How rare earth ore is mined

Rare earths are scattered so thinly through the crust that very few places hold enough to mine.

stations: 4
things downstream: 7

The short version

The 17 rare-earth elements reach industry by two very different routes. Hard ores such as bastnäsite come from open pits like Mountain Pass in California, where crushed rock is ball-milled and floated into a concentrate. Heavy rare earths mostly come from clays, where they cling to particle surfaces and are rinsed out with a salt solution, often right in the ground.

Dig the open pit

At Mountain Pass in California the main mineral of value is bastnäsite. It is dug from an open pit and hauled to a primary crushing and stockpile area.
Ball-mill to slurry

Crushed ore joins recycled water in a ball mill that runs in closed circuit with cyclones. Fine slurry is pumped on to conditioning and flotation equipment.
Float the bastnäsite

Flotation parts the bastnäsite from barite, calcite and dolomite. The concentrate is thickened and filtered, then sold or sent to a separations plant, where the near-identical elements are pulled apart.
Rinse the clays

In ion-adsorption clays the elements sit on particle surfaces, so a sulfate or chloride salt solution can swap them out at ambient temperature. Most recovery has been done in place in the ground. One patent notes that this route tends to pollute groundwater, and leaching in a reactor is proposed instead.

End of the lineRare earth ore Next it goes into neodymium magnet.

Worth repeating

Rare earths are often found with thorium and sometimes uranium, so mining them can bring radioactive waste.
In 1787 a strange black mineral from a quarry at Ytterby, Sweden, led to the discovery of the first rare earths, and several elements are named after that village.
China raised its share of rare-earth production from 21% to 60% between 1985 and 1995.