It’s About the Cerium

A Column by Dr. Stan Trout

It might seem strange that an article about a rare earth element that is not usually associated with magnets would appear in Magnetics Business & Technology Magazine, yet the commercial future of cerium may have more influence on the permanent magnet industry than the neodymium, samarium, dysprosium or terbium we currently use in our rare earth magnets. The reason cerium is important to consider is because of a concept rare earthers call balance. In order to minimize the processing costs, miners need to balance the sales of rare earths into the marketplace with the rare earths they are extracting from the ground. This is an impossible task, rarely accomplished, because supply and demand are so independent of each other. Yet the need to balance supply and demand cannot be ignored; severely out of balance operations have difficulty being profitable.

These days, neodymium and dysprosium are the rare earths that are driving the business, an unprecedented event in the rare earth industry. In the past, cerium and lanthanum alternated as the prime rare earths. Mining to recover neodymium for the magnet market creates large amounts of cerium and lanthanum, which are now difficult to sell in the volumes necessary to balance supply and demand.

Historically, there have been two ways to push the market toward a more balanced position, pricing and application development. In terms of pricing, the market responds the way you think it should. It creates upward price pressure on the rare earths in demand and downward pressure on the prices of rare earths that are in excess. This pricing encourages the market to move in the right direction.

Most people are familiar with the chart from the USGS, which shows the growth of the rare earth industry over the last 50 years and the shift of production to China. But behind the graph is the story about how rare earth markets grew. From 1960 through about 1990, the growth in the rare earth market was primarily due to new application development work by a number of companies and institutions, and pricing took a back seat. These applications included catalysts, glass polish, magnets and phosphors. Since about 1990, growth in the rare earth industry has been largely due to pricing alone. Activities to develop new applications for cerium and lanthanum have been drastically reduced. Any recent growth in applications has been more organic than active application development.


We have now entered a stage where we need again to be in the active development of new applications of less popular rare earths. Molycorp has its Sorbx product, a step in the right direction, to be sure, since it uses cerium. But we need more than one potential new application for cerium on the horizon to save the day; we need several of them, if we are to have the hope of keeping supply and demand reasonably balanced in the long run.

The permanent magnet industry will be much happier when it is not driving the rare earth industry, as it is today. Increasing the demand for cerium, and to a lesser extent lanthanum, will put us in a much better place.

StanAbout the Author
Dr. Stan Trout has more than 35 years’ experience in the permanent magnet and rare earth industries. Dr. Trout has a B.S. in Physics from Lafayette College and a Ph.D. in Metallurgy and Materials Science from the University of Pennsylvania. Stan is a contributing columnist for Magnetics Business & Technology magazine. Spontaneous Materials, his consultancy, provides practical solutions in magnetic materials, the rare earths, technical training and technical writing. He can be reached at


  1. Dr. Trout,

    The need to balance our supply and demand is obvious. You mentioned Molycorp and cerium but only in the context of Sorbx. Were you aware of the General Motors ARPA-E Cerium based permanent magnet project? Molycorp is involved as a supplier. You may want to look up the Journal of Applied Physics publication “Magnetic properties of CeFe11−xCoxTi with ThMn12 structure” It’s my understanding they’ve developed the magnet and meet their project objectives. It’s not as powerful as the best neodymium magnets but that wasn’t their goal.

    Project Objective: Develop a Ce-TM based permanent magnet with a Curie temperature in excess of 300˚C, a remnant magnetization in excess of 10kG, and coercivity in excess of 10 kOe.

    “The collaborations with General Motors and NovTorque provide the evaluation of the material for traction motors with a specific power greater than 1.9 kW/Kg. Molycorp, LLC will provide the important materials supply chain and development path for commercialization of these materials.”

    Jan 29, 2014 Journal of Applied Physics

    So the permanent magnet industry may have another option in the works.

  2. Thanks for your comment. Yes, I am familiar with the work done on Ce-containing magnets. I’ll be sure to read the paper.

    To be sure, this is a helpful development, to understand just how helpful it might be, a back of the envelope calculation might be enlightening.

    In round numbers, global production of CeO2 is about 60,000 tons and global consumption of Nd2O3, mainly for magnets is about 20,000 tons.

    If Ce-based magnets are successful, they are likely to ultimately displace a few percent of neodymium consumption in a few years. This would be helpful in reducing some of the froth in this market, if any froth remains.

    However, to put a real dent in the over-supply of cerium, we need several new applications that are comparable in size to the entire market for neodymium. That is a difference of one or two orders of magnitude and that is why this is a daunting task.

  3. The Journal of Applied Physics has suppressed the full article since I last looked, it now requires a subscription. However 2 patent filings still present some earlier claims which might help.

    Publication date: 2012-11-15

    Publication date: 2013-06-27

    Cerium seems to be a remarkable element. I was just reading an article, “Under Pressure, Atoms Make Unlikely Alloys.” It seems some new Cerium alloys can be produced under high pressure and these new states are quenchable and persist under normal atmospheric pressure. In the case of Ce-Al the Cerium atoms collapse in volume by 15% under approximately 250,000 atmospheres. The net result is that both size and electronic structure are put in range that the cerium and aluminum atoms can comfortably nestle together, forming an alloy. The author suggests that the alloy may retain some of cerium’s magnetic properties. Interesting times we live in, the possibilities for Cerium are just opening up.

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