The Battle For Earth's Rare Metals

We’ve come a long way since our ancestors discovered copper and fashioned the first rudimentary metal objects. In recent decades, we have put the rarest metallic chemical elements to use in the most exotic applications, from smartphones to fighter jets. These abundant but highly dispersed, difficult-to-extract metals – the rare-earth elements – have become one of Asia-Pacific’s most important strategic resources.

Elizabeth Lim

WHAT ARE RARE EARTH METALS?

The Periodic Table of Elements contains chemical information on over 118 different elements and their various properties that can be found on Earth today. Out of these 118 elements, 17 of them are known as rare-earth metals (REMs) or rare-earth elements (REEs). They were first given the name “rare earths” because it was originally thought that there was a short supply of these elements on Earth. These elements are typically dispersed and rarely found in concentrated amounts, but further studies have shown that there is in fact an abundance of these elements in many workable deposits around the world. These metals were only deemed rare, because they were often found in very small concentrations at a time, meaning ore deposits are not commonly economically exploitable. Ideally, for a rare earth metal ore to be economically viable, it should contain more than 5 percent rare earths. If they are mined along with another product, such as iron, this allows economic recovery when concentrations are as low as 0.5 percent by weight.

The existence of these rare metals did not come to light until the 18th century. Swedish army Lieutenant Carl Axel Arrhenius found a unique black mineral in a small quarry in Ytterby, did a small town near Stockholm. The mineral was found to be a mixture of rare earths, and in 1803, cerium (Ce) was the first individual element to be isolated. The first commercially produced rare-earth element was later mined in the 1880s in Sweden and Norway, before moving to foreign production in Brazil in 1887, and then India in 1911.

The 17 rare-earth metals and some of their common applications

Sc Scandium: Atomic weight 21. Used to strengthen aluminium alloys

Y Yttrium: Atomic weight 39. Used in superconductors and exotic light sources

La Lanthanum: Atomic weight 57. Used in specialty glasses and optics, electrodes and hydrogen storage

Ce Cerium: Atomic weight 58. Makes an excellent oxidiser, used in oil cracking during petroleum refining and used for yellow colouring in ceramics and glass

Nd Neodymium: Atomic weight 60. Used in magnets, lasers and as purple color in ceramics and glass

Pm Promethium: Atomic weight 61. Used in nuclear batteries. Only man-made isotopes have ever been observed on Earth, with a speculated 500–600 grams naturally occurring on the planet

Sm Samarium: Atomic weight 62. Used in magnets, lasers and neutron capture

Eu Europium: Atomic weight 63. Makes coloured phosphors, lasers, and mercury-vapour lamps

Gd Gadolinium: Atomic weight 64. Used in magnets, specialty optics, and computer memory

Tb Terbium: Atomic weight 65. Used as green in ceramics and paints, and in lasers and fluorescent lamps

Dy Dysprosium: Atomic weight 66. Used in magnets and lasers

Ho Holmium: Atomic weight 67. Used in lasers

Er Erbium: Atomic weight 68. Used in steel alloyed with vanadium, as well as in lasers

Tm Thulium: Atomic weight 69. Used in portable X-ray equipment