How Strong Are Rare Earth Magnets?
Magnets are an integral part of many technologies and appliances in the 21st century.
From tiny fridge magnets that hold to-do lists to powerful ones that create magnetic fields for electricity generation from wind turbines, there are many different types of magnets.
The world’s strongest magnets, also known as rare earth magnets, are made by alloying certain rare earth elements with other materials.
But just how strong are rare earth magnets, and what makes them so powerful?
Measuring Magnet Strength
The above infographic uses data from First4Magnets to compare the strength of magnets. But before looking at the strongest magnets, it’s essential to understand how to measure magnetic strength.
The maximum energy product, measured in mega-gauss-oersteds (MGOe), is one of the primary indicators of magnetic strength. It is a multiplication of two measurements: a magnet’s remanence and its coercivity.
To become magnets, ferromagnetic substances need to enter the magnetic field of an existing magnet. Remanence, measured in Gauss, is the magnetism left in the magnet after removing the external magnetic field.
Coercivity is the energy required to bring a magnetic material’s magnetism down to zero. Measured in oersteds, it essentially captures the magnetic material’s resistance to demagnetization.
The Strength of Rare Earth Magnets
Each magnet has a grade, which typically denotes its strength. For example, a neodymium magnet of grade N42 has a strength of 42MGOe.
To put the power of two common rare earth magnet grades into perspective, here’s how their strength compares with common grades of other permanent magnets:
|Magnet (Grade)||Composition||Maximum Energy Product (MGOe)|
|Neodymium (N42)||Neodymium, iron, boron||42|
|Samarium Cobalt (SmCo 2:17)||Samarium, cobalt||28|
|Alnico (Alnico-5)||Iron, aluminum, nickel, cobalt||5.5|
|Ferrite (Ferrite-8)||Ceramics, iron oxide||3.5|
|Magnetic rubber (Grade Y)||Strontium or barium, synthetic rubber, PVC||0.8|
Note: While the N42 neodymium magnet is used more commonly, the strongest available magnet is of grade N52.
Neodymium and samarium—two of the 17 rare earth elements—are ferromagnetic, meaning that they have inherent magnetic properties and can be magnetized. These metals are first mined, refined, and then combined with materials like iron, boron, and/or cobalt to make the strongest magnetic alloys.
Neodymium magnets are typically composed of one-third neodymium, along with iron and boron. Some of the neodymium in magnets can be replaced with praseodymium, another rare earth material. For this reason, neodymium magnets are also known as NdPr magnets.
Due to their strength, neodymium magnets have found their way into various technologies, from phones and laptops to motors in electric vehicles. In fact, according to Adamas Intelligence, 90% of all EV motors use NdPr magnets. Because these magnets also offer relatively high strength for a smaller size, they are also the predominant choice for wind turbines, reducing turbine weight significantly.
Samarium-cobalt magnets exhibit exceptional resistance to extreme temperatures. These magnets can operate from temperatures as low as -270℃ up to 350℃ and are also highly resistant to corrosion. Consequently, they have important applications in harsh marine environments and technologies with high operating temperatures.
The Demand for Neodymium Magnets
Global EV sales more than doubled last year, up from around 3 million cars in 2020 to 6.6 million in 2021. Similarly, renewable energy is expanding at a record pace, with capacity installations in 2022 set to break the record set the previous year.
With that in mind, it’s no surprise that the demand for rare earth magnets is expected to increase. Neodymium magnet consumption is forecasted to grow from more than 100,000 tonnes in 2020 to 300,000 tonnes by 2035, with EVs and wind turbines driving growth.
However, the supply chain of neodymium magnets remains a concern with China controlling the majority of rare earth extraction, refining, and downstream magnet production.
How Is Aluminum Made?
Aluminum is one of the world’s most widely used metals, but producing it is a complex process. Here’s a look at where it comes from.
How is Aluminum Made?
Aluminum is one of our most widely-used metals, found in everything from beer cans to airplane parts.
However, the lightweight metal doesn’t occur naturally, and producing it is a complex process.
The Three Stages of Aluminum Production
Each year, the world produces around 390 million tonnes of bauxite rock, and 85% of it is used to make aluminum.
Bauxites are rocks composed of aluminum oxides along with other minerals and are the world’s primary source of aluminum. After mining, bauxite is refined into alumina, which is then converted into aluminum.
Therefore, aluminum typically goes from ore to metal in three stages.
Stage 1: Mining Bauxite
Bauxite is typically extracted from the ground in open-pit mines, with just three countries—Australia, China, and Guinea—accounting for 72% of global mine production.
|Country||2021 Mine Production of Bauxite (tonnes)||% of Total|
|Saudi Arabia 🇸🇦||4,300,000||1.1%|
|Rest of the World 🌍||15,500,000||4.0%|
Australia is by far the largest bauxite producer, and it’s also home to the Weipa Mine, the biggest bauxite mining operation globally.
Guinea, the third-largest producer, is endowed with more than seven billion tonnes of bauxite reserves, more than any other country. Additionally, Guinea is the top exporter of bauxite globally, with 76% of its bauxite exports going to China.
After bauxite is out of the ground, it is sent to refineries across the globe to make alumina, marking the second stage of the production process.
Stage 2: Alumina Production
In the 1890s, Austrian chemist Carl Josef Bayer invented a revolutionary process for extracting alumina from bauxite. Today—over 100 years later—some 90% of alumina refineries still use the Bayer process to refine bauxite.
Here are the four key steps in the Bayer process:
Bauxite is mixed with sodium hydroxide and heated under pressure. At this stage, the sodium hydroxide selectively dissolves aluminum oxide from the bauxite, leaving behind other minerals as impurities.
Impurities are separated and filtered from the solution, forming a residue known as red mud. After discarding the mud, aluminum oxide is converted into sodium aluminate.
The sodium aluminate solution is cooled and precipitated into a solid, crystallized form of aluminum hydroxide.
The aluminum hydroxide crystals are washed and heated in calciners to form pure aluminum oxide—a sandy white material known as alumina.
The impurities or red mud left behind in the alumina production process is a major environmental concern. In fact, for every tonne of alumina, refineries produce 1.2 tonnes of red mud, and there are over three billion tonnes of it stored in the world today.
China, the second-largest producer and largest importer of bauxite, supplies more than half of the world’s alumina.
|Country||2021 alumina production (tonnes)||% of total|
|Saudi Arabia 🇸🇦||1,800,000||1%|
|Rest of the World 🌍||15,100,000||11%|
Several major producers of bauxite, including Australia, Brazil, and India, are among the largest alumina producers, although none come close to China.
Alumina has applications in multiple industries, including plastics, cosmetics, and chemical production. But of course, the majority of it is shipped to smelters to make aluminum.
Stage 3: Aluminum Production
Alumina is converted into aluminum through electrolytic reduction. Besides alumina itself, another mineral called cryolite is key to the process, along with loads of electricity. Here’s a simplified overview of how aluminum smelting works:
- In aluminum smelter facilities, hundreds of electrolytic reduction cells are filled up with molten cryolite.
- Alumina (composed of two aluminum atoms and three oxygen atoms) is then dumped into these cells, and a strong electric current breaks the chemical bond between aluminum and oxygen atoms.
- The electrolysis results in pure liquid aluminum settling at the bottom of the cell, which is then purified and cast into its various shapes and sizes.
China dominates global aluminum production and is also the largest consumer. Its neighbor India is the second-largest producer, making only a tenth of China’s output.
|Country||2021 Aluminum Smelter Production (tonnes)||% of total|
|United Arab Emirates 🇦🇪||2,600,000||4%|
|Rest of the World 🌍||9,400,000||14%|
As is the case for alumina production, some of the countries that produce bauxite and alumina also produce aluminum, such as India, Australia, and Russia.
Roughly a quarter of annually produced aluminum is used by the construction industry. Another 23% goes into vehicle frames, wires, wheels, and other parts of the transportation industry. Aluminum foil, cans, and packaging also make up another major end-use with a 17% consumption share.
Aluminum’s widespread applications have made it one of the most valuable metal markets. In 2021, the global aluminum market was valued at around $245.7 billion, and as consumption grows, it’s projected to nearly double in size to $498.5 billion by 2030.
Mapped: U.S. Mineral Production, by State
This infographic breaks down $90.4 billion in non-fuel mineral production by state.
Mapped: U.S. Non-fuel Mineral Production, by State
Just how many minerals does the U.S. consume? In 2020, non-fuel mineral consumption worked out to around 19,000 pounds or 8.6 tonnes per person.
This includes metals like copper, iron ore, and zinc, along with construction sand, stone, cement, and other industrial minerals. With such high demand, changes in the production of these commodities often reflect how the overall economy is performing.
The above infographic maps U.S. non-fuel mineral production by state in 2021 using data from the United States Geological Survey (USGS).
The Most Valuable Minerals
As the U.S. economy restarted in 2021, American mines generated over $90 billion in non-fuel mineral production, a 12% increase from 2020.
Before diving into the breakdown by state, here’s a look at production value by mineral type:
|Category||Production value||% of Total|
|Industrial minerals (excl. construction)||$27.4B||30.3%|
Each of the categories accounted for roughly one-third of the total production value, with metals making up the largest share. Within metals, copper and gold collectively accounted for 66% of the total, followed by iron ore (13%) and zinc (7%).
The production of sand, gravel, and crushed stone—important inputs for construction—also made up a significant chunk of the value, along with other industrial minerals. Furthermore, crushed stone was the leading non-fuel mineral in 2021, with $19.3 billion in production value.
Which States Lead in Mineral Production?
Arizona, Nevada, Texas, California, and Minnesota—the top five states—accounted for nearly 40% of non-fuel mineral production value.
|State||Value of Non-fuel Mineral Production||% of Total|
Arizona and Nevada, the top two states, are the country’s biggest producers of copper and gold, respectively. Arizona also produced over $1 billion worth of construction sand and gravel in 2021, in addition to being the country’s leading producer of gemstones.
In third place was Texas, where mines produced nearly $6 billion worth of non-fuel minerals, of which 38% came from crushed stone. California, meanwhile, led in the production of construction sand and gravel, and was the country’s sole source of rare earth elements.
Minnesota also made the top five as the nation’s largest producer of iron ore. In fact, mines in Minnesota and Michigan shipped 98% of domestic usable iron ore products in 2021.
The Missing Critical Minerals
Although the U.S. is a major producer of non-fuel minerals, it still relies on imports for the supply of several minerals.
In 2021, the U.S. imported $5.3 billion worth of raw materials, in addition to $90 billion in net imports of processed mineral materials. Of the 50 minerals deemed critical to national security, the country was 100% net import reliant for 26, including graphite, manganese, and several rare earth metals.
To meet the rising demand for these minerals, U.S. President Biden announced major investments in domestic critical mineral production, including a $35 million grant to MP Materials for the processing of rare earths.
It remains to be seen whether these investments will pay off in building more resilient, end-to-end domestic critical mineral supply chains.
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