As I understand it, it's more of a problem of processing the rare earths. It's incredibly polluting and the US preferred to offload that pollution on China
It's this. If you include the new discoveries in Colorado and Wyoming, the US has the largest reserves of rare earths on the planet. Additionally, the US has an estimated 11 million metric tons of rare earths in coal ash waste pools which can be reprocessed.
The problem with rare earths is multifaceted. I'll give a little insight into each step and why it sucks ass.
1. Mining: you'll notice I said "reserves" and not "deposits," because unlike traditional natural resources we mine, like iron, coal, or gold, rare earths do not exist in these dense veins. "Rare earths" is a misnomer, as they are not rare at all, they are found everywhere as a very small percentage of the earth's crust. Instead, what you see is areas of relative abundance, where companies just dig these massive strip mines. To give you an idea of the sheer amount of unused waste rock produced in this process, we'll use the numbers from Bayan Obo, the largest rare earths mine on the planet. Bayan Obo's strip efficiency is generally around 10:1, meaning for every ton of
ore that is produced, ten tons of waste rock is produced. Now, the ore on average is around a half a percent to a percent of rare earths, meaning that you need
one to two hundred tons of ore per ton of rare earths. So, for one ton of rare earths, you are producing between one and two
thousand tons of waste rock. That's a lot of waste rock.
2. Processing: We'll focus on hydrometallurgical processing, which is the most common type of processing rare earths. This will all be grossly simplified and I am not an expert so if I get anything too terribly wrong I apologize. First you use physical separation, where to take all the ore, crush it, and dump it into a water tank where you add collectors, frothers, and depressants. Collectors are generally things like fatty acids to bind to rare earths to make them float in the tank. Frothers, like MIBC or pine oil, stabilize the froth created by the collectors to make harvest easier. Depressants are chemicals which bind to everything you aren't looking for to keep them from floating. That all gives us the concentrated ore, so next we get to the fun part, chemical leaching. This is where you take all the stuff from the physical separation and dump a shit ton of acids on it in order to dissolve the rare earths. The primary acids used are sulfuric and hydrochloric, sometimes nitric, and for alkaline leaching generally they use sodium hydroxide or carbonate. This just gives you a soup of rare earths though, which is still useless, as we need to separate them further. The answer to this is more chemicals, obviously. There's an absolute ton of different ones used depending on purity needs and what elements you're looking for, but generally they are some kind of phosphor based acid. Generally kerosene and the like are used as diluents in this step. The final step of processing is to take these new acid soups and create useable metals, oxides, or whatever else, and the chemicals involved vary significantly depending on the element. Hydrofluoric acid is a common one for cerium and neodymium, for instance.
3. Waste: So, for one ton of rare earths, we, on average, have a couple thousand tons of waste rock, a couple thousand tons of toxic waste chemicals, a ton of low grade radioactive waste like thorium and natural uranium, about a hundred cubic meters of waste water heavily laden with leachates, acids, and heavy metals, and about ten thousand cubic meters of waste gas, including off gassing of chemicals like sulfuric and hydrofluoric acid. This is an absolute shitload of waste. In America, we are generally pretty responsible, so we take all this waste, process it using even more energy and chemicals, and then store it long term in waste pools, transport it off site, or, if clean enough, dump it back in the surrounding area. The waste processing is expensive and logistically challenging. China saves a ton of money and just skips this step by dumping all of it back into the fucking pit it came from, because who give a shit if the ground water for half a million people is so heavily laden with waste metals that it couldn't make it through a metal detector? That's not the CCP's problem, because even though the health of these people may be harmed, the collective health of China will be greater if we just let these people die of heavy metal poisoning or have severe generational birth defects in perpetuity.
This is the primary reason that China dominates the rare earth market. The United States is more than capable of competing. If we look at, currently, the only operating (but still significant) US rare earth mine, Mountain Pass, which is in California, their ores are of higher quality and their mining is generally more efficient. The highest ore grade you generally see in China is about four percent, whereas Mountain Pass sees grades as high as twelve percent.
