7 ms·

This is great - but isn’t hafnium pretty rare?

by dharma1 7y ago

igravious 7y ago
Yes, but at least it's twice as abundant as forthnium.
- benj111 7y ago
  You mean quartnernium.
  - igravious 7y ago
    Yanks say "one fourth", Brits say "one quarter": https://forum.wordreference.com/threads/a-fourth-a-quarter.3065667/ https://forum.wordreference.com/threads/a-fourth-a-quarter.3... I knew there was a high likelihood that I would be downvoted to oblivion for making a terrible Dad joke, but it was worth it. I feel that a few years back I could maybe have cracked that joke without my karma being bludgeoned.
    - benj111 7y ago
      "Yanks say "one fourth", Brits say "one quarter"" Didn't know that, thanks, you'd have thought I'd have worked it out by now, but then it took me far too long to work out what a 'fawcet' was. Re karma. You will live a much happier life not worrying about some random on the internet downvoting you.
marcosdumay 7y ago
I may be common enough for a 3 atoms wide layer. Is there any large scale tentative of refining it?
maxerickson 7y ago
It's about 1000 times more abundant in Earth's crust than gold.
- hn_throwaway_99 7y ago
  So, still very rare then.
  - maxerickson 7y ago
    To me the question was about availability rather than pedantry.
kragen 7y ago
Kind of, but not enough to matter for this application anytime in the next several years. The USGS report at https://www.usgs.gov/centers/nmic/zirconium-and-hafnium-statistics-and-information https://www.usgs.gov/centers/nmic/zirconium-and-hafnium-stat... says the US imported 36 tonnes of hafnium last year. If a three-atom-thick layer of hafnium is 0.6 nanometers and weighs 13.3 g/cc, those 36 tonnes would cover 4500 km², enough to produce about 700 GWp of solar energy. The US installed 10.6 GWp of photovoltaic generation capacity last year, which would amount to one seventieth of its hafnium imports. (China installed 45 GWp.) It is relevant once photovoltaic energy becomes the main power source for the humans, because the materials used in current photovoltaic cells are dramatically more abundant than hafnium.
- dharma1 7y ago
  Thanks for putting it into context! Generally I wonder about sustainability of rare earths (and other elements with limited supply like helium). We build a lot of products that don't last very long - some of it gets recycled, a lot of it doesn't. Wonder what humans 200 or 2000 years later will think of our consumption
  - kragen 7y ago
    Helium is a special case: when it leaks into the atmosphere, it eventually escapes into space. So the humans really do consume helium, just as the humans consume fossil fuels. By contrast, all the lithium, phosphorus, carbon, aluminum, iron, hafnium, zirconium, and erbium ever mined on Earth is still on Earth, except for the extremely small amounts sent to Venus, Mars, the Moon, and interstellar space on spacecraft, or transmuted to other elements in nuclear reactors. It is not consumed, just moved around a bit. Where is it? Well, it varies by element. While some of the phosphorus makes up human bones, most of it is dissolved in the ocean as phosphate, enormously less concentrated than the original deposits of apatite and other minerals it was mined from. At some point the humans might run out of easily accessible apatite deposits, since phosphorus only makes up 0.1% of the Earth's crust. If we consider only the top 2 km of the continental crust (29% of the surface) to be "easily accessible", that's only 3.0 × 10⁸ km³ of rock, or about 7.1 × 10¹⁷ tonnes, of which about 7.1 × 10¹⁴ is phosphorus. Since phosphorus is currently being mined at 153 million tonnes per year, the humans are currently on track to deplete most of it in only 4.6 billion years, considerably earlier than the Earth is on track to be destroyed by the sun. As for the carbon, it's mined for its chemical potential energy, which is lost when it is burned; but the carbon remains on Earth. 870 billion tonnes of it is in the atmosphere, of which about a third is due to the humans setting rocks on fire; a comparable amount has been added to terrestrial biomass and carbon in the oceans. The part in the atmosphere is relatively easy to recover; existing processes have comparable cost to the cost of digging up rocks. This is not being done at scale because it is "unprofitable". More than half of the aluminum that has been mined on Earth is still in use. The other half is mostly in landfills, where it is less concentrated than the bauxite ores that are commercially mined, but less oxidized. Most of the iron that has been mined is in landfills, but not only ores but also slag heaps near foundries are a more concentrated form of iron. Rarer metals like gold, hafnium, zirconium, and erbium are mostly in landfills. They mostly do not readily form soluble ions to leach into the ocean or groundwater, and they mostly only find their way into the air when incinerated. Their concentrations in landfills are dramatically higher than the concentrations in the ores they are mined from, and this is becoming a "profitable" way for the humans to spend their lives before being killed by the hazards of the landfills. Presumably automation will speed up this process.

This is great - but isn’t hafnium pretty rare?

igravious 7y ago

Yes, but at least it's twice as abundant as forthnium.

benj111 7y ago
You mean quartnernium.
- igravious 7y ago
  Yanks say "one fourth", Brits say "one quarter": https://forum.wordreference.com/threads/a-fourth-a-quarter.3065667/ https://forum.wordreference.com/threads/a-fourth-a-quarter.3... I knew there was a high likelihood that I would be downvoted to oblivion for making a terrible Dad joke, but it was worth it. I feel that a few years back I could maybe have cracked that joke without my karma being bludgeoned.
  - benj111 7y ago
    "Yanks say "one fourth", Brits say "one quarter"" Didn't know that, thanks, you'd have thought I'd have worked it out by now, but then it took me far too long to work out what a 'fawcet' was. Re karma. You will live a much happier life not worrying about some random on the internet downvoting you.

marcosdumay 7y ago

I may be common enough for a 3 atoms wide layer. Is there any large scale tentative of refining it?

maxerickson 7y ago

It's about 1000 times more abundant in Earth's crust than gold.

hn_throwaway_99 7y ago
So, still very rare then.
- maxerickson 7y ago
  To me the question was about availability rather than pedantry.

kragen 7y ago

Kind of, but not enough to matter for this application anytime in the next several years. The USGS report at https://www.usgs.gov/centers/nmic/zirconium-and-hafnium-statistics-and-information https://www.usgs.gov/centers/nmic/zirconium-and-hafnium-stat... says the US imported 36 tonnes of hafnium last year. If a three-atom-thick layer of hafnium is 0.6 nanometers and weighs 13.3 g/cc, those 36 tonnes would cover 4500 km², enough to produce about 700 GWp of solar energy. The US installed 10.6 GWp of photovoltaic generation capacity last year, which would amount to one seventieth of its hafnium imports. (China installed 45 GWp.) It is relevant once photovoltaic energy becomes the main power source for the humans, because the materials used in current photovoltaic cells are dramatically more abundant than hafnium.

dharma1 7y ago
Thanks for putting it into context! Generally I wonder about sustainability of rare earths (and other elements with limited supply like helium). We build a lot of products that don't last very long - some of it gets recycled, a lot of it doesn't. Wonder what humans 200 or 2000 years later will think of our consumption
- kragen 7y ago
  Helium is a special case: when it leaks into the atmosphere, it eventually escapes into space. So the humans really do consume helium, just as the humans consume fossil fuels. By contrast, all the lithium, phosphorus, carbon, aluminum, iron, hafnium, zirconium, and erbium ever mined on Earth is still on Earth, except for the extremely small amounts sent to Venus, Mars, the Moon, and interstellar space on spacecraft, or transmuted to other elements in nuclear reactors. It is not consumed, just moved around a bit. Where is it? Well, it varies by element. While some of the phosphorus makes up human bones, most of it is dissolved in the ocean as phosphate, enormously less concentrated than the original deposits of apatite and other minerals it was mined from. At some point the humans might run out of easily accessible apatite deposits, since phosphorus only makes up 0.1% of the Earth's crust. If we consider only the top 2 km of the continental crust (29% of the surface) to be "easily accessible", that's only 3.0 × 10⁸ km³ of rock, or about 7.1 × 10¹⁷ tonnes, of which about 7.1 × 10¹⁴ is phosphorus. Since phosphorus is currently being mined at 153 million tonnes per year, the humans are currently on track to deplete most of it in only 4.6 billion years, considerably earlier than the Earth is on track to be destroyed by the sun. As for the carbon, it's mined for its chemical potential energy, which is lost when it is burned; but the carbon remains on Earth. 870 billion tonnes of it is in the atmosphere, of which about a third is due to the humans setting rocks on fire; a comparable amount has been added to terrestrial biomass and carbon in the oceans. The part in the atmosphere is relatively easy to recover; existing processes have comparable cost to the cost of digging up rocks. This is not being done at scale because it is "unprofitable". More than half of the aluminum that has been mined on Earth is still in use. The other half is mostly in landfills, where it is less concentrated than the bauxite ores that are commercially mined, but less oxidized. Most of the iron that has been mined is in landfills, but not only ores but also slag heaps near foundries are a more concentrated form of iron. Rarer metals like gold, hafnium, zirconium, and erbium are mostly in landfills. They mostly do not readily form soluble ions to leach into the ocean or groundwater, and they mostly only find their way into the air when incinerated. Their concentrations in landfills are dramatically higher than the concentrations in the ores they are mined from, and this is becoming a "profitable" way for the humans to spend their lives before being killed by the hazards of the landfills. Presumably automation will speed up this process.