07-18-2025, 09:00 AM
https://www.sfgate.com/tech/article/appl...772874.php
For those interested in the rare earths supply. The Mountain Pass mine switched years ago to solvent extraction instead of foam flotation. This was done for environmental reasons, as solvent extraction is generally more expensive than flotation. The solvent extraction process isn't great environmentally as such, but it produces much, much less volume of pollutants. Flotation produces lots and lots of "contaminated" water, thereby giving it a larger environmental "footprint".
Solvent extraction is more expensive per ton of ore processed than flotation. With high grade ore that greater expense may be insignificant. As the ore grade goes down the relative disadvantage of solvent extraction increases rapidly. At some point, the graphs cross and solvent extraction becomes financially untenable. Mountain Pass (MP) mine has been around for "awhile". Lots of ore has already been pulled out, but there is lots of ore still in the ground. Normally the "high grade" ore is extracted first, in so far as possible. That may mean MP will be fighting some economic factors. China has different standards regarding environmental damage. I expect they continue to use legacy flotation techniques for the vast majority of their rare earth mines. MP would be too if it was environmentally possible. That competitive advantage was a major factor in MP ceasing production previously. This issue won't go away.
OTOH the recycling of batteries is fairly well suited to solvent extraction processes. That is just about the only way to do such recycling. You can't feed batteries to a ball mill. It isn't like crushing ore. The good news is the battery "ore grade" is fixed by the battery design. You know what the costs of extraction will be and they will remain consistent. Building a solvent extraction plant to recycle batteries is expensive and probably has fairly low margins. It is also very sensitive to the exact price of the extracted rare earths. That is why there is presently very limited ability to recycle EV batteries :-). MP involving itself in that process is clearly a "win" for them. They have a solvent extraction plant anyway. Eventually they may make more money extracting Chinese rare earths from used batteries than they do from mining their own ore :-).
For those interested in the rare earths supply. The Mountain Pass mine switched years ago to solvent extraction instead of foam flotation. This was done for environmental reasons, as solvent extraction is generally more expensive than flotation. The solvent extraction process isn't great environmentally as such, but it produces much, much less volume of pollutants. Flotation produces lots and lots of "contaminated" water, thereby giving it a larger environmental "footprint".
Solvent extraction is more expensive per ton of ore processed than flotation. With high grade ore that greater expense may be insignificant. As the ore grade goes down the relative disadvantage of solvent extraction increases rapidly. At some point, the graphs cross and solvent extraction becomes financially untenable. Mountain Pass (MP) mine has been around for "awhile". Lots of ore has already been pulled out, but there is lots of ore still in the ground. Normally the "high grade" ore is extracted first, in so far as possible. That may mean MP will be fighting some economic factors. China has different standards regarding environmental damage. I expect they continue to use legacy flotation techniques for the vast majority of their rare earth mines. MP would be too if it was environmentally possible. That competitive advantage was a major factor in MP ceasing production previously. This issue won't go away.
OTOH the recycling of batteries is fairly well suited to solvent extraction processes. That is just about the only way to do such recycling. You can't feed batteries to a ball mill. It isn't like crushing ore. The good news is the battery "ore grade" is fixed by the battery design. You know what the costs of extraction will be and they will remain consistent. Building a solvent extraction plant to recycle batteries is expensive and probably has fairly low margins. It is also very sensitive to the exact price of the extracted rare earths. That is why there is presently very limited ability to recycle EV batteries :-). MP involving itself in that process is clearly a "win" for them. They have a solvent extraction plant anyway. Eventually they may make more money extracting Chinese rare earths from used batteries than they do from mining their own ore :-).