Dysprosium elemental abundances

Dysprosium is the 43rd most abundant element on Earth and ranks ninth in abundance of the rare-earths found in the Earth s crust. It is a metallic element that is usually found as an oxide (disprosia). Like most rare-earths, it is found in the minerals monazite and allanite, which are extracted from river sands of India, Africa, South America, and Australia and the beaches of Florida. It is also found in the mineral bastnasite in California. 

Even more striking in the old tooth is the abundance of rare earths (dysprosium, holmium, erbium, thulium, ytterbium, and lutetium) and the elements tantalum, tungsten, gold, thorium, and uranium. Rare earth minerals are found in Scandinavia (in fact, many rare earth elements were discovered there), but what were they used for Did people prepare food with them Did they somehow get into the food chain ... 

Seven naturally occurring isotopes of dysprosium are known. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element s name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. The four most abundant isotopes of dysprosium are dysprosium-161, dysprosium-162, dysprosium-163, and dysprosium-164. 

Yttrium is one of the most abundant rare earth elements and its purification is easily accomplished. Yttrium fractions from a bromate series are freed from dysprosium, holmium, and erbium by fractional precipitation with ammonia, K2OO4, or NaNC>2. The latter is probably the most effective. Yttrium salts give no absorption lines ini the viable portion of the spectrum, consequently the removal of holmium and erbium is easily observed by the direct vision spectroscope. 

It would be a preferable situation if the demand for elements that are very abundant would control the REE market. Unfortunately, this is not the case. The most wanted elements at this time are neod3unium and dysprosium (Binnemans et al. 2013). Cerium, praseodymium, and the heavy REEs holmium, gadohnium, thulium, ytterbium and lutetium are produced in excess, and are stockpiled. 

REEs are classified as lithophiles and are partitioned into the earth s crust and mantle. The name rare earths originated over a century ago when the elements were first identified in minerals that, at the time, were rare. The elements are actually distributed widely over the earth and relatively accessible on the earth s surface. For a comprehensive description of REE geology, geochemistry, and natural abundances, see Geology, Geochemistry, and Natural Abundances of the Rare Earth Elements. In 2010, the United States Geological Survey (USGS) estimated that there were REE reserves of 110 million metric tons (mt). The static depletion index, the ratio of reserves to present-day production, for REEs is approximately 870 years. Thus, the primary immediate consideration is whether REE production can match demand, and particularly whether it will be possible to increase the use of dysprosium and neodymium in wind turbines and the batteries of electric vehicles. 

The rare earth minerals are composed of scandium, yttrium, and the lanthanides. The lanthanides comprise a group of 15 elements that include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Cerium is the most abundant element in the rare earth group at 60 ppm, followed by yttrium at 33 ppm, lanthanum at 30 ppm, and neodymium at 28 ppm. Thulium and lutetium are the least abundant at 0.5 ppm. 

Low and high here are relative to adjacent elements only. So, lanthanum is four or five times more abundant than either gadolinium or dysprosium. 

It surprises most people to learn that several of the so-called rare earth elements are not actually that rare compared to much more familiar elements. Neodymium, praseodymium, samarium, gadolinium, dysprosium, erbium, and ytterbium are all more abundant than more familiar elements like bromine, uranium, or tin. Europium, holmium, terbium, lutetium, and thulium are more abundant than iodine, silver, or mercury. Yet few people have even heard of most of the rare earths. The reason is that rare earths tend not to concentrate in large ore deposits in the way that better known metals do. Historically there have been fewer profits to be made from mining rare earth elements, and there have been fewer applications developed for them in industry. 

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