5 ms·
>All the surface metal deposits are gone. Well, they're not so much gone as converted into various structures all over the globe. I see no reason why later civ
by ginko 12y ago
>All the surface metal deposits are gone.
Well, they're not so much gone as converted into various structures all over the globe. I see no reason why later civilizations couldn't mine the remains of former cities.
- XorNot 12y agoPretty much this - mining would be done on old landfill sites and cities, at least for metals. Fossil fuels are a different type of problem - we're not going to get all that carbon back. Conversely maybe a reboot civilization would develop differently - forests to solar thermal to PV and batteries. It would be slower, but certainly possible.
- codeulike 12y agoHow are you going to do any metalwork with your scavenged metal? Heat it up with a big mirror? Its very very hard without high energy density fuel. The article suggests charcoal (did you read the article?) but thats problematic too.
- XorNot 12y agoJust because it would be a slower development path doesn't mean it's impossible. It would be slower, but any given civilization would have only a few viable options for development - so yes, I think you'd find a civilization which values glass and mirrors and polishing technology to get the heat necessary for metal working.
- tinco 12y agoI don't think a civilization built on a shit load of aluminium scrap is going to develop very slowly. Don't forget aluminium is a wonder metal that's only been around for like a hundred years. All really important metals can be melted at temperatures that can easily be reached with a well built furnace and natural fuel like wood.
- balabaster 12y agoPlus, we already know what we did to get to where we are now. We can adapt that knowledge to get back to where we are now. It's going forward we're going to be stumbling in the dark, but we're doing that now anyway.
- eropple 12y agoSee my reply to your comment in a sibling thread. A wood fire can hit 1050C. There's plenty of easily-available metal in that range, and building a forced-draft charcoal burner will get you to 1350C. Iron melting points start around 1150C; steel is probably out of the question, but that doesn't mean much.
- yellowapple 12y ago> How are you going to do any metalwork with your scavenged metal? With a wood-fired forge. Blacksmithing predates fossil fuels by quite a long time.
- Sanddancer 12y agoWe can, make new hydrocarbon fuels. Grow plants that are high in fatty acids that we can run catalytic cracking processes on to make usable fuels. Or, use fermentation and the like to make alcohols from plants with a high sugar content. Again, slower, but at the same time, it would be part of the process.
- ars 12y agoYou can just dry and burn the plants directly. You can replace coal almost directly with dried plants.
- Sanddancer 12y agoIndeed you can. It's definitely the simplest way of doing it. However, by pulling the fatty acids out, etc, you can also pull out a lot of other useful products, like ammonia and hydrogen sulfide. Additionally, a fire will produce a lot of ash and smoke, which both will need to be mitigated in one way or another.
- jhallenworld 12y agoYeah, low tech wood fires are an air-pollution disaster: http://www.samharris.org/blog/item/the-fireplace-delusion http://www.samharris.org/blog/item/the-fireplace-delusion
- ars 12y agoIt's possible to burn plants cleanly - you need lots of air, and possibly a catalytic converter. Not something you would do at home, but a power plant can. We should, today, switch from burning coal to burning switchgrass.
- mariusz79 12y agoOne of the reasons why mining the remains of ancient cities could prove to be impossible, is that a lot of the metal would get oxidized (aka rust)
- yellowapple 12y agoIn the case of rust, there are a lot of chemical similarities between it and hematite (though contamination with iron hydroxides might be a problem), which might (theoretically at least) make it potentially suitable for smelting into pig iron. I don't think any existing industrial processes do this, though.
- ars 12y agoIt's not a problem to remove rust from iron. Just heat it in a low oxygen atmosphere, and add carbon which will react with the oxygen in the iron. You do need to carefully control the amount of carbon though.