Rare Earth and Ignition

Auermetal was discovered by Carl Auer von Welsbach, an Austrian chemist in 1903. He found that Ferro cerium produces powerful sparks when scraped against a rough surface. Ferrocerium is a man-made metallic material which composed of iron and cerium. One of the applications of ferrocerium is the cigarette lighter flints. In modern times what is commonly called “flint” is actually ferrocerium or Auermetal. This metal is used in lighters as the initial ignition source for the fuel. The first factory of Auermetal production was opened in 1907.


Cigarette lighter flint


Ferrocerium has the same function as the steel had in traditional fire stating by natural flint and steel. Lighters using ferrocerium, have a tube containing the ferrocerium and a disc or wheel against which the ferrocerium is. The wheel acts by friction upon the ferrocerium and it should be moved quickly enough to create heat by friction. The ignition temperature originated by cerium has the temperature between 150-180°C.


Recent ferrocerium metals produced mostly of iron with an alloy of rare earth metals called cerium mischmetal. The composition consist of approximately 50% cerium, 45% lanthanum, and small amounts of neodymium and praseodymium. This rare earth alloy is too soft to give good sparks, hence 20% iron oxide and 2% magnesium oxide are used to form a harder material. The composition is:


Iron: 19%
Cerium: 38%
Lanthanum: 22%
Neodymium: 4%
Praseodymium: 4%
Magnesium: 4%


Michmetals are used in Steel industry as an additive for steel treatment as well as in water equipment industry. They have lots of other applications as alloying elements, however traditional and most common use of michmetal is in lighter flints production.






Carl Auer von Welsbach



Carl Auer von Welsbach was born in Septembeer 1858 In Vienna. He was a chemist and engineer with unique talent of understanding how to pursue fundamental science and, at the same time, of commercializing his discoveries in science into successful products. In other words he was both scientist and inventor.

He studied math, chemistry, physics and thermodynamics in technical University of Vienna and the University of Heidelberg. He started to work with chemical separation methods for investigations on rare earth elements in 1882. Auer developed a new method for separating Didymium, based on crystallisation of didymium ammonium nitrate solution. He gave the pink components the name Neodidymium (which was later changed to neodymium), and the green component, the name Praseodymium. In 1885 he produced the first incandescent mantle out of lanthanum oxide. In his original production that he patented in 1885, he used a mixture of 60% magnesium oxide, 20% lanthanum oxide and 20% yttrium oxide. These mantles which were also called “Auerlicht” gave off cold-greenish light and had a short length of use. Auer improved his production to stronger mantles with whiter lights by using a new mixture of 99% thorium dioxide and 1% cerium dioxide. His new mantle was commercialized in 1892 and was quickly spread out in the streets of Europe. Meanwhile he developed a crystallization method for preparation of pure Thorium oxide. He also found the effect of the purity of the thorium oxide on its light emission.


Carl Auer von Welsbach was Robert Bunsen’s student, and he had learned from him how to produce sparks from cerium by mechanical means. In 1903, he patented his pyrophoric cerium-iron alloy containing 70% cerium and 30% Iron for spark production.

In 1905 Auer wrote a report on the results of the spectroscopic analysis which showed Ytterbium is made up of two elements. He named the elements after Aldebaranium and Cassiopeium. He also tried to develop separation method based on the partial solubility of these elements oxalate. Moreover, he successfully performed large scale chemical separation of radioactive substances.

At that time Cerium was produced based on the electrolysis from the fused salts ( rare earth fluorides). He investigated the use of Cerit and Allenite minerals as source substances for the electrolysis. The production process of cerium was further improved by using Monazite and also the residues from the incandescent mantle production.

Beside the discovery of 4 rare earth elements Neodymium, Praseodymium, Ytterbium, and Lutetium, he also produced Ionium (known today as Thorium-230) .

Auer is particularly known for his discoveries and inventions on the rare earth metals, however he is also well known for production of metal filament light bulbs. His improvement in osmium filaments made the path towards the tungsten filament and the modern light bulb invention.

Carl Auer von Welsbach died on 1929 at the age of 70. His unique talents and qualities has ensured him a prominent lasting place both in science and industrial history.







Rare Earths and Colors

Ability to change colors in one moment is an amazing phenomenon that happens in nature. Chameleons and octopuses are able to change the color of their skins in different conditions. The same phenomenon happens in some kind of glasses created by man. These glasses change color under different lighting condition.

One of the early examples of dichroic effect glasses is Lycurgis cup from the 4th century AD. The glass in the Lycurgis cup appears green in reflected light and changes to wine-red in transmitted light. This cup is now in British museum [2].

lycurgus cup

Figure 1: Lycurgis cup under two different lights

During the 15th to 17th century Chalcedony and Girasole glass with interesting visual effects was developed by adding small quantities of transition metals in the recipe.

Neodymium color glass was invented by Kolo Moser in Bohemia and commercially produced by his company in 1927 [1]. This glass contained 4% neodymium oxide. He named it Alexandrite glass. After that other glass companies started to develop their own color glasses and having their own name for Alexandrite: Heatherbloom, Wisteria and Twilight [1].

Alexandrite glass is lavender under incandescent lighting and changes to pale blue under fluorescent lights.

This color change is based on the sharp absorption bands of electromagnetic spectrum of neodymium which cause the excitation of the atoms and changing their energy level. Neodymium is also used together with praseodymium in safety glasses in order to obliterate the strong light emitted by hot sodium in the glass. The mixture of neodymium and praseodymium elements is called didymium. Didymium is also used in camera filters (enhancing filters) to increase the certain color intensity such as orange, brown and red by removing portion of spectrums in orange region [4].


Figure 2: Pictures with and without enhancing camera filter

The filtering ability of neodymium is also used in incandescent light bulbs to filter out yellow wavelengths and provide whiter light more similar to the sunlight [5]. The same property is used in automobile rear-view mirrors to provide color-corrected light. Elimination of the excessive yellow light provides the driver better distinguish of the object contrast [6].


1-     http://web.archive.org/web/20080403165916/http://coloradosprings.yourhub.com/CrippleCreekTellerCounty/Stories/Arts/Story~443258.aspx

2-      http://books.google.nl/books?id=KbZkxDyeG18C&pg=PA102&hl=en#v=onepage&q&f=true

3-      http://education.jlab.org/itselemental/ele060.html

4-      http://www.tiffen.com/camera_filters.htm

5-      http://avalonraremetals.com/rare_earth_metal/rare_earths/neodymium/

6-      http://www.google.nl/patents/US5844721


Rare Earth power game!

The United States biggest concern on the rare earth issue is based on its reliance on technology, especially for military applications. This text talks about the rare earth elements that are used in defense-related technology.

The pentagon claims that only 5% of world’s supply of rare earth is consumed by the United States Department of Defense. Yet it should be considered that for producing some of the most powerful weapons, US is completely dependent on China [1].

Two commercially available permanent magnets of rare earth elements are samarium cobalt (SmCo) magnets, and neodymium iron boron (NdFeB) magnets. SmCo is used for military technologies such as precision-guided missiles, smart bombs, and aircraft, since its magnetic strength is retained at elevated temperatures. NdFeB magnets, known as the world’s strongest permanent magnets are used for smaller and lighter defense weapon systems [2].

Rare earths used in missiles and smart bombs can provide directional capabilities. They are also used in detection devices for enemy mine detection, interrogators, underwater mines, and countermeasures. Other critical application of rare earth elements in defensive applications are laser targeting systems, range-finder lasers, radar surveillance, optical equipments and communication systems [3]. Rare earth alloys are also replacing piezoceramic materials in several devices such as Sonar transducers for submarines [4].


The use of rare earth elements in different of military applications are shown in figures 1-5 [2]:

1- Rare earth elements in missile guidance and control systems for controlling the direction of the missile

1- Rare earth elements in missile guidance and control systems for controlling the direction of the missile


2- Rare earth elements in disk drive motors installed in aircraft, tanks and control centers; in defense electronic warfare

2- Rare earth elements in disk drive motors installed in aircraft, tanks and control centers; in defense electronic warfare

3- Rare earth elements in targeting and weapon systems

3- Rare earth elements in targeting and weapon systems

4- Rare earth elements in electric motors

4- Rare earth elements in electric motors

5- Rare earth elements in electronic and communication for optical equipment and speakers.

5- Rare earth elements in electronic and communication for optical equipment and speakers.

The United States was the leader in global production of rare earths from 1960s to 1980s. Since then China has been ruling in rare earth production due to lower costs and environmental standards. In July 2010, China announced cutting rare earth mineral exports by about 72%. This could be very problematic for U.S as the biggest consumer of rare earths by imposing economic and national security risks.


In January 2011, three Members of Congress wrote a letter to Secretary of Defense asking for an immediate action for providing a detailed accounting of supplies of rare earth availability [2]:

“Clearly, rare earth supply limitations present a serious vulnerability to our national security. Yet early indications are the Department of Defense (DOD) has dismissed the severity of the situation to date…

As the ultimate customer, the Department has the right and responsibility to require their contractors to provide a detailed accounting of the various rare earth containing components within their weapon systems. This information should then be aggregated into an element by element overall demand for DOD. With that knowledge, DOD could compare expected supply and demand of each rare earth element with overall consumption by the Department to identify critical vulnerabilities in our supply chain. This will enable the Department to establish policies to ensure the defense supply chain has access to those materials. For example, one policy may be for the DOD to establish a limited stockpile of rare earth alloys that are in danger of supply interruption to ensure security of supply of both metals and magnets.”


In the same year another advisor of Department of Defense stated [5]:

“The Pentagon has been incredibly negligent…there are plenty of early warning signs that China will use its leverage over these materials as a weapon.”


In order to overcome the economic and military dependence of US on China, actions were needed: Stockpiling the rare earths as a short term solution; as it has been already done in South Korea and Japan [6]. Developing new mines was another solution. However it can take over 10 years until a new mine can start running efficiently. Finding materials as substitutes for rare earth metals without loss in performance was another option. Developing new technologies for refining and recycling rare earth elements was another promising alternative.

The investigations and research is still ongoing to determine who will win the rare earth power game!





1-. Ratnam, Gopal. “Rare Earth Shortage Would Spur Pentagon to Action”. Bloomberg News, April 9, 2012.


2- Valerie Bailey Grasso. “Rare Earth Elements in National Defense: Background, oversight Issues, and Options for Congress” Congressional Research Service. December 23, 2013


3- http://www.molycorp.com/products/rare-earths-many-uses/defense-technologies/


4- James B. Hedrick. “Rare-Earth Industry Overview and Defense Applications” U.S. Department of the Interior and U.S. Geological Survey”. February 18, 2005


5- Emily Coppel “Rare Earth Metals and U.S National Security” American security project. February 1, 2011


6- Hounshell, Blake, “Is China Making a Rare Earth Power Play?” Foreign Policy, September 23, 2010