The value of many "rare earths" suddenly plummeted recently when an iron+nitrogen [edit: not "nickel"] alloy/crystallization ("allotrope") was discovered that approximates the properties of the best lanthanide magnets.
("Rare-earths" are not, incidentally, needed for [edit:batteries], wind turbines, or solar panels, however much certain people wish they were, or confidently claim.)
> "Rare-earths" are not, incidentally, needed for electric vehicles, 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
Solar panels use silicon, indium, gallium, selenium, cadmium, and tellurium. Neodymium and dysprosium are mainly used in the permanent magnets of offshore wind turbines
The graph you linked shows that this is not true. See the tiny purple graph at the right side of the bar? That's the rare earth minerals and their amount in an electric car is tiny.
Isn't 0.5kg per vehicle a lot for rare earth minerals?? Sure it looks tiny compared to the amount of copper, nickel, manganese, etc used, but the whole point is that they're 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
ferrocerium is the cheapest of the rare earths, but if we're talking about purified elements, cerium and yttrium are probably cheaper than neodymium
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
> Because of their geochemical properties, rare-earth elements are typically dispersed and not often found concentrated in rare-earth minerals. Consequently, economically exploitable ore deposits are sparse (i.e. "rare").
For the purposes of this conversation, which is about economics not geochemistry, they are in fact rare. At least the minerals are
ore deposits that aren't economically exploitable are uneconomic because the price in the market is too low to pay the necessary costs, which are higher when the concentration is lower
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
> Because of their geochemical properties, rare-earth elements are typically dispersed and not often found concentrated in rare-earth minerals. Consequently, economically exploitable ore deposits are sparse (i.e. "rare").
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"
Vanishingly few things show up in "pure form", anywhere in nature. Gold is is all mixed up into quartz, save for flakes in riverbeds. Nitrogen and argon, famously unreactive, nonetheless come mixed with the other, with oxygen mixed in besides.
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.
most solar panels do not currently use indium, gallium, selenium, cadmium, or tellurium, none of which are rare earth elements (though indium is pretty rare)
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.”
antimony is toxic, rare, and expensive, and silicon is none of these, so antimony-based solar cells are unlikely ever to be an economically superior alternative to silicon-based solar cells
It's just a name. They are not necessarily rare.
It should be "certain transition metals", but transition is not what it seems in regard to "changing" in the common sense, either. So, certain metals, it is.
It's just a name. They are not necessarily rare.
It should be "certain transition metals", but transition is not what it seems in regard to "changing" in the common sense, either. So, certain metal ores, it is.
It's just a name. They are not necessarily rare.
It should be "certain transition metals", but transition is not what it seems in regard to "changing" in the common sense, either.
"Rare-earth" means lanthanides plus scandium and yttrium. But scandium and yttrium are not used in magnets, so they would confuse people less by saying "lanthanide magnet" instead of "rare-earth magnet".
("Rare-earths" are not, incidentally, needed for [edit:batteries], wind turbines, or solar panels, however much certain people wish they were, or confidently claim.)