5 ms·
It's a little misleading to suggest that "co-production" of iron and chlorine can meaningfully save energy. Annual production of steel is about 2000 Mt, of Cl2
by scythe 3y ago
It's a little misleading to suggest that "co-production" of iron and chlorine can meaningfully save energy. Annual production of steel is about 2000 Mt, of Cl2 is about 100 Mt (a similar figure for NaOH). So you'll get many times more chlorine than the economy can presently use. You could neutralize it by a variety of processes[1], but this isn't thrifty.
IIRC there was already a thread some time ago about electrolysis of iron ore in sodium hydroxide (as reusable solvent) where I was wondering about the cost of NaOH and how much would have to be replenished per cycle. But that process easily whoops this one.
1: Cl2 + MgO >> MgCl2 + O2, for one. (Stoichiometry exercise for the reader.)
- pfdietz 3y agoIf we release Cl2 into the daytime troposphere, it will be rapidly photolyzed to chlorine radicals, which rapidly react with methane. It would be a way of scrubbing methane out of the atmosphere.
- FredPret 3y agoWill we all turn blonde though?
- lazide 3y agoOur lungs will probably be bleeding first.
- pfdietz 3y agoIt would be best to release the gas at low concentration (there's only a little methane in any parcel of air), and it would probably be released over oceans to avoid too much human exposure. A bigger concern could be making sure very little was transported up to the stratosphere before it reacted.
- euroderf 3y agoWhat are the products of the reaction ?
- pfdietz 3y agoMethyl radical and hydrogen chloride. The former is oxidized further to CO2; the latter gets rained out eventually. If this rained out acid goes into the ocean, the sodium hydroxide can be released there to neutralize it, although first using the NaOH to capture atmospheric CO2 could be beneficial.
- lkbm 3y agoAt what ratio does this process produce steel and Cl2? I'm guessing it's not a ratio of 20:1, but I don't know. The final paragraph of the article suggests it's not an awful ratio: > Even so, scaling production to match industrial chlorine gas needs would still produce tens of millions of tons of CO2-free iron and chlorine annually
- sanxiyn 3y agoThe article mentions it's 1:1. > The Oregon group's setup generates essentially as much chlorine gas as it does iron, notes Iryna Zenyuk, a chemical engineer at the University of California, Irvine.
- sokoloff 3y ago1:1 by mole, but not 1:1 by mass (which is what the industrial usage ratios are in).
- nine_k 3y agoChlorine is 1.6 times lighter than iron. Depending on how many atoms of iron are reduced per one atom of chlorine exhausted, the balance may be not as starkly bad. But likely replacing 100% of steel industry with this process would still produce more chlorine than can be profitably sold currently. Maybe it would do with replacing 30%, for starters.