Germanium - The Hidden Treasure from Recycling Germanium Materials
Germanium is a rare earth metal that belongs to a group of 17 metals that form under the earth's surface and are difficult to extract. Despite the challenges in obtaining rare earth metals, most, like germanium, provide critical functions for the technology and defense industries.
Germanium is a metalloid, which are materials that exhibit properties belonging to both metals and non-metals. The brittle crystalline structure of germanium gives the metalloid characteristics like those seen in silicon. Pure germanium is an excellent semiconductor, making the material well-suited for extensive use in the electronics industry.
History of Germanium
The Russian Chemist, Mendeleev first theorized the existence of germanium when he discovered there was a gap between silicon and tin on the periodic table.
Mendeleev initially labeled the element as eka-silicon, but it was later named germanium after Clemens A. Winkler first isolated it in 1886. The first examples of germanium were discovered in a mineral excavated out of a mine in Freiberg in Saxony, and Winkler's native country, Germania, gave him the inspiration for the name.
Germanium is a hard, off-white to grey semi-metallic element featuring a brittle crystalline structure. Due to its crystalline properties, germanium cannot be rolled or drawn. It's properties as a semiconductor are part of the reason the material is so versatile, but it also features a high refractive index that makes it a valuable addition to IR systems.
Germanium also belongs to a small class of elements which have the unusual property of expanding when they freeze (like water) which also includes silicon, gallium, antimony, and bismuth.
Germanium Resources Around the World
Germanium is a by-product of metal refining. Some of the world's supply is extracted from fly ash of germanium containing coal deposits that are burned to supply power to the electrical grid.
In 2011, germanium producers delivered approximately 118 tons of the rare earth metal, with the most significant quantities coming out of Russia, China, and the United States.
Most of the world's supply of germanium is extracted from sphalerite zinc, where the metal is found in concentrations of around 0.3%. The most significant yields of germanium are found in low-temperature sediment-hosted Zn-Pb-Cu(-Ba) deposits, but it is also mined from carbonate-hosted Zn-Pb deposits.
Recent studies indicate there may be as much as 10,000t of germanium locked away in the world's zinc reserves, with significant quantities thought to be held in Mississippi-Valley type deposits.
While sphalerite provides the most abundant quantities of germanium, it is also extracted from other metals such as silver, copper ores, and tin.
Germanium has found its way into many different technological applications, but its most notable contribution is in the form of germanium tetrachloride for fiber-optics applications.
The high refractive index of germanium also makes it incredibly valuable in the field of infrared optics, where it finds extensive use in lenses and windows requiring high transparency to infrared radiation.
In 2007, germanium use was divided as follows:
35% in the fiber-optics industry
30% infrared optics
15% polymerization catalysts
15% solar electric and electronics
The remaining 5% is accounted for the in the fields of metallurgy, chemotherapy, and phosphors.
Germanium in Optics
Low optical dispersion and a high index of refraction make germanium uniquely suited to wide-angle camera lenses, fiber-optic cables, and microscopy.
Using germanium in place of titania as the dopant for silicone fiber allowed manufacturers to avoid the heat treatment that produced the inherent brittleness of the previous generation of fiberoptic cables. By using germanium, manufacturers could deliver a superior product, and by 2002, the optics industry was responsible for 60% of germanium consumption in the U.S.
Thermal imaging cameras working in the 8 to 14-micron range for military hot-spot detection and passive thermal imaging benefit from germanium's transparency to infrared wavelengths. The metalloid also finds uses in firefighting applications, mobile night vision, infrared spectroscopes, and many other applications where sensitivity to the infrared spectrum is essential.
The high refractive index of germanium means that optics must be coated with antireflection agents. Because much of the technology will be subjected to harsh environments, a diamond-like carbon coating is used to provide the optics with antireflection properties as well as endurance.
One of germanium's most notable contributions to science was via the first two Mars Exploration Rovers, which used germanium substrates to create gallium arsenide solar cells for powering their famous treks across the harsh and inhospitable Mars terrain. Triple gallium arsenide used on germanium cells also powers many of the satellite's currently orbiting the earth.
The security industry also finds value in many of germanium's inherent properties. For example, single-crystal high-purity germanium can accurately identify radiation sources, which makes it a valuable material for developing more efficient airport security equipment.
More recently, germanium is proving to be a valuable ally in the quantum computing field and spintronics (the study of the intrinsic spin of the electron). Germanium has shown that it can deliver long coherence times for donor electron spins.
Why We Should Recycle Germanium?
Germanium is only able to be accessed in small quantities as a by-product of other activities such as mining or burning coal. The relatively small amounts able to be obtained by these methods means that germanium will always be highly sought after and prized by technology industries and the defense forces.
The properties of germanium also make it suitable for use in a wide range of applications, which only serves to increase its value and demand even more. For these reasons, there is a lot of value to be achieved from germanium recycling.
From What Products Can We Reclaim Germanium?
There is a wide array of products from which we can reclaim and recycle valuable stores of germanium. Damaged and broken germanium optics, solar panels with germanium, fiber-optic cables, and waste streams from IR coating chambers, can all contain reclaimable quantities of germanium.
Germanium sputtering targets are an often-overlooked resource for germanium because the process is not 100% efficient. There is always some material left over, which can be recycled.
If you suspect you have any scrap materials containing germanium, then be sure to research its value before disposing of it, because you may be throwing out good money. Germanium is a valuable and non-renewable resource, and recycling is one way you can help the planet, as well as recoup some of your expenses.
Contact Oryx Metals for your Germanium Recycling needs
If you are interested in learning more about germanium recycling or just interested in the value of your germanium materials then head on over to www.oryx-metals.com - where our team of highly experienced experts would love to answer any questions you might have.