Assume a location which is heavily polluted with dust of several types of elemental metals (copper, silver, nickel, cobalt etc) or their respective oxides and salts (whatever is stable in humidity and air). It's in the water, in the dirt, basically everywhere. All organisms consume it with their food all along the food chain.

There is an apex predator on top of the food chain, which is resistant to metal poisoning and gets enriched heavily with those elements over the course of its lifespan. Of its 150kg body mass, about 1,5kg to 2kg are metals.

Everything above is for context. Now to my question:

Assume savvy iron-age hunters trapping and killing the beast. They know of the metal-content of the corpse and want to scavenge it.

Given Iron Age tools (including fire, basic smelter etc.), is there a way for our brave foragers to extract the metal out of the body of the dead predator?

The body itself is not the main obstacle, because it consists of pretty standard mammalian mix of hide, muscle, flesh, organs and so on. I thought about fire, but all those metals have different melting points, right?

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    $\begingroup$ That's fairly easy, kill it, cremate it, smelt the ashes. $\endgroup$
    – John
    Sep 30, 2019 at 13:33
  • $\begingroup$ "Of its 150kg body mass, about 1,5kg to 2kg are (heavy) metals." That's as much heavy metal as we have calcium in our bodies. $\endgroup$
    – RonJohn
    Sep 30, 2019 at 20:39
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    $\begingroup$ "They know of the metal-content of the corpse". How? $\endgroup$
    – RonJohn
    Sep 30, 2019 at 20:40
  • $\begingroup$ @RonJohn 1. I will probably raise the metal content a whole lot, following the advice of one of the answers. 2.That is explained within my story and out of scope for now. Thanks for your concern however :) $\endgroup$
    – user6415
    Sep 30, 2019 at 20:45
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    $\begingroup$ I know the splash of interest can make SE seerm really fast. However there are many brilliant minds who visit once a day. Picking "best answer" after 24 hours encourages exemplary answers... $\endgroup$ Sep 30, 2019 at 21:07

3 Answers 3


Do you know which parts of the creature body accumulates the minerals?

For example, if the metals get fixed in the bones, it might be sufficient to dissolve the bones in some acidic solution to help the extraction. The calcium of which bones are made of will dissolve in the solution, while the metals and some other elements will fall on the bottom of the tank.

I think a similar process may be used if the highest concentration of minerals is in the skin.

Another interesting option would be if these creatures developed a particular organ, responsible for their immunity to metal poisoning, that filters and accumulate the metals. Some sort of liver-like organ. This would make it much easier to extract, as the whole useful minerals are mixed with little organic material.

If instead, the metals are spread all around the body i can only think about some composting procedure... something gross like letting maggots eat it out, and collect the metal rich remains when the process is over. I think this would however be the most difficult solution as i suppose that those remains would need further refining before being usable for anything.

  • $\begingroup$ It was really hard chosing the answer, but I will go with a 'metal resistance and accumulation organ' so I chose yours. Thanks! $\endgroup$
    – user6415
    Sep 30, 2019 at 17:58
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    $\begingroup$ Kidney stones!! $\endgroup$
    – Daron
    Sep 30, 2019 at 23:26

Of its 150kg body mass, about 1,5kg to 2kg are metals.

That's a 1-1.5% concentration, which is probably impossible for iron-age technology to refine, and even if it weren't, it competes very poorly with mineral ores. About 60% of a human body is water, so if this species has a similar amouunt, a thorough drying increases the concentration to 1.67-2.5%, but depending on the metal that's still quite low.

  • Copper ores were available in the recent past with concentrations of 12%, and were likely much higher in the distant past (the bronze age needed easily accessible copper, after all). Modern ores can be as low as 0.6%, so your organisms would be viable for mining in the modern industrial era, but in the iron age it would probably be impossible.
  • Nickel is harder to get hold of, and a 2% nickel ore would be pretty high grade. It is an important metal in the modern day, but wasn't really very useful until steel was invented. Compared to bog iron, a comparatively rich and fairly widely available source of iron which was exploited during the iron age, the paltry amounts of nickel available here just wouldn't be worth the effort even if they could be extracted. Which might not be possible with the technology of the day.
  • Silver would be more interesting... the galena that would have provided silver in antiquity was sometimes as high as 1-2% (along with plenty of useful lead). It is remotely possible that lower yields of silver in your creatures might be worth exploiting, but in the absense of other high-yield useful metals it seems dubious. Also, lowering the rarity of silver will reduce its value, and it doesn't have many uses beyond art and currency, so you may choke your own market immediately.
  • Cobalt wasn't refined as pure metal until the late 1700s. Depending on the form it has in the organism, some cobalt compounds might be useful for other purposes, such as colouring glass or ceramics. That was done as least as far back as the bronze age. The concentration, therefore, doesn't really matter.

So depending on the exact metals in your corpse-ore, it'll either be impossible or pointless for iron age people to extract, and somewhere between pointless and borderline for modern-day industry.

Also note that it is much more straightforward to refine regular high-grade mineral ores... iron bloomeries existed as long ago as 3000BCE, but your low-grade meat-based ore would almost certainly need much more sophisticated chemical and metallurgical technology in order to refine. And once that technology does exist, why would anyone bother using it on borderline mineral sources?

Instead, consider that the environment in which this organism lives sounds like an excellent place to set up an open-cast mine. So slaughter all the inconvenient wildlife, and get stuck into the useful minerals instead.

I thought about fire, but all those metals have different melting points, right?

Separating metals is somewhat easier than refining very low-grade ores. Fire and a bit of clever chemistry will sort you out eventually, but it is unlikely to be worthwhile in this situation.

  • $\begingroup$ Thanks for the detailed analysis! In my story those scavengers are under time constraints, so I would introduce the creature as gaining metal supplies relativly quick. Maybe I will raise the metal contents thanks to your advice. $\endgroup$
    – user6415
    Sep 30, 2019 at 18:33
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    $\begingroup$ @openend under time constraints, the best thing to do would be to mine some decent ore and smelt that, or raid somewhere that had some of what you needed ;-) $\endgroup$ Sep 30, 2019 at 18:42
  • $\begingroup$ Yes, here logic is in the service of the story I want to tell :) $\endgroup$
    – user6415
    Sep 30, 2019 at 18:48
  • $\begingroup$ @openend maybe pick something else to get from the animal in question? super hard corundum teeth, etc. $\endgroup$ Sep 30, 2019 at 18:52
  • $\begingroup$ Thanks for your input, but most circumstances are fixed by my story and would be too longwinded to talk about here. $\endgroup$
    – user6415
    Sep 30, 2019 at 19:48

Your main problem is that all that metal won't be accumulated in the body as pure metal, but probably chelated by some organic molecules.

What you need to do is therefore degrade those molecules and extract the metal.

Any chemicals that I can think of could maybe used by gatherers as result of some synthesis (i.e. acetic acid as degradation product of alcoholic beverages), but hardly by hunters.

Naturally occurring acids or basis might be found in given locations (i.e. formic acid by fire ants, sodium hydroxide by lake natron).

Probably, if you don't aim at writing a scientific paper on the process, you can get away with some not better specified naturally occurring heart and chemical, which is used to free the metal from the organic part.


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