Industrial Minerals by Harold Hough

What do cars, precision-guided missiles and television have in common? They all depend on rare earth elements, unusual metals that are sprinkled inside almost every piece of high-tech you can think of. Unfortunately, we have become so reliant on rare earths that a few years ago, an intense global power struggle broke out over their free flow. The reason is that one country has a virtual monopoly - roughly 90 percent -- of the mining, refining and processing of rare earths -- China. And in 2010, it used that power to disrupt the world's supply.

Ironically, it was the United States that started the rare earth revolution in the first place. During the 1960s, Americans were clamoring for colored TVs, and engineers at General Electric, RCA, and Westinghouse were working on better color tubes. It was then that they discovered these elemental oddities, specifically "europium," enhanced the color red in TV sets. Thus began the commercial rare earth industry.

Today, many modern technologies, including the “green” technologies rely upon these rare earths. Some of them are phosphorescent. Erbium amplifies light, and is used in fiber-optic cables. Gadolinium has magnetic properties and is used in MRI machines and X-rays. And, neodymium makes your phone vibrate, thanks to a small motor that contains a tiny neodymium magnet in it. The new F-35 fighter jet, the most technologically advanced weapons system in history, contains nearly half a ton of rare earths.

Hybrid cars contain from 20 to 25 pounds of rare earths where a standard vehicle can contain on the order of 10 pounds. Powerful Neodymium-Iron-Boron (NdFeB) magnets are vital in the electric motor and regenerative braking systems found in most electric vehicles and are also crucial to several other systems in the vehicle. Virtually all “green” cars on the road today also rely on rare earths (primarily lanthanum) in the battery pack which stores energy normally wasted during coasting and braking and saves it until needed by the electric motor. In fact, the Prius automobile is the biggest commercial user of rare earths in the world.

Rare earths have other applications. They are at the heart of the most powerful magnets and superconductors. One of the most common green applications of rare earth elements is their use in energy efficient lighting. Phosphors of rare earths are applied to the insides of the bulbs and generate light when energy is applied. These compact fluorescent lamps (CFL's) are replacing the standard incandescent light bulbs at a rapid rate. Incandescence bulbs waste 95% of their energy and convert only 5% to actual light. Contrast this to the CFL which converts 25% of input energy to visible light via the rare earth phosphor coating. This efficiency results in much lower lamp temperatures, significantly longer life (estimated at 6 to 10 times as long), and less total energy consumed.

Rare earths are seventeen elements in the periodic table that are hardly rare. The term "rare earth" arises from the minerals from which they were first isolated, which were unusual oxide-type minerals found in Gadolinite extracted from one mine in the village of Ytterby, Sweden. However, with the exception of the highly-unstable promethium, rare earth elements are found in relatively high concentrations in the earth's crust, with cerium being the 25th most abundant element in the earth's crust.

Until recently, rare earth demand was modest and until after World War Two, all the demand was met by mining sands in India and Brazil. Later, South Africa became the rare earths producer. However, recently China has begun to monopolize the production of these elements. In fact, today 90% of rare earth production comes from China.

Fortunately, there is a domestic solution. Molycorp’s Mountain Pass Mine in California is considered the world's richest reserve of its kind, with ore deposits averaging a concentration of rare earths above 9 percent. Most deposits around the world outside China report ore grades under 5 percent. Processing the ore at Mountain Pass requires several steps in order to separate the various elements. The ore, called bastnäsite, is ground into a fine powder, and goes through a floatation process to separate the bastnäsite from the barite, calcite, and dolomite. The concentrate is then acid washed with hydrochloric acid to separate the insoluble cerium.

That is just the beginning of a complex series of chemical separation steps that separate up to 14 commercially important elements. The rare earths that were dissolved by the acid treatment then go through a series of solvent extractions to separate the europium and the other elements. Finally, the remaining concentrate goes through high temperature calcination to remove other rare earth compounds. Molycorp is also looking at recycling rare earths found in consumer products. Although the amounts are small (like the neodymium magnet that vibrates your cell phone), many consumer electronics end up in recycling centers, where their magnets and LCD screens can be used to produce a rare earth concentrate that can be processed much like the original ore.