Rare Metal Resources
A chemical element that belongs to the other metals group, indium was discovered in 1863 by German chemists Ferdinand Reich and Hieronymous Theodor Richter and named for the indigo color in its spectrum. I’m sure many of you are familiar with the abbreviation ITO in this context. It’s ITO, or indium tin oxide, that makes this element so valuable. ITO is practically everywhere, since it’s used as a thin film on various displays like LCDs, plasmas or touch screens. As much as 90 per cent of all indium is used for this purpose, and its value is best reflected in its twenty-year price history. Two decades ago, indium cost less than $200 per kilogram. However, its current prize is floating around $500 — not to mention the rapid increase in indium prices from 2003 to 2005, when the price multiplied to more than five times its initial value.
Indium is a metal with properties similar to base metals, which means that it commonly occurs together with zinc, tin, lead, and copper. The deposits are primarily found in zinc sulphide ores, copper and tin ores, and base metal sulphide deposits, which are the most important source of indium. This element, like other rare metals, is a so-called trace element, and its frequency in other ores is usually very tiny, with up to 50 parts per million (ppm). That means that there are as little as 50 grams of indium per tonne of ore, which is a relatively small amount. The estimated reserves in the whole world as of 2011 were 12,400 tonnes in zinc ore, and the estimated resources were 95,000 tonnes, also in zinc ore. At this point, it’s important to realize that obtaining 12,400 tonnes of indium requires 250 million tonnes of zinc ore.
As for individual countries, China, with 75 per cent of the world’s reserves, is the unchallenged leader in indium production. Other countries that should be mentioned are the United States, Russia, Canada, and Peru, reaching together only 8 per cent of the world’s indium reserves. As for resources, indium is estimated at 95,000 tonnes in 1.9 billion tonnes of zinc ore.
The bad news is that the total indium consumption is unknown. In 2009, the highest indium consumers were Japan and the U.S., but current consumption declined due to recession and poor LCD sales. However, future trends may change — especially when we take into consideration the popularity of touch screens and the application of ITO in solar panels. The good news is that the recycling of production residues or scraps is very prolific, and already in 2009, the biggest indium producers were able to meet 50% of global indium demand. Nowadays, recycling exceeds primary production, and many scientists are striving to find alternatives not only for touch screens, but also for solar panels.
Another crucial (though not very well-known) chemical element of the 21st century is erbium. It belongs to the lanthanides group, and it was discovered twenty years earlier than indium — in 1843 — by the Swedish chemist Carl Gustaf Mosander. Mosander named it after the village of Ytterby. The most common and important application of erbium is as an amplifier in optical fibers known as EDFA, or erbium-dopes fiber amplifiers. Erbium amplifies the laser beams carrying signals in optical fibers and enables us to enjoy such ordinary marvels as sending and receiving emails. Another area where this element is growing popular and probably will boom in the upcoming years is the medical industry, where it is used as an erbium laser. A funny, if trivial fact is that erbium is used to achieve a pink or rose shade in glass. Anybody a fan of rose-colored glasses?
In the case of erbium, the price increase is even more interesting than what we saw with indium, because the trading price of erbium oxide has gone up from $33 per kilogram to $981 per kilogram in the course of just five years. As we can see from this example, erbium is a great rare metal investment. And the difficult extraction of this metal doesn’t push the price down either, because if indium was difficult enough to extract from various ores, erbium presents even more of a challenge. It occurs together with other elements and minerals like xenotime and monazite. Other deposits are found, for instance, in uranium ores. As for the concentration of this trace element, it’s as little as 3 ppm.
The largest resources are located in China and the United States. China is also the world’s largest consumer. China accounts for as much as 94% of overall erbium production.
Europium is a chemical element similar to erbium that also belongs to the lanthanides group. Discovered by French chemist Eugène-Anatole Demarçay in 1896, it has become one of the most important elements in modern technologies over the past 50 years. Were it not for this chemical element, we would probably still be watching TV and working with computers displaying orange color instead of red. Due to its luminescent qualities, europium is used as a red phosphor not only in TVs and monitors but also in various lamps and billboards. Europium was named after the continent of Europe, and there’s more than just a name that connects it with Europe: it’s also used for anti-forgery marks on the Euro.
The price of Europium is where matters start to get quite interesting. The demand for this resource is so large that the price per kilogram has jumped from $680 to $15,575 in the past five years. Well, that’s an investment!
The largest deposits of this chemical element are located in China, the United States, and Russia (along the Kola Peninsula). Europium is mostly contained in minerals like bastnastie, monazite, loparite and allanite. The average concentration in the Earth’s crust is only 1 ppm.
The last exceptionally important element in everyday use that I’d like to mention is rhenium, which belongs to the transition metals group. Its discovery in 1925 is usually attributed to the German chemists Walter Noddack, Ida Noddack, and Otto Berg — although the Japanese chemist Masataka Ogawa announced the discovery of the 43rd element of the periodic table and named it nipponium. Later, an analysis showed that had been the element 75, rhenium. The symbol Np was used for the element neptunium discovered in 1940, and element 43 was named rhenium after the Rhine River.
The occurrence of rhenium in the Earth’s crust is exceptionally rare. With only 1 part per billion, it’s the leader in the chart of rare metals. Furthermore, rhenium is an exception in other aspects too. Its melting point and density are very high, which brings us to its application. Additionally, due to its resistance to corrosion and its rigidity, it is used to produce superalloys — usually with nickel or cobalt (which accounts for as much as 70% of its consumption). The possibilities of its application are really immense, ranging from aircrafts, aerospace, and nuclear reactors to various electrical devices, contacts, and even biomedical devices. In aircrafts, rhenium superalloys are used in jet engines (mainly combustion engines and turbine blades), as a coating for rotors, and in gas turbine engines. It’s also widely used for space systems and missile propulsion, where it is usually used together with carbon to enhance heat resistance.
About 20% of global rhenium consumption lies in the petroleum catalyst industry for so-called catalytic reforming, a procedure of converting petroleum refinery naphthas into high-octane products. Rhenium is also used in electrical contacts, electromagnets, heating elements, and a great number of other devices. In medicine, the isotopes of rhenium are used to treat liver cancer. That makes it a pretty important metal, doesn’t it?
Due to demand, the price of rhenium has changed quite significantly in the last ten years. The current price per kilogram is about $3,700; the price peaked from 2006 to 2009, when the demand for superalloys caused this metal to rocket up to $12,000 per kilogram.
As far as rhenium deposits are concerned, the biggest can be found in Chile. Some other countries with rhenium resources are the United States, Russia, Peru, Canada, and Kazakhstan, where rhenium is extracted from copper and molybdenum ores.
General Electric, the world’s major consumer of rhenium, launched a program to recycle rhenium some years ago. As a result, approximately 10% of their supplies derive from recycled rhenium. Although this may seem as a relatively unimportant figure, it is still a step forward that could help us endure longer until we find a better solution to cope with our rapidly diminishing resources.