Q&A on Rare Earth Minerals

Nd electron


Q: So, how rare are they?

A: Despite their name, rare earth elements (with the exception of the radioactive promethium) are relatively plentiful in the Earth’s crust, with cerium being the 25th most abundant element at 68 parts per million (similar to copper). However, because of their geochemical properties, rare earth elements are typically dispersed and not often found in concentrated and economically exploitable forms.

Q: Which rare earth is important in the aquarium business?

A: That would be neodymium. It is a soft silvery metal that tarnishes in air. Neodymium is not found naturally in metallic form or in pure form, and it is usually refined for general use. Although neodymium is classed as a “rare earth”, it is no rarer than cobalt, nickel, and copper ore, and is widely distributed in the Earth’s crust.

Q: How is neodymium made?

A: Neodymium is never found in nature as the free element, but rather occurs in ores such as monazite and bastnasite that contain small amounts of all the rare earth metals. Neodymium is typically 10% to 18% of the rare earth content of commercial deposits of the light rare earth element minerals bastnasite and monazite. It is made by extracting it from these minerals.

Q: Is it difficult to produce?

A:  It is laborious and hazardous to produce. In fact the processes of extracting and isolating it can be quite hazardous. A particular hazard is mildly radioactive slurry tailings resulting from the common occurrence of thorium and uranium in rare earth element ores. Additionally, toxic acids are required during the refining process. Improper handling of these substances can result in extensive environmental damage.

Q: Why is neodymium so expensive?

A: Most Western nations have strict environmental policies governing the mining and production of rare earth minerals. The costs associated with complying with these policies have driven up the production costs in countries where these policies are in place. Countries without these environmental and health regulations can produce neodymium much more cheaply. China has become the main producer, accounting for over 90% of the world’s neodymium supply.

Q: Why has the cost of neodymium increased in recent years?

A: Since 2006 the Chinese government has implemented various export controls and nationalization measures on many rare earths including neodymium. This has caused the prices of certain rare earths to skyrocket, with some increasing fivefold in a few short months.

Q: How have aquarium equipment companies reacted to this price increase?

A: In a variety of ways. While the goal of manufacturers is always to resist increasing retail prices, this is not always possible. Apart from increasing prices, manufacturers also look to alternative materials to replace neodymium when possible.

Q: Is there any hope prices will come down again?

A: Yes. Increased demand and higher costs have made neodymium mining attractive again and many nations are reexamining its value. Canada and the United States are both poised to help meet global demand.

Q: Which properties of neodymium make it so useful?

A: Mainly, its strong magnetism. Neodymium magnets (Nd2Fe14B.) are the strongest permanent magnets known. A neodymium magnet of a few grams can lift a thousand times its own weight. These magnets are cheaper, lighter, and stronger than samarium-cobalt magnets. However, they are not superior in all ways, as neodymium-based magnets lose their magnetism at high temperatures and tend to rust, while samarium-cobalt magnets do not.

Q: Neodymium magnets can rust?

A: They can. When used in aquarium applications they are usually coated with a protective covering to keep them isolated from the corrosive saltwater.

Q: What are some products that rely on neodymium?

A: There are many. In the aquarium industry they’re used in magnet holders, magnet cleaners, and high efficiency impellers.

Outside the aquarium industry neodymium magnets appear in products such as microphones, professional loudspeakers, in-ear headphones, guitar and bass guitar pick-ups and computer hard disks. They’re used where low mass, small volume, or strong magnetic fields are required. Neodymium magnet electric motors have also been responsible for the development of purely electrical model aircraft within the first decade of the 21st century, to the point that these are displacing internal combustion powered models internationally. Likewise, due to this high magnetic capacity per weight, neodymium is used in the electric motors of hybrid and electric automobiles, and in the electricity generators of some designs of commercial wind turbines (only wind turbines with “permanent magnet” generators use neodymium). For example, drive electric motors of each Toyota Prius require one kilogram (2.2 pounds) of neodymium per vehicle.

Q: What are some interesting facts about neodymium?

A: Size and strength of an impending volcanic eruption can be predicted by scanning for neodymium isotopes. Small and large volcanic eruptions produce lava with different neodymium isotope composition. From the composition of isotopes, scientists predict how big the coming eruption will be, and use this information to warn residents of the intensity of the eruption.

Its first commercial application was to color glass products. Neodymium has sharp absorption bands which cause the glass color to change under different lighting conditions, being reddish-purple under daylight or yellow incandescent light, but blue under white fluorescent lighting, or greenish under trichromatic lighting.



All information sourced directly from Wikipedia. More information can be found here, here and here.


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