Each of the elements found in the periodic table have their own characteristics. After they have been cooked in the pot of the universe, these substances that are offered to our service can be radioactive (like uranium), metallic (like magnesium) and even gaseous (like helium). Seventeen of the elements not easily found among the layers underground have unique properties. These elements are called rare-earth elements, because it is hard to discover and mine them.
Rare-earth elements are in many of our everyday devices. The data projected on a computer screen is transmitted via optic cables containing erbium. The light of a tablet device is generated by the phosphorescent element europium. We actually touch indium covered surfaces when we scroll our fingers on touch screen monitors. When listening through headphones, we are using neodymium magnets that are ten times stronger than iron magnets.
From space technologies to defense industries, from cell phones to LED lighting, many such rare-earth elements are used in every stage of our lives. These elements – many of which we cannot live without, even though we've never heard of them – were recorded into the Critical Materials Strategy Document published by the U.S. Department of Energy in 2010. In a public announcement, the department declared fourteen of the elements as specially significant regarding clean energy, listed six of them as critical, and the other four as near critical. Fifteen elements, beginning with lanthanum and ending with lutetium, numbered between 57 and 71, comprise lanthanides. Combined with scandium and yttrium, these make up the seventeen rare-earth elements.
he elements that we touch on screens
Indium (atomic number 49) gains the properties of electrical conductivity and optic transparency when combined with tin, which, at number 50, is indiums's neighbor on the periodic table. Optical transparency is a desired property for plasma screen and television technologies. Indium is also an important material for mobile phone touchscreens. Interestingly, when indium combines with cadmium, also as a neighbor at number 48, it loses the optical transparency. Instead, it is able to absorb light. Light harvesting is a very critical feature in the production of solar cells.
The relationship of indium with its two neighbors opens new horizons for scientists. In the near future, it is hoped that many unknown and interesting features will be unearthed by investigating the known elements of the periodic table. It is amazing that these elements have been around for thousands of years in the universe only to be discovered by technological advancements.
The need for rare-elements in the world is around fifty thousand tons. The current recorded reserve for rare-earth elements is 110 Million tons. Currently, 95% of the demand for rare-earth elements is supplied by China, yet the country only has 35% of the world's reserves. Therefore scientists are constantly searching for rare-earth element mines to eliminate the Chinese monopoly and to boost the production of these rare materials. In recent years, China has gotten into political debates with Japan and the United States by curbing rare-earth element exports. Economic journals covering these debates wondered if "element wars" were near. In 2010, a massive reserve of elements, enough to sustain worldwide demand, was discovered in the Pacific Ocean. Developed countries are now planning to recycle rare-earth elements from used devices due to low reserves.
Yttrium, europium, and terbium (atomic numbers 39, 63 and 65) have been known for a long time. Terbium and yttrium are named after the Swedish town of Ytterby. Yttrium is the first rare-earth element discovered, at the end of 18th century. Plastics containing europium are used to make laser products; it's also used as an element to provide the red color on television screens. Yttrium has a supplementary role that enhances europium's red color production. And terbium oxide activates the green phosphorescence of television tubes with its yellow-green phosphorescent property.
Terbium also enables an 80% reduction of energy consumption in light bulbs. This makes it one of the most wanted elements in the $2 billion rare-earth element market. Today, when we purchase class A type light bulbs, we are actually buying rare elements like terbium.
Neodymium (number 60), which emits a green light via laser pointers, is also used in the magnets of electric motors. When neodymium combines with boron and iron, it makes a magnet twelve times stronger than simple iron magnets. Because it is significantly less dense than iron, it makes electric motors and laptop computers much lighter. Another interesting feature of neodymium is that it enhances the data storage capacity of hard drives. Furthermore, neodymium is wanted for electrical devices and wind turbines.
The union of elements
Dysprosium was discovered in 1886 and can never be found in a free form in nature. This is because it exists in a compound form with other minerals, like gadolinite. Dysprosium is also known for its magnetic property, and when mixed with terbium and iron, it forms a substance called Terfenol-D. In a magnetic field, Terfenol-D has unique transformational abilities. Dysprosium is utilized in laser production together with vanadium, and it emits infrared radiation when used with cadmium.
The magnetic alloys of iron, boron, and neodymium lose their magnetic features beyond 300 degrees Celsius. However when this alloy is combined with dysprosium at a 5% ratio, that problem disappears. Therefore, these magnets are used for electric turbines and hard disc motors. Dysprosium also makes magnets in electric motors 95% lighter. And dysprosium and nickel mixed fillings are used as cooling rods in nuclear reactors.
The human mind becomes fascinated after seeing all the wisdom and properties involved in these lifeless elements. Either we conclude that these elements have doctorate degrees in physics and chemistry from Harvard University, or we may express our weakness and fascination in front of The Grand Creator who created and presented these elements for our benefit.
Is the yellow color in glasses from the planet Ceres?
Since Dell recalled four million laptop computers in 2006, because of a possible explosion caused by overheating battery, scientists' eyes have been focused on lanthanum and cerium. These two elements are considered to be safer than other alternatives. Lanthanum and cerium are used in electrical equipment and energy saving light bulbs, and are classified as critical elements in these processes, along with tellurium. Cerium, named after the planet Ceres, is responsible for the yellow coloration in glasses. Cerium is also used in polishes, ceramics, and petrol refineries. Tellurium is produced indirectly, unlike most other elements. The production of cadmium takes place during zinc production, and tellurium during copper refining. Tellurium is a cheaper element that has been used in combination with cadmium on solar cells since 2009; before then, most solar cells used expensive silicon panels.
Elements in our lives, from space rockets to ultrasound imaging
Hafnium, tantalum, erbium, and technetium are important elements, even though they are not listed critical. Even though hafnium and technetium are not rare-earth elements, they were still added to the critical material strategy document produced by the US Department of Energy. Hafnium is employed in space rockets for its resistance against extreme temperatures and wearing. Hafnium oxide is a valuable material for electronic transistors since it is a very effective electric insulator. It is 20% faster than the silicon oxide that is commonly used in transistors. A transistors length is around 65 nanometers when silicon oxide is used, but it is only 32 nanometers with transistors made of hafnium oxide. This 50% decrease enables smaller devices.
Touchscreens containing indium, laptop computers powered by lithium ion batteries, and cell phones with hafnium transistors are some of today's technological wonders. Would these inventions still be possible without these elements? Could we reach the high capacities in hard discs without the tantalum? Would we be able to protect ourselves from electric leakage in computers without high quality electric insulators such as tantalum oxide?
Radioactive technetium, which was discovered in 1937, is the first artificially produced element. The technetium 99 isotope is used in nuclear medicine. Technetium produced from uranium has a half life of 211,000 years, as opposed to the 6 hour half life of the technetium 99 isotope. The number of technetium based nuclear medicinal tests, like ultrasounds and x-ray imaging, is estimated to be above thirty million annually.
We take advantage of these elements in every stage of our lives, from medicine to technology. Could we become dependent upon elements the way we are upon petroleum? Only time will tell. Either these elements will be replaced by other materials, or other technologies will outdate the current technologies. It is also possible new elements will be discovered.
A majority of our modern technologies would not exist without these elements that were dispersed among the earth billions of years ago. These elements were placed here for our benefit, and so we could utilize them, and produce institutes of scientific research and education to study them.
Kadir Can and Mehmet Ramazanoglu are science teachers in Ankara, Turkey.