Sciencemadness Discussion Board

Is there any experiment to produce carbon-neutral steel?

SupFanat - 29-5-2015 at 15:28

Provided there's enough renewable supply, iron oxide can be reduced with electrochemically produced hydrogen and even carbon can be extracted from greenhouse gas carbon dioxide using the same hydrogen.

I like paradox decisions such as producing renewable energy in places with only little sunshine. So some windy place is needed.

Sulaiman - 29-5-2015 at 15:37

What is wrong with air and charcoal ?
whatever CO2 produced will be consumed in the next generation crop for charcoal = carbon neutral

j_sum1 - 29-5-2015 at 15:43

Yup.
Grow a tree. Make steel. It just takes a bit longer.

SupFanat - 30-5-2015 at 00:03

Aren't there some places on Earth which aren't suitable for growing trees but suitable for producing hydrogen?

Texium - 30-5-2015 at 07:28

Quote: Originally posted by SupFanat  
Aren't there some places on Earth which aren't suitable for growing trees but suitable for producing hydrogen?
Let me guess what you're thinking– Antarctica?

j_sum1 - 30-5-2015 at 15:49

I don't know of any standard steel-making processes that use hydrogen.
If you ever get a chance -- visit a steel refinery. It is just not the sort of place that you could run off a windmill and a couple of solar panels. There is coal and lots of it.

The concept of "carbon-neutral" is a bit ill-defined in many practical situations but basically means that over the entire process the total amount of carbon dioxide released into the atmosphere is offset by the amount of carbon dioxide absorbed from the atmosphere. Not many industrial processes use CO2 from the air. One method for achieving carbon neutrality is to substitute the energy source for something that does not release CO2, but this is only really viable if you are using electricity as your energy source. And then it is a bit of an accounting exercise rather than anything real since for most practical situations the electricity comes from the national grid over which you have no real control. By rights you should also factor in the CO2 emitted during the manufacture of your wind turbine or solar panels or whatever.
For industrial processes where electricity is not the primary energy source (such as steel-making), the simplest solution is to continue with the standard manufacturing practice but to also invest in a program for sequestering carbon -- such as the planting of trees. If you buy something that claims to be carbon neutral, this is likely what has been done.

So, make steel. Plant a tree. (And trees do not grow that well in Antarctica.) There are plenty of places on the earth that could do with some desert reclamation and reforestation however.

macckone - 31-5-2015 at 13:57

Hydrogen causes steel to become brittle. Not what you want in steel making. You can however use aluminum to produce carbon neutral steel. Provided the electricity is carbon neutral. The termite reaction was one method of producing zero carbon steel over a century ago.

*edit* If you are refining on the moon for example aluminothermic reactions are the way to go. Infinite sunlight but very little carbon to be had.

[Edited on 31-5-2015 by macckone]

Polverone - 31-5-2015 at 14:29

So called "direct-reduced iron" is made from iron ore and methane, and the process is already in use on an industrial scale. If you wanted to make it carbon neutral you would capture the waste CO2 for hydrogenation back to methane with electrolytic hydrogen.

Hydrogen appears to be usable by itself; I don't think there would be much residual hydrogen after the crude product is melted for alloying. The main difference is that pure hydrogen reduction is endothermic:
<a href="http://arxiv.org/pdf/0803.2831.pdf">A LABORATORY STUDY OF THE REDUCTION OF IRON OXIDES BY HYDROGEN</a>

<a href="http://babel.hathitrust.org/cgi/pt?id=mdp.39015078527085;view=1up;seq=7">Melting pyrophoric hydrogen-reduced iron powder for production of steel</a>

The carbon that is actually incorporated in the steel can come from charcoal as others have suggested.

blogfast25 - 31-5-2015 at 17:24

Thanks for these papers.

macckone - 2-6-2015 at 09:59

Quote: Originally posted by Polverone  
So called "direct-reduced iron" is made from iron ore and methane, and the process is already in use on an industrial scale. If you wanted to make it carbon neutral you would capture the waste CO2 for hydrogenation back to methane with electrolytic hydrogen.

Hydrogen appears to be usable by itself; I don't think there would be much residual hydrogen after the crude product is melted for alloying. The main difference is that pure hydrogen reduction is endothermic:
<a href="http://arxiv.org/pdf/0803.2831.pdf">A LABORATORY STUDY OF THE REDUCTION OF IRON OXIDES BY HYDROGEN</a>

<a href="http://babel.hathitrust.org/cgi/pt?id=mdp.39015078527085;view=1up;seq=7">Melting pyrophoric hydrogen-reduced iron powder for production of steel</a>

The carbon that is actually incorporated in the steel can come from charcoal as others have suggested.

From the second article, you also have to deal with an iron and hydrogen substance that is highly combustible. In other words feasible but may not be practical. It also doesn't give end product properties which are the primary concern with hydrogen embrittlement. However it does give ideas for a superb reducing compound.

blogfast25 - 2-6-2015 at 10:08

Quote: Originally posted by macckone  
It also doesn't give end product properties which are the primary concern with hydrogen embrittlement. However it does give ideas for a superb reducing compound.


You're referring to super fine, pyrophoric iron, I assume?

macckone - 2-6-2015 at 16:41

Assumptions are occasionally correct.