A nice little table of the technologies utilizing the lanthanide elements.
I am not going to fully cover the paper from which this graphic comes, because it is on the subject of recovering elements from flowback water from the "fracking" industry in China.
The paper is this one: Rare Earth Elements Occurrence and Economical Recovery Strategy from Shale Gas Wastewater in the Sichuan Basin, China (Liu et al., ACS Sustainable Chem. Eng. 2020, 8, 32, 11914–11920)
As I have made clear, many times, I oppose all dangerous fossil fuels, the mining of all dangerous fossil fuels, and frankly, any technology which attempts to claim to mitigate the tragedy, because all of these attempts have and will prove trivial as compared to dangerous fossil fuels.
One of the huge waste profiles of dangerous natural gas - which many people who believe that so called "renewable energy" ignore based on their toxic fantasy that dangerous natural gas is "transitional" - is flow back water, the chemical and mineral laced water that is used to hydraulically shatter rocks permanently in the earth's crust so our generation can work to get the last molecule of methane burned and its waste, carbon dioxide, dumped into the planetary atmosphere, this at the expense of all future generations.
Many putative "green" technologies actually depend heavily on lanthanide elements, the overwhelming majority of which are mined and processed in China, often under decidedly dirty conditions that are hardly "green."
These elements, once thought as laboratory curiosities - I don't think we spent more than 5 minutes discussing them in my high school chemistry class when I was a child - are now key to many technologies.
This graphic from the paper shows how things have changed in my (long) lifetime, and how many technologies rely on access and purification of these elements which are, in general, not "renewable."
The caption:
With the exception of scandium (Sc) (which could in theory be made via the neutron irradiation of calcium) all of the elements listed in this table up to (and more or less including) gadolinium (Gd) are present in used nuclear fuels, although some of them would require fairly long cooling before being available for non-nuclear applications and/or applications in closed systems. (Some closed system applications would be improved by using the radioactive forms of these elements rather than the stable form, but that's not current practice.) Others, such as yttrium, lanthanum, praseodymium, neodymium, would require very short (or no) cooling times, cerium only moderate cooling times. However the same energy to mass ratio that makes nuclear fuels superior in a purely environmental sense to all other forms of energy, means that the amounts available would more or less be trivial when compared to those available from the ores we are working so hard to deplete.
One of the elements listed, promethium, does not occur on earth except in minuscule amounts, from spontaneous fission in uranium ores. It has no stable, non-radioactive isotopes. Pm-147 can, and has been isolated from used nuclear fuels, but its use in signage, lighting and batteries has been limited because regrettably, nuclear fuel recycling has been limited.
I knew of most of these applications, but it was nice to see them all in one place, and I thought I'd post it.
I hope you're having a wonderful weekend.
= new reply since forum marked as read
It's called "Yttria stabilized Zirconia." ZrO2 is an important component of thermal barrier coatings on superalloys, but it does undergo a solid phase transition at high temperatures which can cause cracking. Adding yttria stabilizes the zirconia to avoid this phase transition.
Jet engines and gas turbines in combined cycle plants actually operate at temperatures higher than the melting point the superalloys, but the low thermal conductivity prevents these heat from passing through to the alloys.
Yttrium is also a component, as a metal, of several creep resistant alloys.
NdFeB magnets can also be improved by the addition of yttrium, although in general, dysprosium is a superior additive. Dysprosium is, however, far more rare than yttrium, so there's a cost benefit of the the former. I suspect that dysprosium will be one of those elements that will not be available from ores for generations not too far off. By contrast we have relatively more yttrium, and of course, it's a fission product with no especially long lived radioisotopes, so can be recovered from used nuclear fuel.
A rather remarkable refractory is yttrium silicide which has a rather remarkable phase diagram:
J Mater Sci (2018) 53:3981–4000
And of course, Y-90, a decay product of Sr-90, besides generating most of the heat in Sr-90 thermoelectric generators, is an important isotope in radiomedicine.
It's a cool element; not one, admittedly, most people are inclined to spend time considering, but quite interesting when you look into it.
The thermal barrier coating was the first application into which I really looked with any depth, but I was familiar with YAG lasers in practice, if not theory.
