8 ms·

New research shows hydrogen-reduced iron has superior properties

112 points by tda 4y ago

seunosewa 4y ago
The claim is that "Hydrogen-reduced carbon-free DRI is highly metallized and has superior mechanical and aging properties compared to direct reduced iron using fossil-based reducing gas such as natural gas." I wish there were more details.
- aardvarkr 4y ago
  Agreed. This claim is so vague, and it sounds like this is just one part of the smelting process.
- ortusdux 4y ago
  Yes, there is little value in a press release about research that does not include a link or refence to said research.
- lazide 4y ago
  Hydrogen is well known and studied to cause many issues with steel, generally brittleness and crystal structure defects. In situations where it’s important that cracking doesn’t occur, it’s common for low/no hydrogen electrodes in welding be required, for instance. That using a method of production that naturally exposes it hydrogen would produce higher quality steel is surprising! We should still definitely have a link to the study!
  - yborg 4y ago
    This process produces direct reduced iron, not steel.
    - lazide 4y ago
      What do you think Steel is, but reduced Iron (to a specific level)? Cast Iron is also impacted by hydrogen embrittlement, albeit iron is usually already pretty brittle so folks don’t use it where that kind of failure matters as much.
      - metal_am 4y ago
        It produces an intermediate product. You can't use it without further processing. In any case, the hydrogen won't be a problem.
      - xyzzyz 4y ago
        You mean, cast iron is pretty brittle. Pure iron is not brittle.
        lazide 4y ago
        If you're talking pure iron, then yes - it's very ductile and malleable. However, the low end of carbon allowed while still calling something steel is .3%, so with a few exceptions (wrought iron, which is arguably very soft steel), it's rare to run across it. There are of course ways to treat cast iron so it's decently durable (ductile iron), but it's still pretty brittle compared to 99% of steel in the real world.
        robocat 4y ago
        > low end of carbon allowed while still calling something steel is .3% Incorrect. That is the maximum for low carbon steel (also called mild steel - the most common form of steel). Wikipedia says “The carbon content of steel is between 0.002% and 2.14% by weight for plain carbon steel”. “Plain carbon-iron alloys with a higher than 2.1% carbon content are known as cast iron.” https://en.m.wikipedia.org/wiki/Steel https://en.m.wikipedia.org/wiki/Steel https://en.m.wikipedia.org/wiki/Pig_iron https://en.m.wikipedia.org/wiki/Pig_iron https://en.m.wikipedia.org/wiki/Cast_iron https://en.m.wikipedia.org/wiki/Cast_iron https://en.m.wikipedia.org/wiki/Carbon_steel https://en.m.wikipedia.org/wiki/Carbon_steel https://en.m.wikipedia.org/wiki/Alloy_steel https://en.m.wikipedia.org/wiki/Alloy_steel https://en.m.wikipedia.org/wiki/Iron https://en.m.wikipedia.org/wiki/Iron
  - dodobirdlord 4y ago
    This is a process for refining iron ore, as opposed to using a blast furnace, or using the same process with decomposed natural gas instead of just hydrogen. In steel production it would be subsequently smelted.
    - lazide 4y ago
      Do you think that removes the concern? I don’t see how it would.
      - photochemsyn 4y ago
        This process produces sponge iron, which is then fed into an electric arc furnace. There is no free hydrogen around at that point. Whatcomes out of an electric arc furnace is carbon steel. The issue with hydrogen, which was first noted IIRC in the high-pressure Haber-Bosch ammonia production process, in which H2 and N2 at high pressure over a catalyst in a steel chamber forms NH3, is that free hydrogen reacts with the carbon in the steel under these conditions, which caused the pressure chambers to regularly explode (solution was a sacrificial lining of the chambers which was regularly replaced). For low-pressure H2 it may not be much of a problem, but that's not very efficient for transport.
        lazide 4y ago
        Thanks for the background! So likely due to the complete remelt and re-alloying expected, it should work out?
        pstuart 4y ago
        Speaking of ammonia, any thoughts to share on an ammonia economy vs hydrogen economy? The former seems a lot more practical.
        photochemsyn 4y ago
        Ammonia as fertilizer is the only ammonia economy that makes sense; hydrogen economy doesn't make much sense either. Methane economy is the optional long-term solution for chemical energy sources, just CO2(atm) + H2 (water) -> CH4. Ammonia combustion generates NOx smog, and ammonia is pretty toxic to store and transport as a gas. For fertilizer it's stored as (NH4)(NO3) or similar. Hydrogen production has a few major use cases, but replacing natural gas is not one of them. Iron reduction, nitrogen reduction, carbon reduction, in industrial settings, is about it.
  - jbay808 4y ago
    For what it's worth to reduce surprise/skepticism, a hydrogen atmosphere is already commonly used for annealing electrical steels (eg. motor laminations or magnetic parts). https://www.tlclam.net/annealing-process/ https://www.tlclam.net/annealing-process/ https://www.vac-met.com/hydrogen-annealing/ https://www.vac-met.com/hydrogen-annealing/
- ghastmaster 4y ago
  Using natural gas introduces carbon. After the DRI stage, further treatments would be required to remove the carbon as it oxidizes. With less carbon there should be more consistent oxidizing of the iron, especially since it looks like carbon monoxide(from the natural gas) is not required which would introduce unwanted oxygen. I wish there were more details as well.
  - LarsAlereon 4y ago
    The thing is you usually WANT Carbon in your Iron, so if you use Hydrogen DRI you have to further process the Iron to add the Carbon back in. There's a lot of potential for using mixtures of Hydrogen and Natural Gas to produce Iron with the exact desired Carbon content.
    - moron4hire 4y ago
      It seems to me that, when you want carbon in your iron (to make steel), you want a lot of control over how much carbon is in that steel. To start from a base iron that has no carbon in it whatsoever seems like it would be better for being more precise in your steel production.
      - LarsAlereon 4y ago
        While you certainly can add or remove Carbon during processing, you get the lowest costs if your input Iron is as close as possible to the desired Carbon content for your application.
        moron4hire 4y ago
        Again, it seems to me that, if you care about extreme precision in your steel-making process, cost is the least of your worries.
    - ghastmaster 4y ago
      Carbon is wanted for steel production, but at specific levels. DRI is further worked to oxidize carbon and remove it before processing. Eliminating the carbon/oxygen from natural gas reduction allows a more controlled introduction of carbon and or less processing to make ready for steel production.
- deleted 4y ago
  [deleted]
scythe 4y ago
Can this reasonably be more efficient than the direct electrolysis process? There was a major breakthrough in 2013 with a ferrochromium anode: https://europepmc.org/article/med/23657254 https://europepmc.org/article/med/23657254 which led to an NSF grant: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1534664 https://www.nsf.gov/awardsearch/showAward?AWD_ID=1534664 which spawned a startup that is now seeking private investors: https://www.bostonmetal.com/transforming-metal-production/ https://www.bostonmetal.com/transforming-metal-production/
- actionfromafar 4y ago
  Maybe not but the hydrogen process is probably a game changer regardless, because there is less research and productisation needed. It is similar to existing processes. It’s also perfectly positioned to take advantage of wind power. The gas storage tanks can make up for variations in electricity production. It’s all set to be deployed at a large scale already. Watt for watt it might not (I have no idea) be as efficient as electrolysis, but as a total solution I see how it could be deployed at scale. Combined with the advances in electric mining equipment like what Volvo is offering, the industry is all set to go fully carbon neutral and electric. (No tech hurdles left.)
- pfdietz 4y ago
  It's not just a question of efficiency. How expensive is the equipment? And in particular, if it's using intermittently available power, how expensive is the part that must be ready to absorb that power? For hydrogen it's electrolysers (and perhaps compressors); for that scheme it would be the oxide electrolysis cells.
- jl6 4y ago
  I recently came across Boston Metal’s proposed use of this inert anode material but I couldn’t find much detail on whether the “breakthrough” claim was genuine. It still seems early days, though if true it would be a transformative enabler for the production of low-carbon steel.
halfdeadcat 4y ago
This is just a PR release. I hope their claims prove out. But there is no evidence supplied and breathless PR releases seldom go anywhere.
arctan 4y ago
FWIW, iron reduced in hydrogen is known to have a very high magnetic permeability, surpassed only by one of the Metglas alloys.
lvxferre 4y ago
What the link is "conveniently forgetting" to mention is that most industrial hydrogen production emits CO₂ (steam reforming: CH₄ + 2H₂O → 2H₂ + CO₂). And there's a good reason for that: electrolysis consumes a lot of electricity. I won't do the maths here but, if the electricity was generated through fossil fuels, I wouldn't be surprised if the process actually increased CO₂ emissions instead of reducing them. But let's say that the hydrogen is from fossil-free electricity. You could be plugging that fossil-free electricity elsewhere instead. The press and media link does not mention that. >Hydrogen-reduced carbon-free DRI is highly metallized That can mean two things: 1. They're able to retrieve more iron from the oxide. Good, but it isn't enough to replace the current processes; at most to add hydrogen as the "chef's kiss" to the iron produced through another method. 2. Less cementite aka iron carbide aka the stuff that actually makes steel "steel" instead of plain iron. That's great or awful depending on application. >has superior mechanical [...] properties Again, it depends on application. I expect their iron to be rather soft and malleable, but lacking tensile strength. >This new knowledge is a direct result of close value chain cooperation, determined innovative thinking and bold efforts in piloting new technology – a recipe to copy for other industrial sectors,” >Hybrit Development AB has filed patent applications describing the included inventions to the European Patent Office. "Guys, we made something to copy for other industrial sectors, except that we're smearing patents on it so you can't copy the process~". There's another detail that the press and media link doesn't mention: hydrogen makes steel brittle. ______________________________________________________________ Take this link with a grain of salt.
- cinntaile 4y ago
  Sweden, where this facility is supposed to be built, hardly has any fossil fuel electricity production. Also you should compare the natural gas hydrogen process to the currently used coke process.
  - hypertele-Xii 4y ago
    Correct. https://en.wikipedia.org/wiki/File:Electricity_production_in_Sweden.svg https://en.wikipedia.org/wiki/File:Electricity_production_in...
JoachimS 4y ago
The press release from Vattenfall relates to a research program called Hybrit. Vattenfall (an energy company), together with the iron ore company LKAB, the steel manufacturer SSAB, and Luleå University of Luleå (LTU) are partners in the project. For more details about Hybrir see: https://www.hybritdevelopment.se/en/a-fossil-free-future/ https://www.hybritdevelopment.se/en/a-fossil-free-future/ https://www.hybritdevelopment.se/en/research-project-1/ https://www.hybritdevelopment.se/en/research-project-1/ The research group list of papers (not all of them related to Hybrit): https://www.ltu.se/research/subjects/Processmetallurgi/Publikationer?l=en https://www.ltu.se/research/subjects/Processmetallurgi/Publi...< A working paper related to Hybrit: https://cdn.sei.org/wp-content/uploads/2020/07/bigger-is-sometimes-better.pdf https://cdn.sei.org/wp-content/uploads/2020/07/bigger-is-som...
photochemsyn 4y ago
Here's a good steel production flowchart that shows where this process would be used (replace the natural gas-powered direct reduction feed-in to the electric arc furnace with a hydrogen-powered direct-reduction step). Overall, it's part of the electric arc process which avoids the need for coke from coal in blast furnaces. https://www.steel.org/steel-technology/steel-production/ https://www.steel.org/steel-technology/steel-production/ Of course, making this fossil-fuel free requires significant hydrogen production from sources like hydropower (or nuclear) powered electrolyis, or my favorite, photoelectrochemical reduction of water, such as: https://techxplore.com/news/2017-08-decades-technology-nrel-solar-to-hydrogen.html https://techxplore.com/news/2017-08-decades-technology-nrel-... As far as the claims about producing a superior product with hydrogen compared to natural gas, that's hard to evaluate without more data. I imagine quality of the incoming ore is a major factor. If you want a technical paper on it, here's something recent from what looks like a China-Germany research collaboration: https://sci-hub.se/10.1016/j.actamat.2021.116933 https://sci-hub.se/10.1016/j.actamat.2021.116933 "(2021) Influence of microstructure and atomic-scale chemistry on the direct reduction of iron ore with hydrogen at 700°C" P.S. The issue of hydrogen embrittlement of steel doesn't apply here, although it is a major issue that doesn't bode that well for replacing natural gas with hydrogen anywhere other than in industrial processes where the hydrogen is being consumed almost as fast as it is produced. Making synthetic natural gas from atmospheric CO2 and water-sourced hydrogen is a (currently expensive) option, however.
- hinkley 4y ago
  Methane digesters would probably be more efficient, but I’m not sure about the volume.
- ncmncm 4y ago
  It is substantially more efficient, by unit of collecting area, to produce electricity using a regular solar panel and then electrolyse water for hydrogen. But of course collection area efficiency is not what matters, cost is. We don't know what the electrophotochemical equipment costs, or how that compares. It does seem more elegant, at a remove. In practice, of course, you drive your electrolyser from solar, wind, hydro, geo, tidal, numerous forms of storage, or an unholy mix of all of them at different times -- whatever comes off the grid. At first, it will include NG sometimes, and nukes, until those are priced off of the market.
steve_john 4y ago
mcswell 4y ago
From the article: "One element behind the high quality of the sponge iron produced is the high-quality iron ore from LKAB’s mine..." So would this process produce high quality sponge iron from iron ore of lesser quality from other mines?

112 points by tda 4y ago

The claim is that "Hydrogen-reduced carbon-free DRI is highly metallized and has superior mechanical and aging properties compared to direct reduced iron using fossil-based reducing gas such as natural gas." I wish there were more details.

aardvarkr 4y ago
Agreed. This claim is so vague, and it sounds like this is just one part of the smelting process.
ortusdux 4y ago
Yes, there is little value in a press release about research that does not include a link or refence to said research.
lazide 4y ago
Hydrogen is well known and studied to cause many issues with steel, generally brittleness and crystal structure defects. In situations where it’s important that cracking doesn’t occur, it’s common for low/no hydrogen electrodes in welding be required, for instance. That using a method of production that naturally exposes it hydrogen would produce higher quality steel is surprising! We should still definitely have a link to the study!
- yborg 4y ago
  This process produces direct reduced iron, not steel.
  - lazide 4y ago
    What do you think Steel is, but reduced Iron (to a specific level)? Cast Iron is also impacted by hydrogen embrittlement, albeit iron is usually already pretty brittle so folks don’t use it where that kind of failure matters as much.
    - metal_am 4y ago
      It produces an intermediate product. You can't use it without further processing. In any case, the hydrogen won't be a problem.
    - xyzzyz 4y ago
      You mean, cast iron is pretty brittle. Pure iron is not brittle.
      - lazide 4y ago
        If you're talking pure iron, then yes - it's very ductile and malleable. However, the low end of carbon allowed while still calling something steel is .3%, so with a few exceptions (wrought iron, which is arguably very soft steel), it's rare to run across it. There are of course ways to treat cast iron so it's decently durable (ductile iron), but it's still pretty brittle compared to 99% of steel in the real world.
        robocat 4y ago
        > low end of carbon allowed while still calling something steel is .3% Incorrect. That is the maximum for low carbon steel (also called mild steel - the most common form of steel). Wikipedia says “The carbon content of steel is between 0.002% and 2.14% by weight for plain carbon steel”. “Plain carbon-iron alloys with a higher than 2.1% carbon content are known as cast iron.” https://en.m.wikipedia.org/wiki/Steel https://en.m.wikipedia.org/wiki/Steel https://en.m.wikipedia.org/wiki/Pig_iron https://en.m.wikipedia.org/wiki/Pig_iron https://en.m.wikipedia.org/wiki/Cast_iron https://en.m.wikipedia.org/wiki/Cast_iron https://en.m.wikipedia.org/wiki/Carbon_steel https://en.m.wikipedia.org/wiki/Carbon_steel https://en.m.wikipedia.org/wiki/Alloy_steel https://en.m.wikipedia.org/wiki/Alloy_steel https://en.m.wikipedia.org/wiki/Iron https://en.m.wikipedia.org/wiki/Iron
- dodobirdlord 4y ago
  This is a process for refining iron ore, as opposed to using a blast furnace, or using the same process with decomposed natural gas instead of just hydrogen. In steel production it would be subsequently smelted.
  - lazide 4y ago
    Do you think that removes the concern? I don’t see how it would.
    - photochemsyn 4y ago
      This process produces sponge iron, which is then fed into an electric arc furnace. There is no free hydrogen around at that point. Whatcomes out of an electric arc furnace is carbon steel. The issue with hydrogen, which was first noted IIRC in the high-pressure Haber-Bosch ammonia production process, in which H2 and N2 at high pressure over a catalyst in a steel chamber forms NH3, is that free hydrogen reacts with the carbon in the steel under these conditions, which caused the pressure chambers to regularly explode (solution was a sacrificial lining of the chambers which was regularly replaced). For low-pressure H2 it may not be much of a problem, but that's not very efficient for transport.
      - lazide 4y ago
        Thanks for the background! So likely due to the complete remelt and re-alloying expected, it should work out?
      - pstuart 4y ago
        Speaking of ammonia, any thoughts to share on an ammonia economy vs hydrogen economy? The former seems a lot more practical.
        photochemsyn 4y ago
        Ammonia as fertilizer is the only ammonia economy that makes sense; hydrogen economy doesn't make much sense either. Methane economy is the optional long-term solution for chemical energy sources, just CO2(atm) + H2 (water) -> CH4. Ammonia combustion generates NOx smog, and ammonia is pretty toxic to store and transport as a gas. For fertilizer it's stored as (NH4)(NO3) or similar. Hydrogen production has a few major use cases, but replacing natural gas is not one of them. Iron reduction, nitrogen reduction, carbon reduction, in industrial settings, is about it.
- jbay808 4y ago
  For what it's worth to reduce surprise/skepticism, a hydrogen atmosphere is already commonly used for annealing electrical steels (eg. motor laminations or magnetic parts). https://www.tlclam.net/annealing-process/ https://www.tlclam.net/annealing-process/ https://www.vac-met.com/hydrogen-annealing/ https://www.vac-met.com/hydrogen-annealing/
ghastmaster 4y ago
Using natural gas introduces carbon. After the DRI stage, further treatments would be required to remove the carbon as it oxidizes. With less carbon there should be more consistent oxidizing of the iron, especially since it looks like carbon monoxide(from the natural gas) is not required which would introduce unwanted oxygen. I wish there were more details as well.
- LarsAlereon 4y ago
  The thing is you usually WANT Carbon in your Iron, so if you use Hydrogen DRI you have to further process the Iron to add the Carbon back in. There's a lot of potential for using mixtures of Hydrogen and Natural Gas to produce Iron with the exact desired Carbon content.
  - moron4hire 4y ago
    It seems to me that, when you want carbon in your iron (to make steel), you want a lot of control over how much carbon is in that steel. To start from a base iron that has no carbon in it whatsoever seems like it would be better for being more precise in your steel production.
    - LarsAlereon 4y ago
      While you certainly can add or remove Carbon during processing, you get the lowest costs if your input Iron is as close as possible to the desired Carbon content for your application.
      - moron4hire 4y ago
        Again, it seems to me that, if you care about extreme precision in your steel-making process, cost is the least of your worries.
  - ghastmaster 4y ago
    Carbon is wanted for steel production, but at specific levels. DRI is further worked to oxidize carbon and remove it before processing. Eliminating the carbon/oxygen from natural gas reduction allows a more controlled introduction of carbon and or less processing to make ready for steel production.
deleted 4y ago
[deleted]

scythe 4y ago

Can this reasonably be more efficient than the direct electrolysis process? There was a major breakthrough in 2013 with a ferrochromium anode: https://europepmc.org/article/med/23657254 https://europepmc.org/article/med/23657254 which led to an NSF grant: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1534664 https://www.nsf.gov/awardsearch/showAward?AWD_ID=1534664 which spawned a startup that is now seeking private investors: https://www.bostonmetal.com/transforming-metal-production/ https://www.bostonmetal.com/transforming-metal-production/

actionfromafar 4y ago
Maybe not but the hydrogen process is probably a game changer regardless, because there is less research and productisation needed. It is similar to existing processes. It’s also perfectly positioned to take advantage of wind power. The gas storage tanks can make up for variations in electricity production. It’s all set to be deployed at a large scale already. Watt for watt it might not (I have no idea) be as efficient as electrolysis, but as a total solution I see how it could be deployed at scale. Combined with the advances in electric mining equipment like what Volvo is offering, the industry is all set to go fully carbon neutral and electric. (No tech hurdles left.)
pfdietz 4y ago
It's not just a question of efficiency. How expensive is the equipment? And in particular, if it's using intermittently available power, how expensive is the part that must be ready to absorb that power? For hydrogen it's electrolysers (and perhaps compressors); for that scheme it would be the oxide electrolysis cells.
jl6 4y ago
I recently came across Boston Metal’s proposed use of this inert anode material but I couldn’t find much detail on whether the “breakthrough” claim was genuine. It still seems early days, though if true it would be a transformative enabler for the production of low-carbon steel.

halfdeadcat 4y ago

This is just a PR release. I hope their claims prove out. But there is no evidence supplied and breathless PR releases seldom go anywhere.

arctan 4y ago

FWIW, iron reduced in hydrogen is known to have a very high magnetic permeability, surpassed only by one of the Metglas alloys.

lvxferre 4y ago

What the link is "conveniently forgetting" to mention is that most industrial hydrogen production emits CO₂ (steam reforming: CH₄ + 2H₂O → 2H₂ + CO₂). And there's a good reason for that: electrolysis consumes a lot of electricity. I won't do the maths here but, if the electricity was generated through fossil fuels, I wouldn't be surprised if the process actually increased CO₂ emissions instead of reducing them. But let's say that the hydrogen is from fossil-free electricity. You could be plugging that fossil-free electricity elsewhere instead. The press and media link does not mention that. >Hydrogen-reduced carbon-free DRI is highly metallized That can mean two things: 1. They're able to retrieve more iron from the oxide. Good, but it isn't enough to replace the current processes; at most to add hydrogen as the "chef's kiss" to the iron produced through another method. 2. Less cementite aka iron carbide aka the stuff that actually makes steel "steel" instead of plain iron. That's great or awful depending on application. >has superior mechanical [...] properties Again, it depends on application. I expect their iron to be rather soft and malleable, but lacking tensile strength. >This new knowledge is a direct result of close value chain cooperation, determined innovative thinking and bold efforts in piloting new technology – a recipe to copy for other industrial sectors,” >Hybrit Development AB has filed patent applications describing the included inventions to the European Patent Office. "Guys, we made something to copy for other industrial sectors, except that we're smearing patents on it so you can't copy the process~". There's another detail that the press and media link doesn't mention: hydrogen makes steel brittle. ______________________________________________________________ Take this link with a grain of salt.

cinntaile 4y ago
Sweden, where this facility is supposed to be built, hardly has any fossil fuel electricity production. Also you should compare the natural gas hydrogen process to the currently used coke process.
- hypertele-Xii 4y ago
  Correct. https://en.wikipedia.org/wiki/File:Electricity_production_in_Sweden.svg https://en.wikipedia.org/wiki/File:Electricity_production_in...

JoachimS 4y ago

The press release from Vattenfall relates to a research program called Hybrit. Vattenfall (an energy company), together with the iron ore company LKAB, the steel manufacturer SSAB, and Luleå University of Luleå (LTU) are partners in the project. For more details about Hybrir see: https://www.hybritdevelopment.se/en/a-fossil-free-future/ https://www.hybritdevelopment.se/en/a-fossil-free-future/ https://www.hybritdevelopment.se/en/research-project-1/ https://www.hybritdevelopment.se/en/research-project-1/ The research group list of papers (not all of them related to Hybrit): https://www.ltu.se/research/subjects/Processmetallurgi/Publikationer?l=en https://www.ltu.se/research/subjects/Processmetallurgi/Publi...< A working paper related to Hybrit: https://cdn.sei.org/wp-content/uploads/2020/07/bigger-is-sometimes-better.pdf https://cdn.sei.org/wp-content/uploads/2020/07/bigger-is-som...

photochemsyn 4y ago

Here's a good steel production flowchart that shows where this process would be used (replace the natural gas-powered direct reduction feed-in to the electric arc furnace with a hydrogen-powered direct-reduction step). Overall, it's part of the electric arc process which avoids the need for coke from coal in blast furnaces. https://www.steel.org/steel-technology/steel-production/ https://www.steel.org/steel-technology/steel-production/ Of course, making this fossil-fuel free requires significant hydrogen production from sources like hydropower (or nuclear) powered electrolyis, or my favorite, photoelectrochemical reduction of water, such as: https://techxplore.com/news/2017-08-decades-technology-nrel-solar-to-hydrogen.html https://techxplore.com/news/2017-08-decades-technology-nrel-... As far as the claims about producing a superior product with hydrogen compared to natural gas, that's hard to evaluate without more data. I imagine quality of the incoming ore is a major factor. If you want a technical paper on it, here's something recent from what looks like a China-Germany research collaboration: https://sci-hub.se/10.1016/j.actamat.2021.116933 https://sci-hub.se/10.1016/j.actamat.2021.116933 "(2021) Influence of microstructure and atomic-scale chemistry on the direct reduction of iron ore with hydrogen at 700°C" P.S. The issue of hydrogen embrittlement of steel doesn't apply here, although it is a major issue that doesn't bode that well for replacing natural gas with hydrogen anywhere other than in industrial processes where the hydrogen is being consumed almost as fast as it is produced. Making synthetic natural gas from atmospheric CO2 and water-sourced hydrogen is a (currently expensive) option, however.

hinkley 4y ago
Methane digesters would probably be more efficient, but I’m not sure about the volume.
ncmncm 4y ago
It is substantially more efficient, by unit of collecting area, to produce electricity using a regular solar panel and then electrolyse water for hydrogen. But of course collection area efficiency is not what matters, cost is. We don't know what the electrophotochemical equipment costs, or how that compares. It does seem more elegant, at a remove. In practice, of course, you drive your electrolyser from solar, wind, hydro, geo, tidal, numerous forms of storage, or an unholy mix of all of them at different times -- whatever comes off the grid. At first, it will include NG sometimes, and nukes, until those are priced off of the market.

steve_john 4y ago

mcswell 4y ago

From the article: "One element behind the high quality of the sponge iron produced is the high-quality iron ore from LKAB’s mine..." So would this process produce high quality sponge iron from iron ore of lesser quality from other mines?