the basic oxygen furnace, where the metal is treated with a supersonic jet of pure oxygen with the temperature rising to 1700C to remove phosphorous, carbon, manganese and silicon.

Later there's reference to the use of pure argon gas for alloying purposes. The purification of argon, which represents about 1% of the atmosphere is also an extremely energy intensive process.

There's quite a bit in this text, including some wonderful pictures of a steel plant in Dearborn, Michigan, Sevarstar Steel, then the American subsidiary of a Russian company that as of today has been sold to an American company AK Steel. The chapter also contains wonderful pictures of other industrial facilities to process other metals. If you can find access to this book, and you're at all interested on a profound level on the subject of sustainability, it's almost an essential read, along with reading Smil.

Smil's argument is that there is simply not enough carbon available in biomass to replace coal.

I would counter that there is certainly enough carbon in the atmosphere to replace coal however, if one can reduce it.

In the future in this space, I hope to write a commentary on a paper in the current issue of Chemical Reviews which is dedicated to "Sustainable Chemistry" to discuss carbon dioxide/water splitting thermochemical cycles.

Is it conceivable that we can replace carbon from coal for processing iron with nuclear energy? I believe it is. Is it easy to do so? Probably not. My impression is, however, that irrespective of overcoming the unsustainable temporal psychology of "free markets" we have a moral obligation to all future generations to explore this.

My insomnia, under which I write this piece is finally being overcome, and I'm going for a nap. If interested, stay tuned. I'll leave you with a link to what Vaclav Smil sees when he sees a wind turbine, with a cool graphic dripping with oil:

What I See When I See a Wind Turbine

I see something different, something worse than Smil sees - the future unless we change our minds - but neither of us are fond of wind energy, which is not clean, not "green" and not sustainable.

Have a pleasant weekend.

[hunter]

1. If we can somehow achieve a declining human population...

... it's possible a civilization could make do with the steel that's already been made.

[NNadir]

2. Invariably, there are losses, not only with steel, but with all elements in the periodic table.

One of the most critical elements right now is indium, which is a component of many devices that require materials with the property of being transparent as well as being electrically conductive.

In cell phones, and in solar cells of the (CIGS) type, indium is in the form of ITO, indium tin oxide.

There are no pure ores of indium, and its solubility in ocean water is extremely low. It is a side product of the refining of zinc and a few other element ores.

In order to meet a requirement that we simply use indium that has already been isolated - the endless "we'll just recycle it" stuff that always ends up as a panacea statement whenever one makes a point that, for example, wind turbines and solar cells are not, in fact, "renewable" - it must be the case that 100% of the world's cell phones and 100% of its CIGS solar cells make it back to a recycling plant. Moreover indium, even if it is an essential component, is in low concentrations in these devices, and therefore one must invest considerable energy to recover it, not to mention using large amounts of materials, solvents, reagents, acids, bases, what have you.

Much steel is recycled of course, but the existence of rust demonstrates that it cannot be 100% recovered.

Secondly, there are lots and lots and lots of steel alloys, vanadium steels, low carbon steels, steels with manganese, etc., etc.

For particular applications one might need to add or remove other elements. This is, in fact, part of the issue with the steel processing described in Fahlman's book.

Recycling is a good idea; an excellent idea, but it will require above all energy, since all materials used by human beings exhibit not only the property of being distributed - itself an energy consuming exercise - and the requirement of being recentralized - also an energy consuming exercise - but the requirement to overcome the entropy of mixing, that is repurification.

When I grew up "recycling" was a great buzz word, and I thought that everything would be wonderful if we "just" recycled everything.

(Living systems actually do this; there is very little waste, other than the unfortunately huge deposits of oil, coal and gas).

But I was far more simplistic as a child, and until I challenged myself to address the arguments made by people like Vaclav Smil, I remained a child, and possibly - even though I'm an old man - I stopped being a child only a short time ago.

We should recycle, common materials like steel, and uncommon things like indium, but unless we experience a huge decrease in population - which we might stumble into through stupidity - we are still going to mine stuff well into the future, especially if we keep lying to ourselves about how great so called "renewable energy" is.

This is why I constantly refer in this space to energy to mass ratios, which - absenting some breakthrough in nuclear fusion - is the highest for actinide elements, making their use superior to everything else.

[hunter]

3. For a case study I've been thinking about high speed rail.

It requires at a minimum 140 kilograms of high grade steel per *meter* of track.

China's high speed rail is using considerably more steel per meter than that in the reinforced concrete viaducts, bridges, tunnels, etc. supporting their ambitious high speed rail system.

So, yes. A high energy industrial economy needs plenty of carbon just to make steel.

One source of non-fossil fuel carbon might be the ocean rather than the atmosphere.

Power plants, desalinization schemes, etc., might be a good source of carbon dioxide which could be turned into fuels such as DME and carbon for the steel industry.

For example:

EXTRACTION OF CARBON DIOXIDE FROM SEAWATER BY ION EXCHANGE
RESIN PART II: USING STRONG BASE ANION EXCHANGE RESIN

http://www.dtic.mil/get-tr-doc/pdf?AD=ADA514460

I think it's a grave mistake to bet the future of the human race on fusion power as many supporters of "natural gas is a transition fuel" seem to do. A gas-solar-wind hybrid economy is just as deadly in the long run as a coal economy. Fracked gas and oil are every bit as awful as coal.

[NNadir]

4. I've been following Dr. Willauer's work for quite some time now.

It's one of the more interesting approaches to the removal of carbon dioxide from seawater I've seen, but I'm not clear on the efficiency.

What is nice is that it breaks the water into an acid component - in which CO2 is insoluble - and a basic component which can readily absorb higher amounts of CO2 from the atmosphere.

All that is required is carbon free energy; there's the rub.

One thing that is very certain is that the best mechanism for the removal of carbon dioxide from the atmosphere, with the possible exception of the thermal conversion of biomass, will involve seawater.

In volume terms, seawater carries far more carbon dioxide than air.