- The ocean has around 20 million tons of gold in it.
That's something like $700 trillion worth of gold.
And the cubic mile of seawater behind me
has somewhere around a million dollars worth.
So how do I get some of that?
(indistinct)Hello, I am Sam Jones, I'm here for reactions.
All right, I'm ready.
I'm of course, not the first person to have thought of this.
In 1872, a British chemist named Edward Sonstadt
discovered that there was gold in seawater,
but he didn't actually try to get rich off of it.
The first person to try was New England pastor,
Prescott Ford Jernegan in 1890s.
The story goes that he comes down with typhoid fever.
He's totally delirious, clinging to life
and he has a bizarre dream where he sees seawater
being turned into gold.
So he survives the typhoid and he's like,
all right, I'm gonna do that.
And he creates what he calls the gold accumulator.
It was essentially a wooden box with holes in it
that inside had a sheet of solid mercury
that was mixed with a secret ingredient.
And then it had a wire attached to a battery
that ran through the mercury and electrified it.
Jernegan was selling this weird electrified wooden box
to people so that they could get rich quick
by sucking gold out of the water.
This is a chemical process that scientists often refer to as
a scam, the science just wasn't there,
but not all attempts to get gold
out of seawater had been scams.
In 1900 inventor Henry Clay Bull filed a patent
for a method of extracting gold from seawater,
where he lowered the acidity of seawater
to supposedly pull out dissolved ions, including gold ions,
but there's no record of Bull even trying his own device.
In the 1920s, Nobel Laureate, Fritz Haber
spent years working on this and actually came up with
what was apparently a legit process that involves
a massive centrifuge.
But then he realized he made a very simple
mathematical error early on, and his process turned out
to cost more money than you'd actually get back in gold
but where they all failed, I think I can succeed, right?
I mean, it can't be that hard.
Got it.
So we'll boil off the water in seawater,
which will just leave the salt behind
and then I'm gonna try and extract gold from that.
Hmm, now that I have salt,
I just need to separate the gold from the other stuff in it.
Typically when people extract gold from rock or sediment
in nature, they use a technique called a gold cyanidation
where gold is essentially dissolved.
Gold cyanidation relies on an oxidation reduction
or redox reaction, which is a type of reaction
where electrons are transferred from one species or atom
to another.
In this case, oxygen removes electrons from gold atoms
leaving them with a positive charge
so that they can form a complex with negatively charged
cyanide.
Hey George, can I get a thumbs up for using
cyanide in this video?
While I was trying to figure out how to buy something
that's been used as a chemical weapon to extract gold,
I got to thinking, how much gold could I actually get
from this?
In 1990, researchers figured out that there's about
one gram of gold for every hundred million tons of seawater.
So I boiled down one liter of seawater
and seawater contains about 50 femtomole per liter
of gold, that equates to about 10 picograms.
$1 gold is about 0.01769 grams of gold.
So if I just want a dollars worth of gold,
I would need to go through 2 billion liters.
Hmm, okay.
Well, a quick call to a chemist
should help me sort this out.
If I brought a hundred liters of seawater to your lab
and I was trying to extract gold from it,
what would you tell me to do?
- If you brought it to the lab
we could try to remove it doing something like
electrochemistry,
where do we try to reduce it by providing electrons to it?
- So what's the drawback of just doing that.
I mean, just bring you buckets and buckets of seawater.
- Well, my lab isn't that big.
So this would be really challenging.
It would also be quite expensive to transport
that much seawater because there's so little gold
in that water that you would need to bring
millions of gallons.
There has been some work done where people
have actually removed gold from seawater
using metal, organic frameworks.
- A metal organic framework, or MOF is clusters
of metal ions linked together by organic molecules.
MOFs can be modified to trap different molecules
of interest and their large surface area
means they can absorb a lot of whatever they're collecting.
- A small piece of metal, organic frameworks say
the size of your hand, might have the surface area
of say a football field.
- So then what's the holdup?
- Well, these things bind ions,
but a lot of ions look similar
and given the small amount of gold you're gonna get
out of the water, it actually ends up
not being cost efficient.
I think if you were talking about doing it profitably.
People would kind of find that to be a little silly.
- Ah, okay.
Well for now, I'm not gonna get gold out of this,
but I did get to go to the beach to film this video.
So it wasn't a total loss.
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