When you think of rare earth elements, that group of chemically similar, soft, silvery-white, heavy metals on the Periodic Table, from Lanthanum (Atomic No. 57) to Lutetium (Atomic No. 71) plus Scandium (Atomic No. 21) and Yttrium (Atomic No. 39), you probably aren’t thinking of ‘colour’. Instead, you might rather be thinking about their unique magnetic properties and their use in manufacturing permanent magnets.
Clockwise from top center: oxides of praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Photo by Peggy Greb, USDA-ARS.
But did you know that these elements have enjoyed an outsized significance in the history of colour and applied sciences?
Take for example the case of Yttrium. In 1952, at the dawn of the Cold War, the Mountain Pass mine, located in San Bernadino County California and first explored as a uranium deposit, began operation as the world’s only major source of rare earth elements, a monopoly it enjoyed until the 1990s.
Mountain Pass Mine, California, USA
In the early 1960s it was discovered that a brilliant red phosphor was created when transparent yttrium orthovanadate crystals were doped with the rare earth element Europium, mined at Mountain Pass. This discovery ushered in the proliferation of color TV sets. Europium is still used today in the manufacture of TVs and computer monitors.
A second significant chemical discovery featuring rare earth elements and colour was made in 2009 at Oregon State University. While conducting experiments into the electronic properties of manganese oxide, chemist Mas Subramanian, Milton-Harris Professor of Materials Science at Oregon State University, and grad student Andrew Smith, serendipitously created the first new blue pigment since the discovery and commercialization of ‘cobalt’ blue in Europe in the early 19th century. This was achieved by combining oxides of Yttrium, Indium and Manganese and heating them to c. 1200 degrees Celsius.
The brilliant new hue of blue was named YInMn Blue, after its formative elements.
YInMn blue pigment, photograph courtesy of Oregon State University
The new pigments enjoys many advantages over other blue pigments, including stability and durability, non-toxicity, and the ability to reflect infrared radiation, making the pigment a good choice for energy-saving cool coatings.
If you are interested in rare earth elements, equity holding Commerce Resources Corp. is a junior mineral resource company focused on the development the Ashram Rare Earth and Fluorspar Deposit located in Quebec, Canada. The company is positioning to be one of the lowest cost rare earth producers globally, with a specific focus on being a long-term supplier of mixed rare earth concentrates and/or NdPr oxide to the global market.
Commerce Resources Ashram Deposit is characterized by simple rare earth (monazite, bastnaesite, xenotime) and gangue mineralogy (carbonates), large tonnage at favourable grades, and has demonstrated the production of high-grade (>40% REO) mineral concentrates at high recovery (>70%) in line with active global producers. In addition to being one of the largest rare earth deposits globally, Ashram is also one of the largest fluorspar deposits globally and has the potential to be a long-term supplier to the met-spar and acid-spar markets.