Yeah, I was wondering why you would ever want to do that, except to sabotage infrastructure.
No. No they did not
Well I wasn’t there so I can’t say for sure, but there are a number of archaeologists and researchers who think they did. And why wouldn’t they? The amount of carbon needed for carburizing a chunk of steel would be trivial and bone carbon is relatively free of contaminants.
https://www.google.com/amp/s/bigthink.com/amp/norse-rituals-2632488097
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Yes, I’m aware of this theory but I don’t agree that Terje has argued conclusively that his theory is true.
For reference: it’s based on this paper.
As you can see, first of all we can discount that we are talking about “Vikings”. The archaeological evidence the paper is based on is from the Roman Iron Age and Migration period, i.e. the era before the era before the Viking Age.
So now we have two questions to ask ourselves: did these people make steel from bone ash and did they make it from human bone ash?
Let’s start with the second one because it is easily dealt with: there is no direct archaeological or written evidence whatsoever for the making of steel in Scandinavia from human bones, or indeed from bones in general. As you can see in the paper, Terje bases his argument on rather tenuous associations from literature that was literally written a millennium after the archaeology he describes was created.
So, did they make steel from bone ash at all? Well, Terje has proven they could have done it, albeit he did so following manuals from the mid-20th century. That is the problem with experimental archaeology of this kind: saying something could have been done with the hindsight of modern science doesn’t mean it was done.
Let’s look at the archaeological evidence he has: a putative smithy (because of the presence of slag I’ll grant him that iron or steel was produced in the smithy, although I would not expect that process to be done near habitation in the Iron Age otherwise) with evidence of (unburned!) bone. Bone is found everywhere in prehistoric habitats, that alone doesn’t say much and I can think of several reasons why one would need it in a smithy off the top of my head (raw material for hilts or fittings is one, smoothing objects is another).
As you can see this is a very tenuous argument and I would absolutely not say that it proves in any way that Vikings (or even their ancestors that this paper is about) used bone ash in steel production at all, let alone human bone ash, let alone that of their ancestors.
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I’m not entirely clear on that. Cause the end result is sponge iron. Which is not pure iron, but iron with 6-10% carbon. And they have to be adding carbon for that.
Most of these processes tend to have multiple steps so maybe that’s a step one. Get rid of slag, then another step to introduce carbon. ETA: Or Hydrogen is gonna burn if you pump it into molten iron, so one step. And the hydrogen contributes heat but isn’t the main source.
I did some poking around after this press release first hit the news last week. Seems like a lot of related processes burn natural gas for heat and/or to generate power for electric furnaces, and were originally developed to deal with rising coke prices and reduced availability in Europe. It also seems like most steel mills using electric furnaces generate power on site rather than drawing from the grid. With a lot of recycled heat, and fuel serving multiple purposes.
That’s seems to be part of why this is hard to gloss or accurately describe in a press release. The big improvements are kind of in logistics. Where you get heat, where you get your fuel, where the electricity is coming from.
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and yet, it defies the laws of physics. It’s very difficult to eliminate carbon atoms-- what is needed is way to remove carbon dioxide, methane, and other greenhouse gasses that contain carbon.
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Not sure about this mill but most of Sweden’s electric power comes from hydro, nuclear and wind.
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Now do cement! That would make a huge impact!
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Yup. Sweden has a lot of both nuclear and hydroelectric power plants, and of course they’ve got tons and tons of wood, and produce heat and electricity with the leftovers of their forestry industries.
For Finland, 85% of our electricity comes from nuclear, hydro and renewables. And that’s going to just go up when (eventually, knocks wood) those nuclear reactors I mentioned go online.
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Lots of people are working on it
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Fossil-free steel…?
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Yeah and that’s the thing. I don’t think most of the steel industry pulls most of their power from the grid. So even where there’s a clean grid, the steel mill might not be using it.
The traditional approach on modern industrial processes seems to have been built around burning coke and coal for all of it. To generate power, to melt/smelt the metal, to make the coke, to get the carbon in.
Stepping off that has been mostly about reducing costs or dealing with low access to coal until recently.
That’s kinda what I was saying about being a logistics thing. The whole frame work on where heat and power are coming from, and how you get heat and carbon up in there is different here.
There are apparently similar processes operating at scale (albeit relatively small) in a few places. But they’re mostly where natural gas is inexpensive, and coal/coke are not. So they burn natural gas for power or heat.
There have been some experiments in smelting iron ore using natural gas which is cleaner than coke, but still produces carbon dioxide. Until now, smelting has always relied on carbon monoxide to reduce the ore to metal, but this is using hydrogen as a reducing agent. Going for true, green hydrogen (not the scams of grey or blue hydrogen) is the dream scenario.
Meanwhile here in the UK, the government is still not blocking proposals for a new coking coal mine in Cumbria, most of whose output would be exported. As always, on the wrong side of history.
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If they are injecting hydrogen into the mix I would interested in seeing how the chemistry works out in all of this. I know at lower temperatures, like for heat treating, you can get into hydrogen embrittlement and have to low bake the material to release the excess hydrogen and not cause issues. Perhaps at the molten temperature range hydrogen doesn’t interfere in the same was as atmospheric hydrogen would.
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If anything, I’d say the problem is that the article title should say “decarbonize steelmaking.”
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Technically burning off the carbon in steel (as others have noted to make iron) would be decarburize rather than decarbonize no?
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yeah I think that’s part and parcel of the linguistic weird here. For getting carbon in and out of steel it’s carburizing/decarburizing. Carbonize is what you do when you make wood into charcoal. Or to coal to make coke. Which is not how it’s being used, but they may be doing that anyway?
On top of that.
It’s not carbon free cause you still need to add carbon.
it’s not carbon emission free because some of that will still get into the atmosphere.
It’s kinda can’t be carbon neutral for the same reason, and there are other steps processing can’t cover.
It’s only even really fossil fuel free in the sense that where ever they’re getting the carbon, it isn’t fuel even if it comes from a fossil fuel.
Seems a weird thing to turn into a headline.
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Well, it could be worse. They could have settled on decarbonate. The Coke and Pepsi lobbies would never have allowed that! 
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It’s one step on a very long path, but that’s a kind of nuance headline writers ignore for the sake of eyeballs.
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