
A new way to make steel could cut 5% of CO2 emissions at a stroke - bryanrasmussen
https://www.technologyreview.com/s/611961/this-mit-spinout-could-finally-clean-up-steel-one-of-the-globes-biggest-climate-polluters/
======
Robotbeat
One thing that human space exploration/settlement teaches us more than
anything is how to do everything without net carbon emissions. Solar power?
Nuclear power? Both essential to and pioneered in part by space exploration.
Same for fuel cell tech. On the International Space Station, CO2 is sucked
from the cabin air, combined with hydrogen (produced as a byproduct of
producing oxygen by splitting water, much of which was recycled from the air
and waste water and urine) to make methane and more water.

ISS also is getting a plastic recycling machine that will be used to 3D print
replacement parts from plastic waste and old parts.

Human spaceflight is like the Sustainability Olympics.

~~~
makapuf
Right, some nice inventions are due to space race but just after two giant
boosters worth of propergol were burnt. And making those things that go to
space are not completely carbon neutral either.

~~~
TeMPOraL
Rockets seem like giant greenhouse gas emitters because they burn a lot of
fuel in a short time. But it turns out, they're actually comparable with
airplanes.

Random googling gives following two figures to compare:

"A jumbo jet (Boeing 747-400) flying from London to New York burns
approximately 70,000 kilograms of fuel"[0]

Falcon 9 Full Thrust - Takeoff mass (tonnes) 549, Payload to LEO (kg) (from
Cape Canaveral) 22,800 (expendable)[1]

So, roughly 70 metric tons of fuel for a London->New York flight, vs. 500
metric tons for a LEO launch. It's quite comparable. Now consider that there's
_five orders of magnitude_ more flights than there's rocket launches[2]. Even
if you take an order of magnitude off that to account for most flights being
shorter than LHR->JFK, you still end up with space launches barely
registering. And then some rocket fuels are non-carbon-emitting.

\--

[0] - [https://www.flightdeckfriend.com/ask-a-captain/how-much-
fuel...](https://www.flightdeckfriend.com/ask-a-captain/how-much-fuel-does-a-
jumbo-jet-burn/)

[1] -
[https://en.wikipedia.org/wiki/Falcon_9#Performance](https://en.wikipedia.org/wiki/Falcon_9#Performance)

[2] - [https://garfors.com/2014/06/100000-flights-day-
html/](https://garfors.com/2014/06/100000-flights-day-html/) says > 100k
flights per day, and there's less than 1 space launch per day.

~~~
StavrosK
How can there be fuels that don't emit CO2? Don't they burn?

~~~
TeMPOraL
Combustion is exothermic oxidization; that's something completely unrelated to
carbon. E.g. hydrogen burns in presence of oxygen, releasing water. Or
magnesium burns into magnesium oxide. It so happens that most of the fuels we
burn have carbon in them, but that's not a requirement.

~~~
StavrosK
Huh, yeah, when you put it that way I guess oxidization requires oxygen but
obviously does not require carbon. I'd never thought of that, thanks!

~~~
marcosdumay
It does not require oxygen either. Oxidization happens when a substance reacts
to any other one that attract more electrons.

~~~
StavrosK
Ah, that I didn't know at all, thank you.

~~~
TeMPOraL
That's a little thing that they tell you in high school chemistry classes
(remember "reduction–oxidation reactions", or "redox"?), which you then
promptly forget. I only remembered because of an unhealthy interest in home-
made rocket propellants :).

~~~
StavrosK
> remember "reduction–oxidation reactions", or "redox"?

Clearly no :P Also I realized that, unless I have a specific problem I need to
solve, I don't remember or like reading about things. I have been taught
things in school/uni that I thought were terribly boring and was bad at, until
I needed to solve a problem with that information and then I had to re-learn
everything. Kind of a waste of time, but I can't change my brain!

------
peter_d_sherman
Excerpt: "NASA had offered a quarter-million-dollar prize to the first
research team that could figure out how to extract oxygen from the moon’s
surface, a precondition for establishing lunar bases. Sadoway proposed using
an electrolytic cell—which produces an electric current to break down
compounds—to extract oxygen from lunar rocks. The by-product was molten metal,
a realization that led him to explore the possibility of using a similar
approach to process metals back on Earth."

Two for the price of one! (Well, potential solutions to problems that is! One,
how to generate oxygen on other planets, and two, how to smelt metals on this
one while generating less carbon emissions. Well played!)

~~~
sveme
Interestingly, this is exactly the process used in Andy Weir's new novel
Artemis and makes oxygen the least of the problems of the moon city that the
novel is named after.

~~~
NickBusey
I highly recommend the audio book version read by Rosario Dawson.

------
symplee
From the article:

 _Until the product is actually built and tested at commercial scale, it’s too
early to say how well or affordably it will really work._

 _Moreover, merely producing a green version of a product for around the same
price won’t be enough to transform the industry, given the billions of dollars
in sunk costs in steel mills that can operate for decades._

 _Even if the perfect technology came on the scene today, it’d probably be
several decades before we could effectively transition to it_

Talk about playing the long game...

I wonder how much cheaper their method would need to be, given the above.
Would it be faster/cheaper to develop perfect scrubbers to retrofit onto
existing mills? (Funded through donations, and/or to sell to offset carbon
taxes.)

Still good to have this new technology available to transition to down the
line.

~~~
Gibbon1
I read a retrospective paper by a Norwegian group that worked on
electrowinning iron from mixed sulfide ores. Taking iron sulfide waste and
converting it to sulfuric acid and iron sheet. I think they were getting
4.25kwh per kg. Nop idea if that is good or not but at $0.15/kwh that's
$640/ton.

I thought about that over the last few years because it's aqueous process so
should be able to run intermittently.

Edit: Paper

[http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.843...](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.843.3769&rep=rep1&type=pdf)

~~~
hectormalot
640$/ton won’t be profitable as that’s about the current price for high end
steels.

OTOH, I remember industrial electricity prices to be closer to 7-10cents per
kWh, so it won’t be that far off what we have now.

~~~
jillesvangurp
Energy prices are going to be key here. The mistake would be assuming they are
a constant though. They've been trending down and lately coal has been
considered on the expensive end of the spectrum. Those prices have been
trending down due to clean energy prices dropping. Both solar and wind are now
winning bids on price that used to go to coal plants. Also as coal plants shut
down and coal mines are closed, coal might actually get more hard to get (i.e.
more expensive). Some recent solar plants are delivering power well below the
prices you cite (I've heard prices going as low as 3-4 cents/kWh).

I could imagine most steel plants are big enough that they'd want their own
infrastructure in any case. So, for a future steel plant based on this stuff
with its own cheap energy supply, it might end up being cheaper and cleaner.
That could end up being really disruptive.

~~~
salty_biscuits
Energy prices and the price of carbon dioxide emissions, especially in Europe.

------
hexane360
The steel industry isn't really as "conservative" as is being portrayed here.
In the past 30 years, the amount of recycled metal being used has skyrocketed,
and entire companies have come to power because of it. Sure, big old U.S.
Steel is behind the times, but that's true for any industry.

~~~
bigpicture
> Sure, big old U.S. Steel is behind the times, but that's true for any
> industry.

U.S. Steel operates integrated mills, which make steel from raw materials.
"Mini-mills" make steel using electric arc blast furnaces to recycle existing
steel.

If you need very high quality steel, you have to get it from an integrated
mill. Everyone else can use the recycled stuff. The real benefit that you are
talking about is the fact that recycled steel quality is improving enough to
be useful in more applications.

PS - U.S. Steel is converting their Alabama mill to an electric arc blast
furnace (they may have finished by now).

~~~
hexane360
>If you need very high quality steel, you have to get it from an integrated
mill.

This just isn't true anymore. Process control has improved a lot since EAF
mills were first created.

EAF mills also provide more flexibility because they can make much smaller
batches. This allows for more niche alloys to become accessible.

------
londons_explore
TL;DR: This is a well known technique, but isn't used because the economics
don't work out.

This technique looks nearly identical to the technique used to make aluminium
from aluminium oxide.

The only difference is it needs to happen much hotter (1500C vs 700C).

The process uses a _lot_ of electricity, so much that it is the main cost of
aluminium production.

The process, when used in steelmaking, would use 824.2 kJ/mol of iron(III)
oxide, producing 111.6 g/mol of iron. That works out to 7.42 kJ / g, or 2 kwh
per kilogram of steel. Price varies widely worldwide, but with the cheapest
electricity in europe that works out to about $0.10.[1]

Thats lots of electricity for the refining process, and it seems likley that
0.7kg of coal [2] works out far far cheaper at $0.05 [3].

[1]: [https://1-stromvergleich.com/electricity-prices-
europe/](https://1-stromvergleich.com/electricity-prices-europe/) [2]:
[https://www.worldcoal.org/coal/uses-coal/how-steel-
produced](https://www.worldcoal.org/coal/uses-coal/how-steel-produced) [3]:
[https://markets.businessinsider.com/commodities/coal-
price](https://markets.businessinsider.com/commodities/coal-price)

~~~
strainer
Looking into those calculations, I see the current average energy used to make
1 kg of steel is about 10 thousand BTU [1] - about 3 kWh. 75% is consumed in
blast furnace and "About 50% of an integrated facility’s energy input comes
from coal, 35% from electricity, 5% from natural gas and 5% from other gasses
[2]"

Your estimate of 2kWh per kilo would look very promising for this process.
Also the comparison of electrical price, with the price for raw coal surely
begs some adjustment.

[1] [https://www.quora.com/How-much-energy-does-it-take-to-
produc...](https://www.quora.com/How-much-energy-does-it-take-to-produce-
steel)

[2]
[https://www.worldsteel.org/en/dam/jcr:f07b864c-908e-4229-9f9...](https://www.worldsteel.org/en/dam/jcr:f07b864c-908e-4229-9f92-669f1c3abf4c/fact_energy_2016.pdf)

------
tomatotomato37
At a stroke*

*Not including the time required to retool the entire Earth's iron smelters into electrolytic smelters and build out associated electric infrastructure needed to accompany the exponential increase of a country's energy intake.

~~~
ajross
That's spinning too hard in the other direction. This is a technique for
smelting. Once smelted and shipped, the metal is always going to be remelted
anyway to mix and cast the final alloy. And in fact in the modern world the
bulk of this work is done with electricity already in an electric arc furnace.

We're talking about a constant factor on top of a steel industry already very
dependent on electrical power, certainly not (sigh) an "exponential increase
of a country's energy intake".

------
SomeAmerican
"In the main approach to steelmaking today, iron oxide is placed into a blast
furnace with coke, a hard, porous substance derived from coal... This and
other steps in the process pump around 1.7 gigatons of carbon dioxide into the
atmosphere annually, ... And that’s before taking into account the fuels
required to fire the furnaces."

The coke _is_ the fuel that fires the furnaces.

~~~
Hextinium
Blast furnaces do not need fuel to create iron, the process in which iron
oxide is converted to iron is endothermic but the coke itself is the fuel in
the furnace. It actually is necessary to do this to produce carbon monoxide
which reacts with the iron oxide.

~~~
bigger_cheese
It can get very complicated. There are a few different reactions which occur
in a Blast Furnace some are exothermic some are endothermic.

BF is very simplistically a giant counter current reactor. Ore and Coke (the
reactants) are added at the top at room temperature and hot gas (the "blast")
is injected at the bottom and they flow past each other.

CO is not the only reductant that plays a role Hydrogen primarily from the
humidity contained within injected gas also plays a role in the heat balance
of the furnace.

Hydrogen is actually very efficient at reducing iron and avoids the CO2
byproduct. I know in the past some alternative ironmaking methods have looked
into using things like hydrogen gas and natural gas (CH4) to directly reduce
iron ore using a process abbreviated as DRI (Direct Reduced Iron) and for a
while in the '90's this was marketed as a Blast Furnace alternative I haven't
really kept up with technology.

I started my career as a Metallurgist (Materials Engineer) working at a Blast
Furnace they are hugely complicated beasts.

------
black-tea
Great! That means we can make more steel.

