How to Recycle Magnets

The magnet made from rare earth is not a new technology. It was developed by scientists as early as 1982. Its official name is “NdFeB strong magnet”. The method is to extract Nd, Fe, and B from rare earth to form the metal body and then turn on current to magnetize.

The neodymium magnet is the most powerful magnet at present, and the loss of magnetic force is very slow, almost reaching the effect of the permanent magnet. Neodymium magnets are now widely used in computer hard drives, Halbach array, mobile phones, eardrums, speakers, and battery-powered electronic products.

Recycle Magnets

Turning old into new

Permanent magnets recycle means the extracting the rare earth elements from the magnets again. However, it is very hard and expensive.

The scientists of the Fraunhofer Project Group for Materials Recycling and Resource Strategies IWKS in Alzenau and Hanau of the Fraunhofer Institute for Silicate Research ISC are now pursuing a different approach to recycle the entire material instead of trying to regain each individual type of rare earth.

Because the composition of the material is already almost as it should be, this process only needs a few steps, and this is much easier and more efficient.

The first magnet successfully recycled
The scientists rely on the melt spinning process that already tried and tested for other alloys, also known as “rapid solidification”. The details are as below:
The researchers liquefy the magnet in a melting pot. The liquefied material, heated to more than 1000 degrees Celsius, is directed via a nozzle onto a water-cooled copper wheel that rotates at a speed of 10 to 35 meters per second. As soon as the melted droplet comes into contact with the copper, it transfers its heat to the metal within fractions of a second and solidifies.
The scientists call the emerging material formations “flakes”. The special feature is the structure formed inside the flakes. If the melted material were allowed to solidify in the normal way, the atoms would “line up in rows” in a crystal lattice. In the melt spinning procedure, however, crystallization is avoided: Either an amorphous structure is formed, in which the atoms are completely irregularly arranged, or a nanocrystalline structure, in which the atoms arrange themselves in nanometer-sized grains to form a crystalline structure.
The advantage: The grain sizes – meaning the areas with the same crystalline structure – can be specifically varied. They can be used to change the properties of the permanent magnet. In a further step, the researchers mill the flakes into a powder, which can then be further processed. “We press it into its final shape”, Diehl says

If the price of rare earth elements continues to go up, magnet recycling will be more cost-efficient and recycling permanent magnets from wind turbines and electric motors will be popular.

Now they have already set up a demonstration plant and have managed to recycle magnets there. This demo system can process up to half a kilogram of molten material and is somewhere between a lab and a large-scale plant.

In many cases, the rare earth magnets are extremely difficult to remove from the engines. So the potential ways of creating a collection cycle for used engines, and also of a design more suitable for disassembly is what the scientists want to develop.

NdFeB Magnet on New Energy Automobile

High-performance of rare earth magnet refers to high magnetic energy products or combination property of the coercivity & magnetic energy products in the conventional sense. Currently, the development degree of the high-property rare earth magnet is influenced by the demand of the application industry.

SmCo magnet and NdFeB magnet both belong to rare earth magnet family because of the Sm, Co, Nd, B, Dy, Ga elements in their composition. They are the strongest type of permanent magnets available, producing significantly stronger magnetic fields than other types such as ferrite or alnico magnets, for SmCo has magnetic energy product about 15 – 30MGOe and sintered neodymium magnet has about 27- 50MGOe.

The constantly upgraded motors in the new era ask higher coercive force. So the higher working temperature and coercive force can ensure the strong ability of anti-demagnetization. For example, because of high transient load, the drive motor in the new energy automobile have the critical requirement on the magnet coercive force.

New Energy Automobile

Is the high corrosion magnet the future research direction?

To ensure that the electric car can still run after going through more than 20 kilometers cold summer heat, there are many aspects need to research, such as magnetic property, relative physical performance and reliability working life. So in the premise of guarantee the basic magnetic performance, to prolong rare earth magnet’s using life is one of the current and future permanent magnet development direction.

What are product homogeneity and the relationship with magnetic declination?

Magnet module homogeneity is related to the current stability when the motor output. With bad homogeneity, distribute unevenly magnetic field will cause motor vibration. There are lots of influence factor caused magnetic declination; one is homogeneous materials, the other is uniform magnetization, and some process like magnet perpendicularity is also a factor.

What is the highest working temperature for sintered neodymium magnet?

At moment, no neodymium magnet can meet 300℃ working temp. Actually, the working temp. of neodymium magnet depends on its operating environment. Take the drive motor in the new energy automobile for example again, the heat resistance requirement of this drive motor magnet, whether 180℃ or 200℃, rests with the power of the engine. And in actual production, it’s necessary to leave some space to keep its temperature stability by choosing higher working temp magnet than originally working temperature. By this reason, some company will request 220℃ magnet.

Which magnet performance has an impact on motor power and speed?

It’s a simple structure, small volume, lightweight, low loss and high efficiency of rare earth permanent magnet rotor. So motor power speed is often about magnetic force.

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The Most Popular Motor Magnets-Neo Arc Magnet

Arc segment motor magnet has advantages of easy manufacture and low cost compared with radial ring magnets. It’s still the most common motor magnet shape, especially for PM DC motor and magnet rotor.

As we all know, permanent Magnet is the core of PM motor.
In order to ensure the steadily electrical performance and long-term safe and reliable operation of electric vehicles, it requires the magnetic property of permanent magnet material remains stable. Considering magnetic performance influenced by the work environment, temperature and time, the reliability of permanent motor magnets can be divided into thermal stability, time stability, chemical stability, and magnetic stability.

rare earth magnet

1. Temperature stability can be shown by Curie temperature and the maximum operating temperature. As the temperature rises, the magnetic properties gradually reduce. When raises to a certain temperature, the magnetization disappears. This certain temperature is the Curie temperature of the permanent magnet materials, also known as the Curie point. The deficiency of NdFeB permanent magnet is relatively low Curie temperature, but higher temperature coefficient. Therefore neodymium magnets will be lost much magnetic force if work under high temperature. Due to the high-temperature coefficient of NdFeB permanent magnet, the magnetic properties are poor. To this end, it must pay more attention to Max. working temp.of sintered NeFeB magnet when you select a magnet grade. The test method of magnet temperature stability is the aging test

2. Chemical stability refers to the anti-oxidation and corrosion-resistant of permanent magnet material. Compared with the traditional ferrite or samarium cobalt (Smco) or alnico magnets, the chemical stability of sintered NdFeB magnet is the worst. Currently, the primarily solution is adding some alloy elements such as Co, Ni, Al and Cr, etc., while in the sintering process, increasing the density and reducing the porosity of magnetic material. Another approach is made certain magnet surface treatment such as electroplating. This can obtain a practical corrosion resistance for the magnet.

3. Time stability is putting the permanent magnet at a certain temperature for a long time, observing the change of its magnetic properties over time. These NdFeB permanent magnets added Co + Dy + Nb will obtain better time stability.

4. Magnetic stability is based on the magnetic material, and also affected by temperature, time, external magnetic field, chemical corrosion, radiation, mechanical vibration or shock and other factors.

Compared with electro-magnetic, we can list more advantages of segment arc motor magnet:
1. Simplify the structure of the motor
2. Easy maintenance
3. Light weight
4. Small volume
5. Operational reliability
6. low energy consumption

How to choose motor segment material?
For traditional AC motor, ferrite and AlNiCo segment magnets are most applied. With the higher request on motor power, more and more motor manufacturers use ndfeb and smco magnet which have super high magnetic energy product. However, they are more expensive because neodymium magnet and samarium cobalt magnet segments belong to rare earth magnet.

How to join neodymium arc magnets, which are diameter magnetized, to create a cylindrical ring that is radially magnetized?
The general approach is to make a sleeve or frame to put neo arc magnets in that will keep them in order and don’t jump around. The sleeve here has to be made of something sturdy and nonmagnetic, such as aluminum, copper or Q235 low carbon steel. Due to a strong repelling force, it’s better to operate by those experienced workers. If you are the first time to assemble segment magnets, just be careful. Halbach array magnets also utilize a frame or other tools to overcome the strong magnetic repulsive force between the same pole sides of two magnets and keep them fixing together.

What Do Magnets Do

Magnets consist of iron, cobalt, nickel and other atoms. The internal structure of the atoms is quite special, and they have magnetic moments themselves. Magnets can generate magnetic fields and have the characteristics of attracting ferromagnetic materials such as iron, nickel, cobalt and other metals.


Different magnets have different uses.

Classification of magnets:

Shape magnets: block magnet, arc magnet, special magnet, cylindrical magnet, ring magnet, disc magnet, bar magnet, magnet frame magnet.

Attribute magnets: samarium cobalt magnet, neodymium magnet (strong magnet), ferrite magnet, aluminium nickel cobalt magnet, ferrochromium cobalt magnet.

Industry magnets: magnetic components, motor magnet, rubber magnet, plastic magnet and so on.

Magnets are divided into permanent magnets and soft magnets. Permanent magnets are added with strong magnets, so that the spin of magnetic materials and the angular momentum of electrons are arranged in a fixed direction, while soft magnets are added with electricity. (It’s also a way to add magnetism) If the soft iron is removed by the equal current, it will gradually lose its magnetism.

shape magnets

Use of different types of magnets:

1. Nd-Fe-B permanent magnet is a modern magnet with strong magnetism and is widely used.

It is mainly used in electroacoustics, permanent magnet motors, communications, automotive electronics, magnetic machinery, aerospace, computers, household appliances, medical devices, office automation, toys, packaging boxes, leather products, magnetic accessories, and other fields.

2. Permanent magnet ferrites are used as constant magnets in meters, generators, telephones, loudspeakers, TV sets and microwave devices. They are also used in recorders, pickups, loudspeakers, magnetic cores of various instruments, radar, communication, navigation, telemetry, and other electronic devices.

3. Samarium-cobalt magnets have been widely used in detectors, generators, radar, instrumentation, and other precision science and technology fields because of their high working temperature of 300 degrees, corrosion resistance and oxidation resistance.

4. Aluminum-nickel-cobalt magnets are heat-resistant and corrosion-resistant. They are mainly used in motors, sensors, medical instruments, hand tools, loudspeakers, and various instruments.

5. Rubber coated magnets are different and heterosexual, and their homosexual attraction is weak. They are mainly used for propaganda (refrigerator stickers, car stickers, etc.), decorative gifts, refrigerator stickers, toys, teaching materials, etc. Heterosexual magnets can be used in small motors, sensors, magnetic adsorbents, etc.

Understanding the use of different magnets is very important for enterprises. Making full use of the characteristics of different magnets can better improve product performance.

What Magnet to Use for The World’s Smallest Phone Charger

Today, I will introduce the world’s smallest phone charger – The Nipper.
Comprised of two tiny 17mm x 17mm x 17mm squares, this super handy charger stay together with the use of three strong neodymium block magnets and a small leather strap, weighing only 10g and is as small as key ring accessories.

The Nipper
This Nipper charger is originally designed for emergency use utilizing magnetic force to hold two AA batteries (one of the most common household items) in place between the squares. Meanwhile, it is equipped with a micro USB connector that makes it compatible with Samsung, HTC, LG, and any other devices with this type of port.

Here is a key component – Sintered Neodymium Magnet
The magnets in the Nipper charge are the strongest magnet king- neodymium magnets. These three magnets have two functions of holding the batteries together while at the same time making an electrical connection to the circuit board. This circuit is called a boost converter, it turns the power from the batteries into a 5v power supply, and then it can charge your phone.

Neodymium Magnet

The use of powerful neodymium magnet also saves the connected components, come to simplify the structure, manufacturing technique and raw material saving. Hope this product can inspire you to consider other applications of super-strong rare earth neodymium magnet.
You probably already know that permanent strong neodymium magnets have a very strong magnetic force.

But do you know other properties of the magnet, like conductivity?

Yes, we all know, the magnet is conductive!
Strong permanent magnet contains many metallic elements, such as nickel, cobalt, and iron. All these are electrically conductive. So all strong magnets are conductive, only the degree of electrical conductivity is different.

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What Are The Strongest Magnets Available

At present, the strongest permanent magnet is neodymium magnets, so it is also called neodymium super magnets. The neo magnets produced by Stanford Magnets is mainly special-shaped strong magnet. They are often used in magneto, servo motors and micro motors.

But the magnets used in different environments are also different, if you want to say which magnetic force is strong in the ordinary environment, it is OK to use N grade NdFeB magnets, we can use N35-N52 according to the situation, the higher the grade of is, the stronger the magnetic force of magnets with the same specification is), the highest operating temperature is 80 degrees.

Many people will think that the magnetic force adding H, SH, UH behind grade will be stronger, in fact, the higher the temperature is, the lower the magnetic force is, the inverse ratio is not proportional.

ferrite magnets

Which part of the magnet attracts the most?

This is a magnet with a strong magnetic force at both ends, which can also be measured by a gauge. The magnetic field at the center of the magnet is lower than that at the edge of the magnet.

What magnet is the strongest magnet in more than 200 degrees Celsius?

In the environment above 200 degrees Celsius, samarium cobalt magnet is the most powerful magnet. The price of magnets is slightly higher than that of neodymium magnet. Because iron is a small part of the samarium cobalt magnet, it is not easy to be corroded. Generally speaking, it is not necessary to make electroplating treatment. For beauty, electroplating is also acceptable.

If the samarium cobalt magnet is used in seawater, some rust spots will appear on the surface of the product, but it will not affect its performance and use. Due to the physical properties of the samarium cobalt magnet, which is very brittle (even brittler than glass), and the edge part will be short of edges and corners if a little force is applied.

As far as ferrites magnets are concerned, magnetism is relatively weak and the price is very low. In case of extra high temperature, it is usually chosen.

strong magnets

What are the main differences between universal magnetism and strong magnetism?

Ordinary magnets, including ferrite magnets, that is, we usually say it the iron absorption stone, the surface does not need to do surface treatment, the appearance is black.

Strong magnets, generally refer to rare earth permanent magnet, including powerful neodymium magnets, the surface is usually galvanized two kinds of nickel plating, of course, there are many coatings.

The biggest difference between the two is the appearance, high-temperature resistance, and price, if the magnetic force is not much required, as long as the cost is low, then the use of ordinary magnetic can be, like some packaging, handbags, leather products, mostly ordinary magnetic. If there is great demand for magnetism, then strong magnetism is the first choice.

Why do we use heteromorphic magnets? What are the advantages of heteromorphic magnets?

The special-shaped magnet has high-cost performance and good mechanical properties. It has high magnetic energy product and coercive force, and has been widely applied in modern industry and electronic technology. Heteromorphic magnets are widely used in electroacoustics, electrical appliances, magnet rotors, mobile phones and so on.

Are Neodymium Magnets Stronger Than Ceramic Magnets?

In general, the magnetic induction near permanent magnets (AlNiCo alloy magnets, ferrite magnets, etc.) is about 0.4-0.7 tesla.

But rare earth magnets (neodymium magnets, samarium cobalt magnets) can produce a magnetic field of more than 1.4 tesla, is much larger than the usual Al-Ni-Co or ferrite magnets.

ceramic magnets

Among permanent magnets, rare earth magnets produce the greatest magnetic field, which is much larger than aluminum-nickel-cobalt magnets or ferrite magnets. Rare earth magnets generally produce a magnetic field of more than 1.4 teslas, whereas ferrite or ceramic magnets produce only about 0.5 to 1 tesla. Two of the most common rare earth magnets are: neodymium magnet and Nd-Co magnet. The two magnets contain Nd and Sm in rare earth elements, respectively. Rare earth magnets are very brittle and vulnerable to corrosion, so they are usually coated with other metals to protect themselves.

The Ferrite permanent magnet is also known as a Ceramic Magnet and even as hard ferrite magnet. The name is interchangeable but they all refer to exactly the same material type. They are known as Ceramic Magnets because they are electrically insulating. Ferrite permanent magnets exist in two forms – Strontium Ferrite magnets and Barium Ferrite Magnets. The Strontium Ferrite Magnets is the most common.

ceramic magnet

Ferrite magnets are darker grey in color and are often referred to as having a “pencil lead” appearance.

Ferrite / Ceramic permanent magnets are technically known as hard ferrite materials (when exposed to a brief external magnetic field, the material retains magnetism due to having high coercivity, Hc). They are not the same as soft ferrite materials as used in transformer cores (which do not retain magnetism after exposure to a brief magnetic field because soft ferrite materials have low coercivity). The high coercive force of Ferrite Magnets means they are classified as hard materials, like all the other permanent magnets.

Ferrite magnets are extremely popular due to their characteristics. Ferrite magnets are corrosion free – for the long-term performance they are superb; if looked after they are capable of exceeding most products lifecycles. Ferrite magnets can be used up to +250 degrees C (and in some cases up to +300 deg C). Ferrite magnets are also low cost, particularly in high volume production runs.

The Strongest Permanent Magnet-Neodymium Magnets

At room temperature, the neodymium magnet is the most powerful permanent magnet.

But this is only at room temperature. Early Neo magnets had an annoying flaw: they were sensitive to temperature, and when the temperature rose, the magnetism dropped dramatically, and when it was above 100 degrees Celsius, it was completely demagnetized. But now an improvement has been found by adding a small amount of dysprosium, another rare earth metal, which is less sensitive to temperature changes.

neo magnets

At the same time, a technological revolution driven by permanent magnets opened the curtain. Anywhere you want to produce the strongest magnetic field with the least amount of material, Neo permanent magnets are preferred: car engines, spindle motors on CD and DVD readers, electric signals converted into sound diaphragms in headphones and speakers, and super magnetic fields needed in medical magnetic resonance technology… By 2010, even though cheaper ferrites still dominated the market, neodymium permanent magnets were worth more than a dozen or even hundreds of times more than ferrites in terms of volume.

However, when Neo permanent magnets were developed, the demand for rare earth metals surged. Rare earth metals aren’t really rare on the planet — they are a few parts per million in the earth’s crust — they’re “rare” because they’re hard to find.

Search for new permanent magnet materials

Each computer needs only 50 grams of Neo permanent magnet. It doesn’t seem like much, but given the number of computers around the world, it’s almost an astronomical number. Now, with the rise of green energy technology, the consumption of computers has become a great mystery. Turbine motors in wind farms, as well as electric cars and bicycles, require lightweight and powerful permanent magnets, and only Neo magnets currently meet the requirements. Each electric vehicle consumes 2 kilograms of Neo permanent magnets. The power of megawatt wind turbines will consume 2/3 tons of Neo permanent magnets. Therefore, it is imminent to develop new and stronger permanent magnets. It is better to reduce the number of rare earth metals. The ideal situation is to stop using rare earth metals.

Neo magnet

The United States has invested huge sums of money in finding new permanent magnets. At present, scientists are trying to improve the performance of Fe Ni alloy permanent magnets. Usually, when two magnetic metals, iron and nickel, are fused together, they form disordered structures in which it is difficult to align electrons in the same direction. One exception, however, is that iron and nickel atoms are arranged in regular layers in a mineral called cubic nickel rubble. Once a magnetic field is applied, the electron spins tend to move in the same direction.

But this mineral is very difficult to form under natural conditions, especially on the earth. In fact, the only orthoclase sample in the world today comes from a meteorite that took at least billions of years to form. One billion years is certainly too long for us. The goal of scientists is to synthesize it in the laboratory and do what nature needs to do in billions of years.

Another ongoing attempt that seems to be completely different is to use carbon as a permanent magnet. It is well known that graphite and diamond are nonmagnetic, and the incorporation of carbon into pure iron also makes it lose its magnetism. But making compounds of carbon and other elements into nanoparticles is another matter. Scientists found that the material showed strong magnetism. For commercial secrecy, what the material is and how to make it is not convenient for scientists to disclose. But they say the permanent magnet will one day beat neodymium at both performance and price.

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