May 4 SciCafe: The Race for Rare Earths and Other Metals
by AMNH on
Cell phones, hybrid cars, missile defense systems — and many other modern technologies — depend on components that include elements known collectively as rare earth metals. At the next SciCafe on Wednesday, May 4, Curator James Webster of the Museum’s Department of Earth and Planetary Sciences will be discussing these elements’ properties as well as the pressing issues of supply and sustainability. Dr. Webster recently answered a few questions about the topic.
What are rare earth metals?
It depends on who you ask. To many, the rare earth metals are 17 of the heavier known elements that exhibit similar but unique chemical, magnetic, optical, and electrical properties. They are silver to gray in color, relatively soft, chemically reactive, exhibit high melting temperatures, and are crucial to many modern technologies. But these metals have been mischaracterized and are incorrectly named. Most of the rare earth metals are simply not that rare: they are actually more abundant in the crust of our planet than metals like silver and lead.
What are some of the most common applications for these metals?
The rare earth metals are critical to modern and emerging products including lasers; components of electronic equipment; high-powered magnets capable of working at high temperatures, which are vital to “green” technologies like hybrid cars and wind turbines; rechargeable batteries; liquid crystal displays of cellular telephones, televisions, and computers; and catalysts required for converting or refining crude oil to gasoline and other hydrocarbon-based products.
Where are these metals found?
They are extracted from scarce and interesting minerals that are concentrated in ores of mineral deposits located around the world. Significant deposits of rare earth metals in the People’s Republic of China are typically associated with rocks that were once molten in our planet’s crust. This geological association is significant because the formation of most known metal deposits involved, and for deposits that are actively forming still involve, the actions of hot water. Hot water-rich fluids moving through the rock of Earth’s crust selectively dissolve, transport, and deposit these metals in the mineral deposits that we exploit.
How has demand grown, and what is the outlook for meeting it?
In the past decade, the demand for the rare earth metals has grown by as much as 20% per year for several rare earths. Without additional mining and more efficient recycling, this demand will outpace supplies. Presently, more than 90% of the world supply of rare earth metals is controlled by the People’s Republic of China. China and other Asian countries are experiencing major technological and commercial development and are consuming massive quantities of the world’s supplies of rare earths and other metals. This development, as well as China’s economic policies regarding these metals, have reduced the export of China-sourced rare earths and other rare metals like indium, of which China is the leading producer. At this time, no deposits of rare earth metals in North America are in production, but companies are moving rapidly to begin locating and exploiting deposits to help offset the increasing demand.
Are there alternatives to rare earth metals?
For most modern applications, there are few materials that serve as replacements. To maintain recent levels of manufacturing and to meet increasing demand, we must improve the efficiency of recycling our electronic products. More than 100 million cellular telephones are “retired” each year in the United States, but less than 20 percent of these are recycled. Also, if we continue our development and use of new rare element-bearing products, we must be prepared to live with increased mining activity in future.