As a bit of a giggle, a mate of mine sent me a short blurb from the Minerals Council of Australia, one of the lobby groups for the mining industry. It gives a list of a few minerals and suchlike that they mine1.
The short list on the splash page gives something like the little squares in the periodic table with the symbols Au, U and C. These are for gold, uranium and carbon, respectively. However, while there is a blurb under the Au symbol on gold, and under the U symbol on Uranium, under the C symbol there is not a blurb on carbon but on coal1. That coal blurb states “Our high grade metallurgical coals are amongst the best in the world for modern steel making.”1
The earliest evidence of steel production is over three thousand years old, when it was discovered that iron became harder, stronger and more durable when it was left in furnaces in which carbon-rich fuel was burnt. China is commonly credited with being the first mass producers of high-quality steel. They likely used techniques similar to the Bessemer process, which was only developed and commercialised in Europe in the 19th century. Early examples of high-quality steel in China can be traced back to the 2nd century BC, with mass production taking off in the 3rd century AD2.
It would be a little surprising if the Minerals Council blurb had contained promotional tripe for thermal coal given its rapid decline as a fuel for electricity generation. It is declining so rapidly that even the Minerals Council must realise thermal coal is a lost cause, simply because it is a relatively inefficient process and contributes about 20% of the greenhouse gasses pumped into the atmosphere3.
Metallurgical coal still produces around 7% of greenhouse gas emissions. According to some estimates, global demand for steel will nearly double by 2050. ‘Green steel’, therefore, is urgently needed if the world is to limit the damage from climate change4.
What is ‘green steel’? Essentially, it is the steel manufactured without the use of fossil fuels. One of the ways to do this is to use ‘green hydrogen’. When ‘burned’, hydrogen emits only water. And if that hydrogen is produced via electrolysis using just water and renewable electricity, then it is completely free of CO₂ emissions and is termed green hydrogen4. Electric arc furnaces are another option provided they are powered by renewable sources.
Electric arc furnaces have been in operation for well over a century, while the use of hydrogen to produce steel is only a few years old. For example, in 2021, the Hybrit venture in Sweden, first delivered steel to vehicle-maker Volvo5. However, green steel is attracting billions in funding, with numerous corporations getting in on the act6, 7.
The assertion from the Minerals Council that their metallurgical coal is the bee’s knees for “modern steel-making” reeks of desperation.
Sources
- https://minerals.org.au/
- https://steelfabservices.com.au/who-invented-steel/#
- https://www.iea.org/commentaries/it-s-critical-to-tackle-coal-emissions
- https://www.newyorker.com/news/annals-of-a-warming-planet/the-promise-of-carbon-neutral-steel
- https://www.theguardian.com/science/2021/aug/19/green-steel-swedish-company-ships-first-batch-made-without-using-coal
- https://www.canarymedia.com/articles/clean-industry/worlds-first-major-green-steel-project-locks-down-5b-in-funding#
- https://climatesort.com/green-steel-companies/
i read your piece with interest. my original somewhay limited lay belief was that by some destructive process, metalurgical coal (or coking coal) was somehow incorporated into the physical/chemical structure of the iron ore to produce ‘tougher’ steel.
reading your piece took me down a google rabbit hole.
so … metalurgical coal is both the fuel source and as a reducing agent in smelting iron ore in a blast furnace.
when metalurgical coal is heated above 1,000 °C to 2,000 °C, one of the products is coke, a hard and somewhat glassy solid.
what i found unclear, in steel making, was whether to coke was produced initially and subsequently ‘introduced’ to the iron or whether it was a continuous process.
either way…… ‘green steel’ obviously does not use the coking coal as a fuel source BUT does it still incorparate ‘coke’ or is it actually the hydrogen, (via an electrolosis process) uncorporated into the stucture of the steel, that replaces coke as a ‘tempering’ agent?
I found all the ‘green steel’ a little vague in this respect.
as an aside, i guess tradition steel making could (disengenuously) be called a sequestration of carbon…. which obviously wouldn’t be necessary if the coal weren’t burnt in the 1st place.
Clive,
I had a mate who, during university holidays worked at the coke ovens at BHP in Newcastle; the coke is made beforehand. I do not know how the green steel is produced except that it doesn’t use coal or coke. I don’t know where they obtain the carbon for the steel, although I did see a suggestion that CO2 could be used.
* I found all the ‘green steel’ blurbs a little vague in this respect *
Somewhere in this wide brown land is steel I had a small, nay infinitessimally tiny, hand in producing. For I once was a trainee metallurgist at AIS in Port Kembla and along with a partner trainee we were tasked with throwing a can of metal pellets (haven’t got a clue what they were now) into certain recently poured ingots (they were numbered iirc) in an open hearth furnace section of the mill. We stood behind thick steel plates which shielded most of the direct heat, well above the ingots, then using gaps between the shields we quickly dropped the pellets into ingots as they slowly moved along a train line. Didn’t matter if a few missed apparently. Exciting stuff seeing the giant bucket pour moulten metal into relatively small sleeves. Obviously we had protective gear on, including thick leather gaiters – which I stilll have, heat resistant coats, and safety helmets with thick face shields. Given the timeframe, in reality “my” steel has probably already been recycled many times over.
Green steel is what the aliens use to build their flying saucers. As the religious say about their Gods, prove me wrong!!