("Rare-earths" are not, incidentally, needed for [edit:batteries], wind turbines, or solar panels, however much certain people wish they were, or confidently claim.)
What exactly does this mean? EVs use a ton more rare earth minerals than conventional cars
https://www.iea.org/data-and-statistics/charts/minerals-used...
Solar panels use silicon, indium, gallium, selenium, cadmium, and tellurium. Neodymium and dysprosium are mainly used in the permanent magnets of offshore wind turbines
Current EVs use some lanthanides in magnets (soon to be displaced, as noted), but not in the batteries.
Permanent magnets are used mainly in the smallest wind turbines, where offshore turbines are the biggest.
in fact, almost all minerals contain trace amounts of rare-earth elements (and non-trace amounts are very rare)
0.5kg of neodymium is around $200 and it's probably the cheapest of the rare earths
0.5kg of europium is around $3,750
Obviously lots of variation there, but maybe ratio of how much it costs vs the total cost of all the other minerals is a better metric to use here than pure weight
the reason the purified elements are expensive is that they're so hard to separate from each other
rare earth elements aren't actually rare
they're called that because we've inherited alchemical terminology from the 18th century when alchemists were first starting to discover that there were more than four elements, and that in particular there were several different kinds of earth, such as magnesia, silex, etc., and as it turns out things like thoria are in fact quite a bit rarer than silex
For the purposes of this conversation, which is about economics not geochemistry, they are in fact rare. At least the minerals are
all this means is that there is a wide range of concentrations among ore deposits
it doesn't have anything to do with how high those prices are or how rare the minerals are, and as you pointed out upthread in https://news.ycombinator.com/item?id=34357834, the prices are pretty low
you said neodymium was US$400/kg; gold, the standard rare element, is US$60893/kg today
They are not, in fact, rare, as is almost always pointed out when they are mentioned.
Regardless, they never show up in a pure form in nature so what we should really be looking at is how common minerals that they're easy to extract from are not how common the atom itself is. And the useful rare-earth minerals are indeed "rare"
Diamond, almost pure carbon, is the only that comes to mind.
So, it is meaningless to single out lanthanides for this. What does distinguish them, instead, is that they are expensive to separate from one another. In certain places such as Yterby and the site mentioned in the original article, ore contains a concentrated mix of many lanthanide compounds. It remains a chore to get the praseodymium and the neodymium into separate ingots.
The amount of magnesium in the human body is .1% by weight. That's not too far different from the amount of rare-earths in an EV.
In the case of a human, i would not wish magnesium deficiency on them, it is not fun, can have severe long-term consequences (such as death), and generally is something that medical professionals will find concerning.
In the case of an EV I don't know what the consequences of removing rare-earths would be, but the fact that it's a tiny percentage of total mass doesn't imply that they can just be dismissed.
the solar panels that used those cannot economically compete with silicon pv for utility-scale solar any more (perhaps that will change)
silicon is also not a rare earth element (and is not at all rare)
evs and wind turbines can use rare earth elements, it's true, but it's just a relatively minor engineering tradeoff not to use them
"According to Philip Pesavento, Cove then managed to refine the composition of the alloy close to Zn4Sb3 – a zinc-antimony alloy with proportions of 4 parts zinc to 6 parts antimony. That, we now know, is also a semiconductor. However, it has a bandgap of 1.2 eV – very close to the bandgap of silicon (1.1 eV). Consequently, it turned his thermophotovoltaic generator into a photovoltaic generator:
“In his enthusiasm, Cove probably made up a larger number of plugs and somehow got the proportions “wrong” on one batch. He then measured an even larger voltage. Finally, he made a careful study of zinc-antimony alloys and found that the 40-42% range zinc alloy gave the highest voltage (compared to 35% zinc in ZnSb). Having – accidentally – discovered Zn4Sb3, the higher bandgap of this semiconductor meant that it no longer worked when it was exposed to the heat from a wood stove. However, it worked even better when it was exposed to solar energy – because it was now converting far more of the visible spectrum of sunlight efficiently into electricity.”
Using colored glass filters, George Cove determined that most of the response was from the violet end of the spectrum and only a little from the so-called heat rays. His earlier PV plugs had responded equally well to heat rays and violet rays, while the older thermoelectric generators (German silver at both sides) did not respond to the violet rays at all.
Bring back the Schottky solar cell? Schottky junction solar cells have commanded only a small amount of attention from researchers and corporations – few solar cell designs use metals in the active region, other than for contacts. [22] Nevertheless, Philip Pesavento believes that it would be worthwhile to attempt to fabricate some Schottky solar cells according to Cove’s design:
“If it could be demonstrated that Zn4Sb3 (bandgap 1.2 eV) can be used in a photovoltaic cell, there is a good chance that such a solar cell design will be sustainable. It would be a good candidate for a quick EROI and have an acceptably long operational life with a surplus energy output over several decades. It’s astounding that everyone seems to have missed this material and its application to photovoltaic cells and that no development has been done – even after researchers briefly recognized it as being a possible option in the early to mid-1980s. It fits in the category of a premature discovery which should mean it could be developed very quickly in this day and age.”
You may ignore claims there that they are essential for batteries and wind turbines. But they are important in electric drones and robots.
https://www.nironmagnetics.com
https://hackaday.com/2022/09/01/iron-nitrides-powerful-magne...