What is Rare Metal?
For the past few years, we frequently hear of “the rare metal problem” or “the rare metal crisis”. The terminology, “rare metal”, is not an academically defined one, and there is no consensus on which element it pertains. Recently, the term is often used to refer to the 47 metal elements shown in Figure 1, according to the definition set normally. Sometimes, the 17 rare earth elements are counted as one kind, and the total is counted as 31. There are a total of 89 existing elements in the natural world, and therefore, it can be said that over half of the elements are rare metals.
Elements as titanium, manganese, chromium, which are found in abundance in the earth’s crust, are also considered to be rare metals. This is because manganese and chromium have been essential elements for the industrial world since its early days, used as additives to enhance the properties of iron. Titanium is considered “rare” because it is a difficult metal to produce as high technology is required for refining the abundant ore in form of titanium oxide. On the other hand,from historical circumstances, gold and silver, which have been in existence since ancient times, are not called rare metals.from historical circumstances, gold and silver, which have been in existence since ancient times, are not called rare metals.
