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Comment by ars | Hacker News Reader

Metal rather than plastic is not a good thing, metal uses far more resources.

We’ll have agree to disagree. Aluminum uses a lot of energy to refine and cast, yes but is more durable and recyclable.

And it doesn't breakdown into billions of micro particles that stay in the environment. (Though lots of micro plastics come from apparel rather than consumer electronics)

If you do a full lifecycle analysis on the part plastic usually wins. Even if you recycle the metal, you can burn the plastic (which is the environmentally best way to handle it) and get back virtually all the energy embodied in it.

Using a metal part, when plastic will do, just costs extra energy.

Obviously some things need to be metal for strength, I'm talking about when that's not necessary.

“which is the environmentally best way to handle it”

Citation sorely needed.

Read the rest of this thread. Burning plastic for energy reduces the need for oil from the ground. It's by far the best way to handle plastic.

It removes waste, it's emits less CO2 than pull extra oil from the ground, and it's cheap. You don't get a triple win like this very often when it comes to the environment.

His point might be that the carbon in the plastic will some day be released to the atmosphere, either through decay, combustion, or even digestion. Might as well burn it now and recover some energy in the form of heat from it.

Also means your laptop doesn’t snap at the hinges like most plastic ones do.

Most metals in common use are recyclable. Whether they actually are recycled or not probably depends on what they're attached to. A washing machine, for example, contains plastic and rubber, and those have to be separated from the metal for the latter to be recycled. Perhaps someone can comment on that.

Copper is of course valuable enough that at times people have stolen copper wiring to sell it for recycling. I don't know whether that's a thing today.

At one point, printed circuit boards contained gold--used, as I understand it, to coat traces (sort of like wires) to prevent corrosion. Tiny amounts, of course, but apparently enough to warrant recycling. I actually knew someone who stripped the traces off of old boards and sold them. Again, I don't know whether that's still a thing.

Currently, the US is getting about 60% of steel recycled, and 80% of aluminum. Nucor Steel, the biggest steel company in the US, runs mostly on recycled steel. Their success came from figuring out how to make good sheet metal from recycled steel. Before that, recycled steel was mostly used to make rebar, which is low quality steel.

Here's a Nucor steel plant video.[1] Good overview of the process. Note that this is a spherical video and you can change the camera angle to look around. Seven categories of steel junk go in and are mixed depending on the desired product. The video is a bit vague about how the continuous caster works - that's partly proprietary technology. This particular plant is a joint venture with Yamato, but Nucor has other totally-owned plants.

[1] https://www.youtube.com/watch?v=pjxJRaAItow

USGS stats give the iron/steel at ~50%, aluminium at ~53%, and the highest achieved rate for lead, at 75% (largely from batteries IIUC):

[I]n 2018, recycled material as a percentage of apparent supply of various metals, including aluminum, chromium, copper, iron and steel, lead, magnesium, nickel, tin, and titanium, ranged from a low of 22% for tin to a high of 75% for lead (table 1). in 2018, the United states recycled 58.6 million metric tons (Mt) of metals with a total value of $37.7 billion (excluding zinc, for which data were withheld to avoid disclosing company proprietary data in 2018).

2018 Minerals Yearbook: Recycling --- Metals (2018)

<https://pubs.usgs.gov/myb/vol1/2018/myb1-2018-recycling.pdf> (PDF)

Various ways to compute this.[1][2] Steel products and scrap are both imported and exported, which confuses things. The data at [3] above seems to treat steel imports as new metal because their recycling inputs are not known.

[1] https://www.steel.org/wp-content/uploads/2021/08/AISI-and-SM...

[2] https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-iron-steel...

[3] https://pubs.usgs.gov/myb/vol1/2018/myb1-2018-recycling.pdf

It's interesting that the USGS itself (your 2nd reference) seems to disagree with itself (my own ref). I'd need to dig further into figures to see how that emerges.

(I'm ... somewhat discounting the AISI data as more likely to be skewed industry-positive, that is, with a higher claimed recycling rate.)

It's hard, but the statistics by usage are more clear. Over 90% of automotive and structural steel is recovered. Rebar in concrete, far lower.

> Copper is of course valuable enough that at times people have stolen copper wiring to sell it for recycling. I don't know whether that's a thing today.

You can scrap copper for anywhere between $1-$3/lb depending on quantity, quality, and location. Copper is commonly recycled.

But do people still steal copper to sell for recycling? (I suppose I should ask whether they ever did, but I think it's been documented.)

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