The material is created by fusing an alloy of iron and nickel
© Klaus Pichler / ÖAW / futurezone.at
Smartphones, headphones, or hard drives: Many electronic devices contain components rare earth Contain. One of the most sought after of these chemical elements is metal neodymium. This is used for what is called extremely powerful permanent magnet Used, for example, for electric motors or wind turbines.
However, these minerals are limited and only found in a few countries. China has the largest reserves in the world. Due to the expansion of renewable energies and the growing trend towards electric vehicles, the demand for rare earths and thus the dependence on the resource can continue to increase.
Environmental pollution from precious metal mining is a particular problem. In order to win in small amounts, a lot of ore must be mined with great effort. Massive amounts of water and energy consumer. When separated from the rock, toxic waste is produced. In addition, radioactive substances are released.
This set includes 17 chemical elements neodymium, lanthanum, cerium, terbium, praseodymium, dysprosium, erbium, europium, gadolinium, holmium, lutetium, promethium, samarium, scandium, thulium, ytterbium and yttrium
44 million tons According to a study conducted by US Geological Survey in Chinese soil. The second largest reserve in Vietnam is half that
9 out of 10 neodymium permanent magnets come from China
local researchers Baran Sarak, Jurgen Eckert And the Sergey Kitov from the Austrian Academy of Sciences (OeAW)Together with colleagues from The University of Cambridge and the Istituto Italiano di Tecnologia have created an environmentally friendly alternative to the neodymium and other rare earths used for permanent magnets. It’s the metal Tetranitate. The item usually just comes meteorites Before.
The idea to produce this came about serendipitously during casting auditions, as Sarak explained in the Future Zone interview. As a general rule, a tetratinite forms after a piece of rock from space hits the Earth. The mixture from Iron and nickel It cools very slowly in the meteorite over millions of years. The atoms of the two metals create a special crystalline structure – the material acquires magnetic properties.
Reduce environmental pollution
Austrian researchers have accelerated this natural process many times over with a simple procedure. This is achieved by using an alloy of iron and nickel in small amounts phosphorus and carbon added. According to Sarak, these two elements ensure that the atoms of the two metals move faster and form the crystal structure within a very short time. Specifically, the cast metal rods, up to 3 millimeters long, were able to cool down within a few milliseconds.
“We believe we can convert this discovered structure into commercial permanent magnets free of rare earths,” says the materials researcher. It can not only be liberated from dependence on resources, but also protect the environment.
on every continent
In any case, the magnetic properties of industrially produced teratinite give reason for hope. In general, the highest power products can currently be achieved with neodymium magnets today. The energy product is a quantity that serves as a measure of the magnetic energy of a magnet. The higher the energy, the stronger the magnet forces. Tests have shown that lab-grown tetranitrite achieves magnetic properties similar to neodymium and can perform the same functions.
There are no drawbacks compared to neodymium and other rare earths, but there is one major advantage: “Compared to rare earths, iron and nickel are found all over the world,” Sarak says. Tetranitite magnets can also be made inexpensively and used in a wide variety of applications. In addition to wind turbines and electric motors, radar and satellite communications systems as well as electrical positioning systems can benefit from them. “Permanent magnets are also used in dentistry and medicine – for example to monitor and treat tumors,” says the materials researcher.
The technology has now been patented. In the next step, the properties of the material must be further improved. “Then we want to produce tetranitrite on a large scale,” says Sarac, adding, “We are currently in talks with many startups and large companies around the world.”
According to the materials researcher, it will be difficult to predict when super magnets might actually be used. This is highly dependent on the further progress and interests of companies. “But if all goes according to plan, it could be available in 5 to 10 years.”
Rare earth mining is a complex process. Minerals only occur in rocks as traces in mixtures with other compounds and must first be separated from the rock. Among other things, environmentally harmful acids and ammonium salts used.
In particular for the extraction of heavy rare earth minerals such as terbium or yttrium Large amounts of ammonium sulfate are pumped into the slurry layers. This allows the metal ions to be detached from the surface and washed away.
For the environment, this means colossal harm. Because in the course of mining, large areas are damaged and the soil becomes acidic – ammonium in high concentrations is toxic to plants.
reduce the quantity
Now Chinese scholars Guangzhou Institute of Geochemistry developed a new method by which the quantities of ammonium salts could be significantly reduced in the future. Specifically, support can be provided by Electrical voltage Making mining more environmentally friendly.
Although harmful solutions are still needed to extract rare earth metals, the amount can be significantly reduced by adding electric fields.
In the lab, the researchers have a layer of clay with a force field 0.07 volts supplied per centimeter. This made it easier to release the metal ions. According to the study, the amount of solvent required can be reduced by about 80 percent.
In small amounts, extracting metal ions with an extra electric voltage really worked. In the next step, Chinese scientists want to use the method even 2000 tons Put the mud.
If this experiment also works, the researchers will then want to power entire ore mines with electric field forces. This can be done via buried electrodes.
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