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Comment by littlestymaar | Hacker News Reader

> This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Or it make leach lead into the real world making it not safe to deploy.

Lead is still routinely used in many applications today, either in metallic form, from ICE car batteries, to fishing or hunting gear, or as chemical compound in different kinds of glass. And the same can be said about other heavy metals like Cadmium or Mercury. Industries also routinely work with much more nasty things than lead, so it really doesn't sound like a show-stopper.

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In particular, lead is still extremely common in radiation shielding, possibly because the drop in demand for other applications made it so cheap. Lead-lined drywall is the default approach for setting up a radiography, fluoroscopy or CT suite.

> possibly because the drop in demand for other applications made it so cheap

Maybe a little bit. But I think it is more that it is a material with heavy atomic nuclei and high density, and thus effective at blocking radiation. And it is also relatively cheap.

Lead is absurdly cheap. One dollar a pound! Cheaper than much more common metals like aluminum or magnesium. So I diagnose a low demand.

They used to talk about using barium cement but it just can't compete, price-wise.

I believe that most of the lead used today is a by-product or co-product of mining other more valuable metals like Zinc and silver. Lead is quite abundant in the Earth's crust and found in easy to access deposits.

I think >80% of the current industrial use of lead is for batteries. It's probably still in the top ten most mined metals by dollar value and definitely by mass.

The mineral containing Zinc is called Sphalerite, which is based on a greek etymology for "deciever" because it commonly occurs with Galena (which has Lead and Silver) and looks similar.

It may not come as a complete surprise that the economics of metals are more complex.

Aluminium, was so expensive until the Hall/(that other guy) process was developed, that it was used for jewellery [1].

Even today it's expensive and difficult to reduce Al ore to metal, which is a supply side problem.

[1]https://www.bellandbird.com/products/aluminum-bangle

75% of aluminium supply is from recycling aluminium products.

The economy sort of has a "working capital" quantum of aluminium which also grows steadily from aluminium mining.

Lots of metals have very different and complex supply structures and thus completely different $$$ / volume curves for their supply.

Understanding the $$$ / volume curve of commodities is not something that is commonly considered when people try and predict the future. Mining a billion tonnes of Aluminium from an asteroid for example and safely landing it on Earth can never be profitable because the $$$ / volume curve for Aluminium is $0.00 at billion tonne volume.

Now I'm curious where that recycled aluminium is coming from? My guess would be mostly from airplanes and beverage cans...

Engine blocks too. If you go to a scrap yard though you’ll be pretty amazed at all of the stuff they’ve got collected and sorted. Metal recycling (compared to, say, electronics recycling or plastic recycling) has a very clear economic model and financial incentives. If you’re demolishing a building or scrapping old machinery it will cost significantly less to recycle the metal (because you get paid decently by the pound) than to take it to a landfill (where you pay by the pound instead).

Cars too

TIL! Aluminium is an extremely useful metal, but I would never have thought it would be used for jewelry - I mean, it's not enough for the metal to be expensive, it also has to look and feel desirable, which soft and dull Aluminium definitely doesn't. If you have ever held Aluminium cutlery in your hand, it just feels cheap compared to stainless steel (not to mention silver).

Today it isn't used for jewelry. 200 years ago it was - not so much to wear, but to show off that you were rich enough to afford it. Only royalty could afford things made out of aluminum.

As a young fella, I carried a lot of that lead-lined drywall, it's (obviously) really heavy, and expensive so you got yelled at a lot if you damaged the edges, couldn't just trim it off like normal drywall.

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