Science

There’s $700 Trillion Worth of Gold in Seawater! Can We Extract It? [Video]


The ocean has about 20 million tons of gold in it — that’s around 700 TRILLION DOLLARS worth of gold! In this episode of Reactions, we explore how, for over a century, people have struggled to collect it. And we see if, where they failed, we can succeed.

Video Transcript:

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.

Before you go, we wanted to invite you to participate in PBS digital studios, annual audience survey. Your feedback really helps us understand what our audience is interested in so that we can give you more of it. So if you have a few minutes, we’d love your input.

You even get to vote on potential new shows. There’s a link in the description below, thanks.

https://to.pbs.org/2021survey





Source link

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button