>Iron ores are abundant, but still a finite resource.

The iron doesn't go anywhere (ok, except for the iron making up our space probes). It is infinitely recyclable.

It doesn't concentrate itself, at scale.

That's what ores are. Ores are useful because they are concentrated, the result of some ore-formation or ore genesis process.

The "not going anywhere", after it's been dispersed throughout the lithosphere, is precisely the problem.

<https://en.wikipedia.org/wiki/Ore_genesis>

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meindnoch 3 days ago | parent [-]

But scrap metal is still purer than any ore.

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dredmorbius 3 days ago | parent [-]

And ferrous mineral recycling accounts for roughly 33% of present production (2018 data, most current available):

<https://www.epa.gov/facts-and-figures-about-materials-waste-...>

That's a loss of 2/3 of production to non-scrap effluvia on an annual basis. I'll let you work out the ultimate resource depletion cycle from that. Recycling is useful, but it's no magic bullet, and there are always losses.

The most heavily recycled metal in the US is lead, per USGS data and prior comments of mine, with recovery rates of about 75%, accounting for 40% of net production.

<https://news.ycombinator.com/item?id=20164506>

<https://news.ycombinator.com/item?id=26412585>

Source citation: "USGS 2020 Minerals Yearbook: Recycling — Metals"

<https://www.usgs.gov/centers/nmic/recycling-statistics-and-i...>

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potato3732842 3 days ago | parent | next [-]

>That's a loss of 2/3 of production to non-scrap effluvia

Considering that the amount of stuff in our world made from steel at any one time is steadily increasing this makes sense.

>The most heavily recycled metal in the US is lead, per USGS data and prior comments of mine, with recovery rates of about 75%, accounting for 40% of net production.

There's little to no "post consumer pre-recycler" use for lead whereas every tom dick and harry can find a use for some old pipes or beams or whatever.

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meindnoch 3 days ago | parent | prev [-]

That just means it's currently more economical to mine iron ore than it is to mine landfills.

	▲	eru 3 days ago \| parent [-]
		And we are presumably still adding to the total stock of iron in human circulation.