5 ms·

Natural Piezoelectric Effect May Build Gold Deposits

88 points by FairDune 2y ago

amelius 2y ago
So, in absence of quartz we could put large voltage sources on rocks and get gold out?
- kragen 2y ago
  basically, yes, but the voltage required is very low (what needs to be large is the current), and you need to get the gold to dissolve. https://www.sciencedirect.com/science/article/abs/pii/S0892687500000923 https://www.sciencedirect.com/science/article/abs/pii/S08926... is one of an enormous number of papers on the process, and ipmi has a careers video on youtube: https://www.youtube.com/watch?v=hAkWMdrLXmo https://www.youtube.com/watch?v=hAkWMdrLXmo. shandong xinhai mining equipment corporation has a bunch of youtube videos marketing their equipment for this purpose to gold mine owners
  - itronitron 2y ago
    Ocean water contains dissolved gold, although I wonder if the other elements in sea water would attach to the quartz or rock electrode first.
    - kragen 2y ago
      i haven't tried, but as i understand it, gold is one of the easiest metals to reduce; even trivalent gold is at +1.52 volts above the she: https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page) https://en.wikipedia.org/wiki/Standard_electrode_potential_(..., and monovalent gold is the noblest of all metals at +1.83 volts. that table doesn't have another reduction to metallic state until platinum at +1.188 volts, then palladium at +0.915 volts, silver at +0.7996 volts, mercury at +0.7973 volts, trivalent thallium at +0.741 volts, etc. the commonplace metals are far away from this: univalent copper is at +0.52 volts, the more usual divalent copper at +0.337 volts, trivalent iron at -0.04 volts, divalent lead at -0.126 volts, tin at -0.13 volts, nickel at -0.257 volts, cadmium at -0.4 volts, divalent iron at -0.44 volts, zinc at -0.7618 volts, etc. in water you can't really electrodeposit metals that are much more negative than zinc because at -0.8277 volts† you start reducing hydrogen from the water instead of reducing the dissolved metal. so things like silicon (-0.909 volts from quartz), vanadium (-1.13 volts) and titanium (-1.37 volts from trivalent titanium ions) are out of reach. by contrast, the difficulty with gold is that you can't keep it from depositing—so you can't get it into solution in the first place voltages like 0.8 volts may not sound like much, but that's because we're used to currents that are, compared to the number of free electrons in the metal, unbelievably small. 0.8 volts is enough to rip apart a piece of metal atom by atom. consider a mole of zinc anodically dissolving; every atom loses two electrons. avogadro's number of electrons is about 96485 coulombs, about 26.8 amp hours. so, if your other electrode is the she, anodically dissolving a mole of zinc (65.39 grams) yields 2 · 96485 coulombs · 0.7618 volts = 147 kilojoules, which works out to about 2.2 megajoules per kilogram. that's a substantial amount of energy because of gold's extreme nobility people usually complex it with cyanide or thiourea in order to do things like electroplating. its standard electrode potential to go to metallic state from the dicyanide complex is only -0.6 volts. but i don't know what form it's in in the oceans ______ † these potentials are all under standard conditions: unit activity for every reagent, 25° temperature, one atmosphere, etc. things like acidity and temperature can shift them a bit; https://en.wikipedia.org/wiki/Pourbaix_diagram https://en.wikipedia.org/wiki/Pourbaix_diagram is all about how they change with acidity, for example. but i don't think there exist conditions extreme enough to electrowin metallic vanadium or titanium
9dev 2y ago
That is as close to alchemy as we’re probably ever gonna get then!
- steve1977 2y ago
  Not really I think, as this is not transforming something else into gold, it just kind of lumps existing gold together (if I understood the article correctly).
  - djtango 2y ago
    We have a name for that kind of alchemy - nuclear fission/fusion. Because gold is so inert (a noble metal) its counterintuitive to see it in other forms eg in solution. In that sense manipulating gold in other forms than its elemental form probably feels like alchemy in common parlance. I know aqua regia is relatively normal but I still find it weird to think of gold being dissolved
    - lazide 2y ago
      Aqua Regia is relatively normal in the sense that being threatened with a knife is relatively normal. If you think it is, you’re probably hanging out in a pretty bad neighborhood. But yeah, most people won’t be surprised it exists.
      - djtango 2y ago
        Well I'd argue getting threatened with a knife is relatively normal in London but that's off topic :) Aqua regia is not particularly exotic as compared with all the fancy ways you can harm yourself or react things in Chemistry. You can probably prepare it at home using stuff that might be buyable over the counter. Getting your hands on things like azides or Polonium 210 or having access to a nuclear reactor to do ad hoc fission/fusion is a lot less normal on that scale. Additionally aqua regia has been known for quite a long time, from before we even knew about gases Fwiw I forgot what the magic cleans everything mix was but I want to say it was H2SO4 and cif which we'd just squirt around in our fume hoods
yieldcrv 2y ago
This isnt a new hypothesis Several years ago I had read something similar about gold in underground water reservoirs forming along the walls based on … essentially earthquakes
v3ss0n 2y ago
So , alchemists might had discovered that somehow ?
- kragen 2y ago
  they did have aqua regia, and crystallizing previously dissolved gold from it was, as i understand it, commonplace
- deleted 2y ago
  [deleted]
ggm 2y ago
Fred Hoyle wrote a pop sci book in the sixties talking about how things worked in early earth formation with prosaic imagery of gold squeezing around in quartz.
OutOfHere 2y ago
What's stopping someone from deploying this in the ocean water to capture gold? Quartz crystal array + electricity -> gold layers?
- gus_massa 2y ago
  1 You have to squish the quartz that cist money unless you put the crystalsbetween two tectonic plates. 2 The concentration of disolved gold is lower in seawater than in hot hydrothermal mud. 3 Perhaps with realistic values, this is very low and even in ideal conditions ypu need a few thousands years to get a visible chunk of gold.
- throwup238 2y ago
  From the abstract [1]: > Gold nuggets occur predominantly in quartz veins, and the current paradigm posits that gold precipitates from dilute (<1 mg/kg gold), hot, water ± carbon dioxide-rich fluids owing to changes in temperature, pressure and/or fluid chemistry. I don't have access to the full paper but if they tested anywhere near those concentrations, it definitely won't apply to seawater. The amount of gold in oceans is estimated at 1 gram of dissolved gold per 100 million liters of seawater. The hydrothermal fluids that precipitate out gold in orogenic deposits are closer to 100,000 kg per 100 million liters. This whole experiment is kind of nonsense. Orogenic gold deposits form under high pressures when tectonic plates collide, creating deep faults and shear zones and causign tons of hydrothermal fluid (at 200-450C) to penetrate those new cracks and dissolve the gold contained in them before carrying it all upwards. The chance that piezoelectricity plays much of an effect in those conditions is almost nil. [1] https://www.nature.com/articles/s41561-024-01514-1 https://www.nature.com/articles/s41561-024-01514-1
Resportdi 2y ago
[flagged]

88 points by FairDune 2y ago

amelius 2y ago

So, in absence of quartz we could put large voltage sources on rocks and get gold out?

kragen 2y ago
basically, yes, but the voltage required is very low (what needs to be large is the current), and you need to get the gold to dissolve. https://www.sciencedirect.com/science/article/abs/pii/S0892687500000923 https://www.sciencedirect.com/science/article/abs/pii/S08926... is one of an enormous number of papers on the process, and ipmi has a careers video on youtube: https://www.youtube.com/watch?v=hAkWMdrLXmo https://www.youtube.com/watch?v=hAkWMdrLXmo. shandong xinhai mining equipment corporation has a bunch of youtube videos marketing their equipment for this purpose to gold mine owners
- itronitron 2y ago
  Ocean water contains dissolved gold, although I wonder if the other elements in sea water would attach to the quartz or rock electrode first.
  - kragen 2y ago
    i haven't tried, but as i understand it, gold is one of the easiest metals to reduce; even trivalent gold is at +1.52 volts above the she: https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page) https://en.wikipedia.org/wiki/Standard_electrode_potential_(..., and monovalent gold is the noblest of all metals at +1.83 volts. that table doesn't have another reduction to metallic state until platinum at +1.188 volts, then palladium at +0.915 volts, silver at +0.7996 volts, mercury at +0.7973 volts, trivalent thallium at +0.741 volts, etc. the commonplace metals are far away from this: univalent copper is at +0.52 volts, the more usual divalent copper at +0.337 volts, trivalent iron at -0.04 volts, divalent lead at -0.126 volts, tin at -0.13 volts, nickel at -0.257 volts, cadmium at -0.4 volts, divalent iron at -0.44 volts, zinc at -0.7618 volts, etc. in water you can't really electrodeposit metals that are much more negative than zinc because at -0.8277 volts† you start reducing hydrogen from the water instead of reducing the dissolved metal. so things like silicon (-0.909 volts from quartz), vanadium (-1.13 volts) and titanium (-1.37 volts from trivalent titanium ions) are out of reach. by contrast, the difficulty with gold is that you can't keep it from depositing—so you can't get it into solution in the first place voltages like 0.8 volts may not sound like much, but that's because we're used to currents that are, compared to the number of free electrons in the metal, unbelievably small. 0.8 volts is enough to rip apart a piece of metal atom by atom. consider a mole of zinc anodically dissolving; every atom loses two electrons. avogadro's number of electrons is about 96485 coulombs, about 26.8 amp hours. so, if your other electrode is the she, anodically dissolving a mole of zinc (65.39 grams) yields 2 · 96485 coulombs · 0.7618 volts = 147 kilojoules, which works out to about 2.2 megajoules per kilogram. that's a substantial amount of energy because of gold's extreme nobility people usually complex it with cyanide or thiourea in order to do things like electroplating. its standard electrode potential to go to metallic state from the dicyanide complex is only -0.6 volts. but i don't know what form it's in in the oceans ______ † these potentials are all under standard conditions: unit activity for every reagent, 25° temperature, one atmosphere, etc. things like acidity and temperature can shift them a bit; https://en.wikipedia.org/wiki/Pourbaix_diagram https://en.wikipedia.org/wiki/Pourbaix_diagram is all about how they change with acidity, for example. but i don't think there exist conditions extreme enough to electrowin metallic vanadium or titanium

9dev 2y ago

That is as close to alchemy as we’re probably ever gonna get then!

steve1977 2y ago
Not really I think, as this is not transforming something else into gold, it just kind of lumps existing gold together (if I understood the article correctly).
- djtango 2y ago
  We have a name for that kind of alchemy - nuclear fission/fusion. Because gold is so inert (a noble metal) its counterintuitive to see it in other forms eg in solution. In that sense manipulating gold in other forms than its elemental form probably feels like alchemy in common parlance. I know aqua regia is relatively normal but I still find it weird to think of gold being dissolved
  - lazide 2y ago
    Aqua Regia is relatively normal in the sense that being threatened with a knife is relatively normal. If you think it is, you’re probably hanging out in a pretty bad neighborhood. But yeah, most people won’t be surprised it exists.
    - djtango 2y ago
      Well I'd argue getting threatened with a knife is relatively normal in London but that's off topic :) Aqua regia is not particularly exotic as compared with all the fancy ways you can harm yourself or react things in Chemistry. You can probably prepare it at home using stuff that might be buyable over the counter. Getting your hands on things like azides or Polonium 210 or having access to a nuclear reactor to do ad hoc fission/fusion is a lot less normal on that scale. Additionally aqua regia has been known for quite a long time, from before we even knew about gases Fwiw I forgot what the magic cleans everything mix was but I want to say it was H2SO4 and cif which we'd just squirt around in our fume hoods

yieldcrv 2y ago

This isnt a new hypothesis Several years ago I had read something similar about gold in underground water reservoirs forming along the walls based on … essentially earthquakes

v3ss0n 2y ago

So , alchemists might had discovered that somehow ?

kragen 2y ago
they did have aqua regia, and crystallizing previously dissolved gold from it was, as i understand it, commonplace
deleted 2y ago
[deleted]

ggm 2y ago

Fred Hoyle wrote a pop sci book in the sixties talking about how things worked in early earth formation with prosaic imagery of gold squeezing around in quartz.

OutOfHere 2y ago

What's stopping someone from deploying this in the ocean water to capture gold? Quartz crystal array + electricity -> gold layers?

gus_massa 2y ago
1 You have to squish the quartz that cist money unless you put the crystalsbetween two tectonic plates. 2 The concentration of disolved gold is lower in seawater than in hot hydrothermal mud. 3 Perhaps with realistic values, this is very low and even in ideal conditions ypu need a few thousands years to get a visible chunk of gold.
throwup238 2y ago
From the abstract [1]: > Gold nuggets occur predominantly in quartz veins, and the current paradigm posits that gold precipitates from dilute (<1 mg/kg gold), hot, water ± carbon dioxide-rich fluids owing to changes in temperature, pressure and/or fluid chemistry. I don't have access to the full paper but if they tested anywhere near those concentrations, it definitely won't apply to seawater. The amount of gold in oceans is estimated at 1 gram of dissolved gold per 100 million liters of seawater. The hydrothermal fluids that precipitate out gold in orogenic deposits are closer to 100,000 kg per 100 million liters. This whole experiment is kind of nonsense. Orogenic gold deposits form under high pressures when tectonic plates collide, creating deep faults and shear zones and causign tons of hydrothermal fluid (at 200-450C) to penetrate those new cracks and dissolve the gold contained in them before carrying it all upwards. The chance that piezoelectricity plays much of an effect in those conditions is almost nil. [1] https://www.nature.com/articles/s41561-024-01514-1 https://www.nature.com/articles/s41561-024-01514-1

Resportdi 2y ago

[flagged]