Factbox: The Complexity of Transforming Rare Earths from Mine to Magnet by Reuters

LONDON (Reuters) – The European Union is facing significant challenges in achieving its ambitious objectives regarding rare earth elements under new legislation aimed at increasing domestic production of critical minerals and decreasing reliance on China.

Although the 17 silvery-white rare earth minerals are not particularly rare in the earth’s crust, economically viable deposits are harder to locate. The real rarity lies in the complicated processes required to separate them into materials essential for manufacturing permanent magnets, which are critical for various important products.

China dominates the global rare earth landscape, accounting for approximately 60% of worldwide mine production. This figure escalates to 90% when considering processed rare earths and magnet production.

The journey of rare earths to becoming magnets used in electric vehicles and wind turbines—two primary sectors driving future demand—involves several intricate steps.

Mining

Rare earth ore is first extracted from open pits or underground mines, crushed, and transported to a nearby processing facility. The raw ore consists of a small fraction of rare earths, from which other minerals are removed using flotation, magnetic, or electrostatic processes to yield a mixed concentrate that usually contains 60% to 70% rare earths. Additionally, some operations garner rare earth concentrates as byproducts from mining waste or materials like mineral sands and iron ore.

Radioactivity

Certain ores, such as monazite, necessitate an extra procedure to eliminate radioactive thorium or uranium, typically involving acid treatments.

Separation

One of the most challenging phases is the separation of individual rare earths. This technology was first pioneered in U.S. government research facilities after World War II.
Separation can be performed using ion-exchange technology, as well as solvents like ammonia, hydrochloric acids, and sulfates. However, some of these chemicals generate toxic waste byproducts linked to health risks. Light and heavy rare earths require distinct separation circuits for the extraction of individual elements. Although environmentally-friendly separation technologies are in development, they have not yet seen widespread application.

Metals and Alloys

After separation, rare earth oxides are converted into metals through electrolysis. The most commonly used permanent magnets are composed of neodymium and praseodymium, mixed with iron and boron. These materials are placed in a vacuum induction furnace to create an alloy. To enhance heat resistance, smaller quantities of dysprosium and terbium are often incorporated.

Magnets

The alloy ingots undergo a breakdown process and are jet-milled in a nitrogen and argon environment to produce a fine powder. This powder then goes through a high-temperature, high-pressure process known as "sintering" before being shaped into magnets.