‘Rare earth elements’ are a group of 17 elements present in the periodic table (15 Lanthanoids, Scandium and Yttrium). Scandium and Yttrium are chemically similar and present in the same ores as Lanthanoids.
These are abundant in the earth (except Promethium). Like copper, Cerium is the 25th most ample (68 parts per million) element. These reserves are scattered, rather than found in clusters and the marketable varieties are called ‘rare earth minerals’. Their name came about due to the scarceness of these minerals. Gadolinite was the first compound discovered in Sweden by Arrhenius, a university professor.
In 1803, another rare earth element ‘Ceria’ was discovered. Soon it was revealed that the substance consisted of other elements within it.
In 1839, the elements were separated from the compound and by 1842; four more elements had been discovered. Now, four earth elements were known to exist- Yttrium, Cerium, Lanthanum, Didymium, Erbium and Terbium. Soon a new mineral was discovered, with more elements within it.
The constituent elements were found by X-ray crystallography. 25 rare earth elements were presumed to exist with an undiscovered chemical element present in them. Shortly, the ion exchange method was developed and extraction of these metals became more efficient.
The 17 rare earth elements include:
-Scandium
-Yttrium
-Lanthanum
-Cerium
-Praseodymium
-Neodymium
-Promethium
-Samarium
-Europium
-Gadolinium
-Terbium
-Dysprosium
-Holmium
-Erbium
-Thulium
-Ytterbium
-Lutetium
They are either named after the discovering scientist or the location where they have first been found.
Cerium is usually found with Monazite and is found in large quantities. Yttrium is found with phosphates and is relatively rarer. It is mainly found in Southern China. Gadolinite and Xenotime, among others, are common minerals which contain Yttrium. Major ores of Cerium include Bastnaesite (California, China) and Loparite (Russia). Deposits of earth minerals are known to be present on the seafloor as well.
Most rare earth elements were produced in India and Brazil, before deposits were found in Africa and California. Currently China is the leading producer. Due to increased demand for the minerals and chance of reserves being exhausting, China has decreased export. Other countries are working to help meet the needs of the population. Recycling of metals is being looked into as prices mount.
Extracting, recycling metal, disposing of toxic waste and the acids used in refining can be extremely dangerous and may cause diseases like leukemia (in Malaysia). Countries do take time off from extraction so as to prevent these side effects (e.g. China). Birth defects have also occurred due to the fact that the ores may be radioactive.
China, whose rare earth industry has accelerated in the past decades, recently became part of this industry since it has better valuable items in comparison to others. Due to domestic need, China will slow down export to 130-140,000 metric tons instead of 129,000 metric tons in 2009 (total used 132,000).
Rare earth metals are sold in private markets and thus, it is hard to monitor their prices. However, people now take the purity of the metal they need in order to price them.
Leaching: The Many Processes Behind the Mining and Crushing of Ore
Leaching is the process of extracting metal from the ore for refinement. Leaching is also referred to as the metallurgical process. It is also simply called metallurgy.
Mineralogy: History, Methods and More
The study of minerals and their structure, chemistry and physical properties is known as mineralogy. Mineralogy also encompasses several other processes, which include classification,distribution worldwide, formation, origin and utilization.
Superalloys: Chemistry, Process Development, Uses and Costs
Superalloys are also referred to as high performance alloys. To be identified as a superalloy it must exhibit great mechanical strength, have good surface stability, have creep resistance when under high temperatures, and resist both oxidation and corrosion. The base of a superalloy is typically cobalt, nickel, or nickel iron.
