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.
この記事は ASIAN Geographic の AG 05/2020 144 版に掲載されています。
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この記事は ASIAN Geographic の AG 05/2020 144 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
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