This is not a kilogram of gold.

It’s a cube that our associate  producer Eve spray painted so it can pretend to be a kilogram of gold, and so I can make a point. Because according to a report published in 2024, to produce one kilogram of gold these days, you have to process three  million kilograms of ore.

And that is like, super inefficient, also not particularly great for the environment. But there’s good news. Scientists already know about a much more concentrated source of gold out there.

They just need to find better ways to process it. It’s the trash. Humanity is sitting on a hoard of gold we’ve already mined and have thrown into the garbage. [intro jingle] According to researchers, humanity threw 270,000 of these little guys away back in 2022.

But it’s not like millions of people kept dropping their wedding rings down the garbage disposal. The vast majority of this gold garbage came predominantly in the  form of electronic waste, or e-waste. Because these days, basically everything with a circuit board has at least a tiny amount of gold in it.

Like a lot of the other metals you can find in electronics… say, silver or copper… gold is great at conducting electricity. But gold is also incredibly malleable, meaning it’s a lot easier to form it into the shape you want. And it’s a lot more resistant to tarnishing, which keeps your circuit in  tip top shape for longer.

On the other hand, it’s also expensive. Today, one kilogram of gold  is worth roughly $75,000. So engineers have to decide how much gold they can get  away with using in their tech, and where it’s going to go.

For example, it’s often used at the connection point of different electronic components, and to bond wires together. So inevitably, as billions of humans around the globe toss out their broken electronics or trade them in for a new, shinier model, those tiny bits of gold in  each item start to add up. In 2022, we produced an estimated 62 million metric tons of e-waste. 270,000 kilograms of that was gold, so we basically threw away $15 billion dollars in gold in a single year.

As for how much gold there is total in all the garbage bins  and dumps around the world, well, that estimate was a bit  harder for us to track down. In 2023, The World Gold Council reported that humans have mined over 212,000 metric tons of gold. And while they do keep track of how much gold gets appropriated for electronics each year, those numbers don’t tell us anything about discarded electronics.

Meanwhile, there was a report published back in 2019 which claimed a whopping seven percent of all our gold is tied up in e-waste. But if you read the source they cite to back up that claim, you’ll see it doesn’t mention gold at all. If you wanted to try some  back-of-the-envelope math, you could guesstimate that there’s up to a trillion dollars of e-waste gold, just sitting there useless.

Of course, we do recycle some of our electronics. The current statistic has been hovering just over 20%. Which is not that great, but that means that there’s a lot of room for growth.

And the more gold we can reuse, the less we have to extract from the ground. Thanks to DeleteMe for supporting this SciShow video! DeleteMe works to keep your  personal information personal.

They remove stuff like your  phone number and address from public search results, giving you back more control over who you share it with. That way, you have less to worry about when it comes to identity  theft and phishing scams. I’m sure you steer clear of responding to emails that you don’t recognize.

But your Aunt Mary might not be  as vigilant about that stuff. So DeleteMe offers family plans to take care of all of your loved ones. … Including the ones that don’t spend as much time on the internet as you. Since the ways companies collect, share, and sell your data are constantly changing, DeleteMe is continuously improving and evolving to address these challenges.

They’ll even remove your  personal information continuously throughout the year to address  anything new that pops up. To get started, go to joindeleteme.com/SCISHOW and use promo code SCISHOW at checkout. You’ll get 20% off DeleteMe US consumer plans!

Now back to the show. Back in the 1980s, Japanese researchers coined the term urban mining… the process of collecting gold, or other precious metals, from discarded electronics. And today, it’s seeing a boom in popularity.

That isn’t to say you should quit your day job and break into the nearest dump to dive for old iPhones. Remember, the amount of gold in any one circuit board is miniscule, so you as an individual  aren’t going to be recreating Scrooge McDuck’s money bin anytime soon. And scientists are still working out the kinks of how best to extract the gold from that e-waste.

Current techniques often require either heating up your electronics to melt the gold off them, or dissolving them using a special kind of acid to then separate the gold out. Not only can these be inefficient  and resource intensive, they can release toxic compounds as a byproduct. And we’re trying to be  environmentally friendly here, so some of the research into alternatives c an sound outright bizarre.

Like in one paper published in 2024, a team of Swiss researchers described how they were able to extract gold from a slurry of dissolved circuit boards using a very novel, and very fancy sponge of their own design. OK so it’s not actually a sponge, it’s an aerogel But that’s less important than the main ingredient in that aerogel: a group of proteins that are  a byproduct of making cheese, called amyloid nanofibrils. They didn’t actually make any cheese, though.

They just did some chemistry to convert whey proteins into a soggy gel of nanofibrils strands, which they then dried out. Meanwhile, on the other side  of the proverbial lab bench, they dissolved twenty  motherboards and their metals in an acid bath. They added little clumps of sponge to that electronics soup for 24 hours, dried them out for another 24 hours, and then set them on fire… TWICE to actually get the bits of gold out.

In other words, I’ve been instructed to tell you DO NOT TRY THIS AT HOME. But this is just one technique  researchers are testing out. Like, there’s an Australian startup using microbes in a proprietary gold-extracting concoction.

And there’s a group of researchers based in Finland that designed a 3D printed mesh to filter out bits that don’t have gold in them. Basically, it’s the modern  equivalent of panning for gold… because it still involves reducing your electronics to soup, first. Urban mining may have a challenging road ahead, but it’s already seeing promising results.

According to a 2018 paper published in Environmental Science and Technology, urban mining is becoming more cost effective than new, virgin mining. And the authors of a Nature Geoscience paper from 2024 predicted that by 2050, our recycling of rare earth metals like gold could meet up to 40 percent of demand in the US, China and Europe. So think twice before you trash your old iPhone, or sacrifice it to that box of old electronics you’ve got hiding in a closet.

Because digging the gold out of there may one day be easier than  digging it out of the ground. [ OUTRO ]