this post was submitted on 19 Apr 2024
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99
How to Escape From the Iron Age? (solar.lowtechmagazine.com)
submitted 6 months ago by [email protected] to c/[email protected]
26 comments fedilink hide all child comments
 

We cannot lower carbon emissions if we keep producing steel with fossil fuels.

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[–] [email protected] 23 points 6 months ago (2 children)

The key problem is that, as the article highlights, iron is widely available and its energetic cost per ton is relatively small. This means that we actually need to reduce steel production, not just replace it with something else and call it a day. Doing the later would cause more harm than good.

For that, I think that consistent application of the three R's (reduce, reuse, recycle - in this order, and stop forgetting the first two R's dammit) would be a good start. And perhaps legislative measures against businesses trying to prevent you from applying the three R's.

In the meantime, perhaps look for alternative steel productiion processes? You need some carbon as it's part of the alloy, but I wonder if the bulk of the reduction could be done by electricity instead. And even the carbon could be sourced from renewable sources; more expensive, but doable.

[–] [email protected] 10 points 6 months ago* (last edited 6 months ago)

The folks who came up with the 3 R's (plastics industry) knew that only the first one made any difference whatsoever.

Even today, plastics recycling only makes a trivial difference. Edit: And a lot of things saying "uses X% recycled plastic" are often referring to the plastic recycled in-house through the manufacturing process, which they've always done (such as flash from injection molding). Unless it says "post-consumer" it's just moral grandstanding.

However, steel is the most recycled material today, and glass is also good at being recycled. But glass has a weight (and therefore energy) penalty, which likely outweighs recycling benefits.

[–] [email protected] 6 points 6 months ago* (last edited 6 months ago) (1 children)

Electric arc furnaces are becoming more common across the steel industry, coke alternatives not so much. Being a commodity, any steel plant that chooses more expensive ingredients is going to quickly go out of business

[–] [email protected] 2 points 6 months ago

any steel plant that choses more expensive ingredients is going to quickly go out of business

That's true, and perhaps governments could/should kick in. The shift would be overall advantageous for society, so I think that it could be viable to tax coke production and use those taxes to subsidise plants using greener energy, offsetting the costs.

In the meantime, perhaps some global measures. Such as a treaty specifically addressing steel-based carbon emissions. Big thing here would be to convince the big three (China, India, and Japan); if the shift is desirable and viable for those three, others are easier to convince.

[–] [email protected] 5 points 6 months ago* (last edited 6 months ago)

I hear bronze is pretty decent. Could always go retro.

[–] [email protected] 5 points 6 months ago* (last edited 6 months ago) (1 children)

Rio Tinto is moving to solar (and some wind) here in Australia for its aluminum refining and smelting operations. Would be good if the same could be done for steel too.

[–] [email protected] 2 points 6 months ago

Aluminium has traditionally been smelted with electricity. It's easy to move to green tech

Steel is harder. There is serious work that had been going on for years trying to come up with new low emissions ways of making steel

[–] [email protected] 13 points 6 months ago (2 children)

How else do u suppose we make steel?

[–] [email protected] 3 points 6 months ago (3 children)

Use renewable and clean energy sources to produce electricity then make steel with induction heater or other forms of electricity-based heat?

[–] [email protected] 1 points 6 months ago (2 children)

electricity-based heat?

The most expensive heat, so probably not feasable.

[–] [email protected] 1 points 6 months ago

For recycling steel we use electricity heat. Though an arc furnace usually. U can make your own with 2 carbon rods and a microwave transformer.

[–] [email protected] 2 points 6 months ago (2 children)

Resistive, sure. Inductive, not necessarily.

[–] [email protected] 0 points 6 months ago

It's the same. It's not because of some losses somewhere on the way. Electricity is simply by far the most expensive form of energy.

[–] [email protected] 0 points 6 months ago (1 children)

I'm not positive, but it seems to me both would require the same amount of energy to increase a given mass to a given temp.

And since electric heating is effective 100% efficient (all the energy is tranformed to heat), I can't really see how either would be more efficient.

[–] [email protected] 2 points 6 months ago

There's usually an interface material when using resisitive heat. And there's heat loss from heating the interface material before the heat getting to the actual material that needs to be heated.

Inductive heating can be applied directly without heating the interface material.

Though this is probably more applicable to cooking vs industrial kilns and furnaces.

[–] [email protected] 31 points 6 months ago* (last edited 6 months ago) (4 children)

That's..... Not how new steel production works.

Coal is a significant component in the production of steel to impregnate it with carbon. It's a fundamental part of how a blast furnace operates. The article literally talks about this...

Even the article about doesn't mention an alternative. An arc furnace relies on scrap it cannot make new steel.

Though, I wonder if we can move more towards charcoals, but even then I wonder if that's just much less effective or if it cannot reach the temperatures or concentrations required for industrial processes.

[–] [email protected] 2 points 6 months ago

Cool, I learned something new today.

[–] [email protected] 6 points 6 months ago

Charcoal steel is actually better, as charcoal is generally purer, and steel suffers from phosphor and sulphur impurities. The problem is that it's costlier.

I think that it would be viable to at least reduce the carbon used in steel production just to impregnate it, and conduct the bulk of the reduction through another process.

[–] [email protected] 3 points 6 months ago

The hybrit process that some Swedish steelmakers (including SSAB - not a typo, it isn't Saab) are using looks promising. They've been testing it with Volvo and are apparently making it part of Volvo's regular process in 2026

[–] [email protected] 9 points 6 months ago

How much of the coal in a blast furnace is actually necessary for the carbon impregnation, as opposed to supplying the heat via combustion? Steel contains only a few percent carbon by weight, so it doesn't seem like much carbon is needed (not to mention that the carbon in steel is essentially sequestered).

[–] [email protected] 3 points 6 months ago (1 children)

Coal is required for steel, electricty-based heat would only work to lower carbon emissions (especially when recycling steel since you don't need coal there), but you couldn't prevent them.

[–] [email protected] 8 points 6 months ago

"... Only work to lower carbon emissions" But thats exactly the point, that it is high emissions now.