I'm at the Kennecott Copper Smelter in Utah.
It's at this very facility where engineers
and operators rip elemental copper from the living rock.
While this process was discovered accidentally,
over the untold thousands of years of innovation
and experimentation,
we've actually got quite good at it.
Today, we'll be finding out
how to turn something looking like this,
through this,
into something a bit more like this.
You're in for a pretty spectacular episode.
(dynamic orchestral music)
In the beginning,
copper processing wasn't nearly as complex as it is today.
Throughout the Stone Age,
this is how you get your copper,
in its raw elemental form in rocks
and outcroppings littered throughout the ancient world.
It was a nice looking shiny metal,
which was easy to hammer into shape
without the use of complex tools.
Unfortunately, there wasn't all that much of it,
meaning that its use was limited to one off ceremonial items
or some quite basic weapons.
Copper itself isn't super rare.
However, like other metals, it is quite reactive,
often bonding with oxygen or sulfur
in order to produce other minerals.
One such mineral is malachite.
It's beautiful, but ultimately quite useless,
a bit like pi after rounding it to three.
Around 5,000 years ago,
a skilled potter discovered
that by grinding colored metalloid into powdered dye,
and then painting it onto their wares
before firing it in a heated kiln,
they could produce some visually appealing designs.
Shortly afterward, an unskilled potter discovered
that if they left their painted pots
in the kiln for too long
and too high of a temperature with bad airflow,
then they'd produce tiny metallic globules of copper.
They'd also ruined all their pots.
With metallic copper ore in ready supply
and a bit of tweaking to get the process working at scale,
we soon had a reliable source of the metal.
We found that by adding in tin,
we would get a much harder,
more workable material known as bronze.
The ancient world erupted with new invention.
As empires grew, so too did our demand for copper
and mastery of its refinement.
Ancient Egyptian tombs showcased us producing it
on an industrial scale.
We had well and truly left the Stone Age
and into a new era of empire.
Today, our dependence on copper
is as strong as it's ever been,
hiding at the heart of the modern world.
As supplies of high grade copper ore
have dwindled over the millennia,
we've been forced to take copper mining
and its refinement to the extreme,
which is what brings us back to Utah.
Our copper begins at the Bingham Canyon Mine,
the largest, deepest,
most productive open-pit mine that the world has ever seen.
The main copper mineral mined here is chalcopyrite.
A conveyor carries our jumble of rocks
eight kilometers down the mountain
to the aptly named Copperton Concentrator.
First, we need to break the ore
and rock down into even finer particles.
This makes it easier for us to, later on,
separate it into the stuff that's containing ore
and the other bits, which are just boring rocks.
In the past,
you'd do that by banging the chunks together.
Although today,
we're a bit more technologically advanced
and use these known as ball mills.
They work similar to ocean waves
where they bring the mixture of the ore
and some ball bearings up
and then cascade them down,
slowly grinding it away.
While the ball bearings are significantly harder
than the ore,
they too suffer a bit of a beating.
Here is a bearing as it went in
and this is that same bearing after just two weeks.
It got turned into pretty much nothing.
In the past,
you'd then have to manually go through this material
in order to separate the stuff containing copper
from all the rest.
However, since that is completely impractical
to do at scale,
today, we use froth flotation,
essentially, bubbles.
Our powder containing roughly 1% copper
along with some bubble promoting chemicals
and a lot of water
are added to the bottom of our tank.
A giant whisk agitates the solution
and adds in some bubbles.
Important to the process is the addition
of the long chain hydrocarbon potassium amyl xanthate.
One end is extremely copper-philic,
meaning that it attaches itself
to our copper-containing chalcopyrite.
On the other end, it's extremely hydrophobic
and wants to avoid the water,
which it does by attaching itself
to the inside of one of our bubbles.
As these bubbles rise,
they bring the chalcopyrite along for the ride.
At this point, it's roughly 27% copper.
All of that copper mineral containing foam
makes its way out here
into what is appropriately known as Niagara Falls.
From here, it makes its way into three large settling tanks.
By this point, most of the bubbles have already popped,
so our copper mineral is able to sink to the bottom.
Excess water spills over the sides
where it's collected to be reused in the facility.
The sunken slurry is pushed to the center
where it enters a series of pipes.
For almost 30 kilometers,
the copper concentrate
snakes its way down the mountain range,
eventually finishing up at the Kennecott Smelter.
Here, the slurry gets dried
before being loaded into the flash smelting furnace.
We start by heating up the copper ore,
which breaks apart its delicate lattice structure
into copper sulfide, ferric sulfide,
and sulfur dioxide gas.
In its gas form,
sulfur dioxide is actually pretty harmless.
However, when it gets in contact with moisture
such as the moisture inside my lungs,
it forms deadly sulfurous acid.
Fortunately, most of the SO2 gas
gets collected as it's produced,
eventually being sold to make some industrial acids.
However, for the small amount that escapes,
I'm going to be wearing this full face respirator
to ensure that none of that SO2 gets into my lungs.
This electronic gas detector
will give me a heads up
if SO2 concentrations get too dangerous
and I need to get out of the facility.
Back inside the flash furnace,
a stream of pure oxygen gas
reacts with our molten iron and copper sulfide,
replacing the sulfur ion with one of oxygen
and producing an insane amount of heat.
We separate the mixture based on its density
with the less dense iron and rock components at the top,
while at the bottom, we have copper oxide.
That's the dense bit we need for processing later on.
We tap into the furnace to let that copper oxide out.
The upper layers known slag get moved into large buckets,
which are unceremoniously dumped outside.
Glowing in the cold winters' air,
the whole thing reminds me of Mount Doom.
Meanwhile, our molten copper oxide,
now containing 70% copper by weight,
flows to the anode furnace.
This is one of the hottest parts of the entire facility
acquired in order to give a bubbling of methane
enough energy to rip away that pesky oxygen atom.
When the waste products burn off,
giving us a nice green flame,
we also get 99% pure elemental copper.
The molten copper is passed through a series of channels
where it enters an awaiting trough.
Once precisely 380 kilograms of the stuff are measured out,
it gets pour into an awaiting casting basin.
This is located on a turning platform,
which eventually cools it down
and passes it on to the next stage of the facility.
The whole operation from above
reminds me of Ironman's Arc Reactor.
Upon cooling, these slabs are known as copper anodes.
For the vast majority of human history,
this is the best quality copper which money could buy.
You know what's better than 99% pure copper anode?
99.95% pure copper cathode.
While this may sound like overkill,
it's what's required for today's electrified,
copper driven world.
Coincidentally, the way we get it there
is by using electricity
in a process known as electrolysis.
The anodes are transported to our final facility
via a dedicated rail link.
Here, they're submerged into a copper sulfate solution
with thin pure copper cathodes
interspersed in an alternating pattern.
A voltage is held across adjacent plates,
which sucks away electrons from the anode
and dumps them onto the cathode.
This causes some of the surface copper atoms
to enter solution as ions.
Meanwhile, the impurities just fall to the bottom
as a sort of sludge.
Now in solution,
our positively charged copper ions
are attracted toward the negative plate.
When they reach it,
they regain these missing electrons
to return to solid metallic form.
Copper at 99.95% purity.
Copper and its refinement
are just another part of our everyday world,
but what's allowed that world to come into being?
Part accident, part intergenerational scientific endeavor,
it's taken us from the Stone Age to the Space Age
and even beyond.
Until next time,
this has been James Dingley from the Atomic Frontier.
Keep looking up.