Infrared night vision goggles
Recently, the situation in Ukraine has continued to be turbulent, touching the hearts of people all over the world. Upon waking up, the situation has undergone new developments and changes. Through the media, we can see a lot of pictures of night battles. In the era of cold weapons, due to the lack of light, soldiers were very restricted from fighting at night. The restrictions on modern military operations at night are getting smaller and smaller, because infrared optical imaging systems have become the eyes of soldiers in the dark, so that everyone has "night vision eyes". Infrared navigation and aiming equipment allows fighters to move freely at night or in conditions of low visibility, and thermal imaging cameras become the secret weapon for soldiers to conduct military operations at night. Germanium is an indispensable raw material for infrared optical imaging systems.
Germanium metal
Germanium, the chemical symbol is Ge, is located in the periodic table of chemical elements in the 4th cycle, the IVA group, the content in the earth's crust is about 0.0007%, not the least, but very dispersed, is a typical rare dispersed element.
In 1886, the German chemist Venkler accidentally discovered germanium while analyzing minerals, and named the new element "germanium" after the German name (germania), and the element symbol was set as Ge.
Germanium is a silvery-gray hard and brittle semi-conductive metal that is chemically stable and does not interact with air at room temperature. Germanium metal and its compounds have good semiconductor properties, excellent infrared optical properties and good transmittance to microwaves. According to the United States Geological Survey (USGS), the global consumption structure of germanium accounts for 30% of the optical fiber communication industry, infrared optics account for 20%, polyethylene terephthalate (PET) accounts for 20%, solar energy and electronics account for 15%, and other fields such as medicine account for 15%. From these data, it is not difficult to see that germanium has a wide range of important applications in optical fiber communications, infrared optics, semiconductors, aerospace, solar cells, chemical catalysts and biomedicine, and is an important strategic resource.
Tiangong-1 space station
Why is the content of germanium not much, but there are many application areas? This is closely related to the duality of germanium.
Although germanium is a metal, it has many properties similar to non-metals.
It is clear in the periodic table that germanium is located on the dividing line between metallic and non-metallic elements, and the elements near the dividing line are often both metallic and non-metallic.
The 1991 Gulf War was the first modern war in human history, and the disparity in the ratio of war losses between the two sides directly affected people's views on war, and was a watershed between traditional mechanized warfare and modern informationized warfare, as well as a watershed in the world's military changes. Speaking of the Gulf War, we have to mention the debut weapon "rookie" - infrared thermal imaging system.
Infrared monitor
The night low-altitude infrared navigation and aiming system was applied on a large scale in actual combat for the first time, becoming the "eye" of fighter night combat, so that soldiers can move freely in the dark as day.
Since then, militaries of various countries have begun to equip infrared thermal imaging equipment in large quantities. The manufacture of key lenses, prisms, windows, filters and other optical components such as infrared radar, infrared detectors, night vision devices, and infrared trackers is inseparable from germanium.
In the civilian field, high-definition infrared detection cameras can take images of rare wild animals at night, which helps people better understand and protect wild animals and contribute to biodiversity.
In addition, human beings cannot explore the universe in the vast expanse of space. Germanium-based solar cells have good resistance to space radiation and high temperature resistance, higher photoelectric conversion efficiency and lower power generation costs, and are widely used in space stations and other fields. Germanium is also the "eye" of aerospace vehicles - the lens composition material of infrared tracking instruments.
Germanium has some applications in optical fibers
In the Internet era, presumably everyone has such an experience, the delay in loading the progress bar when watching the news makes people upset, the caton when brushing the video makes people scratch their ears, and the operator upgrade bandwidth can solve the above problems. If broadband is the "road" of information communication, then optical fiber is the "highway" in the road, and germanium is the "paving stone" of the highway. Germanium tetrachloride can be used to make optical fiber preforms, play a doping role and photoelectric conversion role, and is an indispensable raw material for making optical fibers.
Optical fiber is a widely adopted communication conductor, and there is currently no other product to replace. Since the 21st century, the annual growth rate of global optical fiber demand has reached 20%, especially the demand for communications in developing countries has continued to grow at a high speed. With the development of the mainland's "Broadband China" strategy, the implementation of the "Internet +" concept and policies such as "speeding up and reducing fees", and the advent of the era of 5G Internet of Everything, the demand for optical fiber continues to increase.
Health and longevity has been a topic of concern since ancient times. The Shennong Materia Medica and the Compendium of Materia Medica all list Ganoderma lucidum as a medicine and are treasures in precious medicinal materials. Modern medical research shows that Ganoderma lucidum contains a variety of alkaloids, the main components of which are "germanium" ions and polymer polysaccharides, which can enhance the body's self-healing and immunity and improve human health. In addition, precious Chinese herbs such as ginseng, goji berries, and fox eyes, as well as vegetables such as garlic and potatoes, contain organic germanium. Mainland scholars have found that the germanium content of wild ginseng in 20 years is 400×10-6, while garden ginseng (artificially cultivated) rarely exceeds 50×10-6.
Reishi mushroom
Photography / Shi Kejun
Is anything that contains germanium edible? not necessarily.
Germanium is divided into inorganic germanium and organic germanium, inorganic germanium is mainly derived from coal and sulfide ore, processing and extraction of germanium single crystal, bismuth germanate crystal (Bi12GeO20) can be used in the field of infrared optics. Only germanium in the form of organic salts is called organic germanium, which is beneficial to the human body. Organic germanium can be divided into synthetic and natural. In 1887, the first organic germanium, tetraethyl germanium, was synthesized, and more than 200 kinds of synthetic organic germanium have been synthesized so far. Among them, the most important is that in 1967, Japanese medical doctor Kazuhiko Asai et al. synthesized the water-soluble organic germanium oxide Ge-132 (scientific name β-carboxyethyl germanium sesquicanide). It can induce the body to produce γ-interferon, and can induce the transformation of "sleeping" macrophages into anti-tumor macrophages, thereby inducing the activity of anti-cancer interferons. Since then, organic germanium has begun to play a role in the fields of pharmaceuticals, health care products and cosmetics.
At present, organic germanium has been used clinically to treat various cancers, rheumatoid arthritis, cataracts, hypertension and other symptoms, and the medical community has praised organic germanium as the "salvation germanium" of mankind in the 21st century.
Global germanium resources are scarce but concentrated. Germanium as a rare element usually hides in or symbiosis with other minerals in a dispersed state. Germanium resources are relatively poor, and the proven reserves of germanium metal are only 8600 tons, which is 1/10 of gold. Germanium resources are very concentrated in the world, accounting for about 45% and 41% in the United States and China, respectively.
Due to the backward processing technology and production equipment in the mainland, a large number of germanium primary products are exported abroad, and the proportion of global output has been maintained at 65%-70% for a long time. However, at the same time, it also imports deep-processed germanium products from abroad, which has caused a serious waste of resources and funds.
The United States has the world's largest germanium reserves, but it is reluctant to mine, because at the current mining rate, germanium resources will be exhausted after more than 40 years. As early as 1984, the United States passed a bill to protect germanium and carry out strategic reserve protection, and after 2013, it stopped mining completely. In February 2022, the U.S. Geological Survey released the latest 50 key minerals list, germanium is still an "old member" of the "key minerals list".
It is clear that as geopolitical instability continues, germanium's strategic significance will be further enhanced by its importance in the military, communications, and space fields. As an emerging material mineral in the 21st century, germanium is a key mineral and strategic resource to ensure the safety of mineral resources in the mainland.
Editor-in-charge | Liu Dan
Typography | Winnie
Audit | Liu Dan
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